A water-miscible organic precipitant such as methanol, ethanol, or acetone is added to a sulfate-containing nacl solution obtained in a process for separating zr and hf, resulting in precipitation of nearly pure na2so4. The organic precipitant is removed and the so2-- free nacl solution is recycled to the process. For example, in the zr-hf separation process a 3.0M nacl solution is used to strip zirconium sulfate from an organic solution of tri-n-octylamine, decanol, and kerosine. Gaseous nh3 is added to this solution to precipitate the zr. The remaining nacl solution contains 0.75M so2- and 2.36M nacl. Addition of sufficient ethanol to provide a 55 vol pct concentration of ethanol results in 94 pct removal of so42-, and the na2so4 precipitated has a purity of 99 pct.
U.S. Pat. 4,242,312; Dec. 30, 1980; Chem. Abstr. Not Found