磷石膏的高效利用——硫酸钙晶须的制备与应用

摘要

The high efficiency utilization of phosphogypsum is a problem needing to be solved in phosphate and compound fertilizer industry in China.The preparation of widely used and high value added calcium sulfate whiskers is one way of solving that.The experimental results indicate that,it is unable to get calcium sulfate whiskers with uniform morphology and high aspect ratio from phosphogypsum under hydrothermal condition,due to the influence of impurities,such as P,Si,Fe,and Al.Via the acid pretreatment,most of the impurities in phosphogypsum can be removed,then through hydrothermal-roasting process,anhydrous calcium sulfate whiskers with the main content more than 90％ (mass fraction),white content of 87,length of 70～200 μm,and diameter of 1～3 μm were obtained.At last,some preliminary exploration on papermaking process with calcium sulfate whiskers was made.The gypsum whisker paper with white content of 85 and longitudinal and lateral tearing strength of more than 600 mN could be got in the effect of special emulsifier and binder.%磷石膏的高效利用是中国磷复肥行业亟需解决的问题,用磷石膏制备用途广泛、附加值高的硫酸钙晶须是途径之一.实验表明:直接水热处理磷石膏时由于磷、硅、铁、铝等杂质的影响,无法得到形貌规则的高长径比硫酸钙晶须；磷石膏经酸溶除杂后可脱除大部分杂质,再经水热—焙烧处理得到主含量大于90％(质量分数)、白度为87、长度为70～200 μm、直径为1～3 μm的无水硫酸钙晶须.在此基础上初步探索了硫酸钙晶须造纸工艺,借助特种乳化剂和粘结剂的作用,得到白度大于85、横/纵向撕裂度大于600 mN的石膏晶须纸.