基于正交实验对煤灰中锂提取率多因素分析

Multi-factor Analysis of Lithium Extraction Rate from Coal Ash Based on Orthogonal Experiment

以广西上林万福矿区煤灰为对象,采用活化-焙烧-浸取等实验方法尝试提取其中的锂元素,结合正交试验与数理统计的方法分析该方法对锂提取率的主控因素。结果表明,影响煤灰中锂浸出的主控因素为烧结剂(试剂种类参数)、烧结剂比例(试剂用量参数)、活化温度(温度参数),其余参数(反应时间)对浸出率影响较小。探讨了活化焙烧法最佳试验条件,即活化剂为碳酸钙、烧结剂为硫酸铵、浸取剂为硫酸、活化剂比例为2∶1、烧结剂比例为1∶3、浸取剂浓度为1%、固液比为1∶5、活化时间为30 min、活化温度为800℃、烧结时间为30 min、烧结温度为400℃、浸取时间为60 min、浸取温度为60℃。在最优试验参数条件下,通过4组平行重复性实验验证了锂的浸取效果,平均浸取率达80.40%。广西上林万福矿区煤灰在锂含量上表现出极大潜力,另外Ga,Y,Er,Yb和Lu元素均高于世界平均水平,多种元素的协同提取有望实现效益最大化。

Taking the coal ash in Fulin mining area of Guangxi as the object,the experimental method of activation-roasting-leaching was used to extract lithium element.Further,the main control factors of the extraction rate of lithium were analyzed by orthogonal test and mathematical statistics.The results show that the main controlling factors of lithium leaching from coal ash are sinter agent(reagent type parameter),sinter proportion(reagent dosage parameter) and activation temperature(temperature parameter),and other parameters(reaction time) have little influence on the leaching rate.The optimal test conditions of the activation roasting method were discussed,that is,calcium carbonate as activator,ammonium sulfate as sintering agent,sulfuric acid as leaching agent,ratio of activator is 2 ∶1,ratio of sintering agent is 1∶3,the concentration of the extraction agent is 1%,the solid-liquid ratio is 1∶5,the activation time is 30 min,the activation temperature is 800℃,the sintering time is 30 min,the sintering temperature is 400℃,the leaching time is 60 min,and the leaching temperature is 60℃.Under the optimal experimental conditions,the leaching effect of lithium was verified by four sets of parallel repetitive experiments,and the average leaching rate reached 80.40%.Coal ash in Guangxi Wanfu mining area shows great potential in terms of lithium content.In addition,Ga,Y,Er,Yb and Lu elements are higher than the world average.The synergistic extraction of multiple elements is expected to maximize benefits.