Preparation of ferrous sulfate by solution crystallization of waste electrolyte produced by electrolysis of Fe-PGMs alloy.

Ferrous sulfate was crystallized from the waste electrolyte produced in electrolytic refining of Fe-PGMs alloy by solution crystallization method using anhydrous ethanol as the dissolution solvent. The effects of dissolution time, volume ratio of ethanol to water solution, dissolution temperature, stirring speed, aging time, and anhydrous ethanol dripping method on the crystallization rate of ferrous sulfate were investigated. The results showed that the maximum crystallization rate of ferrous sulfate reached 92.98% when the dissolution time was 60 min, the volume ratio of anhydrous ethanol to aqueous solution was 1:1, the dissolution temperature was 10 °C, the stirring speed was 200 r/min, the aging time was 60 min, and the ethanol was added dropwise. This process not only avoids environmental pollution caused by waste electrolyte during the electrolysis process, reduces the production of finished products, but also achieves the recycling and utilization of electrolyte in electrolytic Fe-PGMs alloys and Fe-PGMs alloy acid leaching solution, which is of great significance. [ABSTRACT FROM AUTHOR]