Utilization Of Raffinate Produced By Acid Leaching Of Beryllium From A Tailing

In a mineral corporation in Chenzhou city,wet acid leaching-extraction process is used to extract beryllium from beryllium-containing tailing with a BeO grade of0.26%to produce beryllium oxide product.The acidic raffinate after extracting beryllium from the leachate mainly contains metal ions such as potassium,aluminum,manganese,as well as a small amount of residual beryllium.The recovery of the main metal ions and the recovery and reuse of beryllium in the raffinate were studied in this paper.The following research work were conducted:（1）Recovery of potassium.The method of generating crystalline aluminum potassium sulfate was used to recover most of the potassium ion and part of the aluminum ion in the raffinate,and the optimum condition for crystal formation was investigated.The test result showed that when the solution was stirred（20 r/min）for4h at room temperature,relatively pure potassium aluminum sulfate crystal could be obtained,and potassium recovery was more than 95.0%.Through laboratory testing and characterization analysis of the crystal,it was determined that the crystalline product was potassium aluminum sulfate crystal.（2）Recovery of aluminum.In the potassium recovery step,about 40%of the aluminum could be recovered together,and the remaining 60%of the aluminum could be recovered by adding sodium fluoride into the solution to react and produce cryolite（Na₃Al F₆）,and the related factors that affect the formation of cryolite such as the reaction time,the pH of the reaction solution,the reaction temperature,the dosage of sodium fluoride were investigated.Under the condition of pH 3.50,adding 1.1 times the theoretical consumption of sodium fluoride,reaction temperature 75℃,and reaction time 30 min,the aluminum recovery was more than 95.0%,with a manganese recovery of less than 5.0%.The cryolite product was analyzed and characterized,and it could be determined that the product was ordinary cryolite.（3）Recovery of manganese.Organic extractant P507(C₁₆H₃₅O₃P)was used to extract and recover manganese.Through extraction and stripping,manganese could be recovered in the form of manganese sulfate,and manganese sulfate product was prepared.The extraction efficiency of more than 96.0%was obtained under the following condition:the concentration of P507 was 40.0%（40.0%P507+60.0%sulfonated kerosene）,the pH of the water phase was 4.0,the ratio of organic phase to water phase（O/A）was 2:1,extracting at room temperature for 10 min.（4）Recovery of beryllium.CaO was added to the waste liquid,and the pH of the liquid was adjusted to 6.5,the small amount of residual aluminum ions and beryllium ions in the solution were precipitated in the form of aluminum hydroxide and beryllium hydroxide.At the same time,the physical adsorption effect of the aluminum hydroxide colloid was used to recover the beryllium ions in the solution through the combined action of"adsorption+precipitation".The grade of the beryllium in the enriched solid was BeO 0.50%,which is more than the grade of beryllium in the tailing（BeO 0.26%）,could be reused in the leaching process.（5）Wastewater treatment.After the extraction and recovery of the main metal ions,the acidic raffinate could be directly reused in the acid leaching process in industrial operation.