Phosphating asbestos fibres by countercurrent circulation

摘要

Asbestos fibres are phosphated by: (a) counter-current circulation in a closed system of a gaseous phosphorous chloride in a first reaction chamber at near atmos. pressure through a dry asbestos fibres mass having a bulk density o 15-325 kg/cu.m.; (b) adsorption of the phosphorous chloride on the fibres at between the boiling temp. (at atmos. pressure) of the phosphorous chloride and 200 deg. C above this temp. for 0.2-4 hrs.; (c) curing, while displacing the phosphated fibres into a second chamber, for 0.1-6 hrs. at between the boiling temp. of the phosphorous chloride and 240 deg. C above this temp.; and (d) flushing the fibres to remove unreacted phosphorous chloride and toxic and volatile by products.