醋酸酸解磷尾矿制备醋酸钙镁融雪剂工艺研究

Study on preparation process of calcium magnesium acetate snowmelt agent from phosphorous tailings by acetic acid hydrolysis

以磷矿经过选矿后产生的固体废弃物磷尾矿为原料,回收其中的有价元素钙、镁制备环保型融雪剂醋酸钙镁并同时富集其中的P_(2)O_(5)。通过醋酸酸解磷尾矿实验研究,考察了醋酸用量、液固质量比、反应温度、搅拌转速、反应时间对磷尾矿中钙镁浸出率的影响,结果表明,在醋酸用量为理论用量的130%、液固质量比为14∶1、反应温度为90℃、搅拌速率为1000 r/min、反应时间为3 h的条件下,CaO的浸出率可达到78.26%,MgO的浸出率可达到76.32%,磷尾矿中P_(2)O_(5)的质量分数从8.82%提高至25.91%。酸解液经调节pH后蒸发结晶得到醋酸钙镁盐,对其进行表征和性能测试,结果表明,其各项指标均符合GB/T 23851—2017《融雪剂》要求,是一种低腐蚀性、可降解、融冰雪性能优异的环保型融雪剂。

Using solid waste phosphorus tailings generated from phosphate ore beneficiation as raw materials,in order to re⁃cover the valuable elements of calcium and magnesium from the solid waste of phosphate rock,calcium and magnesium ac⁃etate was prepared and P_(2)O_(5)was enriched in the solid waste of phosphate rock.An experimental study on the hydrolysis of phosphate tailings by acetic acid was carried out.The effects of acetic acid dosage,liquid-solid mass ratio,reaction tempera⁃ture,stirring rate and reaction time on the leaching rate of calcium and magnesium from phosphate tailings were investi⁃gated.The results showed that the leaching rate of CaO and MgO could reach 78.26%and 76.32%under the conditions of liquid-solid mass ratio of 14∶1,reaction temperature of 90℃,stirring rate of 1000 r/min and reaction time of 3 h,respec⁃tively.The content of P_(2)O_(5)in phosphate tailings could be increased from 8.82%to 25.91%.Calcium and magnesium acetate were obtained by evaporation and crystallization of acid⁃hydrolysate after pH adjustment.The characterization and perfor⁃mance tests were carried out.The results showed that its indicators met the requirements of GB/T 23851—2017“Snowmelt Agent”,and it was an environmentally friendly snowmelt agent with low corrosion,degradability and excellent ice and snow melting performance.