摘要
钙芒硝石膏是工业上采用溶浸法生产元明粉的副产尾矿,与脱硫石膏和磷石膏等工业副产石膏相比其杂质含量高、纯度低、利用价值低。采用酸浸-重结晶工艺对钙芒硝石膏进行提纯,通过酸浸去除钙芒硝石膏中的酸溶性杂质,并将二水硫酸钙(DH)脱水转化为无水硫酸钙(AH),然后控制水化条件,使AH水化为大尺寸的DH晶体,并与小尺寸的酸不溶性杂质分离开来,得到高纯度的二水石膏。研究了硫酸浓度、水化激发剂、液固质量比、反应时间等对石膏提纯的影响。研究结果表明:常压下,在硫酸酸洗液质量分数为35%、反应温度为80℃、石膏与硫酸溶液固液质量比为1∶5、酸洗时间为2 h时能有效去除钙芒硝石膏中的酸溶性杂质;在水化硫酸质量分数为5%、硫酸钾质量分数为1.74%、反应温度为25℃、固液质量比为1∶6、陈化时间为18 h时能有效去除钙芒硝石膏中酸不溶性杂质,提纯后的石膏纯度可达97%以上。
Glauberite gypsum is the by-product tailings produced by leaching sodium sulfate in the industry.Compared with industrial by-product gypsum such as desulfurized gypsum and phosphogypsum,it has higher impurity content,lower purity and utilization value.Glauberite gypsum was purified by acid leaching-recrystallization process,the acid-soluble impurities in Glauberite gypsum were removed by acid leaching and dihydrate calcium sulfate(DH)was converted into anhydrous calcium sulfate(AH).Then hydration conditions were controlled to hydrate AH into large-size DH crystals separated from small-sized acid-insoluble impurities to obtain high-purity dihydrate gypsum.The effects of sulfuric acid concentration,hydration activator,liquid-solid ratio and reaction time on purified gypsum were studied.The research results showed that under normal pressure,when the mass fraction of sulfuric acid pickling solution was 35%,the reaction temperature was 80 ℃,the solid-liquid ratio of gypsum and sulfuric acid solution was 1∶5,and the pickling time was 2 h,it could effectively remove acid-soluble impurities in glauberite gypsum.When mass fraction of hydrate sulfuric acid was 5%,mass fraction of potassium sulfate was 1.74%,reaction temperature was 25 ℃,solid-liquid ratio was 1∶6,aging time was 18 h,it could effectively remove acid-insoluble impurities in glauberite gypsum,and the purity of purified gypsum could reach more than 97%.
作者
尹会斌
李军
郑卓超
YIN Huibin;LI Jun;ZHENG Zhuochao(School of Chemical Engineering,Sichuan University,Chengdu 610065,China)
出处
《无机盐工业》
CAS
CSCD
北大核心
2022年第11期104-111,共8页
Inorganic Chemicals Industry
关键词
钙芒硝石膏
石膏提纯
重结晶
glauberite gypsum
gypsum purification
recrystallization
