PRODUCTION OF THE HIGH VALUE MATERIAL, ALPHA-CaSO4 HEMIHYDRATE OUT OF SPENT CaCl2 SOLUTIONS BY REACTION WITH H2SO4

摘要

CaCl2 can either be found in spent leaching solutions or in waste brines from geothermal fields. One possible treatment option for these solutions is the production of saleable quality gypsum materials by reaction with H2SO4 an increasingly difficult to sell by-product of the non-ferrous metallurgical industry. Such high-value material (alpha-CaSO4 hemihydrate) is finding uses in the building industry. Regeneration/production of HCl out of the spent CaCl2 solutions is another benefit of such treatment process. It is indeed the scope of this work to develop an atmospheric process (80oC) for the conversion of spent CaCl2 solutions to high-value -HH and HCl. In this paper, preliminary data on the crystallization of alpha-CaSO4 hemihydrate out of such chloride solutions is presented