Determination of Chrysotile Fibers in Brakedrum Dust

"It is well known that car-brake lining is made of asbestos fibers and an organic high polymer. When brake operates, dust containing asbestos is emitted and deposited in brake drum. So we studied on the quantitative analysis of asbestos in the dust. The following results were obtained : 1) From the X-ray diffraction pattern of brake lining surface, the used asbestos is crysotile. 2) The ordinary analysis cannot be applied for the purpose of determining of the chrysotile concn in dust, because an organic high polymer in dust adheres to asbestos. 3) When the dust were calcined at 800℃, chrysotile transformed to powderly forstelite and an organic high polymer were removed. 4) Forstelite concn of the calcined dust could be measured with X-ray diffraction analysis using fluorite as binary mixture. 5) The chrysotile concn of the dust in brakedrum installed on a bus was 20-30wt% by means of the above mentioned method.