Document JJjG5VmZJz5B00zOjwYZDZzgX

GRACE Contiruction Product! Diviiion FROM: CC: R. J. Bectacchi H. C. Duecker H. A. Eschenbach 0. M. Favorito R. M. Vtning R. C. Walsh Julie C. Yang File 1184 DATF.: September i , 1983 SUBJECT: Arthur D. Little Documents In the package of ADL documents, which I sene co you on September 7. the letter dated 6/27/83 had no signature from the writer. A signed copy was just received. Please replace the whole letter with the one attached herewith and destroy the unsigned letcer. The new one Is 3 pages instead of 4, but the concent remains unchanged. JCY/ph Attachment 15137289 >82. I jmhndiiT. M* W*4.7-K| T,|,, n;uu /lL Arthur D. Little, Inc. June 2 / 198: Dr. Julie Yang Manager - Research Technologies U.R. Crace & Co. 62 Whictmore Avenue Cambridge, Massachusetts 02 ' Dear Julie: C76494 In accordance with your request of June 23, 1983, we have anal ysed a commercial sample of Monokote MK-5 (U.R. Crace & Co.) for the presence and quantity of amphibole fibers. For ehis purpose, we have defined fiber as any particle with approximately parallel sides and with an aspect ratio of 3 or greater. PROCEDURE An unopened bag of Monokote (Lot 1F1, Easthampton, MA) delivered by you was poured on a polyethylene sheet, coned and quartered until reduced to about four pounds. From this sample, one quarter waa reserved (about l pound) and the opposite quarter was coned and quartered to give a sample of about lOOg. This sample was digested with IN HC1 at 60*C to dissolve the plaster of paris (the major component). Each digestion utilized about 800 ml of add with IS min. of stirring. The suspension was allowed to settle for 10 minuees after which the supernate waa decanted with a squeeze bulb and reserved. This was repeated for a total of seven digestions, after which x-ray diffraction failed to show a plaster of paris (or gypsum) peak. As you recall, a previous analysis had shown that a lg sample of Montana Trcmolitc (asbeatlform variety) wet ground with a mortar and pestle was quantitatively recovered after a similar digestion treatment. After digestion, the residue was wet screened and washed through a 20# screen. The filtrate was added to the previous decants, neutralized with NaOH and made up to 4000 ml. After agitating, samples were withdrawn from the center of the suspension to provide seperate samples of 1, 4 and 16 ml. These were each diluted to 100 ml and filtered through 0,1 om pore size, 47 am lnnH Hm*a l.oadoa MnJna Part, RtaSaJaaaira Saa Fraariaca Saa Paata Tahya Tarawa WasMegtaa WiaabaSae 1X13729C k , /Hi Arthur D. Little. Inc. junt 11, iya3 -3- Dr. Julie Yang Manager - Research Technologies U.K. Crace & Co. Fiber mass concentrations are calculated by Fibers x Fiber mass (?) ^ 1000 ml (sample) 100.2 g (sample) 1 ml (aliquot) I 960 mm~ (tilCcir) 81 x 10 * mm" (pore 16 i^ x T2nU--pTo7re2sZ x ^ (ppn) * 0.24 x 10 " x Fibers x Fiber mass (?) This gives the following results for observed concentrations of treaolite fibers In Monolcoce MK-5. Basis: Average Mass Median Mass Tremollte Treaolite probable treaolite Treaolite * probable treaolite * possibletreaolite l.l ppm 28.4 76.6 1.4 ppa 8.1 14.4 la ay opinion, the median values should be used as the best indication of mss concentration. Based upon our laboratory experience, replicate analysis agree within a factor of two tiaes, indicating a confined treaolite concentration of 1 to 3 ppa and a possible treaolite concentration of 7 to 30 ppa. Please call ae if you have any questions. Very truly yours. Uuos.'t: Patz, Edvard T. Peters 15137292 /k. Arthur D. Little. Inc. Jure . 1983 Dr. Julie Yang Manager - Research Technologies w.R. Grace & Co. dia. Suclepore filters were then carbon coated. Samples (4 or 5) were incised from each and placed on 200 mesh copper electron microscope grids. The filter media was cleared with chloroform using the modified Jaffee wick procedure. When cleared, optical microscopy at 430X indicated the 4 and 16 *1 samples were both heavily loaded. The l ml sample was used for electron micro scopy. . for. analysis. 20 random pore openings were traversed at 10.000X and any particle meeting the fiber definition was measured (length and width) and analyzed by selected area electron dif fraction (SAED). Photographs of several typical fibers and their SAED's were recorded. RESULTS For the 20 pore openings, a total of 59 fibers were observed, r with the following identifications. Category Humber of Fibers Vermiculite (image and SAED) Probable vermiculite (image only) Tremolite (image and SAED) . Probable tremolite (image only) Possible tremolite (ambiguous image) 29 7 2 12 9 59 Based on the measured fiber dimensions and the conservative assumption of fiber thickness being the seme ss the fiber width, fiber weights were calculated on the basis of both assn sad mtdlsa fiber mass. The latter la a more useful indication of central tendency in cases where s particularly large fiber found in the sample arcs analyzed may not be representative of the whole. The calculated values are Category Fiber Mass (g) x 10~^ Mean Median Tremolite Tremolite probable tremolite Tremolite probable tremolite * possible tremolite 2.84 8.44 13.87 2.84 2.40 2.61 15137291 i /tl Arthur D. Little, Inc. June 27, 1983 -3- Dr.-Julie Yang Manager - Research Technologies W.R. Grace & Co. Category Fiber Mass () x 10 Mean Median * -' Treaoliee Treaolice probable treoollte Treaolice + probable treaoliee possible treaolice 2.84 8.44 13.87 . 2.84 2.40 2.61 tci Fiber aass concentrations are calculated by Fibers x Fiber, aass (g) . 4000 al (saaple) 100.2 g (staple) 1 al (aliquot) 960 an2 (filter) 81 x 10~* aa2 (pore area) x----------------- x 10^ (ppa) 0.24 x 1022 x Fibers x Fiber aass (g) 20 pores This gives the following results for observed concentrations of treaolice fibers in Monokete *r5. Basis: Average Mass Median Mass Treatollce TraMllce probable ereaolite Treetolice probable treaolice * possible treaolice 1.4 ppa 28.4 76.6 1.4 ppa 8.1 14.4 11 ' nq3 i /tl Arthur O. Little, Inc. June 27, 1983 -3.0.10rs Julie Veng Manager - Research Technologies tf.R. Grace 4 Co. In sif opinion, the nedian values should ba used as the best indication of mass concentrtcion. Based upon our laboratory experience, replicate analysis agree viehln a factor of tvo tinea, indicating a confined tranolite concentration of 1 to 3 ppn and a possible treaolite concentration of 7 to 30 ppn. Please call me if you have any questions. Very truly yours. Edvard T. Patera r i