Chromate removal by precipitation

摘要

Chromates are removed from aqueous alkali metal chlorate solutions by either of two processes. In the first process, a water-soluble sulfide is added to react with the chromate, and then a ferrous salt is added. The soluble sulfate is converted to elemental sulfur and the chromate is converted to an insoluble trivalent Cr-containing material which is removed from solution. In the second process an "iron mud" is prepared by reacting a ferrous salt with sodium hydroxide and added so as to precipitate insoluble trivalent chromium-containing material.