Regular Article

Optimization of phosphogypsum conversion into calcium carbonate and lithium sulfate monohydrate

Laboratory of Physical Chemistry of Materials (LPCM), Faculty of Sciences, Chouaib Doukkali University, Route Ben Maachou, El Jadida 24000, Morocco

^* e-mail: yassinemaster@gmail.com

Received: 22 January 2021
Accepted: 1 September 2021

Abstract

Phosphogypsum (PG) is an acidic by-product generated during the production of phosphoric acid. Usually this by-product is stockpiled or dumped into water bodies, which causes several environmental pollution problems. The aim of this work is to reduce this environmental risk by producing CaCO₃ and Li₂SO₄.H₂O from the conversion of PG by Li₂CO₃. To optimize the reaction conditions, four parameters have been investigated such as the initial concentration of the reagents, the reaction duration, the temperature and the gypsum purity. In addition, the nature of the resulting products was proved principally by X-ray diffraction technic. The obtained results show that the initial concentration of the reagents and the reaction duration are the most influential parameters, while the temperature has no significance effect on this reaction. Also, the acidity and the presence of impurities into PG induce its reactivity compared than commercial gypsum. The purity of the formed CaCO₃ and Li₂SO₄.H₂O at the optimum conversion of PG is 96.08 and 98.71% respectively.