| 摘要 |
<p>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.</p> |
