Process for recovering calcium compounds and sulphur dioxide from calcium sulphate, and calcium compounds and sulphur dioxide obtained according to this process

摘要

alcium sulphate is decomposed at elevated temperature and in the presence of a carbon source into a calcium compound and sulphur dioxide.;As starting material calciumsulphate anhydrite is used, which is obtained by recrystallizing crude phosphogypsum with H₂SO₄ at a concentration of 20-65 wt.-% H₂S0₄, at 20-90 °C for 5-180 minutes.;Pure products can be obtained from crude gypsum in a very simple manner.