I COLOR.O SCHOOL OF Ml!'JES RESEARCH. TITUTE I I I A Procedure to Examine Talc for the Presence of Chrysotile and Tremolite-A ctinolite Fibers I I I I I I I I I I I I I I I Pre pared for Johnson & Johnson 501 George Street New Jersey Brunswick, New By Colorado School of Mines Research Institute Golden, Colorado December 27, 1973 Project C 10704 APPROVED : ~: :a~ Hei-man Ponder Director Senior Scientist Mini.p.g Division Mining Division Protected Document--S ubject to Protective Order JNJ 000268037 1 of 9 JNJ000268037 Pltf_JNJ_0 0040942 I I I I I I I I I I I I I I I COLOR.O SCHOOL OF MINES RESEARCH.TITUTE CONTENTS Page Introduction 1 Objective 2 Summary and Conclusions 3 Discussion 4 4 Details of the Procedure Samples 4 Separation De tails 4 Microscopy 6 T remoli te -Ac tinoli te 7 Chrysotile 8 8 X-Ray Diffraction Appendix I I I I Protected Document--Subject to Protective Order JNJ 000268038 2 of 9 JNJ000268038 Pltf_JNJ_00040942 I I I I I I I I I I I I I I I I I I I COLOR.O SCHOOL OF MINES 1 RESEARCH . . TnUTE INTRODUCTION The purpose of this document is to report the methods used at the Colorado School of Mines Research Institute for detection of chrysotile and/ or tremolite-actinolite in samples predominantly composed of talc. The methods described herein have evolved over a period of time, with the aid of suggestions from many individuals, and are frequently subjected to review. As the impurity level becomes very low (< ::c 3, 1963. (1) Data from Deer, Howie, and Zussman, Rock Forming Minerals, vol. 2, 1962; vol. width maximum average to length minimum a has it that (2) Fiber -- any material having a form such of 3: 1. • () J: -I -I C -I m "'C ;:::; I"'"" c... z le,_ JNJ000268043 0 0 0 .i::i,. 0 (0 .i::i,. N (.J1 c.. z c.. 0 0 0 l\l a, 00 0 .i::,. (.,) I I I I I I I I I I I I I I I I I I I . COLO.O SCHOOL OF MINES 6 RESEARCH.STITU TE Each sample is well dispersed by thorough shaking of the loaded stoppered funnels, and then centrifuged at 800 rpm for two intervals of 1 / 2 hr. The float material is agitated slightly between centrifuge intervals to aid in releasing high specific gravity particles which may be trapped in the tightly packed floating fraction. The heavy and light fractions are collected sep- arately on O. 45µ. millipore filters, washed with ethanol or isopropyl alcohol, dried, and carefully weighed. The heavy fraction (sp gr >2. 90) will be examined for tremolite-actino lite. The light fraction (sp gr <2. 90) collected above is reprocessed in an identical manner in a liquid of sp gr 2. 65. sp gr <2. 65 will be examined for chrysotile. The light fraction with The fraction with sp gr >2. 65 and <2. 90 is assumed to be predominantly talc and therefore is not subjected to further examination. This fraction could of course contain frag- ments of other minerals locked to the talc. The 2. 65 sp gr liquid_is prepared by diluting Certigrav 2. 90 sp gr liquid with n, n dimethylformam ide having a specific gravity of 0. 95. The heavy liquid can be recovered from the alcohol-n, n dimethylformam ide washings by extraction with large volumes of water. The fractions recovered from the heavy liquid separations generally amount to 20 mg or less. Microscopy: Optical examination of the heavy liquid separates for the presence of fibers is a sensitive examination method. Optical microscopy can detect fibers with a length greater than approximately 2 u, when present at a level Protected Document--Subje ct to Protective Order JNJ 000268044 8 of 9 JNJ000268044 0942 Pltf_JNJ_0004 I. I I I I I I I I I I I I I I I I I I COLO.O SCHOOL OF of approximate zy O. 1% or greater. 7 MINES RESEARCH.S TITUTE If optical examination at magnificatio ns up to approximate ly 625X does not reveal the presence of fibrous particles, the sample can be passed as being clean. If fibrous material is detected optically, then specific identificatio n of the fibers must be attempted. Opti- cal identificatio n is difficult and subject to numerous errors, especially when working with small particles which are near the resolution limit of the microscope . Electron microscopic examination employing selected area electron diffraction and/or x-ray emission spectrograph y may be required in order to specifically identify small fibrous particles. The following optical identificatio n schemes require a great deal of expertise, and are subject to errors introduced by small particle size, the presence of talc fibers, plates lying on edge thereby appearing to be fibers, overlap in optical properties, and variable reaction of chrysotile to the iodine stain. Tremolite-A ctinolite The heavy liquid separate having a sp gr >2. 90 is mounted in immersion oil of refractive index 1. 600 for transmitted light examination under a petrographic microscope. All amphiboles have refractive indices appreciably greater than 1. 600 and will be readily visible. All observation s are made at magnificatio ns of 125X and 250X. Single particles are occa- sionally examit;ed at a magnificatio n of 625X. Tremolite-a ctinolite fibers are identified by having length to width ratios greater than or equal to 3: l; refractive indices greater than or equal to 1. 600; and extinction angle varying between 10° and 21 °. Protected Document--S ubject to Protective Order JNJ 000268045 9 of 9 JNJ000268045 Pltf_JNJ_00040942 JNJ000268037 Metadata BegAttach Confidentiality Custodian DocumentType EndAttach PgCount Text Path Trial_Ex_Number JNJ 000268034 Y Legacy 1 Physical JNJ 000268045 9 TEXT\0276\JNJ 000268037.txt Pltf_JNJ_00040942 ORIGINAL ORIGINAL ORIGINAL ORIGINAL ORIGINAL ORIGINAL ORIGINAL ORIGINAL