| 摘要 |
For calcining the flue gas gypsum produced during flue gas desulphurisation, in particular in coal-fired power stations, heat is required. The required heat is used in the form of industrial, dust-free waste heat, in particular water vapour or hot air, the relatively low temperatures of the waste heat being usable for calcining in that the calcium sulphate dihydrate starting product is intensively mixed with aqueous sulphuric acid and then heated with the aid of the waste heat with a predetermined heating rate. After a temperature of 90-100 DEG C is reached, the gypsum hemihydrate then formed is separated from the aqueous sulphuric acid and subsequently dried at 105-130 DEG C. To obtain an approximately continuously running process, a plant comprising three converters and, if appropriate, three concentrators is provided, in which plant both the mixing operation and the calcining operation, and also the separation operation, take place by steps. <IMAGE> |
