Document Exg3b00KEL8Z0mYR5GvGYbGxL
6 0 L II0 0 IS
NVIIIONMEMTAX. MWBCH S, 106-208 (1009)
Asbestos Minerals in Modern Technology
S. Smol and J. P. LEDacwsua ]ohna~Maneitle Research and Engineering Canter, Manville, New Jersey
Reeetoad August 6, 1908
Asbestos is a generic tens for a variety of hydrated silicate minerals which have one common attribute, namely, the ability to be separated into relatively soft, silky fibers. Although the name is ordinarily associated with those varieties which have technologic importance, it is applicable to all minerals which fit the above description. The term "asbestiform minerals* is perhaps most descriptive.
The known varieties of asbestiform minerals can be divided into two main classes on die basis of their crystal structures: serpentine and aiuphiboles. The sole member of the serpentine class is chrysotile asbestos, which is by far the most common of the asbestiform minerals. It accounts for more than 95S of die asbestos fiber produced today.
There are five recogbized asbestiform varieties of aniphibole: crocidolite, aniosite, anthophyllile, tremolitc, and actinolite. Although the ampliiboles are common rock-forming minerals, the asbestiform varieties are much less abundant than chrysotile.
The physical and chemical properties of the asbestifonn minerals can be directly related to their crystal structure and chemical composition. In turn, die physical and chemical properties arc responsible for the commercial im portance of asbestos. It is understandable, dierefore, that great emphasis has been placed on the elucidation of tho structure and composition of these im portant minerals.
Several comprehensive reviews on the asbestiform minerals have been pub lished in recent years, including Hendry (30), Gaze (25), Hodgson (33), and Deer, Howie, and Zussman (17). Hie objective of diis paper is to bring tliis information up to date with particular emphasis on recent developments con cerning tho physics and chemistry of the asbestifonn minerals. In addition, the uses of asbestos will be discussed briefly in relation to the properties of the individual species.
OCCURRENCE The epigenesis and occurrence of the asbestiform minerals have been the subject of considerable geologic and petrologic research. Chrysotile and amphibole fibers are found in entirely dilTcrent geologic formations. Chiysotilc was most probably formed as a result of two separate mctamorphic changes in ultmbasic rocks of volcanic origin. The first singe involved the fonuation of serpentine by the hydrothcnn.il alteration of the original rock. At some later time the chrysotile was formed in cracks and fissure* in the rock by rccrystallization of the serpentine, again by an aqueous solution and reprecipitation juoc-
106
DOW 06992
! ! I.
MINMVU.S IN
v ' y.*..y
/.`V/; ...... . - ii
II < l|VH*r.V
* -A . .1
>
Iff/
t
ri
;
i'
.:
.ss)<...**:
* i i
v l..
: ,
;
.J
;
<;
**
' . : S
,
*
1 inch
,1 *, i# : i0 ft J ,
~,
Si t#
. *
Fib. I. Crust vi-in lilur dirjiirtlk.
at Tri most case*, chrysofilc ocrurs as "cm fibers" which are oriented In a parallel arm)- across flic veins in llic scrpcnlhic roel as `.'town in Fig. 1. Ocea* skmal occurrences of "slip HIkt" arc fmiml :n which the fiber is oriented parallel to the vein as shown in Fig. 2.
A notable exception to the nonn.il inode' of occurrence of chrjsotilo is the filter found in the New fdria scipvutinitc of Western California and at fitragarl, Yugoslavia (15). The Mew hlria filler is generally rcfcrrvsl to as Coalinga filter. The great bull of this deposit consists of soft powdery jrcllcllilc agglomerate!* of chryxolilc as shown in Fig. '). Hie material inay lie the result of intensive
S T O O I1710
<
F. 2. Slip fiWr rhrjvitlle.
DOW 06993
ICS s. s:*i it. am j. i*. i t:i\i.'. i.w i:
V?
--t
O
O
I -- v
I. :-7*?
* ' *' .
r'4 .. #*# *
l>V..v..
I
*
4
. . *.. * * ..**#*,
%. :
. v*.
*
*4 m
!*, * . '
*. :
*., : V :;V Vv-/, ;
v-v> /'W'.-
| .* , '
:fr 1 inch
. Pie. 3. NoJulf* el coalinsa ctiosoUl*.
crushing and pulverization (luting or after scrpentitif/alion. In addition to its) onujit.il mode* of occurrence, Coalingn chrysotilc is also unusual from tlic stand point of its physical structure. Tin's feature will he discussed in the appropriate section or this paper.
Tlic g 'jtesis of the iimphiliolc fh-.rs is ikiI as clear-cut as that of ehrysotllc. Their name, Infccn from the Crtcl uuid um, hiholoi, meaning ambiguous, Is ii veiy apt choice. 1'iginc -I is a typical example of the mode of occurrence for CToeidolite which is found in the handed ironstones of the Transvaal system of
4 r.
T /
.'*
. If. ; .
..* \
...
.
i v* y : "V. ; '..**.
*j i
*t *(.
` V''!'V
' : ...... . .: ":
. . > %', .* . g
' !- t
v .*
) t nvlt
fv : C"~-'
,
t ,.:i ,t
DOUl 06994
f
ASl'IMm MlMUMA |\ MINI' I'.M IMIlMH.fH.V
100
Smith Africa. Htcy jii* m! iiiMMi tl mkIk of sedimentary origin, whirlr
a<x omits for llie variability in
of tlr* luj%| h*!.n and rtm*.ri|ucntly
of the filicf. Hie only significant III I uriciui' of ain't* in- is abu found in this
area. Cmculolitc H fmmd in other arras, including Bolivia anil Western
Australia.
Asbesliform anthophyllitc. is found in many places throughout the world,
but there are only a few deposits of commercial impoilance in Finland and the
Iftr'rd 5'alcs. Tremolite and a* tiiiofitr arc the resell of mctamorphhm of car*
IrOtutc rucks. Tiny are \v iih ly distributed in nature, but of little commercial
significance. Tremolite is a vuy common contaminant of commercial tale.
CHYSTAI. STRUCn'RK
Chrysolite
The crystal structure of chrysotile nslwstus was first determined by Warren and Bragg (72) and later elucidated by Warren and Herring (CO). These investigators determined that the mineral has a layered-type structure similar to the minerals of the kuotinitc group. The basis of the structure is an infinite silica slicct (Si.O>), in which all tin* silica tHiahrdra arc pointing in the same direction. Attaches! to one side of (fits sheet is a hrucitc Mg(Oll)* layer in which two out of every three hydroxyls are replaced hy the apical oxygens of the silica tetrnhedra. Hie result is a double sheet as shown in Fig. 5. 'lire nv'suntch in the dimensions of the silica ami hrucitc sheets introduces a strain in the structure. Better matching of the layers and relief of the strain can lie accomplished in' three ways.
1. Substitution of larger ions in the silica sheet or smaller ons in the bnicite sheet.
2. Distortion of the octahedral Inucite network or of the tetrahedral silica network.
3. Curvature of the sheet with the hruntc layer on the outer surface.
S T 0 0 I1712
1
l-. -- fca>
F. 3. Knnil.im^niat !" t of rfirywttlta.
00^
iSTO O l 1 7 1 3
170 t SITII. AM* J. I*. UINMY:I.W
Ever sine? tl*e first electron micrographs were jHiWWml showing die ap parent (ulmLir structme of (Tiryvitile (7, 50, 70), there ha* been cumlJirnlile controversy over t!ic morphology of the fiber*. Whittaker (70), by means of careful X-ray diffraction studies, demonstrated that the lattice was definitely curved.
Although he was unable to show whether tire structure was a cylindrical arc, closed circular cylinder, or a cylindrical spiral, he favored spiral structure.
T!c tubular concept was supported further "hen Maser, nice, and Klug (44)
puhlblied lire electron nncrogn'plj of Fig. 0 sliowing an end-on view of a chiysotilc fiber bundle, 'llic fibrils were definitely cylindrical and included many which appeared to l*e pairs of concentric cylinders.
F. 6. Klcdmn mlcn)|',u[<li of ehnjotil-' cm mlira. XlK,OOfl. Reprinted wtlii par* mission from Aiftericon Minciabcl't t3 Gfi0 (IV-O),
A recent paper by Yada (SI) has furnished what appears to be the final
answer to the structure of clirysolife fibrils. By means of high resolution eJeetron'
microscopy, he was able to observe tbc actual crystal lattice planes both parallel
and perpendicular to the filer axis. These pictures, Figs. 7 and 8, show that most of the filter* h.ive a hollrm cyttiidric.it form. The lattice planes have a*
mnltispiral arrangement confirming the prediction of Whittaker (70). Also ap*
parent in seveni of Yada's pictures is die presence of crystallographic disloca
tions which strongly suggest di.it tlu- b.isie structural unit consists of a single
magnesia-silica sheet, rather than a dniibte sbert as previously postulated by
most authors. Yada* o!i-a iva!inns ,iIm confirm Whittaker's hypothesis that the basic spiral h inc ut ciiii-'SN of fixe silica magnesia units with upprnsiiitatrly 10 Silica magnesia units fn!*i.:u-', *.h" 70 \ v.all of a single fibril.
OcsMsionnl (ilnn wen
which xxfic- solid rather than ImHnw. \l
DOW 06996
1
t
A'Kikios minium.% is Monmsc^untxcitocir
171
S T 0 0 I1714
y ti*
. * V. . *VV. j*w.*.. .* "" '
.
*
,
0 \ < *,
.* \
.. .>\<.
.*
:
.
..
.
..*..*
L A *f' , \ # * , ****%
I
/
*./ 'jv. .
v'>':' ;
L ,f:. ' J''i " 'Vi.*1 .V
*
;
'
J* vI x?>
" ' i .v.*:. . ,
*V * *
N
v;
'*..*' ** *#*V/v*
* .. r-` ; '-I . *
v',< *. . ' '
.i *
. :*/V/#V* ..
A *
*. 8 ;S. * j ? *. % .
.
*.
V':'t.*.'.-
.p '-. . . i :.*K-Yrj->/*-
* i :V/~
''!.*7/##**1V'- .
'/ . >
^ *
if.:}/-
/
S'V
* . # **
'4
"
V-. v.
. */.,
*.
/,'. v S *
- w* * Vt ... ;
/
,rV ; a'**. . *. v*
; V;* .> !>';.. .
i *4**'*i.. .#* ' .V,*
V* . >*
>#` ***V
*r*. v
*,4*'
\
.*
* 4'`.
'/4 ^
'. .
*%
( 4\//%NW.'4..4*
F. T ai1 Km. 8. Wish rrwliitton eltiUno mfeios^'P1'* *f c,ir> mnlfilofi from .VW C/tl. 701 (1007).
1
Hrpiiiil*'.! nv*<H
DOW 06997
{
171
S. AXfl J. p. IWNKttTIMJI
S ft 8 ft S? 2 S 8 8 8 8 8 ^ -- o' c -- o' e b jj
85882gsSS288
fiodbbobbdobfi
minis
* *T
1
/ --4 O cn
SSSSS | | 3> i. 8 m O O **
1I*f* X
K
S3S = S3,,&8c 88 - g b o' b o' 3 - b
T - 8 8 2 ft 8 2 3 e fi ft w b b 2
% ?. eft
3
t
*r 9
i
-e??3toE?c 2t* *Fr --*f o o e e e> o <
* $ ? 5 ? ? * -v 5/ ^ ^ { 4^ K m *
? V .3?
'il
r-
DOW 06998
Mr,;nM.X IX Mimi.N tirii\i<*.r
t 173
though tfw.^e filn r% .m- trl.il ivify common in the Minph-s, tlu'j* are not enough
to account for tlic discirpaury Ih'Iwitii tin* measured and wli'il.'ti'J densities
reported by Faidvuk (53).
One filial point .should be: made nlxiut tbo Vaila micrographs. 'Jhe outside
surface of nw^t of tlic fiber* shows tbo prvsmco of highly disorganized or
. amorplmos material, 'lliis is the result of damage to the outer lajcr of fibrils by
the electron beam under the conditions of observation. There an two other serpentine materials fosmd In chrysotile-bcaring
.T*V
fbsnltte and antigorite (20). They both have the same chemical composRM^jg^
and the same fundamental sheet structure as chiysotfle. The differences betwratl^^
these minerals reflects the way the strain In the crystal lattice has been **'*`"!*
Lfzardftc, whlcli Is the principal constituent of massive serpentine,
an extremely fine grained, platy morphology, visible only under the dccoup^-,
microscope In most specimens. fts structure has not yet been ch'.ridated,
r
X-ray difTrnctio.-. patterns indicate Ait rather than curved sheets. AntlguiN, .oiiffifffr
the other hand, docs show evidence of earned sheets. Two of fts unit
mensions arc equal to clirysotile, but the third Is much larger and varisUa^g^. Tills third (b) dimension can vary from 1&5A to as largo as 100 A, compored^p^:
to the 0J2 A value for clirysotile. It Is lxdlcvcd that tlic stnieture consist* of^S^
undulating sheets the periodicity of which corresponds to the variable unit eell-
dimension.
Ampltibofet
:
The basic crystal form of the ninphibolo minerals is less complicated than that of tlic serpentines. Tlic basic structural unit Is a double silica chain (Si,Ou). As in the clirysotile sheets, all of the silica tetrahedra point In one direction. ' a.^'.. These chains are paired, "bnckto-bade," with a layer of hydrated rr.tlons In between to satisfy the negative charges of the silica chains. The 'final stniC(r*^gSg|
is formed by the stacking of these sandwich ribbons in an ordered arrayt: ASSjMBfpictorial concept of this structure Is shown in Fig 9. Hie various mineral* l*^*i&*-
the amphibolc groups arc cli.mcfcnVwd by the cations which occur bi stnieture. Tlic principal cations aro magnesium, iron, calcium, and sodium. Slnco^i^V" tlo bomling between these riM*ons is rather weak, the crystals are easily cleaved parallel to the ribbons along A-A. If the cleavage is very facile, the result Is am asbestifnrm mineral.
For enefi variety of asbestiform amphfholc, there It a conespomlrng mnssft~ v"V" form with a different mineral name. Normally (he nsbcstfform varieties are not found along w ith (he massive counterparts. Undoubtedly, the local geochemical conditions extant at the time of formation contributed to (he relative case of cleavage of any specific deposit and, therefore, to its commercial utility. The massive and asbestiform v.trictfcs have the same chemical compositions and
X-ray crystal sfnicturcs. They can be distinguished by tlieir physical properties and by petrographic examination.
citKMirat. coMrasiTiotr
Hie chemical composition of eommcrrialty available chfyv>llTe firm various
localfom are hnwn In Table I. For o>minri.m
,:r
<uHt.
9 IL II0 0 1 S
DOU 06999
1
174
s. srm.
r. tx
1
=ISS&= mat un>
PUCk
S T O O I1717
I \r Smr-f i*. .
Fm. 9. AnpMbole ctmctaic.
.p
goritc arc included. In atl cases, ft Is apparent that lire composition dltTerswery InocylbcJfosUasd cgBappgftjontbf \<gj(SltO)(OH)>. Tho ftnyrtftljHMrffdpart of (he crystal strut-two or doe to iuioclated'mfiwfflF common impurity Is Iron. This can he hi the form of fem>ea(Fh^),Of (Fcv) Ions. It Is generally assumed (hat the Fe* con he substituted for In the silica sheets, and (he Fef* can he substituted for the mpwtan
fn (he brucito layer. The next most common Impurfty In ctuysotile Is ahmtimjm. Since aluminum can assume either tetrahedral or octahedral coordination ft tan he substituted in either the silica or bruette layer*. Other Impurities* generally
found to he associated with chrysotlle in lesser amounts than froi orthfcnftitmi, are calcium, chromium, nickel, manganese, sodium, and potassium.
Hie ionic radii of the ions commonly associated with chiysotilo art given fn Table H. Since these Ions vary considerably In sfxt, they can hate an tffedeo t) stmlns whldt exist l thio chiyaotiU. laUlcdtJoaaoahich are; Insor than silicon and smaller than mngnesIboa.wIIl tianS^UaiS^tho at stituted in (lie respective layer*. Alumiheut fllf wSrwqSrbocnt sihee ft is intermediate hi sire between sflfoOM and magnesium, larger than silicon so it w ill help relieve the strain when in silica layer. Ferrous iron (n the brudto layer will Increase the strain
TABLE 11' . " `
toxic R.um to* limnn* Amsb*u b^ ftwianu
Ktrment
I
'Vi--*
A
*
>V At**
IV Kr* Xi** IV <>
Mu*tv-
, i*W**'^ .
,0*^1
.s O.M O.JO
0.01
o.r* O.T* 0M o.sn nm
DOW 07000
AWSTOi Mixmu IX MOOSKf TBClUfOCOCY
179
Its Utter RWt-KSnuny, it Is improbable
fen* inch m the
alkali or aAafiao earths, can truly be substituted to any significant extent In the
bereft* layers and when present in appreciable quantities may exist a* "Inter-
hyesp cartons between the primary layers .Various authors Java "nonnalfecd*
chemical analyses of chrysolite, indfcuUng the probable location of the Impurity
ienain the crystal structure.
* . :r_
^
.
Tbs charatraj eerupusiUou of the aabcsrtfocm' aregMbolet fc more complca than. that efdaysotflo. Hie Idealised chemical focneia Tor thOrariou
are-ghrerr-bdour. In these formulas, when-caUoon are .written #!- pafwtbesas wfthoutsabscript* a variable compoirirtoa is indicated with the most abundant
species lint
creAMiU............ tx%rv*iV*jM(Cfk) Amoafta...................... (f*\ M|)AO*(0*h Antbeptqrllhc.............. (MfcJk**hS6AiCO&V ' TmreRt*.........................OnWWVOH). ActlnaBt*...............__________________________
The range of chemical analyses for these varieties of amphiboles are listed ta Table I1L Detailed analyses can be foondla various publications (17, 23, 32),
TABLE 111 CRDiim Cosrwimr or .\Mimraa AxruiMtes*
Asbcvtifoan smpWbola (ranee %)
CreddoRta Ammifa AnthefhjrtlHo - *Adinottta TVttnoliU
SMKghO no refit cAaIoA Kfi
VH<t0fi
41033--44730 034i...r00033----44s030e.....33437
34401---44743 -- ----
0-0.4 3.3t-r4 3
*
73330--431343:^..- - <v31O313---187l300fy-
0.3-1.I>.
--
1.04.0
:011t..400o3--1443n..*4V33-.
". .-. .
.0331.003000131--------033014761.3.00...88438 *
The considerable variation in mmpnsftlmTirfifrh ran nrriiTj^ilraffly noted, Tbr
actual Identification of a particular amphibote spedfes mkJnSejPBBd MwMch of* the idealized compositions the somplo tn qpcsrtoomcst^tesofrareptBrent* This variability In composition is a direct consoqoOricfrbrthofifeEtW the strata* can accommodate many different ions in the space between iKe silica ribbons,
and the variable nature of the host rodcs can contribute different font to this structure.
Accessory Minerals
The analysis of ashcstlform minerals Is often complicated by the fact that tire
-*** '"'V
fragments of tho host rude and Ms nnodated minerals,
ami nlo tfial oiiicr minerals may lie intimately Infergrown in Ute iiior inmiiicm.
4
i'
`*.*l*
co --I O
o
CO
DOW 07001
S T00II7I9
1
IT s. mm and j. f. innwiawir
CbndmtartJon due to host rock fragments fci common In commcrcinl Hirer*. In tire cam of ehrysolllc asbestos, the most-commoo contaminants are the other mipcwtlne minerals- Ibardile and antigorite. While time species have similar overall composition* tho trace element analyses could he Influenced by their presences Other minerals which are found In serpentine masses, and which could be found In commercial chiysotilo fiber* arei magnetite, brecito, chromite, ealefts^. magnesite, olivine, pyraeenc, tremolK* actfnolfte, chlorite, tale, and chaloadouy. The proportions of these minerals will vary considerably with the loctilowaad nstare of (he deposit For specific commercial mfne, the notore and content of the imparities In the ere will he relatively constant Neighboring deposits In the same serpentine belt may differ considerably in thdr Impurities. Several good publications are available (19, ST, 45) which describe die geology i and mineralogy of the various chrysolite producing areas.
Other than Ibsmllte and antigorite, the mo* common minerals associated with , chrysolite are magnetite and Uudtfejtoth- of these species often are found
,In,mrm^ocQraMjy*J^<3^ of the fiber bundles are ___ e&lajfta^FiucL Ammcralogte curiosity which Is
tile deposits Including the Jeffrey mine at Asbestos, Quebec, form of magnesium hydroxide which has been given the name (9). These fibers usually occur 10 bundles which are often several
Jtcimschusscl (00) studied the association of chromium and nickel with care fully separated components of ore from (tic Jeffrey mfne at Asbestos, Quebec. Using a combination of chemical dispersion and magnetic separation, the asbes
tos was divided Into fibrillar chrysolite, serpentine, and magnetic concentrates. All of the chromium was found to be associated with the magnetite phase,
moat probably as an fsomorphous substitute for fenie iron. When chromium appeared In she chrysotfle or serpentine fractions, It was associated with the last traces of magnetite which were impossible to remove.*
Moat of lire nickel in tho ore is also found In the magnetic fraction. A. smell mount may he associated with tho magnetite, hut the majority occura m e separate phase. This pliaso Is die Iron-nickel alloy, aware(to, whose composIHbe ranges from FcNI, to FcNf* It ean be separated by a differential solution method proposed by Nickel (49). Finally, e small amount of nickel, about 0.0081, Is found to be present in the chrysotfic lattice, most probably as substitute for magnesium.
Organic Impurities
into association of bcnzo(n)pyrene and other orputle impurities with ashcort-
form minerals from various sources was Investigated by Jtcinischusiel (00).
The total amount of cxtractahlo organic matter was determined lij- long-term SoxWet extraction with cyclohexane. After drying nml weighing, die organic
residue was analyzed for lcnzo(e)pyrene liy thtn-Iayvr clirb:.n(ographic
(rctiniqurr.
Tire fillers ex'mined iiK'luditt North American and African ehrysortlp* ere.
cidnlitc, nuwsiv, and nutlinpliyllitr. All samples contained meMir.ildc amnrrnts~
DOW 07002
1
Awnoi Ml'CrjnM MS
tmjixcxacy
ITT
of ntncUbk* organic matter, ranging from '10 to 00 ppm. Tilde was, however, no (oncbtfon bcinnn the amount of organic matter ami tlic amount of brtueo (a)pyreno present. The Canadian ami Unitcil Slates filers (It chrysolites and one anthophyllite) contained no detectable Ufl((t)jiyrnic. Tiro' detection limit varied with tho amount and complexity of composition of tho extracted organic . matter, ft'was ss low as 0.02 parts per billion and generally below 5 ppb. All of the fibers from Africa ami Finland, on the other hand, did contain hcn/o()pyrene. The highest concentration (ISO parts per billion) was found in crocidoIfte from the Cape Province, South Africa. Croddollte ami nmosite from the Transvaal Province contained 12-13 ppb; Rhodesian cbrysotlte and Finnish antlrephylTlIe eonlaincd less than 10 ppk
The* results are In general agreement with those reported by Harington (28) except that Harington found no benro(a)pyrene in African chrysotiles. The explanation of this difference may lie in ttse feet that Harington used vfrgfn samples collected in the field, whereas Rcimscbossel analysed typical comma* einl products. This could mean tint at least some of the benw(e)pyrene it Introduced during the processing or shipping of the fiber.
SURFACE CHARACTERISTICS
Tho surface characteristics of the asbesliform minerals are very important in ralatjon to their commercial uses and to their Interaction with whatever environ*
F" they may be exposed to. Most of the discussion relates to chryjotlle because the surface characteristics of tlic asbesliform amphibole minerals have received much leu attention.
Tire external surface of chrysolite Hirers consists of magnesium hydro.xido and, therefore, it Is not surprising that tlic fibers bcluivc In some respects as though they were magnesium hydroxide. For example, rundsack (53) determined that the pH of a suspension of chrysotilc in carbon dioxide-free distilled water is* 10,33. This compares to a value of 10.37 for a magnesium hydroxide suspension under the same conditions, rundsack and Pcimschussc! also determined the"solubility product constants" for various chrysolite fibers (56). Tlic values ranged from 1.0 X 10 " to 3 X 10 " and correspond quite closely to a value of 1.0 X 10'" reported for magnesium hydroxide ((H).
Surface Charges
The electroktiwtic behavior of chrysolite is another manifestation of the mag nesium hydroxide surface. Mart for/ and Zueker (42) studied the effect of pif on tlic surface charge, or rcta potr-nttal. of asbestos ore Irody minerals hy the streaming potential mrtliod. Figure 10 shows the complete pi I vs acta potential curve obtained liy these authors. They found tlie isoelectric point of chrysolite to be IIA At lower pH values, the surface charge Is positive; a1>o\e tho Iso electric point, lire charge lrccnmes m-gaffve. They attributed the sharp increase In potential which was obtained as the pll was lowered from 7 to 3 to removal of hydroxy? gmujix fnnn tlic mii/.k c and resultant cxpusirrc of the magnesium hns. TVloxv pit 3, lire m.igni limi inns are removed ami the silica miifare ex posed, accounting for the d. umm- in /Ha potential in this range.
S T 0 0 I1720
DOW 07003
1
178
and j. r. uwwnni*
1
S T00I1721
j^
fi u. -jsL- l--rnrid-iljtsaj
Ji.". -'-AUrf-l
I_ l- .<__ I__ 1__ L JJU__ L
Fie. 10. Suifae* charge* on terpentine minerals.
^
The clccfiolfnctic behavior of lismlite, also shown In Fig. 10, Is rignfflointly
different from llmt of chrysolite. It has an Isoelectric point of 9.7 with a much
smaller charge than clirysolflc. Furthermore, the sharp rise In potential, between'
pll 7 and 3, Is not found. This would be In accord with the proposed undulating-- ,, structure In which both silica and magnesium hydroxide surfaces are t"ilp000d^v > '
Chemfcally, the surface of the amphfboles Is sfmflar to that of silica* polar In nature, hut not as highly polar as chrysolite. The is negative and smaller in magnitude than the positive charge oT Isoelectric points have not beat ndl established, although It Is presurocdM Uie charge would liecomc* positive at very low pH.
Most materials have a negative surface charge In aqueous systems/-: chrysolite lias a positive charge. It will attract or be attracted (0 most < materials. Ibis characteristic or chrysotile manifests Itself fn many of merrial appRcations. In addition, tlsc highly reactive suriaeo causes many IMtsw v
cstlng surface reactions to tale place which are Intermediate betweerr sfajjtf#'1 adsorption and truo chemical reaction. For tfie sale of better continuity, tbor._
Interactions win lie discussed along with the diemleat properties of the fiSevt- ' '
Surface Area
`
llic specific surf.icv area of chrysolite aslicsios as determined by gas odsorp* lion incusimuintt' li.is Ikvii found to vary comidcr.ihly with the phjslca! eon* dItIon of the filnn. Tor example, PimrUack (31) sported tint putting fibers from a llrv*k of crmli; Jeffrey clirysafile fiber with tweeaers pur products wWt' surface areas, us cht.-rmmol by ndro'^in arf.virptluii, ranging from 4 to 18m*/g
0700^ DOW
1
AOWSTO* MlXtJUM IN MOMM lUClIKOtjOQY
11-
4cpcadlog how thoroughly the fibers were pulled apart. When tliu fibers **n opened farther in a Wiley Mill, tlie comparable surface area w* more Dam m*/g. Valors h ncm of 30 m'/ft were obtained wlicn the fibers weresoohsd In an Aeaaaal OY solution to separate Individual Shells.
Nmnon and Dmher (18) studied the surface areas of various In more detail. They abo found a considerable variation In surface area with degree of fiber opening for most fibers; The two exceptions were the cbrysotifeS. from New Idria (CooSnga) and Stragsri. Tn these cases, them was very fittfrij rarCatlon with the degree of opening. Theoretical surface area* of the chemleaOyu dbparsed,fibers calculated from measurements of fibriT diameter distribution
fin good agreement with the m_e_a_s_u_r_ed--va*l--ors., asA-ow-nbe--low* -- -v
FSimriwa
Obernjm
CStedsUdSA
CrjJ* 7R Ken. Idria
*'/* WnV
Ma'/i
WnVg
The authon proposed, that for those fibers whose surface areas are sensitive i
the degree of opening, the voids between fiber* are partially filled with set material, and lltcrcfore nqt accessible to nitrogen or other gases. In the ease
the New Idria fibers, these interfibril vofclr are available for adsorption. lfcj
cither case; the Intrafibril voids are not available; Several workers (18, 48, SI) lave attempted measurements of the pore*tar
'T^p&tribotion of various asbestos fibers, focfadlng chrysolite and amphlboles; The'
methods have fodnded water vapor adsorption, nitrogen adsorption; and mer-'^ eury penetration. Most nitrogen adsorption results shmr a peak hi die vfcfirfty*-*
of 20 A which has been interpreted as a measure of the radius of the poreswithin the fibrils. Harris (29), however, pointed out that this may be an artlfa of the measuring method and is open to serious questtor*
The surface area of amphihole tubestos Is considerably'lower than ft dees not exhibit any unusual porosity. Patterson xnrf*nfcinpaon(32] that saum blocks of WIttenoom croddolite have surface areas around'5 Hits increases to between 7 and 8 on tearing fibers from the block. The fully? fiherised material had a value of M.8 m*/f>
Adsorption
The adsorption of various materials on the surface? of chryaotfle has^U^n studied from both the liquid and vapor states, Young end HmV'(9fTsfv4ledl the adsorption of several vapors on chrysolite. They found that nltrofm, argon; carbon monoadda, acetylene, it-butane, trfmethyt amtae; afriTdfmefhyiSralne Hr give surface arms of 9.7 mVg on grade 7R Canadian fiber, Ammonia arid watervapor, however, pro surface aims of 17JmVg for (hit same-sample. The difference could not be explained In term* of Acmhorptbn or other spedfio interactions because all the isotherms were completely rcvcnfhle. Their con clusion was that lie extremely polar water and ammonia molocutes could be adsorbed on portions of the surface which are not available to leas polar molecules. Ihey further concluded that feme of (lie pores In dirysntlle may be
S T 0 0 I1722
1
DOW 07005
STOOI1723
1
) i. mu. AND J. P. liJKKWWH
ptit^rd with water, ami that tlieso p!up are porutoabb to pobr vapor* only. Young and Mealy abo icpurtcd a similar anomolous sorption of water vapor
on anligorilc, a nonfibrous serpentine. Antliopliyllilo and trcmolitc, tlie only amphitiolcs studied, did not exhibit this beltavior.
The adsorption of various organic compounds on chrysotfle from both the liqukl and vapor phases H currently being studied by Weeks and Loineweber (75). The fiber used In this study was specially air cleaned to remove moat of the nonfibrous material and extracted with carbon tetrachloride to remove on ganie contaminants. Ethanol, benwne, and hexane all exhibit normal isotherms on chrysotfle. The surface areas, estimated from the botherms are ethanol, 18J8 m'/g: bcoaene; llJKm'/g; and hexane, 9.0m*/g. The nitrogen surface area k Slim'/g, Hie corresponding heats of adsorption are ethanol, 13 keal/g;" enc, 11 Vml/g; and hexane 9 keal/g. Zcftlcmoycr ft 1 (85), reported 18 keal/g for tlie heat of adsorption of water on chrysotfle.
These adsorption data support the obvious premise that the polar surface etvj duysotilo has a greater affinity for pobr molecules than for nonpolar, in agreement with the findings of Young and Hetty.
Adsorption from solution is complicated by the concurrent adsorption of so tmaking die interpretatiga of the bothennt quite difficult Wi studied the following binary systems on the same fiber adsorption studies: beroene^ethanob benzeno-tcrt-buUmol;
bcnTcno-naphthalene;' bemeno-anthraocoe; hexano-oaphtha Typical adsorption fwthenns obtained from these systems am shown in These isotherms of concentration change are plots of the "apparent" or cntbl adsorption of tlie "solute" (the component whose concentratloo b eated on the abscissa) . concentration. These concentration change* determined by means of a differential rrfractomcter. The extremes hi the of isolliermt obtained are illustrated by tlio bcnzene-cthanol system and
.1 .* .* .* . . . .a rriole fraction kelwt*
Flo. II. Snrfidun of ttpnfr ll^nkla an itnyalltp,
07006
os MINIUM.* IN MOtH.KN 1>CIINOf.<T
131
V#EIn (lie former, (lie Apparent ndwrplion of ethanol Is
positive at 1ow-'etaeBntrations and negative at high concentrations, whereas In
the latter i)flln%lke apparent adsorption of hexane is negative throughout.
A qualitativeMttpietatton of these effects Is that the affinity of the surface for
ethanol and beMeare essentially equal, white benzene is more, strongly ad*
sorbed thaWtf^^n affinity of tlte surfaco for tho compounds studied can
be listed in
decreasing order:
tmiM > napfclhatem > uthmcM > henna
QuentttathnslMSSgitlon of these i. dherms by the methods proposed by Kipling nd TdK(DB) was impossible because sufficient information was not available to be abb to extract the individual Isotherms.
-i'-jfcfcl
. CHEMICAL CltABACTUUSTICS
Asbestos has often been touted as tho "Indestructible mineral" In reality, this
Is far from tho case. As far back as 1635 (67). the reactivity of chrysotilo with
adds was recognized and in 1390 Clark and Schneider (10) found that chrysolite
was the most susceptible to acid attack of all the serpentine minerals. Nagy and
Dates (47) and Nagy (<IG) confirmed tills conclusion with electron microscopic
and X*ray diffraction studies on acxi-trcated chrysotilo and antigorite. After
treatment with 1 x 1IC1 for 1 hour at 100*.C, the chrysotlto X-ray diffraction
pattern completely disappeared while that of antigorite was relatively un
changed. Efatren micrographs of the reaction products showed that chrysolite
was very severely etched and had lost its tubular morptology. Faust and Nagy
(21, 22) studied the differential solubility of chrysotilo and serpentine In more
detail They confirmed that chrysolite,!* almost completely destroyed fn 1 n IIC1
for 1 hour at 95*C, while antigorite fs almost untoudied tinder the same condi
tions. The roactlvfly of Kzardite Is Intermediate between that of chrysotilo and
anttgeritre
4'
BodoDct (2, 3) summarized tho available information on die stability of
asbestiform minerals. Strong adds decompose chrysotilo rapidly with the re
moval of all MgO and a total weight loss of 609. Tho residue whfch remains after
add attack consists of amorphous silica which retains a very fragile fibrous
morphology.
In contrast to the sensitivity of chrysotilo, the amphibefo fibers are much
more resistant to adds. Thera air, however, significant dlfferenen between
these fibcis. The data fn Table IV stiows that anttophynita, creddolfto, and
tromolite are significantly more resistant to add attack than amosito and*
dlnolito. Twenty-two days at room temperature had essentially tho same effect
os tl 2-hour reflux exposure. All of the fibers were relatively stable fn 23S
odium hydroxide solutions. The high solubility of actlnolitt wss attributed to
Impurities fn the sample.
Iflscock (33) more recently studied tho rate of decomposition of asbestffonn
fibers in tolling 4 h hydrochloric add. I To feund tho following relative order of
stability as shown in Fig. 12:
tmnefit* > ni?M>|>ti}-nilr >
> aetirvttlif > an*wit# > rfcrywm*
09PO
v/V
DOW 07007
18*'
t. imi. aku j. p. .n\T\vwiw
ST00M 725
Afier an initial rapid weight loss, the rate of attack decreases radically wf0 trcinolitc and anthophyliitc- showing extremely low rates. Recently Weeks (74) studied the rate of decomposition of chrysolite fillers less than 1 jt In diameter In 0.1? N hydrochloric acid at 37*C Decomposition was determined by analysis for magnesium which had gono Into solution. Tho decomposition Is reUtfrdy slow under these conditions ns shown In Pig. 13. Tlio straight line Indicates that
TAISI.K IV
SoLVMii nv or A.nrTro*
is 25% Acn* oa Cavtic*
Per cent bis In irtitM, rsttadnf 9 hours
net CH.COOU lld'O.
WO
NaOIl
Chrymtila
Cruciilolite
Ammi'e Atitl*o|>Tiyllit* Arlt'Hitiir Yifin-.lite
mm
4.3? 12.M 3 nr. *.m at
1 77
lJr|in'tiir'' 11>1*!. | Cii- `
23.43
0.01 3.C3 OCO
12.74 1.00
U.1S 4.37 II.07 3.10 M 10
4 90
W.7S 3.00
It.35 3.73 20 3S 4..V4
0.09 1.35
6.97
1.22 9.35 ISO
rv. .i|. in Mitiitt* .ill Mi-tiiHm/.iii it llnllrlin, .sprit; na.
DOW 07008
Anrsi'*\ iimhwn i*;
iiinsnio;Y
9 Z L iI001S
0mo min) Fie. 11 RnUinq of diiysollla ilh 0.12 n lid 37*C.
the decomposition is diffusion (vi)liullc(L This toiKlu^ion is justifiable because
extraction of the (nfljj!nsiimi from the chrysolite structure leaves a residue of
silica through which both the acid and magne'.iurn ions must diffuse for the
decomposition (o continue.
It is also interesting to note that extrapolation to zero time indicates an initial
decomposition of approximately 63. 'litis decomposition proltably represents the
immediate dissolution of the surface magnesium hydroxide. X-ray diffraction
analysis of the 65-hour reaction product showed no difference from the original
material In spite of the fact that it was more than 50i decomposed. Tire acid
apparently attacks the surface uf the fibrils leaving an unreacted core which
diffracts X-rays the same as ehrysotile, litis is in accord with tho observation
that chcysotilo fibers can lio readily fihriltlzcd by agitation in weak acid. Electron
micrographs of the reaction product show an etched surface on typical chrysotflo
tubes. The residual silica on these partially decomposed fibrils is probably re
sponsible for this etched effect.
Iltc very rapid initial reaction of the surface hydroxyls was also noted by
Pundsnek (50) during the stepwise titration nf chrysolite with 0.5 x hydro
chloric add at 100'C. Amplu time was allowed for equilibrium to lo attained
after each Increment of add. The titrntfon curve, Mg. M, exhibits several in
flection points. The first fncrenvuls of acid cause a sharp decrease in pi I from
an initial value of 10 to about 0.5. Thfs point corresponds to tho reaction of
about 4.55 of the fiber with add. After the first Inflection the curve levels off
until about 675 of tbe fiber is reacted and finally tails off to a pll of 2.1 as the
rcactfon Is completed. Pundsack cstlmatrd that alwnt 73 of the total hydroxyls
exist on the surface, and that 673 decomposition represents reaction of all the
stiuctural hydroxyls. Hie final .113 reaction represents reaction with the silica gel formes! by tho process.
Ilio chemical re-activity of cuieUlolite has licen sludltd In enuddi
d. i.,d
DOUI 07009
* Mill, nil J IV II lM."'l *! *>
S T00I1727
Ki<- I t. Tiir.fS.'ii of tI.I> *olilc.
by Thompson (CS) using films in l!ic diameter range of O.Oj lo 0.15/c In a
Soxhlct extractor, wafer runout! 17 of the silica and C? of the sodium ions.
These values correspond I" a ihp'h of attack of 1 and l/ unit colls, respectively.
Similarly, in huiling alkali tlio attack is limitod to the suif.icc layer.
In 5n hydrochloiic acid at 100`Cl, 207 of the structure is disrupted within 3
minutes, coriesponding to a 57 A penetration. After 3 minutes, the rale drops
rapidly with less (h.ui tune the alios c penetration jftcr C ho ns, agreeing
generally with II bench's findings (31). Thompson proposed that the futninlion
of a tough routing nf jhj!;. .;i- ii.* -.1 silV.i prnficts the crystals from fmliter attack.
This hypothesis is supposed t.) tin fact that the fibers are again susceptible to
acid attack if the si'i< a lajer h ic.nosed by lead ion witli alkali.
In the pn iia.e of 0.2 \ F.llTA at pll 5.5 and 100'C, llie rate of decomposition
of the filler appears to be diffusion controlled. In this ease at least a portion of
the silica Incomes dbp. rxi d in the naction medium. Thompson concluded that
the nnipliiliole Mini (me js net inti in-ic ally resistant to acid attack. "Ibe apparent
rcsi't.inrv i% a n-'nlt of the piotectinn a Glided !)* the silica layer. The lejser
resistance of amnxitr to aiid attack c.in possibly be attributed to faults in the
structure.
The resist nice of the asholiTor minerals lo attack by reagents other than
acids is generally (onsiiti ud excellent at temperatures up to 100'C, but de
teriorates rapidfv at higher ti inpci.ttures. Mali and Taylur (0) studied the re
actions of cliiysolile with msu.i! materials under hydrothermal condiiinnr:.
1Ucrnl studies ly Vang ( V5) indicate that reaction lietwccn ehrysotile and
calcium hsdto.ide is detectable in 2 days at S'JCTC. Similarly Heinnc-husscl (CO)
found that chriMitile \\ax c:n|'?i ! Is dc(om|MtM'il in coneential* d pnt.issinni
by di'\*if.- .,1 .?t!n (' u,i!n`i` .'I h<i*% T hn'n*i-*.M (Ct) showed that cm iilulite is
alt -c* t d In p > m'i i i'i
n li\!:i.J-*.*.d*vi 1(K)*f' and stud . * ?].. Is.':-.
t!--' ! i' a*'i. .'!> a \. i. ..r it**- i . I.. mii iK
l'id. j {>.%*
, tVr j > :i a, .f i!n\ *{il ad't vln. v i!*
r o. 1> I. i
. ... f
i' ' t . I'mid- am! II.
I
DOW 07010
AMUtTU) MINI i UN IN M'HU.IIN IHIIMHJM'
1*5
demonstrated tt>nt fatty acid-.
other weak organic .Kills when dissolved in
noiuqucous solwuls rc.i<t with the hi* r xutface to foirn .1 mOtM'inohrnlar
"thembodied"* layer, The amount of (ht'iuisorhcd acid is nlhilcd by the pres
ence of sorbed water on the filler. 'Ibis it illustrated Uiow.
Mb uid
CitKstWKrTiox or Omc Ac:o i mom ItCNaM it Ctmomiu
Kilr (.intliikitifd fur IS 'toon ai
isjc
% nit
too% n
filar 10.S 7.4 0.S
Equilibrium in these reactions is established very rapidly, probably within seconds. It was also notes! that above a concentration of 0.003 moles of oleic add/kg of benzene, the amount of acid chemisorbed by the fiber Is constant and lias a value of about 1? by`weight of the fiber. Tlsf* value could vary with the exposed surface area of the fiber Even after 15 extractions wi'h hot benzene, 803 or more of the original oli io acid remains fixed -vi the filler surfaco. Fiber which contains chemisorbed fatty acid is somewhat hydrophobic and markedly organophiltie. Tlic h) drophobic character of llto fiber Is of A limited nature, since the fiber can be wet by vigorous stirring in water. : In general, organic cnmpov'lions possessing acidic functional groups dissolved * in nonpolar or slightly polar solvents, such as lien/cue and inetliyl ethyl ketone, exhihit a strong tendency either to chemisorb or to slowly react with chrysotile. Long-chain aliphatic acids, such ns .traric acid, oleic acid, ik1 palmitic acid,
arc chemisorbed by dry filcr. Atonin'ic-type acids, such as Ijcnzoic add and related compounds, arc also c.hcmhorb'`d as arc dibasic aliphatic acids, such as adipic acid. Although the uusv.itratcd ivc.\r1>on sorbic uckt appean to bo chemisorbed by chrysolite, the related shorter carbon chain acrylic, crotonio
acids show some evidence of slow reaction w ith the dry chrysolite even in non polar solvents and there i< a tench ncy for the adxorbcd layer to show an affinity fur water. Maleic acid reacts w itli the hulk filler.
If the fiber contains achnriictl watT, tbc interaction of an organie acid In benzene or MF.K solutions differs iiiaiki.dty from that with the dry fiber. Tito* long cliain alipliatie adds, c.g., stearic, oleic, when dissolved In nonpolar or slightly polar solvents, show little or no tendency to sorb on fibers oontaloing adsorbed water. Adds such ai adipic, hen/o?c or sorbic, which have some slight affinity for water, rract with the bulk fiber structure Instead of chemisorbing as they do on dry fibers.
Tlic reaction of chrysolite with certain anionic wetting agents, such as Aerosol OT. is peculiar in lliat they cause the fiber bundles to separate Into ultimate fibrils. Tills reaction is accompanied by strong chemisorption of tiro agent* with permanent modific.itinn of the smface (51).
When chrysolite filler is decomposed by strong hydrochloric add In the pro*, cncc of ehforotriirethyl silane (21) a vcr>* interesting reaction occur*. Normally, the decomposition hv acid h aves a tvld.ic of amoiphout silica which |iot\wr-
DOUI 0701
J8S ft. snot. AXB J
ins in the ihap* of Dw original fiber.1 with the silks sheet as the magncsfcsn Is mond eriraatfen-efthe sdfca. The final product of (he raidfcali Aeon fotyvm hi sheet form; ThoshoefirM* eJifbfcifftal chrysolite mosphelofjr audbr fafi show e 15A spacing between the laywhjr Xfeftf.t (hopoljnaar sweBs and the X-nqr MaedHkpMlii lh. tabular sheets have vraolhd. This product lr'f ` the besie chpetfle structure is a spiral rather than i
JUoctim sett Wsfrr
`~
he addition to bring vulnerable fir aitKk.h^eettSsh^iiilte^
emmtanecealkahcs asbestoe fillers are also wbfKt to*tfcaxhwitirr] -- *feAyo(fb.wflh water. T" *------
cftiyaotflc
t\ silica, lie abo sugguted that the colloidal silica k\
acid.
* ' " ' V rr-.JiC--;
r results confirm that chryaotlle^b^dcceeBpoesd oy
V&undlhat the concentration of magnesium to thocxtract wasrelath
the first 3-4 hours of Soxhlet extract
decrease fa magnesium concentration sras
__
precipitate of amorphous magnesium sHkatfik^Alher the-firitifil -rfiflid.
megaeriem and silica are removed fn amonafa psOportibod-ie` fa'
composition. Whether tire removal of sitioa proeeodl hp'finq^ef
the* formation of eollotdal silica hjetti however (het chryxrtdo to slowly*#
uDMI CMIKIMV Fbraoddo&te, Thompson (68)
sodium am removed by Soxhlet extraction-uflt'
f was equivalent to that of alkalies at
Chrpaartlf
Numerous Investigators have studied the ryntberis ofcfcyisowc
M tine minerals, Tlicse studioa wort motivated-eWhStJ
or by tho dodra to grow largo synthrtfe eryslaljultfift
tile was sjrnlhcstwxl as early as 1987 (84) fcttfBeR i microscopy and sophisticated X-ray dTflrartion tvchniqnc^ ItS to drstiugnidi among the mineral* of tlic serpentine group* The
i
* a the chemical analysis of the reaction products matched tint of not be considered dMiurtly diagnostic for chiyurtiW . *}
Onyantifo !m Item *)7>t!*eU*i'd only nnd^l^rethVinii>tj>ni^|Mi
awKl i IIU 1C \iwy Ut'llltIMXMUt' MMt
W . - - m
lilu Is formed at fiftpsrcW
STOOI1729
t
DOUJ 07012
- ' ' - r .* *
. lUpiVS'3fj??* *
-
.
S T00I1730
JtofiaiHejr (63) enm Ml
tfoo mfosrmls wflh magncsh
othre.fMfc Replacement of
prtdKtMA wm cflher pfaty
fmtfamduoride-lndfofonMi)nunbtinfc3!bQre>stef dwi
- - by
*> jMpendtte. aftwra! whfch formed
S&ifl
-: partial-sobsttatSon of aTumlauni ta-brahjw.pieldedffidy"ilendnuBfei
ponthwT (MgtAtXABUOwHOII)* Another wrpefltfoe^pbi&e was ato-i
.. itafnd from nickel and pmalum NICea0(01I)> ouch also had a pVi^
structure. It was not possible to produce serpcntlne'typo phases sot
imingmrnv sfae; cobalt, fans chromium, or galllom for magnesium. This,,
over, does not preclude the poss&ftly of .tya<y . amounts of these foosl
present In naturet or synthetic materials. Hie tuthon concluded tKaFtSeful
structure of chrysolite is not only a consequence of (he ton sizes, bot~<
external Influences as welt
-''J.*
.t . c.
A*tph(Mm
.'*'
'
The ampUbole minerals can be
efthertpyrogenfe
thermal methods. Recent studies at the
grad, are probably the most comprehensive te this 1
SooriheMbstHutcd for hydroacyl were produced by.hertftsj^mftfureoti
end luoridcs to 000-1100*C in tightly closod phUmimW^eraMfe vsauft (I & ta ^rra>ir7fcfeadusra! phase end the morpholngio
on the composition of the Initial mixture* ihtfilbitfbeM
turn Tho bomorphous scries o< fibrous. Ubero^unphlhOW Included
variety of cations comprising a mixture ofNb ot otl<>i^<rJMJfafcdi
ptus either Mg*. Fe*\ Cr**. Cu*% CP, NP. 1^; or Cd^Wfthhi tho ireottobY^
mt*, crystals of 0.5-1.0 mm in length, and OU-tO* ht'dfehTwter were formed
with crystals as long as SO mm. on the surface of the reaetftrfmasa. The physleaU
properties of the synthetic fluoreamphftoles wore statcdlo bo superior (0 die
best natural varieties with tcmila strength of tOflOP-WflCO bgfcm*. Thermal
decompaction did not occur until the temperatore exceeded 000*C. .
Ifyrimsy amphitotes containing comhinatlons of Xa or Ca plus either
DOW 07013
l. i inn. amd j. p. uuxawcarai
"Jror NP* were formed under hydroUiermel conditions (30). lioin were 330-600*C with pressure* ranging from 30Q-2C
( Umes of 0 hours to 3 days, fiber* ns long as 4 inm were of _s ranging from O.l-l.O^ The hydrothermal fillers were too their mcdumkul propertlc*. Thdr themuil stobilily was of the
iltudc as the natural materials.
r3Sp**gf(
NIYS1CA1. PROPKRTIES
Met is used primarily as a reinforcing filter. Its tensile strength is* - fore, of prime significance. Hie measurement of tensile properties is
by the combination of sliort length end smell diameters resulting in a widei of values from the same type of fiber as reported by Bedollet (2). Zul end Caxc (86) sliowcd a strong dependence of strength on fiber length imurimum vnhies of 01,000 kg/cm* and 58,000 kg/cm* for croctdolitc end' ^tfUuraap i ctivcly, with a. fiber length of approximately 2 mm. Motion showed; that fiber failure normally occurred by rupture of weak hite bonds, rather than true tensile failure of a fiber. Using a newly dcvclopod ^(ensile machine, comparable data were obtained by Burman on a ..' asbestos filler* 4 mm king and 10*20 p fn diameter (33). Croeldolito andchi tile had tfie greatest strength followed closely l>y amosife, with the amphiho'c* significantly weaker. More recent work by Bunnan (13) in Til
TAW.K V Phymcai. PKoi-KKriijk or AMi:*rmittM MisKMua
Or* ampin
Tensile strenftM <X10% kc/nn
Younfi modulus (XIO*
Am*c* crea sectional arcai
filler* tnM
<xio-*4|
Clirynailr, Arinina, VR.A. Ctiryxitffcv Ttislturil, Cniuulm CfocfcMita, Knrpn*, C*n| 1'roviiwm Croriilathe, Knems ftpc Province OndWIlt, PumfM, Cn|<e Province CmMuiite, IWirl, Capo I'nvinn CreeUidte, Coehalmmlju, IMivin Amoaile, rvnge, Transvaal
Am ailr, IVn*r, Traitflvirtl Autt|ili>'llile, ISinhUla, llnlaml
ws 37.1 no
31.6 47.6 , 30.3 14.7
30.3
30.3 36.0
1.49 1.40 1.0 .
1.64 1.73 1.79 1.73
1.40* 1.40
1.60
i.oHI
3.13 *3 1.66.3 1.0*1
. .1.04jjf i.sr^l
t.4Mg i.n^
in 0.96 .
easts doubt on t!e validity of Assigning specific tensile strength values to asbcslironn mineral, although the same rrlalivo order Is maintained. All appear to have strengths less than the theoretical value of over 100,000 atlrilMilnhtc to silicate chain structures. The fact that chrysolite ami l the amphilmles give ta nearly the same values has lest Whittaker (77) to that tlie filler slruigth Is affected more liy llic tvystal Imperfections i during filler foriiMlioti nth-r tli:ui by the atomic arriuigpnxnt or i
S T00I1731 t
DOW 07014
1
t
n t
>mrnAij ut m
iraixotooT
consistent with the hypothesis llut amphftwlc fiber* Arc built crystallites held together by If--O--II coorJiiwte linkages or krs. Chrysotilc fibers, on the other hand, are bundles of funda* relatively constant diameter, but vnrying length. 'Hie difference chrysolites fs best exemplified b>* CoaKngn fiber (KIg. 15)
comfat of overlapping Ibrils approximately 0.3-2 n long and Jeffrey dirysoUle which has long Individual fibrils
cm also explain the gradual time-dependent loss in strength
".*'v
oo --t o o
u PO
S.
r if
fr * rf it
i
IrK f>5*/ >'v */ /n **v ... -- v/:;-r; . j'. o ^\ -V I
/* - kr/*---'*V^r3
e yf'/f iflw P%r$Kt. i
..J
C ^
r.! . l.-i ------ \
rr.. 13.
t.iirtf.rjpti (if cnatlng.1 c1n)ot(1e. XOOOO.
y ---
DOW 07015
S T 0 0 I1733
(
Fic. 10. FVctrnn nrcrnjnph of Jeffrey cfio^tile. X0000.
of asbestos, fiber* \vft) increasing (cnip^nturr Mow (lie decomposition tem perature of the crystal. Small times of water tn (lie curly singes of dehydration for both cftry*otitu ami ampln'Mcs are probably associated with reducixl edgewise tondiug Iniwren tin* fibril* nr ct)>!.itli(c* comprising the ndvestos filiei s, resulting in reduced "tensile strength" of tlir filler.
I/tirtfniret
Hie t,nn "li.uslni.-ss*" I-. ret.ifi d t** tin- flexur.il mridutu* of the wdiektlfot in
ri ... *. t* ... .. . i -i
ii .. . ,ii. i i . i . i .
.................. ..
..................
*
i
n . *> ii t ** MM 1 t.Utll I)
DOW 07016
>IIM n.U.ft IX* MOOt.UX T>.UCfOXXlt
191
etfii in the.final tt*n Awn in the electron micrograph of Mg. 17. AJthoagh matt dnywiSkBbtnare soft, xmihnnh fiber* ere atso cornmerctaJly available. Ilmh.chvyaolfle b not asually commercially significant Hie difference in the
h weR fllotrated by the photomfcrograplia of Mgs.
open, bully, fajt-Rlrtfef
*> *-
- "IF- i- *
V*
ST00II 734
_U
'*
Kw. 17. Kk:tmi !?.**>>; tpii of
*<"*!*.
DOW 07017
. sncn. mo j. r. uaawrrw-
S T 0 0 I1735
-v . v-i-:.
/.
`S' *
TO! '
.ft
r-ti&m
jlT^ \ . -v.V*
^ ';
.* v^* %t#
limr;\itos* % . ->#\ i .*/1 . i ^*,**9 \iA\\
j/ -
- -i-w.' '-**..
^
**ti*i#ii
Fib. IS. Soft eTirywCle. X1S0..
tribute of soft chrysotftc b often serious <
nkjurs employed in tfte manufacture of
ehrysotfle (iters, wtien economically available, or eroddolfte cm
place soft chrysoMe to Improve (iltr.itkm. Chemical techniques may atsefeeaod
to accomplftli tin* same objective citficr by adding poIyvJedrolyte* (D/urVyr^
treating flic (ila-r with sodium sflfcutu (68).
*'
Considerable rosenrdi b.w Urn demoted to corn-late-haishaesrsflW'ftliihv"?
mental pbysknl or cbnnfr.il f.icforx. WondmoTe (SO) has Indicated a rrtalkm. *"
dfn wj1 it>r
,;w. in iiiu* with (Ids, lladollcl nr
JL mt* m.t*X
* *-
DOW 07018
rn
I) Iki%c p.t- uliil . (<
for iii*.ri'the li.iiilim'i of chrysolite hy
ish e.dciniiej in i!m* i.u.*;e of ."X'lJ' (' In drive off port of live eh* nnV.dfy (two*
Ined *estr \fnrc rmMy, f.urp-r and Kerr ($7) have indicated :t correlation
villi Rue mineral inlvr^ruw llis in |1i liuudlct id iihrill wmiwWtijj eln).aUte.
Innthcr hjputhesis is iti.a hardiness is related to the relative contents of tint
[two cryilailirjrapliie forms, clinochrysotite and ortho chrysolite in the fitx*r front
spectQe sonree (Whittaker and Znswrinn (77)),
----- T T'
A
:
* s '
r\ |--sv --r-ir- **! ;i. * -
* // ; : *"1*;*"
t
: r-
i; V
i
/ . *>\ ,///
v vV
; |*i!
/ f **,
fX VrVA
; #
. /'Vi
*' j
dal *
: . I-
.V
,1 .,***
$
%*
e I
.V.. .. ri
>
ti ................................................
. 'y
.
* ' r.
- i
'V '
v-
+*<'* /
.. - s :
. 1N
'* , //' r
/
. \(i- j . *
STOOI1736
cU-
rd. lo
rd
I'R 1'X Harm chijfisuk
DOW 07019
' 191
t. ftpwi. Axn j. r. u.iNKWiuiwi
Tttermal DceompoaUlon
Asbestos minerals, despite tlicsr relatively high fusion temperature arc <
plcteljr decomposed at temperatures of 1000*C or lower, depending on
v S'*.
mineral specks.
'v ^
The course of tl>e tbennal decomposition can be followed by three dUTerwOi-^-y
but interrelated techniques: differential thermal analysis (DTA), t)
metric analysis (TCA), and static dehydration.
The actual decomposition phenomena in ampldboles are extremely
cated and depend on the type of atmosphere and particularly on the
amphibole involved. Typical curves for the !>chavior of croddolite in aft
given in Fig. 20 from Hodgson (33). The first chemical change, co
- ***r. T-.v i
%- .
W%*0ht-.^VZyii; Lot.***- .* .-VssJ'C^.' * .
.v^C-Tv*
M IM IH
Tompornture <*C)
Fie. 20. Thermal iwljws ef crocktolite l o\)gen.
to an apparent loss of water, occurs at 420*C with .the final decomj
tfie ampliiliolc Into a pyroxene mineral, cristolinlltc, and iron oxide occur
900*G. Tliis water is formed by migration of protoiis wliich are oxidized oil
surface by oxygen In the air.
The other amphibole: lose water primarily by condensation of hydroxyl?
Oxidation of divalent iron has a profound effect on the tliermal bchavioBt
these minerals and this become* very evident by comparing the reactions In iir-v.'
and In an Inert atmosphere, llotli the dehydioxyfution temperature ami dcconii
position temperate.** appear to Inovase with Increased MgO enutent (a. (hit s,
different amplitude species. Hodgson (32) gave a detalhd expirimmlat and^V
theoretical review of these plmtomcna, which include loss of pit) <ic.'.tfy war-
tJIIH tl \>*ut l| It*" O* tm iiiC!!j %
`.! V .!?**?, Vlpt !i*< tt<tr***'n inf>i
decom|wsl|ltM products. These thermal analysts trrhinrpn* hlso proved
DOW 07020
AflMcntM MINKIttl.S IN* Mi*:n.N I'MaiNCM.OCV
m
catcgort/mg miiphfliolc samples from diiTervnl Imnles. Por litc ntiitnls cliurnt*tcrilirs of Iwth antliophyllitc nm!
Thinsvan! species Is often an intimate mixture of crocido-
of chrysotilc h much simpler and Independent of atheating conditions (OTA), dcfiydroxylatfcm occur*
with formation of fonteTite and silfcn, about SIO'C, as Static dehydration experiments, tho initial water loss beJosr
i___ i .j. 109 >99 >90 400 >90 99
uvkm'iunt
*------- .J0 09 909 090
Km, 21. Tticrma? am'
-V
500*C is time-dependent with no dt twtnbl&P'dfingo in the X-ray diffraction
pattern (J2, SO). Martinez (>11) has summarized (he various theories for the
Rtomie rearrangement during tho dehydration and formation of fonteritn. Uto
simplest approach to describing the decomposition above 500*C (static) is to
consider tt as a three-step process: the solid residue of the first step ( <COOC)
is a slightly hydntted amnrp?ous magnesium sltlcnfo with a minor amount of
poorly eiystalKaed forslerite. Tins is followed l>y the fonnatfon of well-crystal
lized forstcritc with same rc>idual amorphous nvtterisl at 000-1000*C.
Finally, heating above !100*C yields a mixture of emtatite and fbntcrite.
This generalized scheme has been confirmed fiy comparisons of Infrared spectra
of heated chrysotile with those of mixtures of pure synthetic minerals (01).
Many Inmlf^tlon have studied (lie thermal dcounposltion of clirjxolfle
from a wide variety nf sources, amt all have J>oen found to yield essentially the
same OTA cunts, neeeiit studies with an extremely sensitive dul'ont Utfler-
entlal *l1iemiaf .huljvrr have iIIucIiihiI slgnlftrunt (llffrnneis between fiber
from dlffcmit- Manxes. For many ehrysotltes, tho 030*"dehydnyTatfon pr.il: is
really a doublet (.TJ). 'Hus riimhli-t nfunoinenon wn (lt !
* v
OOUJ 07021
S T00I1738
S T00I1739
1U6 *. MT.lt. AM) J. P. I.I.INI.WMMJt
liner (10) Iti a fi*i\fnre of two sampl- of tltc* vmic filter which bad limi'sdb' jest,si to different degrees of intensive grinding. *lh dependence of dclr atfon temperature on particle size In tin.* analogous mineral haolhiito ` itinriitl by Spril (00), ft bus not yet been determined whether llw# olxcrvcd doublet peats in specific chrysolites correspond to two fiber1
populations or to some other phenomenon.
Mechanical Disintegration
For effertive reinforcement, tlie n>tx'sliforin mineral sltould be
tltc degree required by (lie specific application. Mcdmnical milting
is (Tie liosie metbod of filx'rizing asbestos minerats. Ideally, the fiber!
stioutd be opened without reducing the fiber length, fit practice, tho
shot tenet! to a degree controlled not only by the severity of the
action, but even more, by the brittleness or harshness of tltc niinctal_1
chrysolites sliow iniinimmi length disintegration during opening whfl^*
same mechanical attrition, die semihursh and harsh chryiolilcs are
significantly. Ainphibnles ary cvm more susceptible to length att
^Tncchanfcal impact, and are usually given their final opening by lliert
.V"*!5V?>*^[^^J$WBumer, often in the actual miring or processing operations.
' ^ "' *
Normally as (lie fi!>cr heenme more open, tho additional energy
for further opening increases rapidly, imposing a practical limit on the-j
of sutxlivision attainable in commercial milled products. Recently, fait
grinding tests with an intensive dry grinder* showed that it h possible tot
dohoy the structure of chrysolite >o that it is no longer identifiable
X-ray diffraction or by the electron micrograph of Fig. 22 (00). Jeffrey 1
heated to TOO^C for I hour jields an niuorplious material with exactly
appearance when viewed by (lie electron microscope. 77ls sugge
changes observed will intemivc grinding were actually caiacd by
locnli/ed temperature surges in a fibril as it nlworlicd the tremendd'
energy. To substantiate this hypothesis, chrysolite was subjected to
dry bait milling which yielded a similar appearing amorphous mass. We
which precluded the possibility of attaining localized high temporatar
duectl short ultimate fibrils which maintained their crystallTno fo
easily identifiable us rlir)sotib.
Theso otjservutIons have been useil to explain the results of contr
wear tests performed at the Johns-Manvillo Research And 1`ngfnceriogfT
(tt5). Wear dust was collected from passenger cur bmlo linings ml ^
series of stops simulating normal traffic and highway driving.. Air
and dehris in the brake dr.iius were collected separately and analysed <
Tire composition of the inorganic fraction of these residues matched thi
original brake lining uhieli contained a total of 707 chrysolite. No
was olwcrvablc in the wear dust by e ither X-ray or opticaf microscopy. Ar
Iron inicrogmpft nf the dut is sjiosui In Ft*. Sh 11m resemblance l.etv
and chrysolite, which bad Ihi m m<-thaiik*.i!ly (uikI,
tlf
'*p,*s Miv /Ntin. M imir.M <.tf. ,1 1iv s>. in.tn.iih.,
Nor Jervy OSS in.
.101 i*,,!; x.,*,.. v
DOW 07022
STOOI1740
t
.no* uixhoii ix mm*mx iroixaoct
--d'L'i-;. 1 at/n*: Fie. 25. Kkvtmn mtcrngnph of Spe*mflbd cfaysatffa' X119K decomposed. Is apparent. Despite (he fact itierilicrwjw^^.wwBwriiKtiCi of (he bnto (tmm trmpcnifurv did not exceed STTQ dMiflwUealrtlaiM htilfa: cntcd that (lie temperature* a( localized pofntfl of contOCT;exceeded lOtXTGL Minute fragments of clirysotlle fibrils eoohl be observed Tnaomeot the electron micrographs ami a modified point count tedmirpe wa* detfaed to determine die chrysotile content. Cgnscnalht estimate* of (lie cfwyautllo content by this method showed di.it more than OST of die dnyiotlW la tintrayed (faring normal bmle-**. Similar studies liv die U.S. Public Health Service sebaWnlfated these results for normal drlvlm* itmdilfmn (33).
DOW 07023
STOOI1741
4
*
lOKNTUTCATtOX Tho positive fdcntlfanrton of the ashcrflfuvm nrfaeorir.fi Irf^r dependent upon such fneton as (Tie physical fn\ the presence of contaminants, priormcdinnfen!, tliemuil or chemical Inntmcnl. lTi*-vnrinhlr Mtm ri the amphi* boles mates It necessary to classify a particular sample ar Itmit closely re seuiMlng* a specific mineral specie*. It Is ohvfnns that, rwn If sufficient material Is available, simple chemical anal* ysls Is nut sufficient t elmractcrl/o an Aslicstlform mineral txcanar all asbc*rt*'~~~ form mlnrmls hast* rnnwlsr mmitrrpnrfs svllh lire same chemical compraftlorv
DOUJ 07024
1
I
AMU1W MIMIUIJ JM >tOMJUt TUCIIXOLOC*
1*
Ono mart, therefore, rely on a combination of mctliods. Tho methods most fro*
qncntly used are dtt-niir.it nnalysK petrographic microscopy, X-fuy diffraction,
(Icdmn microscopy, electron diffraction, and differential thermal anal)1! !
Perhaps the most nMIc method of Identification for particle* down to a
c/>
few microns In diameter Is petrographic microscopy. Using this todin(quo* tho
fibrous nature of die species b evident and the .optical properties can he ttsed to
Jrtawiw which species b present Among the amphlbofcb Kbweecr, the mi*" ^ btst compos*Ion may also effect tho-opttad properties so-that again podth**.'
ffcaCffeutfiNbinay be difficult In such caacsJX*ray diffraction and ef
aitaiyUi brt)TA can be used for
. If the staab below die pructfcalf"'*
diMtwtCiaMw*n? mlMMCMC a(ma (ft iwm oitl^pmomsl
_
bout the shoe and shape so that potiKfo^lWTlaftlisa h
* Ire fnfnrnartwjr^i-:;
spedfie ampMboW. The tnf
mtcroscope b specific. When
. inctfar
lion microscopy a better, but stflTiifff^hfitiffl^l&nttffffc^of anipUbffWfe^
bposaffdo.
. ::
The election mlcroprobe b a refatfndy itceuKdcvtlopiramt which b prorhiff^;7 of great value for die charactcrilionofsirtall5moontaof^material. Whh tlibu^;
Instniment It b possible to obtain a complete chemical ohatyta on a paiBS^*
as small as I y. It b also possible to study the stfme particles with .both (hfr -
electron mlcroprobe and die electron microscope, thus malting a more complete - .
charnctcrfrotlon possible.
Table VI b a listing of the properties of the osbcsUform minerals used fbe`7.^
their charactcrfzAiion.
*
-'
.
sources of'kibbi
:`l^:
Hendry (30) at the 1CG3 Conference on Ttblogle Elf^ro^Asbestos serqwicSffiy
marked tho pertinent aspects of the occurrciicrv prodSrtJShjTand oommerciit^g^
applications of asbestos fiber.
j.
'*,'
Tablo VII presents tho world production of asbestos
'PkpdSeS?$3:
lion has Increased with few changes In the rcWthu standNVKUf the producing ijir.
countries
.. j *'
Tho major difference b the great Increase' h .ItimtairprudSictlmf which now^ ^
outrank* Canada os the major producer. Tho* InciyascdTjfcdlfttl^HrdieUnitedT*
States owr die post few years Is due to die redrat development of dm Coating*
fiber deposits In California. One Important chargedacueBMfcjEthe. dosingeT/:
tho Australlnn erocfdolRe mines and the elEmMatfibr'bTTIdFlourco From (be
maiict. Thus, South Africa remains as the one significant men producing crocid-
olitc and amcsfle.
.
Chrysotile accounts for approximately 09!l of coiranactaTusbcrtoa. Qirysotffe
asbestos from Quebec b available in more dian 90 standard or ^ecfaftmf grade*
to meet specific requirements. Some Of the larger asbcstannOtl such as that of
the Jeffrey mine In Asbestos, Quebec-, produce many of these grades standtanconslv by a complex system of ennttnimus cnishfn*. srrccufng, and arofrattm
from die same mill feet! material.
'
DOW 07025
S1.001174,3
DOW 07026
AWSKI1 MIXMtMJ IX MUWKS 1I.TJINOIjOCV
201
CommUy
r.\nix vii
IVwi tig** or A-mi-iv* i\ lOCft
N. of
lti
Xnrfb Anarim (Mi United State* frlifii iU)
Shut Anavica ArfnHlna
Brilrii (npaV)
*a
IMI 128,919
240* 4
isio
Aatib Ra^ub
Flnkad
flatten
Crenee
Italy
IVtapd VJiS.R.
Yefariavia
Africa Rttemi XM)t
+3kIa*aniU|'
Hhoilewa, S'KiiWm
Sonth Africa, Itrpnbfie of
Swain*nd
United Arab Rcpubfie
1439* 13,220
77JO*
10
mu
S30*
n
175,000* 270,597 98,112
3087
/
China Qym India
Kama, Sooth
PhilUyfaiM Taiwu Ttwbey Oceania Andmfla
XrrZnM
WarUTatel*
140,000* 31,449
70M 17,087-
727
11,472
* Kgthnaln,
* l>|iaMl*h*t data ewuklrrrd Im lw ulhUe (n*4 front IftwnJi YMitauk}.
Alt fiber? from Quebec are claesified by * standanlhccd system which, with tome modification*, fomis lire boat? for other cfcttlRcatfon systems In use throughout the workl. The longed fibers are Croups 1 and 2, with fiber lengths of over fi fix and from 5 to S in., respectively. These consist of haadheelected crow vein fiber amt are termed "rrmlo" aibeitos ^nulct sfnee they arc normally given final preparation by the ultimate user. Croups 3 through 7 am ctanifled a? "mlllctr ffiicr witli decreasing Hint hngth, t< mrectiretl tiy the Quebec Standard Crr.HMt Trar {??)). Knelt t'rcttp f further aulxllvkted Info a noinltrr of sub-
. STQOI 1744,,
1
S,
atf
DOUI 07027
S T00I1745
a. maf^AmJirft
------------- ding to their "c-------- . -
iml-ahMp(h(- pnpvtiei. Subpwpillihfcff
iicccww^f Intordangnblo for spodte **" "
'cmljnhr h ono whfch cunUdaorad
(fiooo fiber Md/gradcs In wMch (he fitei
ara inowiras "opened* grade*
*. .
Table-VTIf givn the approximate dttiitiatfM bygrodesof
produee'f'ftt flmada and tbo UhRed-Statot as compared tethofj
(be-USSR In IfjOR
- -
: - .-.*
T^BLtrm -
v
Amniun (Voetmos or Cwnowu Fisa-- it Ciaw w M
C<.W
UAAIL
V. & and1
Xm. I HimIc
X*3Crfc 3
WO,000
030.000
900.000
M0,000
Apiittetitbni
The commercial npplicnt ions of asbestos are so numerous that thl enn do no IwHer tlwn refer the reader to the many excellent texts Unite!)* covit tlifa subject (S, 02). Tlie uses range from asbestos or floor tile, which consume hundreds of thousands of tons, to speda applications winch may consume only scwml tons annually. Asbesi a grvnt variety of products a combination- of ptopeittor whle nlttilmnl hy ning other materials. Its strong fibrous form rrinforcos sih*!i as plastics or cement, or ronlrots viscosity of many systems; nature (s lui|Htuiit for resistance to Imt and chemical or cmi fis fine .d/e ixinlributcs fillrutlon cflldcncy and Insulating dance nml tmv cost are significant factors In promoting commercid
On live basis of relative abundance atone, chrysotfle wflt bo possible In preference to otlicr forms of asbestos; Whtre-t eoml treme bulllm* charicfcristfro plus tmv water content and high t slstiince air desirable, c.g., thermal Insulations, smostte has fcrrvd. Applications mpilring resistance to adds tmodly take relattwly .;in*d 'arid mhtiinrr of crocklollte. Testlto prodnets silly, longer grade of chrysolite although croridolRo has also acid-resistant textile forms. Geographic considemtlom may exert fluemv to increase the usage of specific nmphibolcs, snrli as ant Mnl.iml or the c-roririolltr* In Smith Afrh.sk AnlhophyllRo has advantages over other asU^tifonn minerals In reinforcing pol)' mis ami U iivit extensively for this purpose*
DOW 07028
. itcmuu a %nmaar iwamofxmt
m
fa general, specific grata of cfuysotile have been developed by the asbesteefndastiy for cachmarUiL Atthai^i Ihe longer Obey? ere considered to bo of
_ better quality,- I would be jiat as {mpraeikat to use relatively long ,4-grade fiber ' In floor Uto aaJtwonkl be to attempt to male nttbfaciory asbestos paper or a*sJriibestburaacatprodocts with 7-grade fibcn. Tirlac^rsoine appBeatfans may creo77 rajuirmthe presence of a considerable amount of the nbnfihsoev finc-gralncdr
partfciktiiaifattic which Is contained* in aoaao of the 7-gradd subgroups*
KonHany^the; consumer selects the least expensive grade of fiber wbfchwflT ;
w V.
ST00 f 1*746
. i..\,
WjpV-r- >
^
V'V' ' -I*.'**;VWNU ^ alemm \
Fa. U Kkvtron micrograph af wwmwhl tale, >/tw'
DOW 07029
S T00I1747
1
1 Mm AND J. r. WajOWTOUD*-
DOU) 07030
ST00II7U8
ASMSTW MIM'RAU W MOOtKX ltXIt.VOl.OUY
--n
cgndit applications. Figure 24, an electrbnmicrognph of a *yi**c*,f ftciated Irahnlrial talc; nnl the presence of considerable fibrvus trcmollte. Appnarfmuicfy 9000 tom of talc arc ud annually u a carrier for iwlk'U** (71). Wtedom rt of. (79) Investigated the distribution of tale In the atinosphcrr and In glacier ami anon* samples to stmly the migration of pesticide*. Their samples covered a wor!(]*\\iilc geographic distribution. In practically every samplr, amphibolcs were detected along with the tale, as migjit.be .anticipated
from the.common occurrence of omphlbolcs ta talc. v
`
Qdby(M) et of. haw recently Investigated.22 cosmetic talcum products. AH.
had significant fiber contents ranging from S'to 90S by count oftlie total taler
particulates; and avrraging 107. The fibrous tale factucfrd trrtnoRte; intnophylUtes-
- and-cbrysotlfe. They made special note of thefact that cosmetic talcum prod -u
Z.... octrshooU be included as a source of fibers, from-which may be.dcrlved ferns*
; ~~ gfcwo bodies obaerved In the limp of huaftiha.'-'}?' ' ' . another famtigfttSon by the V~
;! ' source
identification of respirable fibers;
more
occur fo respirable sfees. In addition
mfocraivthese Inctodedf^
-is-
fallc/s'carth, xeolfte, vrrmfculUe, caklum carbonate^ ppaom. pyrophynrte, tafcfe:^
yjsa.lyanfte; hornblende, mica, magnesite;a*d`manyother*
ji,
Pure serpentfne ft coreIdem! to be composed^of noafiKnm snllgorile or-
Ihardlto based on pctrograplile and X*ray examination Uoureuer, electron-....
microscopy reveals the fact that ad serpentine roefes contain significant amounts' v
of chrysolite. Figure 23 Is an electron micrograph of a practically translucent
"museum grade" serpentine specimen from Warren County, New York, obtained
through Wards Natural Science Establishment. Despite fts apparent* content of
approximately 207 of fibers, optical microscopy showed no chrysolite whatsoever.
Examination of muny other authenticated san^^ of.^pbraljcrpesttne"
revealed the presence of ebrysotfle. Serpentfnfc* loe&dcpcaMHBtf wfcl
throughout the world. In the United States they form the TraAcBom scr
belt along the entire length of California, Just as they form modi of the Appa*~
lachtan range on the East Coast. They arc used as the badsfor mony large-scale-
application^ such as ballast, mad construction, aggrepte, building stone. Dor*
Ing grinding and preparation for sudi commercial usage, therrwold be oppor* tunlty for escape of fibrous material. * ~v -. ^
* /i
COXCT.fSIOXS
It b Important for the medical Investigator of- thmbteiogiogatttcfs of ashesti-
form minerals to properly imdcrstand the wtfc
kiusl to*
dividual asbestos minerals the ubiquitous nahira ot'tKfele o*fttfra>Kc, both in
commercially valuable form and as Impurities In other matofaftt imd tlse wide* spread existence of many other minerals with fibrons form. It b only by relating
experimental biologic evidence with the rariatiom In phpfcnl stes snd form; In
physical strength attributes. In phj-ifeoehtmleal curfaev reaction* Tn diemfcnl reactivity, and In OMncf.it.-d Impurities, that tve con ultimately aniw at valid medical ctmrfuslons.
OW 07031
S T00I1749
& *not Aim-j. p. LNUMnoMi
Aabs'biyTJuSSufa rs.
_ lUr pKhdrto j. VT..Awlmw P. X Balbft <* P. Kfl d Jofww jibiwrflUirmfc ami Kngfnenfog Gmtar Car their li
f A*
1. <7. & rMan* XOOXXMfc Ctat-UUNi Mrt: MESt'(llB^ik
X, aw SnaoAW. C, V. X i Tmo% IL F. W,
v* * m (loo**. ^
(1961);
& BtorMrG, aswTawjou tl F. F,/. AppCCt(k twfa 13^ MS (196$).
7-&*iar. F, Sax* U P, amoUm* F* SMmrlll, 511 (1990).
A Bara* 1% "AstatM IUmV Oom-PnEtO, K^r Torlc (196$).
4. Beam ft, Am, Wnrmh&l
* --
ia Bowo* ft L, axo Tvmjt, a F. JMftMaieFffi* 6^i$r(l9m).
1U Bmxomc* aw, Aim nATAaryX,^ljfcjr9ff.rmrfw $5, J$0 (196S).
___
IX Pmnc.rr. a 17, axo Tbmuak, j,AM&lfflnw>Bir4fr 48T(19577.
-
lLBaan^ IX H, hpcr NSau 1-V ftrfirt.CWtiiww Ac riqctei and CTuinlrtl> f
^ IflwnK 196T.
1m rrruited at Am.
(Wwiw, St Louie, Mo, % 1L
: Ckuxrr, I. J, Am. / //;*. /. 26, 10 < 1066).
1$ Claw, F. W, axo Soixrrom, E. A, Am. /. Set Srr. 3, A 509; 405; 45$ (1990).
17. Dnv W. A, Ilowi* X A, axo Zomtxx, J. *ltoek Tormiag Mineral*" Vol $ and X
\Vfler, New Tod: (1001).
IX Dbaa Faro* M, Fk D. The** IMvcnttjr of Lourmin (J06S).
IX Paimm, C, axo Paimajit, M. S, Can. Iffttfag /. C9 187 (1917).
20. Facit, G. T, and Fahut, J. J, V. X Ceol. Smrrtf, Profem. Ptper 39/-A (1002).
tl. Fautt; C. T, axo Nact, B, Am. UtmnhflH 4Tt 617 (1966)..
XL PAwn C. T, axo .Vact, li, V, X GmL tnmftPn/im KpxlW<l (1967).
,, ^
m. FBakow, J. J, Wn*4 U*8. Ltmtfm , TBf 14*< 1966)7' ' rr ~
w T^'
24. nuance X E, Brnron* J. A, Howie* j, AaoBeani It E, Iticrg; CfWaa. 166P
(1067).
25. Cac* R, Axo. <V. T. A/vd. 3d. J3X *$-50 (1965).
26. Cmokjita, X P, Giiawjma, O. G, axo Pinowar, A. D, Ibprr Na. H OM
Cmfcrraec o tfie Hi>ita and ChemWry of Aifmloc MlnmK 1967.
27. Ham, A. L, CTkIm X A. flcpC. UAwt Oat Urn 01* .Vroa. IX 9M (1990). M. ITamiiwvJ. 9, Am. Pf. 7. Amt Set !$X 91-47 (198B)Ct >
2X Haim* U. X, Cfear. Pt TmwKm 288 (1085)er.,V. vv^'*-v "
$0. lfermr. PC. W, Ann. .V. 7. Amt SeC. 132, Ait 1,12-22 (1006).
31. flour, P. F, axo Claiuc, X G, Mafm 1SS, $87 (1900).
9X ffoocaow, A. A, M/Xfn* Mag. fendm 3X 201 (1606)b
SX IfoiMaM* A. A, "rffnona SlBeaJrV* fb|of Awf. CVna, tiiftn Lrvfnm, MciwrciA*
fcpc* ioox
3L Iaatixc, W, axo MnunoanTxv, X A, CamyX IW. 19^ 017 (1627).
3X Jauxaraj* X
UnpnMWinl rnferrmtim. ^WMamlb Bcwnrdi * Rnglmti*^
Cewinr, Manvlfb, Pfew Jetarjr.
36. ITin.ee* J. J, axo Trrmi. D. A, /. Ctiem. Xw. 193X 41*1
37. Iaww, A, axo Fi nn, ISpcr Ka, 2*2, (Kfnd (Wnm m (be 1W<. ml Chnw*
blip nf
Nflimls 1067.
3X f.vxeff. J. fl, rap-r
m /. Afr fWXrfon Cttmtirf At
DOW 07032
nq/It001S
JUTOTT MWAUi IX MOCOCt maiNOWWT
r
A, KbMTtKOTA, K. X, A.N FtCSOMAT, A. D,
-- w-v N*. 1-t, Orfoed*'
Ar Apia iid ClwiiMiy of Atbttln MiwnK 1907. -
`TfcewfacM 4% 001(1901).
^ a* ww* a/w. ter. a* vmxvtMK a*C,AwZcrno,ai*,/. rf*Cheeib8l,4 (MOO).
_____
, .
C, Jftetvb forte* If. 1 A* After VOftc I and 11,488(1088).
-------- ---
-, te* R. V, am Klcv, IL P,, Aw Mlmenkfkt 43, 09O(lie0fc
.r. A, J*mt IL W,, aw
9, Aw.AftetesA ^
4RlK*?BEbw Gevl 40,901 (190S)c.
Of. JUm^R^aw l*mt T. F, Am. Jflnewfogftf S7 1038 (1990). 4fcr)UP<A^ifcir4Awl>WB^ir.lUilwJfterf0he51jTlt(10t>)i-
48* Xa K. H,
Wwwfcgtrf 8,307 (1998)^
0OTteu,Tr, aw ICntenm, H, .VKrlwwcli/lWl^W> (1080)L-
ft Novm^L J*V. & hM 1jMTjOOfc
-*f/
SB. Mnnn j. IT, aw Tuoamat, It L. hpir Nb. f-S, OiW OmTwn-m
T~ Tbyeieo aiOMmy f Aibcete iiwiKJWff '
SB. Fte^r. L, /. n*. Chem. 9* 801 (NBV
^ssse&r
r.U/.r*i*cftfffct30<nsi)^~
F>.t*,/.rApr.Cftc.90k9ST(109lfcr: * i F. L, aw Ibnacimn, G. P,, /. Afi Cheat. 00,1118 (1190).
J7.. Tvxmmcx, F. L, aw Icnnainia, C. P, U. S. Patent 1304,197.
'^SaiateSs
SSL Akimc^ F. L aw IriMiaiCMi, CL P, U. S. hint 9,1733L
90. terfm for GuyMtfle Admin Fiber.* Quebec; Aabcrioe Mining
mg**' tel W, (1008).
00. Hmnairmt, CL P, UnpublMtcd Information, John*-M.im[flo Reeeiucn Sr Enstnrrrfnf
Center, MamrflV, New Jcncp.
81. Rmnaicssn, CL P, and Wrascrs SL W, Unpublhbcd Information, JlAwManvOfo
Retouch A KagrnecTfng Center, ManeOIr, Mew Jcmp. 01 Rotato, D. V, "Aibcttoa, Id Imlattrial AppfteaUon** Rctnbofct New. YoAt (199)).
03. Rot, ft, aw Rot, D. M, Am. itUxrttnsfti 31037 (1934). 64. Rtxjca*, J. W, Caro*. j, aw Wenntrrepr, M. C, M. fctf. Chem. 31 1087 (1948).
89. Stnct.UA, D, Uupubtlahed Infr-nnatlon, John#*Mam1lle RcreorcH- ft Khgfneertng Center^.
Mur*file, New Jcteep.
98. Sr*it, S, Ormccmiammim, f. II, Pa, J. A, aw Daws, It, U. 1 Bomn Mince*
IWt rupee 091 (1818).
07. Town, A, Comp*. Jleml. 101 *31 (1339).
88. llwwtw It U Idper I-8, Oxford Conference on the Htyatoe end ChemMip of Aabcrioe Mbtereh, 1007.
80. TkMMne^ It t, Riper 1*9, Otftnl Conference on the Phytlca and Chcmbttp of AlbiWo Mineral*, 1007.
m TVwxtkh, U *w lfrtum, J, W Cheat. 91,479 (1919).
71. 17. 9. l>pt. of Agriculture, Agriculture and Commatten Service, The IVttMde Rorlow, 1901
T8. Warkw, B. X, aw Biwen, W. U, Z KH*. f% SOI (1930). .
78. Wamuw, B. R, aw IImuuw, K. W, PAge. Rev. SO, 099 (1911).
74. Wkko, T. J, UnpuMtihn! (nferimtlbtv JefiwMonvIIte Iteeeotch end Cagliieering Center,.. XfoitWRe, New Jereep.
71 Wurea, T. J, aw TxiKiwratn, J, p. Paper No, 97, Oxford Oonfereneo on the Hgihr and Chetnbtry of A<UelM Mfnerali, 1007.
78. 'Vnrrrr*, R. J, \V, Arte Crgt. 8, 747 (1931), ft 371 (1998), % 83* (MB, MS
(1030), 18t MO (1037),
77.
VfVti48rrl*TU9AMtma.t,m. Kt..enmJ.u
Wlai%,p
Paper |.4V8e
No.
!!,
Oxford
Cenfcrmee
on
!*f
Rn*xfci
ami
ChwtitrT
DOW 07033
I
9
i ntWkmras & ). W,
i
7g,\TtawoM II, Ckmi% J. il st, r*
(rk.Y*MK, Ac* opf. m tot(iwn&*;
SSUTam^I. c, UnpdbJkM frft
. Mwttt Ww>Jwfl ' -
ML^twMk cl j, am r. n.
5T, *ft{19san..c. tsw^cl;
R, AXvGuo^lt,
S T 0 0 I1751
t * t i i ii >
i
*
i
\
i
DOW 07034
T39. '/ 7-C/*eJ
COMMOMeAWTH OP PCNNtVLVANIA DtPAHTMCNT OP HfAITM
OIVISIOM OP OCCUPATIONAU HfALTM
if HTOIAMIC INPOmtATION OUlOt NO. T
o
-JL
AStVITOS
(,
-*
PnortVTIILk
/Apaaa* in loapaaf ml a aaaitor af flffnrM aiiaaraln aklak arr alllrataa af
k1 toatratfy ar* af 8 fartaf M
nHIcatn,
Tlttfltorf rtorartrrf*W U a niiactara catpan#4af la*fb.parallal, flailkle lltorm,.,
eapaMa af irprutrM Ua*fca4ial naMWIalaa. Maay varirtla* ata aafTkWaity '
(lnM la W nfmm rat# pan a
aa attfUM Milllr awckbary. MaaafaciarlajUi-
p>wiw raa raa*a ill* taiaatal la kml ip iaia mtmf alaala partial#*.
THRK5M0I.I) MVIT Ml.IT. (arrapiaU# ataaapbark e
paMh
S ailllaa panic Wa pn nkk faat afaiv.
.
aairatiaa far Uaa wark
-4 C/1 IV)
'; i
...
i/V
*.a .
*aU,
kmmcai. Asrwrrfc
r.^rroat--___ _....... ..
l^ip ratiaaa4 iakaltlaa af aMK%il9PfMK'lN___
iaaia kaaaa a* akawk 1W piaafillKrif aaak Milalia la a ettfbtaa
ary flbrnai*. \ rktacmlatfa ffa4fay aftakataala l ito pciaatea af
<K>. **to4lrM hi the laa*n mi apt--. Caaiplrw raetnataltilc a4y af
>kmt mi ki.topattoUpIral Haftay ara aacaaaaryft atakflak tto prcaata - j
Him 4 Uran*. Rwt aladWa itokt* a fefMta nrtaitaaafclp katwta* iahatatlto
af antoaiaa awl i mcrt af tka laajr. hi atoitfti platal irf partita#I awaottotta--
kite Wat lawiaiad .ill iakaltlaa af aatoaiaa.
PRrVKRTICW:
a. Prrplmremrni: Orrapt laaaf Umary la aaacaaalty. A eatplai# pkyatcal r.--iaaiina, kUkir a chat mpt ilnM W --plaalaat.
k, Frtimdir F.xmmimwtimm: A pkyalaarilidtowlipilka aWk a 14 s
i kt a<ay flfca, atoaM W phat mmtMCBMk.GkMttHka*%prakala| rkav. kw acranto 4mU ka nKfiaRMa laplljiwijrit'faip (ioa aa4 mHiralH rralaaiat paMk*^
:xpwii: cnRTRai.i
a. All to*ifrato:lap apartlaaa atoaM to aqafppaJ arflk taaal aakaaat vaaiifailaa. fkw. palkk laaftlaa ar wpipilw af tto aprctlaa toaU to itonaf, iriW> .Ilk tW aa* af vat arlMh
k RatWapiap *toU to aihiaM vhb a claw tc pnitMkftp taia af lapwiifl 4al. Varwaa laalfcafa af cWaafag a ptfccito. <-kaaM to prrfanaat "oll-nliill" or *toa Waal npanw la pint panatal aaaM arrar*
. Ikaia nitor ankW. af raeiral t at faaaIkla, tot raapfnaara, af a ippa ppra.at by ik# I'A Barra# af Wan ft prtatfaa iHm paaaan aalaatwpr(.lariat 4ata, *toaU to aapplM fa ttoaa --play a aafcjaalat la ito <laa MaapWif,
I. \ p*ri"Hi< Irtrnaiaaiina nl tto tot W*la t tto plat Mawpkn. 4aM to to In mala ito xlfWWanr l ito eatral awanaria la at,
- lif t* -
lull, ion11 P Rr\. i *#
f
DOW 07035