钛石膏制备碳酸钙粉体和硫酸铵的工艺条件研究

Study on Process Conditions for Producing Calcium Carbonate Powder and Ammonium Sulfate from Titanium Gypsum

钛石膏是硫酸法钛白粉生产过程中产生的工业副产石膏。为实现钛石膏的资源化利用,以攀西地区某公司提供的钛石膏和碳酸氢铵为主要原料,加入氨水制得钛石膏浆液,采用复分解反应法制备碳酸钙粉体和硫酸铵。研究了固液比、反应时间、反应温度对反应产物碳酸钙和硫酸铵的产率的影响,结果表明:钛石膏和碳酸氢铵的原料比为1∶2.3(w/w),反应温度为60.0℃,反应时间为40 min,钛石膏制碳酸钙的产率最高为90.4%,硫酸铵的产率最高为90.6%,钛石膏中的钙离子和硫酸根离子在反应器中转化为碳酸钙和硫酸铵,为钛石膏的综合利用提供了一条新途径。

Titanium gypsum is a by-product of calcium sulfate dihydrate,which is the main component of titanium dioxide powder prepared by sulfuric acid method in industry.Due to its low comprehensive utilization rate and excessive accumulation,it poses significant harm to enterprises and the environment.The titanium gypsum and ammonium bicarbonate from Panxi region were used as the main raw materials to prepare calcium carbonate powder and ammonium sulfate through multi-step pH adjustment with ammonia water.The effects of reaction time,reaction temperature and solid-liquid ratio on the yield of reaction products calcium carbonate and ammonium sulfate were studied.The results showed that the optimal process conditions for producing calcium carbonate and ammonium sulfate from titanium gypsum were as follows:the material ratio of titanium gypsum and ammonium bicarbonate was 1∶2.3(w/w),the reaction temperature was 60.0℃,the reaction time was 40 min,and the highest yield of calcium carbonate and ammonium sulfate from titanium gypsum was 90.4%and 90.6%,respectively.The calcium ions and sulfate ions in titanium gypsum were completely converted into calcium carbonate powder and ammonium sulfate in the hydrothermal synthesis reaction.Through experiments,a new process for the comprehensive utilization of titanium gypsum was put forward.