Producing a reducing agent containing iron(II) sulfate, used for reducing the soluble chromate content of cement, comprises concentrating spent sulfuric acid and separating the sulfuric acid from the precipitate

摘要

Producing reducing agent containing iron(II) sulfate comprises concentrating spent sulfuric acid and separating the sulfuric acid from the resulting precipitate. Independent claims are also included for: (a) reducing agent produced as above; (b) composition comprising cement, water-soluble metal sulfates and optionally water, containing 0.01-5 weight % of a reducing agent as above.