钛石膏机械驱动强化结晶工艺的研究

Research on mechanical drive enhancement crystallization process for titanium gypsum

将机械驱动强化结晶技术(MDEC)应用于钛白粉含酸废水制备钛石膏,通过控制单一变量考察晶种加入量、反应温度、反应时间、搅拌速率、陈化时间等对石膏粒径的影响,采用XRD、SEM、ICP-OES等方法表征产物。结果表明:在处理量为10 L/h、反应温度为25℃、反应时间为90 min、搅拌速率为40 r/min、陈化时间为2 h条件下,一段MDEC较优工艺条件为m(含酸废水)∶m(石粉)∶m(晶种)=100∶5∶1、pH=3.5,制备的一段石膏平均粒径为103~116μm,Ca SO_(4)·2H_(2)O质量分数为87.21%;二段MDEC较优工艺条件为m(一段滤液)∶m(石灰)∶m(晶种)=100∶2.5∶1、pH=8,制备的二段石膏平均粒径为100~136μm,石膏质量分数为81.53%,两者均达到钛石膏和建筑石膏标准。

Mechanical-driven enhanced crystallization technology(MDEC)was used to treat the acidic wastewater of tita-nium dioxide to prepare titanium gypsum.By controlling a single variable,the effects of the amount of crystal seed added,re-action temperature,reaction time,as well as stirring rate and aging time on the particle size of gypsum were investigated.The product was characterized by XRD,SEM,ICP-OES and chemical analysis et.al.The results showed that when the treatment capacity was 10 L/h,the reaction time was 90 min at 25℃,the stirring speed was 40 r/min,and the aging time was 2 h,the optimal process conditions of first-stage MDEC were as follows:m(acid-containing wastewater)∶m(stone powder)∶m(seed)=100∶5∶1,pH=3.5,the average particle size of the prepared gypsum section was 100~116μm,the mass fraction of CaSO_(4)·2H_(2)O was 87.21%.The optimal process conditions of the second stage MDEC were as follows:m(the filtrate of the first stage)∶m(lime)∶m(seed)=100∶2.5∶1,pH=8,the average particle size of the second stage gypsum prepared was about 100~136μm,and the mass fraction of gypsum was 81.53%.Both of the gypsum met the standards of titanium gypsum and architectural gypsum.