A PROCESS FOR TREATING SPENT ACID FOR REMOVAL OF IMPURITIES CONSISTING OF SILICA ALUMINA AND IRON BEARING COMPOUNDS GENERATED DURING LEACHING METHOD OF COAL WITH HYDROCHLORIC ACID

摘要

The invention relates to a process for treating spent acid for removal of impurities consisting of silica, alumina and iron bearing compounds generated during leaching method of coal with Hydrochloric acid, the process comprises : implementing an adsorption step adapting activated charcoal in which silicate ions and sulphur bearing elements present in the coal is removed; carrying-out a step of ion exchange using a highly anionic exchange resin which enables removal of silica and aluminium bearing compounds in the spent acid; and applying pyrohydrolysis at temperatures above 110°C, for removal of impurities and reuse of the spent acid in coal leaching process.