Home – Home – Jornals – Chemistry for Sustainable Development 2009 number 3

It is established that after leaching calcium by ammonium chloride into solution from the product of thermal decomposition of phosphochalk (technical-grade calcium carbonate) obtained by conversion of phosphogypsum with soda solutions, the insoluble residue is a concentrate of strontium and rare-earth elements (REE); the concentrations of strontium and REE reach 9-10 and 4.5-5.1 %, respectively. The extraction of REE into solution with the help of different acids is considered. It is shown that the degree of leaching the REE into solution reaches 96-97 % in the presence of reducing agents. The leaching solutions contain 4.2-4.6 g/dm³ REE and can be processed to obtain REE compounds. The insoluble residue after REE leaching is a strontium concentrate with strontium sulphate content of 54.5-62.9 %.