Leaching - Extraction Recovery Of Phosphate Tailings, Phosphorus, Magnesium Pilot Study

For the gradual depletion of the phosphate resources and the tending depleted grade of them,in order to satisfy the wet-process phosphoric acid production(WPA) ore quality requirements of raw materials,it will be a large amount of phosphorus tailings per year through the use of various mineral processing technology.If we can take comprehensive utilization of the phosphorus tailings,that not only can reduce the waste of resources,but also prevent occupied land and environmental pollution which the tailings piled up.Through the chemical analysis of phase from this flotation tailings,we found that the main phases in the tailings are Ca(CO₃)₂,Mg(CO₃)₂ and Ca₅F(PO₄)₃,with the content of P₂O₅ from 7%to 9%,the content of MgO is as high as 16 to 18 per cent,which attach a high magnesium phosphate tailings.This article initially explored the new process which using hydrochloric acid and sulfuric acid leaching mixed to decompose phosphate tailings,this new technology research acid solution process conditions of phosphate,and study MgCl₂ and H₃PO₄ extraction.In the process optimization studies of acid conditions,I got optimum conditions in laboratory conditions through the single-factor orthogonal test.The optimum conditions are 60 min's reaction time,80℃'s temperature,the 5:1 ratio of liquid to solid,the 1.05 excessive coefficient of acid.In this condition,the extraction rate of P₂O₅ and MgO are higher,respectively attain 97.2%and 98.5%.And the influence of factors to leaching rate of the P₂O₅ and the MgO are similar.The two most notable factors are the reaction time and the ratio of liquid and solid leaching rate,the least notable factors is coefficient of excessive acid,which mainly caused by the error.Through the extraction experimental study,I determine the choice of n-butanol as the extraction solvent,and then identified the best extraction conditions and the anti-extraction process in the further pilot study.In the best extraction conditions, the P₂O₅ extraction is best and attains more than 68%.The best extraction conditions:H₃PO₄ concentration of 60%,n-butyl alcohol for extraction,extraction compared to 1:1,the room temperature,the extraction time for 5 minutes,churn up with balanced speed..The best anti-extraction process conditions:used water for anti-extraction,the amount is about the volume of 30%of organic phase before anti-extraction anti-extraction time for 3 minutes.At room temperature for anti-extraction, the stripping rate attain 90%.The technological conditions of the test are easy controlled with simple operation and low facility request.It could produce circularly,and only a small quantity of waste slag that is pollution-free to our environment was produced.The research in this paper can provide some valuable reference for exploitation and utilization of Wengfu phosphate floatation tailings.