利用硫磺、碳等还原硫酸法钛白粉生产副产物钛白石膏是处理钛白石膏堆放问题的方法之一。针对硫磺在回转窑分解钛白石膏制硫酸和氧化钙的过程存在时间长、硫磺用量大、硫化钙产量不高等问题,提出了以钛白石膏为原料利用酸浸法去除铁杂质后,利用硫磺为还原剂将石膏在气固竖式反应器中煅烧生成硫化钙和二氧化硫,前者再与硫酸钙煅烧制得氧化钙和二氧化硫,得到的氧化钙可以中和废酸和废水,产生的二氧化硫用来制硫酸的方法。先利用反应热力学计算软件HSC分析确定实验方案,分别在流态化实验（800 ℃,保温40 min）和煅烧实验（1 100℃,保温1.5 h）后得到硫化钙转化率与氧化钙纯度均达到90%左右。再利用Aspen软件模拟了工艺流程,模拟出二氧化硫体积分数可达12.09%,满足制硫酸的需求。硫酸生产成本估算为263.9元/t,具有较大的市场前景。

Reducing titanium dioxide gypsum of by-product of titanium dioxide production by sulfuric acid method with sulfur and carbon is one of the methods to deal with the stacking problem of titanium dioxide gypsum.Aiming at the problems of long time,large amount of sulfur and low output of calcium sulfide in the process of decomposing titanium dioxide gypsum to sulfuric acid and calcium oxide in rotary kiln.It was pointed out that using titanium dioxide gypsum as raw material,after removing iron impurities by acid leaching,gypsum was calcined in gas-solid vertical reactor with sulfur as reducing agent to produce calcium sulfide and sulfur dioxide.The former was calcined with calcium sulfate to obtain calcium oxide and sulfur dioxide.The obtained calcium oxide could neutralize waste acid and wastewater,and the generated sulfur dioxide was used to prepare sulfuric acid.The experimental scheme was determined by reaction thermodynamics analysis by HSC software.After fluidization experiment（800 ℃,40 min for heat preservation） and calcination experiment（1 100 ℃,1.5 h for heat preservation）,the conversion rate of calcium sulfide and purity of calcium oxide were both about 90%.Then the process flow was simulated by using Aspen software,the volume fraction of SO₂ could reach 12.09%,which could meet the requirement of sulfuric acid production.The production cost of sulfuric acid was estimated to be 263.9 CNY/t,which had a great market prospect.