Study of phosphogypsum conversion from Kyzylkum phosphorites with soda ash solution

Abstract Enterprises producing phosphate fertilizers encounter a very serious problem associated with phosphogypsum piled up in huge amounts. To date, about 7 billion tons of phosphogypsum have been piled up all over the world with an average release of 180 million tons, and its utilization remains challenge. The process of phosphogypsum conversion of Kyzylkum phosphorite from JSC “Ammophos-Maxam” with soda ash of UE “Kungradsky soda plant” was studied in the work. The study was carried out in a wide range of concentration (10-20%) and stoichiometric norm (100-110%) of Na2CO3at a temperature of 80°C and a time of 30 minutes. It was revealed that an increase in the concentration and stoichiometric norm of Na2CO3 leads to an increase in the degree of conversion of phosphogypsum into CaCO3and Na2SO4up to 97.07%. The following is optimal: the concentration of Na2CO3is 20% and the stoichiometric norm is 105%, at which the degree of conversion is ⁓96%. As a result, the target product Na2SO4was obtained with a purity of 94% and calcium carbonate - 96.25%. This solution allows producers of phosphate fertilizers to recycle phosphogypsum into products with high demand.