| 摘要 |
This invention provides a process for the production of gypsum from a waste stream containing sulphuric acid including: (A) adding calcium containing basic material to said waste stream to bring pH within the range of from about 2.0 to 2.7 to precipitate gypsum, and recovering the precipitated gypsum from the waste stream, and (B) adding basic material to the waste stream to bring pH within the range of from about 3.0 to 3.4 to precipitate impurities, and removing the precipitated impurities from the waste stream, and (C) adding calcium containing basic material to said waste stream to bring pH within the range of from about 4 to 6 precipitate gypsum, and recovering the precipitated gypsum from the waste stream. |
