硝酸分解磷矿过程中重金属及氟的迁移规律研究

Study on migration law of heavy metals and fluorine during decomposition of phosphate rock by nitric acid

研究了硝酸法生产磷酸过程中反应时间、硝酸浓度、液固比、反应温度对重金属及氟在气液固三相中迁移规律的影响。Design-Expert优化结果显示,液固比对As、Ni、Zn迁移率影响最大,硝酸浓度对Cr、Cu、Pb、F迁移率影响最大。当反应时间为1.5 h、硝酸浓度为35%、液固比为12、反应温度为65℃时,As、Cr、Cu、Ni、Pb、Zn、F迁移率分别为82.51%、80.34%、80.39%、50.12%、86.88%、63.62%、81.75%,此时重金属及氟在气液固三相中的分布率分别为0、78.74%、21.14%和13.43%、86.14%、0.43%。

The effects of reaction time,the concentration of nitric acid,liquid-solid ratio and reaction temperature on the migration law of heavy metals and fluorine in gas,liquid and solid phases are studied in the process of producing phosphoric acid by nitric acid method.Design-Expert optimization results show that the liquid-solid ratio has the greatest impact on the mobility of As,Ni and Zn,and the concentration of nitric acid has the greatest impact on the mobility of Cr,Cu,Pb and F.The mobility values of As,Cr,Cu,Ni,Pb,Zn and F are 82.51%,80.34%,80.39%,50.12%,86.88%,63.62%and 81.75%,respectively when the reaction lasts for 1.5 h,the concentration of nitric acid is 35%,the liquid-solid ratio is 12 and the reaction temperature remains at 65℃.Meanwhile,the distribution rates of heavy metals and fluorine in gas-liquid-solid phases are 0%,78.74%,21.14%,and 13.43%,86.14%,0.43%.