磷石膏制备硫酸钙晶须及其应用的研究

Research on preparation and application of calcium sulfate whiskers with phosphogypsum

以工业废渣磷石膏为主要原料，辅以纯天然石膏晶种和氯化镁晶型助长剂，采用水热压法制备无机硫酸钙晶须。研究了反应温度、反应时间、料浆质量浓度、磷石膏粒径对硫酸钙晶须的影响，得NTN备硫酸钙晶须的合适工艺条件。在此基础上将制备的无机硫酸钙晶须应用到磷建筑石膏基材料中。试验结果表明，在反应温度135℃、反应时间4h、料浆质量浓度2．5％、磷石膏粒径为45-80μm的条件下可制备出形貌规整、分布均匀、平均长径比为75的硫酸钙晶须产品。将晶须产品作为增强组元，添加到磷建筑石膏基胶凝材料中，可以改善胶凝材料的力学性能。

Inorganic calcium sulfate whiskers was prepared with hydrothermal synthesis methods by using industrial phospho- gypsum waste as predominant raw materials and mixing a little of the seed crystal of pure natural gypsum and the crystal type promoter of magnesium chloride. The effects of the morphology of calcium sulfate whiskers were studied in different conditions such as reaction temperature,reaction time, slurry mass fraction and the particle size distribution,as well as the proper technical conditions for preparation of calcium sulfate whiskers received. The test results indicated that calcium sulfate whiskers of morpholo- gy regularity and distribution uniformity were prepared, in addition,average diameter of whiskers were 75 from phosphogypsum. The experiments had showed that the proper conditions of reaction temperature was 135℃,reaction time was 4 h,slurry mass concentra- tion of 2.5%,raw materials size was 45-80μm. Under those conditions,in order to improve the mechanical properties of binding materials,calcium sulfate whiskers as enhanced component were added to phosphorus building gypsum system cementing.