Purification of zirconyl sulfate by solvent extraction. Report of investigations/1984

The Bureau of Mines has conducted bench-scale investigations leading to the design of an integrated process for producing reactor-grade zirconium oxide (ZrO2) from zircon sand, which avoids the air pollution, water pollution, fire hazard, and odor problems associated with the hexone-thiocyanate process. The integrated process consists of three steps: production of crude zirconyl sulfate solution, solvent extraction, and production of ZrO2 from strip liquor. This report describes the solvent extraction step. Multistage, countercurrent liquid-liquid extraction with a tertiary amine in kerosine was used to separate zirconium from a dilute H2SO4 solution containing hafnium and other impurities. These steps were performed simultaneously in steady-state, bench-scale experiments. Zirconium recovery of up to 93 pct was achieved. Results of an economic evaluation are included.