The Comprehensive Recovery Of Alkali Metals In The Waste Liquid Of Extracting Lithium From Lepidolite

Lepidolite is a special mineral resource in Yichun,Jiangxi Province,which is rich in lithium,rubidium,cesium and other valuable metals.A large number of waste liquid that rich in lithium,rubidium and cesium are produced in the process of lithium carbonate by lithium mica sulfate method.On the one hand,it causes environmental pollution,on the other hand,it causes too much waste of the resources.However,due to the similar chemical properties of rubidium and cesium with lithium,sodium and potassium,the extraction and separation of rubidium and cesium from the waste liquid that rich in high potassium and sodium has great challenges.Therefore,it is of great practical significance and theoretical value to carry out the technical research on the comprehensive recovery of alkali metals from the lepidolite sinking waste liquor.On the basis of a large number of references,in order to solve the problem of comprehensive recovery of alkali metals in the waste liquid with high potassium and sodium.The extraction and chemical precipitation behavior of alkali metals in the waste liquid of extracting lithium from lepidolite were studied.The effects of various process parameters on the extraction and chemical precipitation of alkali metals were explored.Based on this,the comprehensive recovery process of alkali metals in the waste liquid of lithium extraction is put forward,and the better technical parameters are obtained by experimental study and cascade extraction calculation.The main conclusions are as follows:(1)The results of t-BAMBP extraction behavior of alkali metals in the waste liquid of lithium mica extraction show that the extraction sequence ability of alkali metals in the waste liquid of lithium extraction is CS~+>Rb~+>K~+>Li~+>Na~+,and the washing and stripping sequence is Li~+>Na~+>K~+>RB~+>CS~+.Under the optimum extraction conditions:The amount of extractant is 0.83 mol/L(its percentage content in organic phase is 41.7%),the pH value of the material is 14,the ratio is 1.0,the concussion speed is 200 rpm,the extraction temperature is 25℃,the extraction time is 5.0 min,the extraction rates of CS,Rb,K,Li and Na are 98.43%,63.14%,22.58%,7.77%and 6.89%,respectively.The stripping rate of Rb and CS by sulfuric acid is 93.48%and 96.46%respectively.The results show that t-bambp-sulfonated kerosene system has a certain selective extraction ability for rubidium and cesium in the waste liquid,but the presence of potassium,lithium and sodium,especially the potassium with high concentration,has a great influence on the extraction of rubidium and cesium,which brings difficulties for the direct extraction and separation of rubidium and cesium from the waste liquid.(2)The study on the chemical precipitation behavior of alkali metals in the waste liquid shows that,tartaric acid has a good precipitation effect on potassium,rubidium and cesium,but it is difficult to separate lithium,sodium,potassium,rubidium and cesium;antimony trichloride has a good selective precipitation for cesium,but it needs strong hydrochloric acid,consumes a lot of hydrochloric acid,it also causes chloride ion corrosion;Sodium carbonate is an effective selective precipitant for lithium;aluminum sulfate is an optional reagent for the selective deposition of potassium and sodium in the waste liquid.When the amount of aluminum sulfate is 3.5mol/L and the reaction time is 120 minutes at 8℃,more than 96%of potassium and sodium can be selectively precipitated,from the waste liquid.(3)The process of"precipitation of potassium and sodium ions with aluminum sulfate,precipitation of lithium by sodium carbonate,single-stage co extraction and cascade extraction separation and purification"proposed in this paper can recover more than 96%of potassium and sodium in the form of aluminium sodium alum and aluminium potassium alum,more than 94%of lithium is recovered in the form of industrial grade lithium carbonate,rubidium and cesium can be concentrated and separated by 99.9%high purity products.The process provides a feasible scheme for the comprehensive recovery and utilization of alkali metals with high potassium,sodium,lithium and mica in the lepidolite sinking waste liquor.