Process and apparatus for the pressureless production of alpha-calcium sulphate-hemihydrate

摘要

In the pressureless calcining of calcium sulphate dihydrate in dispersion by means of a calcining medium to give alpha -calcium sulphate hemihydrate, the dispersion is prepared continuously and divided into dispersion aliquots (18) separated from one another and being transported in succession along a calcining route (19). The rate of transport can be varied. Along the calcining route (19), the temperature of the dispersion aliquots (18) can be changed. Along the calcining route (19), the concentration of the calcining medium can also be increased by local addition of more highly concentrated calcining medium. The ratio of calcium sulphate hydrate to calcining medium can also be adjusted to the desired value by local addition of calcining medium. The dispersion aliquots (18) can be prepared and handled by a dividing and transport device (2) which preferably comprises a screw (3;32;48;52). IMAGE