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PROCESS FOR MAKING CONSTRUCTION GRADE CALCIUM SULFATE ALPHA HEMIHYDRATE FROM MOIST FINELY DIVIDED GYPSUM OBTAINED FROM A POWER PLANT GLUE GAS DESULFURIZATION
PROCESS FOR MAKING CONSTRUCTION GRADE CALCIUM SULFATE ALPHA HEMIHYDRATE FROM MOIST FINELY DIVIDED GYPSUM OBTAINED FROM A POWER PLANT GLUE GAS DESULFURIZATION
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机译：从电厂烟气脱硫获得的湿式细分散石膏制得建筑级硫酸钙，半水合物的方法
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摘要
The process makes calcium sulfate alpha-hemihydrate oressentially plaster of paris from finely divided gypsum made bydesulfurizing flue gas obtain from a power plant fired by browncoal by transforming the calcium sulfate dihydrate in thepresence of saturated steam. A molded body is formed from thecalcium sulfate dihydrate which has a plurality of pores. Thepore volume amounts to 15 to 60 % by volume of the total volumeof the entire molded body. More than 5 % by volume of the porevolume contains air. The molded body is fed to an autoclave.In the presence of a sufficient water quantity in the pores thecrystal habit and the crystal growth of the calcium sulfatealpha-hemihydrate crystals which grow in an aqueous solutionphase are controlled by a process temperature in the rangebetween 110° to 180°C by the pressure of the treatmentatmosphere in the autoclave. The molded body is removed fromthe autoclave after recrystallization transformation anddelivered for use. Key products of this process and theirderivatives are also described.
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