采用高温结晶的方法,通过正交实验和单因素实验,研究了进料液质量浓度、操作温度、停留时间及搅拌速率对硫酸锰结晶率的影响。结果表明:在进料液硫酸锰质量浓度为370.0 g/L时,采用常压结晶法还没有硫酸锰晶体析出,而采用高温结晶法,在压力为1.3 MPa(表压)、操作温度为170℃、保温时间为14 min、搅拌速率为350 r/min条件下,硫酸锰结晶率为84.0%,达到该温度下理论结晶率的88.0%。高温结晶法所消耗的热量是常压结晶法的60.7%,每生产1 t一水硫酸锰可节省蒸汽2.75 t。该工艺对综合利用低品位软锰矿和开发节能降耗生产硫酸锰的新工艺都具有重要的指导意义。
In process of high-temperature crystallization,the effects of feed mass concentration,operating temperature,residence time,and stirring rate on the crystallization efficiency of manganese sulfate were studied by orthogonal and single factor experiments.Results showed that when feed mass concentration was 370.0 g/L,there were no crystals separated out by means of normal-pressure crystallization;while in the high-temperature crystallization process under the conditions of pressure of 1.3 MPa(gauge pressure),operating temperature of 170 ℃,residence time of 14 min,stirring rate of 350 r/min,the crystallization efficiency of manganese sulfate was 84.0%,which reached 88.0% of the theoretical crystallization efficiency at this temperature.Energy consumption of high-temperature crystallization was 60.7% of that of normal-pressure crystallization.Method of high-temperature crystallization could save 2.75 t stream when 1 t MnSO4·H2O was produced.This process has an important directive significance in the comprehensive utilization of low-grade pyrolusite and developing new energy saving technology for the production of manganese sulfate.