Document Y4xKm53ewJLm68je75YE2Y28
FILE NAME: RT Vanderbilt (RTV) DATE: 1966 June DOC#: RTV007 DOCUMENT DESCRIPTION: Book - Nytal, Published by RTV
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FOREWORD
With talc now being recognized as a major
component of ceramic whiteware bodies and paint
formulations and finding increased use in other
industries, we have decided, during this our 50th
anniversary year, to put in book form our accumu
lated knowledge of this valuable and versatile raw
material.
.
Although some of the information in this book emphasizes Vanderbilt materials, there is much that is of general interest to those who are concerned with the use of New York State talcs.
R. T. VANDERBILT COMPANY, INC.
June 1, 1966
The following are registered trademarks, U.S. Patent Office:
AGER1TE CAPTAX DARVAN
ETHYL zimate METHYL TUADS METHYL ZIMATE
NYTAL PEERLESS
pyrax
SULFADS TRU0D0R VANCIDE
VANSTAY VEEGUM ZETAX
Table of C ontents
Page
I
INTRO DUCTIO N..........................................................
2
II H ISTO R Y .........................................................................
2
III GEOLOGY & MINERALOGY
3
IV PR O PE R T IE S................................................................. 4-8
Composition
4
1. Chemical Analyses
General Appearance
4
1. Raw Ore 2. Ground Talc
Grades of NYTAL
6
Physical Properties
1. hardness
2. m
3. sp ecific Gravity
4. B ft
5. Seneen Analyses
6. Particle Size Distribution
.
7, Optical Properties
8. s t a y Diffraction
6
.
V CERAMIC SE C T IO N ................................................... 9-16
Pyro-Physical Properties
9
1. P.C.E. 2. Loss f it teftfion
3. Theroflpfnsion
4. Eutectica w e s
5. Effect tftsftic le Size
S. Differentia) Thermal Analysis 7. Thermal Decomposition 8. CaO-MgO-SIO, Triaxial
Use in W hiteware
1. Semi-Vitreous Ware 2. Vitreous Ware 3. Preparation of Casting Slip
4. Glaze Ingredient 5- Mold OustingCompound
13
'
Use in Refractories
14
1. Theory of Cordlerite Bodies 2. M gO-Al,0,-SiO, Triaxial
VI PAINT SECTION ........................................................ 16-20
VII VIII IX X
XI
RUBBER SE C T IO N ..................................................... 20
PAPER SE C T IO N ......................................................... 21
SPECIALTIES SE C T IO N .......................................... 21-22
GOUVERNEUR TALCCOMPANY
NYTAL Control
Flow Sheet Bottom Loading of Silos
P L A N T ......... 23
23-27
VANDERBILT NORWALK LABORATORIES.. 28-35
XII REFERENCES
36
I INTRODUCTION
I t is the purpose of this booklet to cover the talcs of the Gouvemeur district of New York State. Talc is the common term used for this product but it must not be confused with the pure mineral talc.
NYTAL& is the trade name of the talc as produced
by the Gouverneur Talc Company, Inc., subsidiary of the R. T. Vanderbilt Company, Inc., New York, N. Y.
II HISTORY
The State of New York ranks first in the United States in the production of talc and as far as is known, St. Lawrence County, or more specifically the Gouverneur area, is the largest producer of commercial talc in the world.
Talc mining in New York dates back to the last century. The first discovery of today's producing talc deposits is believed to have been made by a
Colonel Henry Palmer, a participant in the Cali fornia Gold Rush of 1849. Colonel Palmer1 tells of his finding a white rock which he found suitable for paper making. In 1S78 he and associates opened up the first commercial talc mine in New York S tate on the Nelson Freeman farm near Talcville.
From this humble beginning grew what is now
considered to be the most productive talc area in the world. In the fall of 1948, Gouvemeur Talc Company, Inc., began producing talc from a new, completely modem plant at Balmat, New York. With only two producers of talc in the State, gov ernment figures do not reveal the actual tonnage produced. However, it is reliably estimated th at several hundred thousand tons of talc are shipped annually from this area, approximately half of this am ount going to the ceramic industry' and half to the paint industry. A small amount goes into the rubber, paper and miscellaneous industries.
Figure No. 1 shows the location of this Gouver neur district.
Figure I -- Ne- York Talc Area 2
I ll GEOLOGY & MINERALOGY
Talc is usually thought of os a soft material, and
Enstatite
Taic
pure talc is the starting point on Mohs' scale where it is indicated as having the hardness of one. How ever, New York tremolitic talcs -- meaning talcs
4MgO-SiO._. + H.0 + CO.-------3MgO4SiO. HjO + MgCO,
Tremolite
Talc
containing appreciable amounts of combined lime
CaO3MgO4SiO, + Hs0 + CO. --3MgO4SiO. H.0 + CaCO,
-- are quite hard, running as high as six on the Mohs' scale.
Petrographic and X-ray examinations of ores of these deposits have shown them to contain
(
three principal minerals:
Ries, Tarr and Lfndgren3 have pointed out that
Talc
3MgO 4SiOs H,0
SiO, 63.5%
these talc deposits ocoit'kx .schistose layers of en statite and tremolite glMdtslly merging into the
MgO 3 1 7
HsO
4.8
surrounding crystalline fimestone. The most abun dant country rocks of this area are pre-Cambrian
gneisses, the greater portion of which are impure. The limestones have been replaced locally by ensta
Tremolite CaO 3MgO 4SO.
SiO. Mg CaO
57.7% 28.9 13.4
tite and tremolite which later were altered to talc,
Antigorite 3MgO 2SiO, 2H.0
SiO. 43.5%
this change being represented by the following
equations:
(Serpentine)
Mg 43.5 H-0 13.0
STRUCTURE CONTOUR MAP OF THE F00TWAUS OF THE TALC BELTS SHOWN BELOW. Contour Interval 100 Feel Datum Plane 1$ Approximate Sea level-
EXPLANATION
rouwtt Talc Schisi
E2
Sillcalsd And Pontic Mrbtc
on
Amphibolite
5trke And Op Of Foliation
BlUiiit 4*
Zinc Mine Americjtnj
'
Mine
(J T trfrrT T n ^
GEOLOGIC MAP
6tjKM00 0
Fig. 2-- Geological Features Of The Area North Of Balmat, New York
Copyright ^ By A I M E
3
In addition to the above, many calcium and magnesium bearing minerals may be present in small amounts such as calcite, dolomite, magnesite, brucite, apatite, gypsum, phlogopite, periclase, and hexagonite. Therefore, it is quite evident th a t these
talc deposits may easily contain two or more min
erals in greatly varying amounts, depending upon the extent to which the above reactions have taken place. Extreme care in blending is, therefore, essen tial in producing a satisfactory commercial product.
Mineral Composition of N Y T A L 100
Early in the development of the "NYTAL" ore
body, samples were submitted to the Department of Geology, Columbia University and they reported the following mineral composition:
Talc
-- On the order of one-third
Tremolita -- On the order of one-third
Antigorite --Less than one-third
Magnesite -- About 5 per cent
Apatite -- Minor constituent
Periclase -- Minor constituent
Brucite -- Minor constituent
Phlogopite-- Minor constituent
At a later date Dolomite, Calcite, Hexagonite, Rhodonite and Gypsum were also found to be present in minor amounts.
Engel- states that the zones of commercial talc pinch and swell, and curve in sinuous to complexly folded patterns, as shown in Figure No. 2, but are rudely conformable with adjoining marble layers.
The talc zones have a composite strike length of
more than five miles, a probable extent down dip
in excess of 2,000 feet, and widths of as much as 400 feet. Dips along the talc belts are quite vari able, ranging from the horizontal through the ver tical, but averaging about 45 degrees to the north west.
Variations in thickness of the talc belts or of
any included zone may be either abrupt or gradual. The belt near Talcville, which contains one pro ducing mine, varies up to 300 feet or more in thickness, averaging perhaps 135 feet thick in the mines. Much of this thickness is commercial talc. A talc belt north of Balmat and southeast and east of Fowler, along which are 2 active mines, varies up to at least 425 feet in thickness, and averages possibly 125 feet, figure 2. In this belt, however, one of several zones of commercial talc 6 to 25 feet thick, or rarely as much as 75 feet thick, are interlayered with impure or discolored non-commercial zones within the belt. Within these two belts are talc reserves sufficient to last several generations a t the present rate of production, under resourceful mining methods.
IV PRO PERTIES
Composition
Talc has the theoretical formula of 3MgO 4SO. H.O 31.7% 63.5% 4.8%
1. C hem ical A n aly ses NYTAL, being a tremolitic talc, has the average
chemical analyses as follows:
PERCENT NYTAL NYTAL NYTAL NYTAL NYTAL NYTAL 99 I0Q 1Q0HR 200 300 400
SiO.
57.3 56.6 56.6 57.5 56.5 57.5
MgO
28.4 29.4 29.2 28.3 29.0 28.4
CaO
8.0 7.6 8.0 7.2 7.8 6.8
Fe.O,
0.3 0.3 0.3
.2
AI.O.
0.6 0.5 0.5 f 1'5
.7 \ l*
MnO
0.3 0.3 0.3 0.3 0.2 0.2
Na.O
0.3 0.2 -- 0.2 -- 0.2
Ignition Loss 4.8 5.1 5.1 5.0 5.6 5.3
100.0 100.0 100.0 100.0 100.0 100.0
General Appearance
1. R aw O re
As previously stated there are many types of ore blended to produce the usable commercial talc. The two most distinctive types are a hard, grey, massive type mined for tf|% ceramic industry (Figure No. 3) and the sofL ihlny, foliated type mined for the paint industry Ifeigure No. 4).
There is a great difference in the chemical com position of the three major minerals. There is also a vast difference in their physical and pvro-physicai properties. Rogers and Kerr' give the following description of these three minerals when viewed under the microscope.
"TALC occurs in coarse to fine platy or fibrous aggregates. Talc greatly resembles muscovite (mica) and pvrophyllite. I t may lie necessary to make a chemical test in order to prove the identity of talc."
"Tremolite occurs in long prismatic crystals and columnar to fibrous aggregates. Asbesti-
4
RAW ORES
Figure 3-- Hard Ore
Figure 5-- Nylal 99.
. Figure 4-- Soft Ore
form varieties are common. Tremolite has the same general appearance as wollastonite."
Antigorite occurs in anhedral crystals or aggregates of fibrolSrjtll+ir structure. It often occurs as pseudomotpirs after pyroxene, oli vine. etc.:' A wide variation in the unctuousness of these minerals has proven to be the physical property hardest to control and one of the most important as it greatly affects both pressing and casting prop erties of ceramic bodies.
1
I
Figure 6-- Nytal 100
Figure 7-- Nylal 300 5
2. G round Talc
Figures No. 5, 6 and 7 show photomicrographs of 325 mesh residues of NYTAL 99, 100 and 300 respectively. Print magnification = 90X.
In their study of Gouverneur talcs, Stemple & Brindley* state:
"Electron Micrographs have shown th at talc particles exhibit a variety of platy forms and fibrous forms also exist. Single crystal electron diffraction patterns have proven that the fibrous particles consist of a close associa tion of talc and tremolite with a simple orien tational relation between the components. I t is shown that this relation can be interpreted in terms of a simple structural transformation from tremolite to talc."
Grades O f Nytal Talc
NYTAL 99
Coarse Fraction of NYTAL 100
NYTAL 100 Present Standard for ceramic tile
NYTAL 100 HR Special for Casting Slips
NYTAL 200 NYTAL 300
Coarse gr&und Paint grade Fluid-energy ground Paint grade
NYTAL 400 Super-fine Paint grade
Physical Properties
1. Hardness 1 to 6 on Mohs' scale
2. pH
9.2 to 9.8
3 & 4. The Specific Gravity And Bulking Data on Grades of Nytal Talc
GRADES
SPECIFIC GRAVITY
BULK LBS. PER CU. FT.
LOOSE COMPACTED
NYTAL 99
289
65.
79.
NYTAL100
2.84
50.
71.
NYTAL100HR 2.86
51.
73.
NYTAL 200
2.85
28.
53.
NYTAL 300
2.85
22.
50.
NYTAL 400
2.85
12.
36.
6. Particle Size by Sedimentation
NYTAL 99
Finer Than 49 Microns, % 67 Finer Than 28 Microns, % 46 Finer Than 22 Microns, % 39 Finer Than 15 Microns. % 24 Finer Than 11 Microns, % 19 Finer Than 7.7 Microns, % 16 Finer Than 6.3 Microns, % 15 Finer Than 5.1 Microns. % 13 Finer Than 4.4 Microns, % 13 Finer Than 3.6 Microns, % 13 Finer Than 3.1 Microns, % 13 Finer Than 2.8 Microns. % -- Finer Than 2.6 Microns, % -- Finer Than 2.2 Microns, % -- Finer Than 1.3 Microns, % --
NYTAL100
81 63 52 43 35 31 26 23 21 20 18 18 18 13 12
NYTAL NYTAL NYTAL 200 300 400
Finer Than 20 Microns, % 86
95
....
Finer Than 10 Microns, % 62
73
93
Finer Than 7 Microns, % 49
58
81
Finer Than 5 Microns. % 39
46
66
Finer Than 3 Microns. % 29
32
46
Finer Than 2 Microns, % 25
25
35
Finer Than 1 Micron, %
24
Figure No. 8 shows particle size distribution of all NYTAL grades.
5. Screen Analyses
% RESIDUE
NYTAL sa
NYTAL 100
NYTAL 100HA
On 20D Mesh 2.0- 3.7 2.1- 2.8 1.7- 3.0 On 325 Mesh 190-26.0 15.0-25.0 15.0-26.0
NYTAL NYTAL NYTAL 200 300 400
0 2 0.00 0.00 Max Max Max 2.0 0.0$ 0.0
91 9 1 U 9 M 99 91 IS 90 10 70 GO SO 40 30 20 10 S Weight Per Cent Finer Than
Figure 8-- Particle Size Distribution. Deter mined by Hydrometer Sedimentation.
<5
7. Optical Properties1
PURE TALC Mg.COHJ.lSfO-l.
n , - 1.333 to 1.543
Moticac
4J-<?)
n\ - 1.575 to 1.590
n - U 75 to 1.590
IV - 6 to 10 : O p t ( --1 tt or V. 4 ~ , or Z, c i
Cotar--Cotorleu in thin section*. Form--'Talc ocean ir cosre* lo fine p!*ty c t fibrous aggregate* (hat often h ire * mere or few parallel arracfefnenL Shreda and platee are often beat. Euhedra) crystal* of Ulc ara unknown.
Figuro 9-- Orientation O iu n m i o f Talc. Sections Parallel |o (a) (0 0 )) and (b) (0 (0 )
Cfeange perfect in one direction JOOl). Rriief fair a > baham. Birefringenct vary strong, a --n -- 0.030 to
> * 0-050: the maximum interference colors are upper third order. Sections parallel to the deavage give
rtry to1 R nt-onkr gray colots itnct n -- n ir
item 0,
7
exlrnrtion a parallel to the
dV#g
mwi cection*; in a few eectionr
the
is S or 3 -: hence Ulc Is probably
monodin ic.
Orumtatian -- Cleavage traces and shreds are
Unfth.jclnw ax in muscovite.
Fifura--Cleavage flake* fire hi*
axed
figure nth mall u ia l angle.
> > c distinct.
DUitngutfhing fm iu rrj--Talc greatly resembles
muKokitc and pyrophyttite. hut may often be
riblingutdird hy the smaller axisl male provided
an interference figure cm 1 ohtamed.
It may be necessary to m ike a chemical or
fliicmchcmscal text in order to pros- the identify
of (air. The association with other magnesium min-
vmla Indicate? (hr presence of (air rather than
muA'orite or feririte.
f)rvorwk*e--Ta Ic u the principal constituent ol
talc achLxtx and wipxtdne.. It U often a hydro*
therm it mineral formed >t the expens* of antigorite end irematilc In shear tones of terpentine*.
DoinmUt* and magnetite arr frequent ajwcutrx.
*
TREMOUTE-ACTINOUTE
C a.tiM g.Fel.fO H l.lS i.D .,),
MonocUnic
3 -- 7 4 :48`
n - l .$00 to 1.536
n - C613 to 1.644
- 1.523 to 1.655
2 V * "9 1o 55 : Opl. (-- ) b -- a or V. C > or Z -- -- 10 to --201 Cofor--Coloriej* In pale green in thin reerfonx. The green varieties ho* faint pleoebroum. Crecn ferriferous tremolite i known a aetinalifc.
Foret--Tremnlite-sctinoUte occur in long pris matic crystals and columnar to fibroin aggregates.
T r a n OPTICAL MINERALOGY by Paul F. Kerr. 3rd Ed.. Copyright < 1959. McGraw* Hill Book Company. Used by Perm ission.1'
A*bti/omt n rie tta ir t coBmwn. Ths typlal crou section it rhombic with U10 110) Si*.
Figure if l-- O n caU tion Diagram o f Tremo* Itte-Actiaoltic. Section! (a ) Normal lo the
c-A.xlt and ( b ) Parafiti (a (0 1 0 )
Citai?! f ilo ] in l* o dirtctiooi at ancia of about 5$ and 1241. Longitudinal sections show
detract tiara* parallel to tht length. Then may
be partine parallel to (1001.
Relief fairiy high, n > bakam.
Birfringente moderata to rafher strong, ny -- n* --0.022 to 0.027: w the totetfmnc* cobra rance
up to Io or middle second order. Narrow longitudi*
rial sections chow the highest colon. Crocs sections
havs white to yellow interference colon.
The maximum extinction In loogf* tudinal sections varies from 10 to 20*. A few loop*
tudinal sections have parallel or nearly parallel ex
tinction. Cross sections here symmetrical extinc tion.
OnVnretica--Doftfated crystal* are length-slow.
lo cross sections the long agonal lx the dourer
ray.
^
Ttcinnlng ^ T w im with (100) as turn-plan* ara
frequent. Fme polyryntlioiic twinning with (00)) as twin plane Is oeeorihnsllr cnaonterad.
interference Figure -- Tremolite-actiaotitt fires
a biaxial negative figure with very* large axial angle.
T he axial plane U (010). Dltperrion, r < u weak.
Breed <lso gat* sections with (aw interference colon
give f e h b s t figure.
D M ^ k is h ln f Feature!-- T k t
angle
end sjnphibole cross sectrias jl^/elw ^cteristlc.
WcUastonit has the same general appearance as
the trace of the optic axial plane is
m m i t la (he c h a n g e instead of parallel to it as
la trs$di!i*
--A colorless ampbibole, eden*
tie, greatiy resemble* tremofite but has larger ex*
tinetion angle*.
Alteration -- TremoUte-eciinotite Is sometimes
found altered to tale.
Oecumnce--Tramoiite-tcltnallte occurs in con
tic t-metatnorphic deposit*. in schist* and gneisses,
and in meutnorphic limestones, (t is also-found as
a replacement of pyroxene in igneous rocks.
*****
H.Mg.Si.0.
ANTlGORiTE (Serpentine in parti
Orthorhombic - 1.-535 to 1.66$
n - 1.362 to I.ST3
n rw 1.562 to 1.573
2V *- 20 to 90 : Opt. f --I # f i s t Y . f - 1 o rX . e - > o r Z
Color--Coforlc* to pal green in thin sections. Form--AntifOnte occur* in anhedral cryalaU or
aggragatu of fibroUmctlar structure. I t often oc curs as pseudemorphs after pyroxene fbastite).
!
Figure Z2-- O rientation D iagram o f Amigo, rite. Section Parallel to (010)
Figura J J -- (X 20) Atutgorltc in Serpentine (X Nicol)
obrine. etc.
Relief rather low. n > baisara.
Bbttriitgenet weak ft --n -- 0.007 to 0009;
the maximum Interfere* cobt a finl*ordec yel
low. This yettaar is aCghtiy aflomalous since it has
a freeishjfrtffk Fxfincffoo
OiMntaf9^ 'l % i : Ssystak ira length-slaw.
Interference ftg e n t^ T h e figure is biaxial nega
tive with varisble axial angle. The srial plane is
[100]. Disperrioo. r > c weak.
-
DittinguisStng features -- Chrysatik is distin
guished from its dtmarph antigoiiie by the fme
fibrous structure. Afttijrarite usually shows aggre
gale structure m l is in practically all eases an
alteration product of some other sfocate mineral.
Serpophitt has lower txnfrm pnca than anligorife
and shows little or no form or structure.
OcTun-raCf--Antigorite ii the main constituent
of terpentine, a melsmori^ic rock. I t has bran
formed from olivine, ratatil*, augite. etc., hy
hydrothermal alteration. Cammart s*socit*s are
cho*5otlfe- talc, magnelite. chramite, snd picotite.
SEftPOPritTE
HtMf jO,
(Serpentine in past) n 1.50-1.57
Amorphous (MbaraVaid)
Cater--Colarle to very pale green in thin sec tions.
Form--Massive, almost stractundesa. often oc curring in coses surrounded by intlgoriie.
Cicecog* ahcenL Relief very low, n > balsam, n < antigorile.
Birefringence nil to very weak, not over 0.003.
Interference colon: either non* or very low first order p a y .
ifinrti<wi--The extinction of $rpophlte is mora
Figure 14-- (X23) crpophlle (ClearSm ooth Areas) and Antigorile (Rough C ray) With
Secondary Mauctlie in Serpentine
7
1
i
i
Figure I S -^ Sarpop h llc (B lsck or Otrfc
i
Crmy) WUh LetiUcuTar A nilin rit in Serpca*
`
tine* {The Sitne Spot as Figure 1 4 .) (X
IYicoU )
at Wfry od Usuali? relhrr indefinit*.
r ta lu n i -- Strpophiti u distici*
gmsgd
th other serpentini rainetals by ita
veiy &ikk Creinojence and ita teck ol inietta*.
OccurrrncY--etpopbilt ia ut* ef th coutitu-
eoti ol serpentine {usad bere m a rock nana). It
is usuili? inlimttely utociaU d *ri(b antifantc,
HM| jS.O.
a
CHRYSOTltE Oithoriwmbie
- 1.493 io 1.546
n ti, -- 1-504 lo 1.550 rt - 1.517 to 1.557
2 v ' - 0 io 50 ; O pt i - i
CWor--Colorirsi in thin secticns. F orn-- C h ryaqtile DCcurs in <ro-l3)er rinkts. RtU tf low, n tightly freltcr than baisela. Brt(rnf*nce moderate, ny -- n -- 0.011 to 0.014; th roaxoium interferente color u brighi yelhnr of th firat crder. frtZnrfi&ii parsSet Qrknlatin--Tb (beo are kjigth'tlo*.
F ig u re 1C --' ( X 3 0 ) Chrrtgrile Yeialeti in Serpentine With Secondary H*fitltte
Distingimbing F n iu r tt -- The other fomu of
-m'hm gi ilrercioUl, antbopfayliiie, and croridoltte)
*f! b^-s; fjJ|..her indices of refraction than cbrywKUe.
oblique extinction.
d ^ r im e r --Chrysotile usually occurs In vetnfeu
t
that constats largely of the mineral
ntijrarite.
`From O P T IC A L M IN E R A L O G Y b y P a u l F. Karr. 3rd Ed.. C op y righ t @ 1959. M c G ra w Hill Book Com pany. Used by Perm ission."
Studying New York talc from Fullerville, Wright'-' disagrees with published optical data on talc. He also states where talc and tremolite occur there is no transition zone. Rather sharp bound aries of each are apparent.
8. X-Ray Diffraction
Dr. Ralph J. Holmes'' furnished the NYTAL 99 and NYTAL 100 curves shown in Figure 17 along with standards.
NYTAL 99 is lower in Antigorite and higher in Tremolite than NYTAL 100. This is confirmed by their chemical analyses shown previously.
8
V CERAMIC SECTION
IN T R O D U C T IO N
Talc is one of the most versatile raw materials used in ceramics today. By proper compounding' very low or very high thermal expansion bodies can result, depending on s o e 's need. By other com pounding excellent eleetrlcal insulators result. Dur ing the past forty years talc has changed from a minor constituent to one of the most widely used materials in the whiteware field.
Pyro-Physical Properties
1. P. C. E. of NYTAL 100 -- Cone 16
2. Loss on Ignition--Figure No. IS shows relatively low ignition loss of N. Y. talc compared to th at of Texas talcs.
3. Thermal Expansion
New York talc, due to its mode of formation con tains little or no free silica. This condition results in a thermal expansion far more uniform than that of other ceramic materials such as clays, feldspars and pyrophyllites which contain varying amounts of free silica.
See Figure No. L9.
4. Eutectic with Feldspar and Nepheiine Syenite'
Figure No. 20 shows the effect of NYTAL 100 on the fusibility of N orth Carolina feldspar and Ca nadian nepheiine syenite. Four parts of feldspar or syenite to one part of talc form the eutectic point.
5. Effect of Particle Size on Absorption of Electrical Porcelain Body.
Flint
22%
C-6 Conn. Feldspar
30
OM # 4 Ball Clay
15
Bell's Dark Ball Clay 10
PEERLESS S. C. Kaolin 10
Lunday N. C. Kaolin
10
NYTAL Talc
3
Emrich & Hannon* show th at the finer the grind of talc the more vitreous the body becomes. This effect is shown in Figure No. 21.
ion
nn
moo
isoo
non
zaio 2100
rnpMtur*
Figure 18-- Ignition Loss on Texas Tates and iSvlni Talcs
Figure 19--Thermal Expansion of Raw Materials
9
fcr Cent NftjJ 100 Tjk
Figure 20-- Fusion Behavior of Nvial 100 willi A-2 Feldspar, Kona Feldspar, and Sye
nite
6. Differential Thermal Analysis-- NYTAL. 99 and NYTAL 100. Dr. Robert L. Stone7 reports: "The legend on the thermogram (Figure No- 22) will serve to give the mineralogical compositions. The main difference in the two samples is that NYTAL 100 contains consid erably more anthophyllite than NYTAL 99 plus, possibly, additional species of amphi boles. The amphihole-serpenfine suites that are possible in a talc rock are almost endless, and this renders interpretation very difficult. For example, anthophyllite and tremolite which
are constituents of the talc, are both amphi boles; and I think there is another amphibole in these two samples. The reasoning is this: (1) anthophyllite has fhe exotherm a t about 300"' plus a doublet endotherm a t about 1000e but none at 650 - ; (2) tremolite has a weak reaction (endo) at 700 plus a strong endo at 1100'; (3) some amphiboles show a moderate endo at 650' plus the endo at 1100*; (4) ser pentines, particularly chrysotile. show the 650 endo plus a strong exo at S3QCC, the in tensity of which varies with crystallite size; (5) the 850-700 endo in the present samples is larger than would he accounted for by the small amount of i-alcite plus the chrysotile; and (8) the endo at 1100 is a doublet. I might add that the unlabeiled endo at 7507 may be attributed to either an amphibole or to a ser pentine-- it doesn'l coincide with a peak of
10
Figure 21-- Effect of Particle Size of New York Tale on Absorption of Electrical Por
celain Body Fired to Cone 6
any mineral in my collection which would occur in talc ore." Pask-and Warner' state th at DTA is the most informative method for determining the composi tion of talcs because of the sensitivity of the sam ples to thermal effects and lack of complete de pendence on regularity of structure.
7. Thermal Decomposition of Pure Talc
Ewell, Bunting & Geller'" summarized their in vestigation as follows:
"A sample of a nearly pure talc was investi gated both unheated and after heating a t 18 temperatures from 340- to 1,435* C. The studies included the determination of heat effects, weight losses, and changes in true spe cific gravity occurring on heating talc. X-ray and microscopical examinations were made of the heated samples.
W ater in excess of 1 molecule was mostly driven off between 3S0 and 500*C. This water loss was accompanied by a small endothermic heat effect, hut not by any change in crystal structure or optical properties.
The molecule of combined water was driven off between 800* and S40:C. This water loss was accompanied by a large endothermic heat effect and an increase in true specific gravity from 2.S3 to 2.91. and hv breakdown of the talc into enstatite and amorphous silica.
Inversion of tl% enstatite to clinoenstatite took place grad#rfy, both phases being ob served in material heated at I,200: C, and only clinoenstatite in material heated at l r300,:C. The material heated at 1,300`C also showed conversion of the amorphous silica to cristobalite. Thus, the final products of the thermal decomposition of talc are clinoensta-
tite and cristobalite. There was a further gradual increase in the true specific gravity tram 2.91 to 3.01 on heating from S40- up to the highest temperature, l,43o~'C.
The data support the hypothesis of Foshag and Wherry th at water in talc in excess of 1 molecule is not- constitutional and may be held electrostatically between basal cleavage planes." Paul Eno" reports from his study of NYTAL 100 that
"T h e principal phase present in the fired talc is clinoenstatite. This polymorph of cnstatite is found to form pseudomorphically from the talc with the original form and grain size of the talc remaining essentially unchanged."
An unusual phenomenon occurs in the heating up of New York talc which aids in it heing used as a reliable ceramic raw material. As stated pre viously when talc is heated above Cone OS it in verts to clinoenstatite and cristohalite. Tremollte inverts to clinoenstatite. diopside and cristohalite15. No information has been published on the action of Antigorite under heat but thermal expansion curves indicate it also inverts to clinoenstatite.
Therefore, it is to be noted th at although one starts with three different minerals, upon heating ahove Cone 06, only one principal mineral phase remains, namely clinoenstatite.
This is graphically shown in Figure No. 23 where the moisture expansion is affected considerably by firing a high talc body to Cone 06 and 05 with little or no change in shrinkage and absorption.
11
8. CaO-MgO-SiO, Triaxial
SiO;
System CaO-M ^OSiOt (prim ary phases and iso therms). Mertv--merwinite: Mo-- monticellite.
R . U \ R icker an d E . F . O sborn, J . .4 m . Ceram . Sac.. 3 7 [3] 134 (1054).
MgO'SJO,
IM gO -S iO j
fi CaSiQj 11 CoO SiOj
2CoO S.O, IJO *
JCoO S.Oj
J 12
Figure 24
System CaO-MgOSiOr,- showing composition triangles (revised). Short cross lines along metasilicate and orthosilicale joins indicate maximum e sten t of solid solution. Mo--monticellite. Menv --inerwinite.
R . IV. R ic k er a n d E . F . O sborn, J . .4 m . C eram . S a c.. 37 [3 | 134 ( 1954).
I
I
I I
U se in Whiteware
4. Low firing temperatures are possible.
1. Sem i-V itreous W are
5. Fast firing schedules are possible---as fast as one hour cold to cold.
Emrich'1 reports that the greatest amount of
6. Shrinkage and absorption of bodies are fairly
ceramic grade Neiv York talc goes into the semi
constant over a long temperature range.
vitreous whiteware field, especially wall tile. I t has been found to be an ideal raw material for the fol lowing reasons:
1. The formation of enstatite produces high ther
7. Good white fired bodies are possible.
8. Glazes of unusual brilliance and attractiveness can readily be fitted to high talc bodies.
mal expansion bodies resulting in glazes being put
in compression which in turn tends to prevent crazing.
As far back as 1936 HagarM reported the im proved craze-resistance of semi-vitreous bodies when New York talc was used.
2. Low moisture expansion bodies are produced
resulting in good resistance to delayed crazing.
A minor use of talc is as an addition to the clay-
3. The hard, massive nature of the ore aids in flint-feldspar type of dinnerware bodies. I t is added
either dry-pressing or in the making of good casting up to 6% of the body resulting in greatly improved
slips.
craze resistance.
Flint
NYTAl 99
.
NYTAL 1Q0HR
Ball Clay
HS PYRAX Pyrophyllile
Whiling
Woilaslorite
PEERLESS Kaolin
Feldspar
Georgia Kaolin
Firing Range-Cones % Shrinkage % Absorption
TYPICAL SEMI-VITREOUS BODIES
Wail
Wall
Wall
Art
Tile
Tile
Tile
Potteiy
1?
5
35
70
67 .
43
24
30
28
30
16
B
5
12
10
3 5
03-1
03-1
021
0.0
1.0
0.7
8.5
16.5
13.0
13.4
10.0
Art Pottery
64 32
4
06-04 6.2 18.7
Dinner* ware
33
4 32
10 It 10
78 11.0 8.5
2. Vitreous Ware
Another minor use of talc is as an auxiliary flux. Emrich and Hannon'1 state there are two factors which influence the effect of talc:
(1) Its eutectic point with the principal fluxing agent
(2) The fineness of grind of the talc
Both of the above factors were taken up earlier in this booklet.
Dolomite AI.O Flint Feldspar NepheJine Syenite Belt Clay PEERLESS Kaolin N. Carolina Kaolin Florida Kaolin English China Clay NYTAL 100
Firing-Cone % Shrinkage % Absorption
High Alumina
3 85
3
6
3 18 18.5 0.0
TYPICAL VITREOUS BODIES
High Alumina
Electrical Porcelain
Vitreous China
90
22
36
30
17
25
a
5.5
10
10
10
10
11
4.5
3
B
27
9
10
13.0
13.3
14.8
0.0
0.0
0.0
Sanitary Ware
Translucent Artware
18
5
27
46
25
15
16
25
8
6
9
10
4
12.0
14 7
00
0.0
13
; is
J
I
3. Preparation o f C o n e 06-04 Artware C astin g Slip
Batch: NYTAL 100 HR Talc
Term. 5 Bali'stSay
v p l u c k y OM 4 Ball Clay
p o r te d Whiting
64.0 tbs. 16.0 16.0
4.0
100.0
W ater
44.0 lbs.
DARVAN - 7 dispersing agent 0 .0 lbs. 14 oz.
Sp. Gr. 1.800
Oz,/ Pint 29.98
Mix 4 oz. of DARVAN with all th e water. Due
to the slower wetting property of talc, it should
be soaked prior to making up the complete
slip. Slowly add th e NYTAL to th e w ater while stirring and then allow the talc to soak for a t least Vi Ijoui _
After jrSsli' sg. the rem ainder of th e DARVAN is added n, -n the ball clays and whiting are added while stirring and the batch is thoroughly mixed until a sm ooth 411)-is produced.
The am ount of OrRVaM m ay vary due to dif ferences in local 4ett!9K
When m ade up fM hi*' -way, an excellent sta ble casting slip for feats: drain and solid cast is produced.
Figure No. 25 shows the effect of soaking of talc on the amount of dispersing agent re quired.
figure No. 26 show t th e effect on th e vis cosity of sanitaryw are slip when talc is added to the body.
Pgr CM Sodium Sftieitc Plui 0.8% c tJ j Ocfacculanl No. 5
Figure 25-- Efferl of Soaking of Talc on the Amount of Dispersing Agent Required
14
Figure -6 -- Effect on the Viscosity of the Sanitaryware Slip When Talc Is Added to
the Body
`'Jasper" Flint A-2 Feldspar Ky. Tenn. Clay Co. # 4 Ball Victoria Ball Clay Martin #5 Ball Clay Lunday N. C. Kaolin " PEERLESS" Kaolin "NYTAL" 100 Talc
S-l
18.0% 33.0 10.0
8.0 7.0 8.0 16.0
S-2
18.0% 25,0 10.0
8.0 7.0 8.0 16.0 8.0
4. G laze Ingredient Talc is used in glazes as a cheap source of MgO
whenever magnesia is called for in the formulation.
5. M o ld D u s tin g C o m p o u n d To help mold release of large castsvare pieces
finely ground talc is used to dust the plaster molds before pouring of the slip.
U se in Refractories
1. T h e o ry O f C o rd ie rite B o d ie s Whereas high talc bodies give the high thermal
expansion characteristic of enstatite, these are un desirable where a material is exposed to frequent temperature changes. Thum auer'" has this to say on l i e formation of low expansion cordierite bodies:
"Strangely enough, talc again comes to the aid of the ceramist and ceramic materials with extremely low coefficients of thermal expan sion are made by using talc in correct propor
tions and in combination with other raw ma terials.
For a better understanding and explanation of this fact, let us look a t the three component system ALO^-MgO-SiO., shown in Figure 27.
We have drawn a straight line between two jttngii, "A" and "B". Point "A", situated on -i& tm gO 'SiO , axis, represents the position of pure fired talc and point "B ", on the AL,0., SiOj axis, shows the position of fired kaolin
in the triaxial system. Ail possible combina tions of mixtures talc-kaolinite fall on the line connecting the two points "A" and ,;B". It can be seen that bodies high in talc fall into the field of clinoenstatite crystallization and it is a known fact that clinoenstatite crystals are prominent in steatite bodies and their inter
locking structure gives the high mechanical strength peculiar to this type of ceramic ma terial. The high thermal expansion of steatite
bodies is also due to clinoenstatite formation. If the magnesium silicate content is de
creased and aluminum silicate increased cor respondingly, we come into the field of solid
solutions of cordierite crystals, which is sur
rounded by the five eutectic paints of the three component system. Mixtures within this field have a very short firing range and, there fore, are extremely hard to fire to vitrification. It is a generally known fact th a t ceramic bod ies whose chemical composition are close to a eutectic mixture are commercially not prac ticable. Accordingly, in order to get workable
bodies, it is necessary to move down the line further until we get into the field of mullite crystallization. Bodies within this field and with a talc content of 30 to 40 per cent can be fired satisfactorily. The optimum propor tions of magnesium silicate and aluminum sili cate vary, depending upon parity, crystalline structure, fineness of raw materials, etc. Bod ies containing talc up to 40 per cent and fired to approximately 1300 deg. C. contain cor dierite crystals in appreciable quantities. Cor dierite is known for its low coefficent of ther mal expansion and such so-called "Cordierite
materials'' have indeed very low coefficients of thermal expansion. They can be heated to red
2. MgO-AhQj-SiCh
System M gO-A l;Oa~SiOj; revised. Bused o a th e crim inal w ork oi G- A . R an k in an d H . E . M erw in, A m . J . S c L . 4 th S e r.. 4 S , 3 2 2 (L 9 I8 J ; m o d ifie d b y X . L. B ow en an d J . W . G rief, J . A m . Ceram . Soe., 7, (1 9 2 4 ); m odified b y J . \\*. G rie f, ib id ., 13, 12 (1 9 2 7 ); m odified b y J . F. Scharrer, ibid.. 25, 24 L (1 9 4 2 ); m odified b y \V . JL F o ster, ibid., 3 3 , 73 (1950); an d b y K eith and S ch airer (below ). R ecent studies by \V . R . F o ster, ibid.. 3 4 , 2 5 5 (1 9 5 1 ) in d ic a te t h a t t h e field la b e le d *`C Iin o e n sta tlte** s h o u ld re a d " p r o to e n s ta tite ."
M , L. K e ith a n d J . F. Schatrer, J . C to i., 60 (2) l$ 2 (1952).
MgO A ljO j iSpnl> a ia s tz o '
2 030*20';
AI^O* i925j c r 2 030**0"
3Aiz03 2Si02
(Mull lit) 1610 ttO*
2 M g O -2 A I2Q 3 '5 S i 0 2
F ig u re 2 7
?MgO SiO , (ForsieM el
1890* o '
MgO SiO , A (Ciir>oentc'"ei
l555s5'
15
heat and then dropped into cold water with out spalling or cracking.
In the process of firing ceramic products, a complete, or even nearly complete, equilib
rium according to the phase diagram, is never obtained and usually certain crystal forma tions, traceable back to the raw materials, re main unehgflgfcd in the fired article and have a pronouffiid effect upon the properties and
crystal structure of the fired product Fur thermore, the raw materials used for ceramic bodies are by no means chemically pure, but contain impurities such as iron oxides, alka
line oxides, titanium dioxides, etc. These im purities may act as fluxes, lowering the firing temperature of the ceramic material and in creasing the amount of glassy m atter in the fired product, or they may act as mineralizers for a certain crystalline phase. In our case, therefore, the three-phase diagram, MgO
ALOj-SiO,, serves only as a guid for what can be expected in a ceramic body Consisting of talc day mixtures. In actual practice, re actions occurring in a ceramic body during firing are much more .complicated and it is only by empirical methods that the most suit
able composition of a ceramic body can be determined." Hagar & Thiemecke': both showed in early in
vestigations the longer service life resulting when New York talc was added to saggers.
TYPICAL REFRACTORY BODIES
Low CaO Talc Ball Clay PEERLESS Kaolin U S PYRAX Pyrophyliite Calcined A ls0, Calcined Georgia Clay Saw Dust PEERLESS Sagger Clay Oak Hill Fire Clay Medium Grog Coarse Grog PYRAX Granules
Firlne Cose
Heater Plate
Radiant
Sagger
lab Sagger
35
30
9
8
20
15
21
30
20
10
10
5
10
15
29
13
20
21
2B
21
16
16
11
10
6
8
VI PAINT SECTION
A. What Is Talc?
The word talc means different things to different people. There are many materials th a t are like talc in appearance, or feel, or other properties. Among these are pyrophyliite, asbestos, diatomaceous sil ica, pumice, calcium silicate, and some forms of mica. However, to the paint chemist and paint formulator, talc is hydrous magnesium silicate. Furthermore, talc is so defined in the four popular specifications which will be mentioned later in this discussion.
B. Unusual Paint Properties of Talc
1-- Talc is chemically inert in paint systems. 2-- Talc has excellent suspension in paint, rarely settling to more than a soft pigment layer that is easily reincorporated. 3-- Talc is probably the easiest pigment to dis perse--most all grades wet down and disperse to their ultimate fineness by simply stirring nr low speed mixing with the vehicle-
C. The Paint Grades of NYTAL
1--NYTAL 200 is a relatively coarse grade of talc as indicated by its screen analysis which runs
between 1 and 2% retained on a 325 mesh sieve. It produces medium consistency in paints. This is an inexpensive NYTAL for use where paint fine ness and film smoothness are relatively unimpor tant.
2-- NYTAL 300 is a smooth talc giving medium paint consistency. It stirs in to a 4 Hegman fine ness. I t is the popular talc for house paint, flat paint, emulsion paint, and all coatings where paint fineness and film smoothness are important con siderations.
3-- NYTAL 400 is a superfine talc with an aver age particle size of about 3 microns. It stirs in to a 5 Hegman fineness. This talc is generally used by a mix-in process to increase body or to decrease luster without hurting film smoothness.
D. Functions and Uses of NYTAL in Paint
1--NYTAL has many functions in paint. The formulator uses it as an extender pigment to build proper consistency and application properties-- to give desired flow and leveling without sagging. NYTAL literally gives paint the "painty" feel un der the brush. It disperses so easily it may be stirred into an otherwise finished paint for the pur-
16
pose of raising the consistency a few points--or to adjust gloss and sheen.
6-- NYTAL 400 is used wherever high paint fine ness and a smooth paint film is reqttid, This stir-
2-- NYTAL has a variety of desirable character in pigment can be incorporated as the last ingredi
f I
istics. The dry brightness is high, color in oil is ent, if desired, by simply mixing into the otherwise
good, color in water is good, tinting strength is very
finished paint. In this way it serves as a formulat
low-- thus it does not impart muddiness or gray ing tool to adjust a batch of paint to the desired
ness to whites or light tipts. NYTAL wets very consistency, sheen, or other special property. A
easily in all paint liquids such as organic solvents, popular use is in semi-gloss paints, enamels, and
varnishes, alkyds, water. I t disperses readily in lacquers where it functions as a dulling agent to
paint systems, frequently requiring no more than
provide the desired level of sheen or gloss. Since
moderate stirring. NYTAL is chemically inert in
NYTAL 400 may be stirred into the finished paint,
paint systems. It has excellent suspension and
it is very handy as a means of adjusting the batch
helps suspend other pigments, thus retarding their
to the requisite gloss level. A t the same time, it
possible tendency to settle hard.
^ ritfjb u te s to good brushing and sag resistance
3-- NYTAL is used in nearly all types and kinds fe well as aids suspension of all pigments. Table 1
of paint -- primers, undercoaters, flats, eggshell, shows the dulling effects of increasing amounts of
semigloss -- interior and exterior -- lacquer, floor NYTAL 400 when added to a high-gloss alkyd
paint, traffic paint, roof paint, house paint, trim
and trellis, patio---paints for all surfaces-- organic solvent thinned paints; water thinned paints.
4-- NYTAL 200 is used in coatings where paint fineness and film smoothness are either not impor
Table 1
NYTAL 400 Reduces the Gloss of Oleoreslnous Enamels
tant or where some film roughness or "tooth" is
Pounds of NYTAL 400 60* Gloss
most desirable such as, for example, interior wall
per Gallon
primers, undercoaters, sfnd texture paints. Large
None
65
quantities of these talcs go into traffic paints as
0.4
80
specified by the various states.
0.6
54
5-- NYTAL 300 is the general-purpose extender
0.8
37
for all kinds of paints. Its popularity is due as much
1 .0
24
to its uniformity of quality as to its ease of disper
1.2
14
sion. good film smoothness, and all-around talc
properties. Probably, the largest single use of
NYTAL 300 is in linseed oil house paint. Most white house paints contain a substantial amount
enamel. Note that about a half-pound of the NYTAL produces a semi-gloss, and one pound or
of talc--on the dry film basis about 15% talc by so dulls the paint into the flat range. Furthermore,
volume and 25% by weight. Yet this amounts to the film smoothness is maintained because the
only 4% of the raw material cost. There is usually NYTAL 400 has a high stir-in Hegman fineness.
more talc than titanium dioxide, or lead, or zinc, or any other pigment in the film. Only the binder
7--Another popular use of NYTAL 400 is to adjust consistency of finished paint. NYTAL 400
is present in greater amount. W hat does all this
NYTAL do in paint? Well, first, as noted before though not necessarily of prime importance, it helps
has high binder demand, or oil absorption, so a few tenths of a pound per gallon stirred into the paint will raise the consistency appreciably. This
pigment suspension in the can and provides the scheme is becoming more and more popular in the
desirable consistency for good application proper manufacture of linseed oil house paints.
ties. Further, in combination with the other pig
Table 2 gives an example of such a paint to
ments present,, the NYTAL promotes excellent which were added increasing amounts of NYTAL
durability: the film weathers slowly and uniformly
by gentle erosion or chalking, and eventually pro vides a most desirable repaint surface. Also, white ness is maintained throughout the long film life because NYTAL is not discolored by wash-down from iron or copper screens or hardware.
Many white exterior latex and emulsion paints
Table 2
NYTAL 400 Increases the Consistency of Linseed Oil House Paint
Pounds of NYTAL 400 per Gallon
Consistency KU
contain NYTAL as the extender pigment. The rea
None
76
sons are the same as for the linseed oil paints,
0.2
79
namely, good pigment suspension in the can, proper
0.4
83
application consistency and feel under the brush,
0.6
87
good white color throughout the life of the paint
0.8
91
film, and clesirahle repaint surface.
17
400. Bach two-tenths of a pound of talc caused a consistency increase of about 4 KU.
8--NYTAL 400 is gaining attention as an ex tender pigment. It is heing used in high loadings--
is a good paint to illustrate the importance of uni formity of a raw material such as NYTAL 300. A typical formula meeting the requirements of this specification contains almost three and a half
in several cases as high as four pounds per gallon. pounds of talc per gallon. This formula was pre
Here the paint chemist is taking advantage of the pared with seven samples of NYTAL 300 represent
easy dispersion of NYTAL. He can grind his prime pigment and then simply stir in the NYTAL 400 to give a fineness of 5 Hegman. Or he can easily
ing the allowable deviations from our standard. Table 3 shows these listed as A through G. The
push the fineness up a Hegman unit by normal milling on roller, pebble, or high speed stone equip ment. These paint have outstanding properties
Table 3 NYTAL 300 in TT-P-25a Linseed Oil Primer
of suspension, brushabilitv, leveling, controlled sag,
TT-P-25a Formula
and uniformity of film sheen or semi-gloss.
NYTAL Relative NYTAL Consistency Critical
E. Production of Paint Grades of NYTAL
300
1-- The production of NYTAL is carefully con A
trolled with regard to color, screen residue, paint
B
fineness, dulling efficiency, and paint consistency
C
or binder demand. The minerals are processed in
D
several steps--by crushers, pebble mills, fluid en
E
ergy mills, separators, classifiers--all arc used in
F
our modern talc plant. At regular intervals, auto
G
Consistency Plus 3 KU Plus 2 KU
Plus 1 KU Standard Minus 1 KU Minus 2 KU Minus 3 KU
KU
PVC
85
48.3
83
49.7
82
50.3
80
51.4
79
52.2
77
53.5
76
54.5
matic sampling devices withdraw portions for lab oratory testing. Each step of the process is care fully controlled so that the NYTAL entering the finished product silos is uniform within narrow specification limits.
2-- Our plant engineers have developed a novel procedure for filling these silos in such a way that the incoming NYT.-U. is intimately mixed with the talc already present in the silo. Anyone who has tried to mix two dry powders will appreciate the importance of this discovery. W hat does this do
for uniformity? Let us consider the consistency control test we use at our plant. A complete lin seed oil house paint is prepared with each mill
sample. The titanium and zinc pigments are pre dispersed in some of the oil to form what we call "white base." The mineral spirits, the drier, and the balance of the oil are mixed together. The NYTAL sample is simply stirred into this vehicle. Then the "white base" is stirred in to finish the paint. After adjusting the paint to proper tempera ture, the Stormer consistency is determined. Our specification- limits for our NYTAL 300 grade are
second column shows th at these samples deviate by one, two, or three KU from our standard by our consistency control test. The consistencies of the TT-P-25a Specification formula made with these talcs are given in the third column. Note that the increments of consistency are very much like those listed'in column two. But the last column might be of most interest to the paint chemist. This show's that a NYTAL 300 uniformity of plus
or minus one KU (samples C and E ) will be equiva lent to a variation of only plus or minus 1% criti cal pigment volume concentration. Even a t plus or minus 3 KU spread (samples A and G) the NYTAL 300 produces a variation of only plus or
minus 3% critical PVC. It should be noted in pass ing th at TT-P-25a allows a consistency spread of 75 to 90 KU-
2--Another example to illustrate the importance of this uniformity is given in Table 4. The same seven samples of NYTAL 300 were used to make an acrylic emulsion paint. The formulation con-
plus or minus three Krebs Units from our standard
NYTAL. This means that the consistency of the NYTAL entering the finished product silo is within three Krebs Units of standard. As it enters the silo, it is blended with similar material. The net result is that the NYTAL 300 coming out of the silo for bagging and shipment is even more uniform--its consistency spread is now only plus or minus one Krebs Lfnit.
F. Uniformity of NYTAL
I--This uniformity of NYTAL is of utmost im portance to both paint chemists and paint manu
Table 4
NYTAL 300 in Acrylic Emulsion Paint
NYTAL Relative NYTAL
300
Consistency
Consistency Critical
KU
PVC
A
Plus 3 KU
79
52.6
B
Plus 2 KU
C
Plus 1 KU
D
Standard
E
Minus 1 KU
F
Minus 2 KU
79
53.0
79
53.5
78
54.0
78
54.6
78
55.2
G
Minus 3 KU
78
55.6
facturers. The zindess linseed oil primer TT-P-'25a
18
tained to pounds of titanium dioxide and two
and one-quarter pounds of NYTAL 300 per gallon
a t a pigment volume concentration somewhat be
low the critical level. The data show that these
seven paints had essentially the same consistency
--the maximum difference being just one KU. Of
even more importance was the narrow range of
critical
volume concentration--only three
per cent. Fuftlu rmore, where the NYTAL 300
uniformity is plus or minus one KU (samples C
and E) the variation in critical PVC is little more
than plus or minus one-half of one per cent.
G. NYTAL Meets Talc Specifications
1-- Many federal, state, and municipal paint specifications require or allow the use of mag nesium silicate talc pigments. Frequently the type of talc is specified. Usually these paint specifica tions allow the paint chemist reaaom^de latitude in the selection of the talc. Since most hf the paint specifications have fineness requirements, it is usually advantageous for the paint chemist to choose the talc that has a stir-in fineness similar to that required by the paint specification. In fact, one of the reasons for thp development of smooth talcs and superfine talcs was for the use in specifi cation paints having high Hegman fineness re quirements.
2-- NYTAL meets the four popular talc specifi cations as follows:
to specific surface. Another drawback is the infini tesimal sample used in the microscope count. What assurance is there that the sample is representative of a pound, much less a bag, of the talc? The same
objection applies to both air permeation and gas adsorption methods -- only a very few grams of sample are used per test.
2--Probably water sedimentation is the best of the available methods. For one thing, a sizeable sample is used per test. Secondly, it is rather simple to run. And most important, the measured data indicate particle size distribution. The word indi cate is used here because the sedimentation method assumes th at all particles are spheres. However, we are dealing with anything but spherical particles as Figure No. 28 shows. Note the dominant shapes are fibres, rods, plates, and irregular nodules- You could probably count on the fingers of one hand the total number of truly spherical particles in a 50-pound bag of talc. I t should be pointed out th at Figure No. 2S does not necessarily indicate either the size or the frequency of the particles--only their various shapes.
ASTM D605
NYTAL 200. 300. 400
Federal TT-P-403a NYTAL 200, 300, 400
Maritime 52-MA-523a Type I NYTAL 200, 300
Type II NYTAL 400
Military MIL-P-15173A Type A NYTAL 300. 400
Type B NYTAL 200. 300
H. Particle Size
l--There are various methods for measuring particle size, such as air-permeation, gas adsorp tion. micioscope count, and sedimentation. Ac tually the first two named measure merely total pigment surface area and provide no information on size distribution. Pigment surface area, or spe cific surface. is a useful figure because it indicates relative hinder demand, or oil ahsorption, and therefore consistency. Microscope counting is so
intricate and difficult as to be impractical. Under the microscope, one can see the individual par ticles and count them according to size. But the observer must ho sure he is examining a representa tive field. Wu know that talc pigments are made up of pari k ies of many shapes and an infinity of sizes: therefore, perhaps us many a? a dozen differ ent fields would h a v e to he counted to assure an average dklriluitinn. This would he an extremely tedious and time-consuming job. Furthermore, it is most difficult to relate microscope count data to per cent distribution by weight, or volume, or
Figure 28--Shapes of Nylal Particles
3--A deficiency of the water sedimentation method is that it does not accurately indicate the size of particles much smaller than two microns. After all, there is Brownian movement at that par ticle size and smaller, and this behavior upsets the settling laws upon which the sedimentation test is based. Now the smaller the particles the greater is their percentage of specific surface. For example, let us assume that 1 0 7 by weight of a talc consists of particles less than one micron and th at there is a gradual decrease in size to almost zero. It can be demonstrated by rather simple calculation that that 10*7 would account for a larger percentage of specific surface than the 9 0 7 larger than one micron. Anti yet the sedimentation method does not measure this important 1 0 7 of the talc. The effects of relative specific surface are manifest as oil absorption, liquid demand, and paint consist
19
ency and these properties are more easily, directly, and q u ic k ly measured by actually making a paint
with the talc sample. Finally, the coarse end of
the particle size distribution can be measured more
easily and directly by screen tests of the talc and/or Hegman fineness of the talc stirred into
vehicle or paint.
4--The purpose of this brief discussion on par
ticle size distribution of talc is to bring out three points with regard to production and use of these pigments. First, such data as can be measured do
frequently indicate similarity, or differences, among various talcs as materials but all too seldom are the data relatable to pigment and paint properties.
Second, in the production of talc, particle size dis tribution is an impractical control test because it
requires hours for one detealnallon whereas con
trol tests must be run in minutes. Third, we rely on more direct pigment tests to control production so as to supply our customers with NYTAL pig ments that give uniform performance in the coat ings made by those customers-
VII R U BB ER SECTION
U ses In Rubber And Vinyl
Talcs are used by the Rubber Industry as dust ing agents to permit easy factory handling of nor mally tacky compounds in process, and rs fillers in compound design, Vinyl formulations also list talc as a filler in such applications as insulations, extruded gaskets, calendered films and tile.
In handling uncured stocks in process, the talc may be spread over the rubber by brushing ot
other suitable means. I t may also be applied by dipping in a water suspension of the dry powder. In making up talc slurries for dip tank use, a small quantity of DARVAN No. 1 (1% by weight in the tele) is recommended as the wetting agent. Mechanical agitation is generally used to hold the talc in suspension.
ButyL rubber insulation and latex foam are typ ical applications for talc in commercial compound ing. The following are representative formulas:
HEAT and MOISTURE RESISTANT
INSULATION
Butyl 035 .................................................. _...100
Stibin; At .................................. ....... I
"Zi-t'-'z 13,ski' .................. .................................... 5
FsVsMiu ....... -.................................
2
m TAL 4QD .......................... .................. .......... 50
Cotcfcetf C la y ......................................................100
Litharge ..... ................ ............. ........................... 5
SULFAOS ............................................. .......... 3
METHYL ZIMATE............................................... 3
CAPTAX ......................................... ..................... 1.5
270.5
LATEX FOAM CUSHIONING
Rubber (5 0 /5 0 N a tu ra l/S B R )..................... 100
Potassium Oleate ........................................... 1.4
Zinc Oxide ......................................................... 5
S u lfu r................................................................... 2
AGERITE WHITE .................................................... 25
AGERITE SPAR ............................................... 1
ETHYL ZIMATE ..........................................
1
ZETAX ......................
1
Sodium Silicofluoride .......................................... 6
NYTAL 2 0 0 ....................................................... 50
162.25
Talc filler applications in Vinyls are as listed:
INSULATION
PVC (Electrical Grade) ................................... 100
PM halale Plasticizer ...............................
55
Whiting ................................................................ 15
NYTAL 200 ........................................................ 15
VANSTAY Stabilizer .......................................... 1.5
Color .................................................................... q.s.
REFRIGERATOR GASKET
PVC Resin (Extrusion Type)...............................100 Polymeric Plasticizer .......................................... BO Epoxy Plasticizer .................................................. 10 Whiting ..................................................................... 25 NYTAL 200 ............................................................. 50 Color ..........................................................................q.s. VANSTAY Stabilizer ............................................. 2
VINYL-ASBESTOS TILE
PVC Copolymer Resin .......................................... 100 Phthatate P la stic iz e r............................................ 2S Epoxy P lasticizer.................................................... 10 Stearic Add .......................................................... 1 Whiting .....................................................................125 NYTAL 100 ..............................................................100 7R Asbestos ...........................................................100 Titanium Dioxide ................................................. 15 VANSTAY Stabilizer ............................................. 4
SHEETING
PVC Resin ............................................................100 P hthatate Plasticizer ........................................ 30 Polymeric Plasticizer ........................................ 5 Epoxy Plasticizer ............................................... 5 Fatty Acid P hthalate ...................................... 4 Calcium S tearate ........................................................5 NYTAL 200 ......................................................... 20 Whiting ................................................................ 15 VANSTAY S ta b iliz e r.......................................... 2
20
I
VIII P A P E R SECTION
The Use O f Nytal In The Paper
Industry
NYTAL is used as a filler in some grades of paperboard and molded pulp products because of its good retention, chemical inertness, white color, and TAPPI Brightness of SS to 90.
NYTAL 200 is the most common grade of talc
th at is used for this filler application. Since NYTAL tends to be abrasive in nature, the amount used is limited to small percentages. Generally, about 5% NYTAL (based on the weight of the fiber) is considered maximum in board mill appli cations.
IX SPECIALTIES SECTION
The ultrafine, airmillad grades, NYTAL 300 and NYTAL -400, are suggested for pharmaceutical and cosmetic applications. Their excellent white color
and fine particle size permit these talcs to be readily and uniformly mixed with pigments and modifiers for use in cosmetic and pharmaceutical formulas. They are easily suspended in liquid media and dispersed in creams and pastes. Special ties Department Technical Literature contains many product formulas illustrating the use of NYTAL 300 and NYTAL 400 such as Liquid M atte Make-Up Base, Cream Eye Shadow, Pre Shave Talc Stick, Acne Cream and Aerosol Foot Powder.
CREAM EYESHADOW #128
% bywt V6BSUM (Vanderbilt) ............................ 1.75 M Wats i ................................................... 33.45
Sodium carboxy-methylceilulose B (low vise.) .......................................... 0.10
Water .................................................... 9.90
DARVAN s i (Vanderbilt) ..................... 0.30 Propylene glycol ...................................... 5.00
Water ......................
6.00
NYTAL 400 (Vanderbilt) ..................... 18.00 q Kaolin .................................................... 2.00
Titanium dioxide...................................... 5.50 Iron oxides ............................................... 4.50
Stearic acid ...................................... ... 0.80
Glycerol m o n o s te a r a te ..................... 2.00
r j L a n o l in ............................... . . . . 4.00
Sesam e Oil
.
.
... 2.00
Olive Oil
........................................... 1.00
Isopropyl m yristate .......................... 3.00
F TRUODOR Jasm in = 6 (Vanderbilt)... 0.30 Preservative ........................................ q.s.
Procedure:
I. Add th e VEEGUM to the w ater slowly, agitating continually until smooth.
II. III. ' IV. V. VI.
VII. VIII.
Disperse the CMC in w ater.
Add I and II to C. Mlcropulverlze 0 .
H eat E to 7 0 =C. Add IV to III. Hom ogenize. Heat to GO65C . Maintain tem perature for 10 min utes to allow air to escape. Add V to VI an d mix until 4 5 -'C. Add F and mix until cool.
R. T . Vaodactiill Bulletin 44. p. 17. 1964
ACNE CREAM #137
% bywt
VEEGUM (V an d erb ilt)....... - .................. 1.75
A CMC (7 MS ...............................
0.40
W ater ...................................................,,...34.60
Glycerin .................................................... 5,00 Allanloin ......................................................flUPi
E3 Resorcinol ................................................ -MO
Triton X -1 0 0 ............................................. 020
W ater ........................................................ 28.70
NYTAL 3 0 0 (V an d erb ilt)........................16.00 0 . Titanium dioxide .................................. 2.90
Iron oxides ............................................... 1.10 Sulfur ....................................................... 5.00
O Zinc pyridinelhione .............................. 0.10
Procedure: I. Dry blend VEEGUM and CMC and add to the w ater slowly, agitating continually until sm ooth.
II. Add 8 to I. ML Pulverize C and add to III. IV. Incorporate D by m aking up concentrate in
portion of finished cream, triturating thor oughly. Add this to product, milling or ho mogenizing finished cream.
R. T . Vanderbilt Bulletin =44. p. 23. 1964
21
PRE-SHAVE TALC STICK #77
a VEEGUM (V an d erb ilt)....... .......... " Water -- ..............
% by Wt 1.9Q q.s .
o Zinc stearate ..... ....................
4,70
.
Light m agnesium carbonate .............. 1.90
C NYTAL 300 (Vanderbilt) ................._ ...9 l.5 0
Procedure:
I- Add the VEEGUM to ab o u t 3 0 parts of water slowly, agitating continually until sm ooth.
II. Blend B and add to C.
III. Add I to II. Work into a sm ooth paste (add more w ater if necessary).
IV. Pack In stick mold and allow to dry.
ft- T . VmoderbiU Bui [Jo ii+ i, p- 21.1964
LIQUID MATTE MAKE-UP BASE #142
a VEEGUM (V an d erb ilt)...... ......... " Water ..........................
% by w t
O.S0 9.50
R CMC (7U>) .............................................. 0.50
Water ......................................
.49.50
DARVAN " 1 (V anderbilt)..................... 0.30
a- Triethanolamine .......
1.00
Propylene glycol ......................__....... 5.00
Water ..........................................;...... .. 8.40
NYTAL 400 (V anderbilt)........_....... 6.00
p . Kaolin .............................
0.80
Tltanrum dioxide ............ ................... _ 3.00
Iron oxides .............................................. a 20
Stearic acid .............
Jp$)
Propylene glycol m onos tea rate........... 0.10 E Lanolin .................................................... 3 ^ 9
Mineral oil .....................................
4.55
Isopropyl m yristate .............................. 5.00
c z TRUODOR Oriental B ouquet --3
'
(Vanderbilt) ....................... ................ 0-30
Preservative ....................................... q.s.
Procedure: I. Add the V ffS tJM to th e water slowly, con tinually agitating until sm ooth. II. Disperse th e CMC in w ater.
ML Mix A. B and C together. IV. Micropulverize D. Add to 111. H eat to 6 0
65 CC. V. H eat E to 7 0 3C. Add to IV. Mix until cool.
Add perfume.
American Perfumer and Cosmetics, 79. 63, Oct. 1964 *'M*kr-Up Formulas'*
R. T. Vinderbill Bulletin ir44. p. 16. 19
AEROSOL FOOT POWDER #134
Concentrate
% by wt.
NYTAL 400 ........................................................ 86 .0 Magnesium carbonate ..................................... 5.0
Kaolin ...........................
5.0
Zinc Stearate .. , . ....................................... 3 .0
METHYL TUADS (V.i.sdsrtoilt)....................... 0 .5
Isopropyl m yristate .......................................... 0.5
Packaging;
Concentrate ........................................................10 Propellent 12/11 ( 5 0 / 5 0 ) ..............................90
22
Procedure: I. Add to th e NYTAL 4 0 0 each com ponent In th e order listed with high speed mixing after each addition. Mix until uniform . II. Fill co n cen trate in to appropriate containers.
III. Pressurize with propellent
R . T . Vanderbilt Bulletin t t a . 1962
F . V. Walts and Irwtn I. Lubovs, M-D . C o m m it and I k t Skin . p. S21. (Rainhold Pubt. Corp.. N .Y .I
ACNE LOTION #122
% by Wt
a VEEGUM (V an d erb ilt)....- ..................... 0.8 0
M W ater ............
.20.00
Sodium carboxymethylcellulose
B
{type y MSP] ............ ........... .......... .. 0 .8O
Water ........... ............................. -- ........ 15.00
Glycerine ........................ .................. _ ... 5.00
VANCIDE BN (Vanderbilt).................... 0.25
C Allantoid ............................- ..................... 0.25
Resorcinol ........
3.00
W ater .................................
20.00
NYTAL 3 0 0 (Vanderbilt)..... - ................ 8-00
Titanium dioxide ................................... Z &
D lron oxides ..............................
1.10
S u lfu r ..........................................................,* M )
Triton X -1 0 0 ....... - ........
0.20
W ater ........................................ - .............16.70
e T^ g i ^ | ^ fhra B ouquet # 9 ............. 1.00
Procedure: I. Add th e VEEGUM to th e w ater slowly, agi tating continually until smooth. II. D isperse th e CMC in w ater.
III. Mix A and B together. IV, Add C to III. Add 0 and mix thoroughly. V. Add E.
R. T. YnndtrSill Bullalin *32. 1962
Hercules Powder Co. Bulletin jbVC-441 "Hercules Celluloss Gum tt Naliosol 250 in Phannacautiols"
MEDICATED CREAM MAKE-UP WAFER #125
34 by w t
D/sodlum b ith lo n a l........... ....................... 0 .5
Resorcinol ......................................
1.0
. Allantoln .............. ............................
1.0
A Sulfur (co llo id al)............................ _........ 2 .0
NYTAL 4 0 0 (Vanderbilt).......................... 20.0
Zinc oxide ......................................- ........10.0
Iron o x id e s .............. .................................. 0.5
R Polyethylene glycol D Polyethylene glycol
1,000 .......40.0 4 0 0 ............25.0
Procedure: I. B lend A un til uniform . II. M elt B and mix.
III. Add A to B and stir until solids a re uni formly wet. Pass through a roller mill.
IV. Heat to 60-70r C. to release trapped air. V. Allow to cool (45-50 -C.) an d pour into con
tainers.
Mecca. S. 0.. Free. Sri. Sect. TOA, 39. May 2963. "The Function and Applicability of the Allantoinj."
Tantoff. H.. American Pcriamtt 77, 35.38. Sept. 196T "Dstmalo-AppliciUonj ol Sulfur-bejrjne Qrramr Bactcrldde-Funiticidiu''
X GOUVERNEUR TALC
COMPANY PLANT
Gouverneur Talc Company Plant at Balmat, New York
A. N Y T A L Control
As the mineralogy of the Gouverneur area indi cates, constant testing and Mending of the various ores are necessary to produce a satisfactory com mercial product This is done from the testing of the ore in the mine right through the blending of the finished product by bottom loading of the storage silos.
Mine samples are first tested for ceramic nr paint suitability. Then ore samples are taken every three hours and tested again for proper blending. Ground samples of NYTAL from the mill are collected au tomatically and rushed to the laboratory every hour b y pneumatic lubes. The laboratory novelcloses. No shipment leaves the plant until a check reveals that it meets all grade specifications.
From the very beginning of our operations nt Gouvorneur it was evident that chemical analysis, with the exception of a lime determination, was of
no value for control purposes. As a m atter of fact, Treischel1' shows such data could he very mis leading.
The following physical and chemical tests are made at the plant and are the basis of ceramic
control specifications:
1. CaO determination 2. Acid solubility 3. Bulking
4. Screen residue 5. Fired color 6. Specific Resistance
In addition shrinkage, absorption, crazing and
shivering tests are made weekly at our East Nor walk. Connecticut laboratory by introducing a weekly sample into n standard TOG. NYTAL tile body fired to Cone I.
In this way we have been able to produce a very Uniform talc over the past eighteen years.
The Nvtal control for grades other than ceramic
is described under Section VI--Paint.
23
View from silo top shows others at right for finished products. Dust collectors are mounted on silo tops. Dry ore silos can be seen at the left. In all there are 13 finished product silos at the Gouverneur Talc Company plant.
Section where physical tests on paints are made. Note, vacuum tube for rapid receipt of plant
san,P'es
Section where Talc destined for shipment to the ceramic industry is tested for fired color and
for bulk density.
Chemical analysis section 24
Gouverneur Talc Company, Inc
Sim plified Flow Sheet
Underground Mine -- 5 Grades of Ore
Underground Jaw Crusher
(Minus 4" Material)
o
Main Shaft- -- Hoist -- 6 Ton Skip
O Surface Gyratory Crusher
(Minus 1" Material)
O
Belt Conveyor to Grinding Mill
<3^
4 W et Ore Silo s- 9 0 Tons each
<Z>
Fine Crushing and Drying
(Minus 12 Mesh Material)
o
6 Dry Ore Silos -- 500 Tons Each
Fine Grinding and Classifying Circuits
Air Conveying Finished Product to 14 Silos
<3>
Low Pressure Air Conveying Systems
_
_
Bag Packing Plant
O
Box C a rs-- Trucks
Hopper Cars and Bulk Box Cars
25
Figure 29-- Per Cenl CaO of Talc In Consecutive Shipments Under Old and New Systems
Figure 30-- Compacted Bulk Density of Talc in Consecutive Shipments Under Old and New Systems
i.s Figure 31-- 200 Mcsli Uesidue of Talc in Consecutive Shipments Under New and Old Systems 26
NTAL TALC is Bottom Loaded for Better Blendieg
Bottom Loading O f Silos
A word should be said on the revolutionary method of bottom loading of silos for the maximum blending of finished ground NYTAL. The first such idea anywhere was developed and put into com
mercial operation by Gouverneur Talc Company. McClellan reports1' th at variations in CaO con
tent, 200 mesh screen analyses and bulking have been cut in half by this new blending method.
See Figures No. 29, 30 and 31.
27
Vanderbilt Research Laborator
XI VANDERBILT NORWALK
LAB ORATORIE S
The R. T. Vanderbilt Company laboratories are located at East Norwalk, Connecticut. Here re search is carried on in many fields, including ceramics, rubber, paint, paper, fungicides, insecti cides, plastics, petro-chemicals, foods and pharma
ceuticals. On the following pages we present a pictorial
description of our ceramic and paint lalroratories.
28
t East Norwalk, Connecticut
General View of Ceramic Laboratory 2?
1
:
@
Hydraulic Tile Press
Marriott Tube Viscosimiter, Brookfield Viscosimiter and Stormer Viscosimiter
Tinius Olson Hydraulic Mod ulus of Rupture Machine
.
Control Panel for KIlnandTher-
Ii mat Expansion Furnaces
Pereny Laboratory Tunnel Kiln for Fast Fire Tile
Stone Temperature Gradient Furnace
0
Pereny Test Kilns
T
XII REFERENCES
1. P rin te d in N ew York S tar, F eb ru ary . 1890.
2. (a) , (h)
CO
W aldem ar Lindgren. " M in e r a l D e p o s it!," 3rd Edilion. M cGraw Hill Book Co., i t . New York (1928).
VV. A. T a r r . " i n t r o d u c t o r y E c o n o m i c G e o lo g y ," 1st E dition. M cCraw Hill Book Co., Inc., N ew York (1S3Q). H einrich Reis. " E co n o m ic G e o lo g y ," 6 th Edition. Jo h n W iley & Sons, New Yotk (revised 1930).
3. A- E. J . Engel, ''N ew Y o r k T a lc s, T h e ir G e o lo g ica l F e a tu re s, M in in g , M illin g a n d U se s." A m erican In stitu te of M ining, M etallurgy & Petroleum Engineers, p resen ted October 15, 1948.
4. A. F. Rogers an d P aul F. K err, " O p tic a l M in e r a lo g y ."
M cG raw Hill Book Co., In c , New Y ork (1942).
5. I. S. Stem ple an d G.iW Brindley. " A S tr u c t u r a l S t u d y o ( T a lc a n d T a lc-T rem o tite r e la tio n s ." Journal Amer ican C eram ic Society 43 [1} 34-42 (1960).
6. E . W . E m rlch and R . C. Harfhon, "T a lc a s a n A u x ilia r y F lu x in P la stica lly F o rm ed C eram ics." Bulletin Am er ican C eram ic Society 43 [3] 186-190 (1964).
7. R o b e rt L. S tone Co., Austin,. T ex as, p riv a te com m unication, A pril 1962.
8. J . A. Paste and M . F. W arner, " F u n d a m e n ta l S tu d ie s
o f Talc-. C o n stitu tio n o/ T a la ." Journal Am erican C e ram ic Society 37 [3} 118-28 (1954).
9. R a lp h J . Holmes, D ept, of Geology. Colum bia U n i v ersity . p riv ate com m unication, D ecem ber 1960.
10. R . H . E w ell, E . N. B u nting and R. F. C e llar, 'T h e r m a l
D eco m p o sitio n o f T a lc " Research P aper R P 848 N a trona! B u reau of S tan d ard s Vol. 15. Pg. 556, N ovem ber.
1935.
11. P au l W . E n o . J r . , " A n X - R a y a n d T e x t u r a l S t u d y o f th e H ig h T e m p e ra tu re P h a ses F o rm ed fro m a Trentotitle T a lc F ired U n d er N o n -E q u ilib riu m C onditions." J u n e 1964 th esis. College of C eram ics at A lfred Uni* versity. New York.
12. E gon P la n s. " S o l i d S l a t e R e a c ti o n s in H ig h T a lc B o d ies." B ulletin American Ceramic Society 43 [6] 443-447 (1964).
13. H . D , W rig h t. " A n O p tic a l S t u d y o f T a lc - T r e m o tit e R e la tio n e ." Jo u rn al Am erican Ceram ic Society 43 [1] 42-43 (1960).
14. E . W . E m ric h . " T r e in o li tic T a lc -- I t s M o d e r n R o le in C e r a m ic s ." Jo u rn a l C anadian Ceram ic Society. Vol. 31. Pg. 52-GO [19621.
15. D. H a g a r, " E f f e c t o f a T r c m o t i t i c T a lc in W h ite ic a r e B o d ie s ." Jo u rn a l A m erican Ceramic Society 19:14.
16. H a n s T h u m a u e r. ' V t i l i i a t i o n o f T a lc a s a C e r a m ic R a w M a te r i a l." C eram ic Age, P g. 148-14B, M ay 1940.
17. (a) D o n ald H a g a r, " L e n g t h e n i n g S a g g e r L i f e w i t h
Talc." C eram ic Age, Pg. 35. F ebruary, 1933.
(b) H. W . Thfemecke, " N o te s o n C one 10 S a g g er B o d ies w ith T a lc a s a co m p o n e n t." Jou rn al American Ceram ic Society 17 [1] 2-6 (1934).
18. C. C. T re isc h e l, " A v a ila b i lit y a n d C o n tr o l o f C e r a m ic G ra d e T a lc a n d P y r o p h y llite .' Bulletin American C eram ic Society 36 [5] Pg. 177 (1957).
19. R. S. M cC lellan . " V a n d e r b i l t 's N e w S to r a g e M e t h o d Im p ro v e s T a lc U n ifo r m ity b y 5 0 % ." Ceram ic Indus try , P g . 54-57, M arch 1963.