TECHNOLOGY OF PROCESSING CHRYSOTILE ASBESTOS RESIDUE IN MAGNESIUM SALT AND ITS ECOLOGICAL SIGNIFICANCE

In the work, based on experimentally established conditions and modes of processing industrial (Kostanay Minerals JSC) pulverized asbestos-containing waste (PAW) with acid, a scheme for processing PAW consisting mainly of a mineral of the serpentinite group (antigorite, chrysotile and lizardite), where the content of MgO and SiO2 is 32-38 wt.% and 35-40% by weight, respectively. Schemes for the production of magnesium salts MgSO4, MgCl2 and Mg(NO3)2 using sulfuric, hydrochloric, and nitric acids during acid leaching of PAW are presented. It is shown that the quality of the obtained magnesium salts meets modern quality standards, and a dense amorphous layer of polysilicic acid forms on the surface of the acid-insoluble residues, changing their physico-chemical properties, including harmful effects on the environment. The obtained data and statements are substantiated on the basis of the results of the study of the reaction products of the interaction of powdery waste chrysotile asbestos and sulfuric, hydrochloric and nitric acids by chemical and X-ray phase analyses, the quality of the obtained magnesium salts is determined by comparison with the indicators of existing GOST (government)standards intended for these magnesium salts. The technological parameters and conditions for the production of sulfate, chloride and magnesium nitrate are given. Based on the results of the study, an ecological and resource-saving technology for the disposal of chrysotile-containing pulverized waste from the production of chrysotile asbestos is proposed.