Crystalline gypsum

The invention provides a kind of crystalline plaster which can substitute the traditional plaster in cement production. It is made up from salt slurry, some salt waste, water sodium sulfate, waterless plaster, carbamide and some mixers, it accords with the standard GB/T5483-1996. the using quantity is 2í½5% when producing common cement. It can control the initial setting time about 2í½2.5 hours, the final setting time about 3í½4 hours. Three days compression can be upgraded about 3í½4MPa, twenty eight days compression can be upgraded about 4í½6MPa. 本发明提供一种结晶石膏，用于水泥生产，可代替传统方法使用的石膏。这种结晶石膏是利用盐田石膏(俗称盐泥、盐皮)和部分洗涤盐废料、含水硫酸钠、无水石膏、尿素及适量掺和料配置而成，其各项指标符合GB/T5483-1996《石膏和硬石膏》标准。用于通用水泥中掺入量为2-5％。生产强度等级为32.5MPa的通用水泥，在其他物料不变条件下，可使水泥初凝时间控制在2-2.5小时，终凝时间3-4小时，3天抗压强度可提高3-5MPa，28天抗压强度可提高4-6MPa，抗折强度提高幅度更大，其他各项指标完全符合各种通用水泥标准要求，对于砌筑水泥，效果更为明显。