Study On Preparation Of Magnesium Sulfate From Tailings Of Potassium Magnesium Sulphate In Lop Nor

A large amount of flotation tailings is produced during the production of potassium magnesium sulphate fertilizer in the production process of potassium magnesium sulphate,and about 3.5 tons per 1 tons of potassium sulfate and magnesium fertilizer are produced by flotation tailings.After preliminary analysis,the main components of flotation tailings are Magnesium Sulfate and sodium chloride.In order not to be abandoned as industrial waste to cause environmental protection and other problems,how to recycle the useful components in the flotation tailings is of great significance.In this research,the fractional dissolution was used firstly to separate Na from Mg and increasing Mg content in the feed.First,it was used as flotation medium,and then it could be used as raw material of Mg.After dissolving,the recovery rate of Mg was 98.17%,and the recovery rate of Na was 44.21%.The flotation tests were carried out with the step dissolution solution as the flotation medium,and alkylmorpholine and sodium petroleum sulfonate as collector respectively.The flotation effect was not ideal.Most of Mg entered the flotation medium,and only had the effect of separating Na from Mg.After analysis,the flotation liquid can be used as the Mg raw material.In the two step after dissolving liquid as raw material of Mgliquid cooling test,considering the climate characteristics of Lop Nor area and the temperature difference between day and night,evaporation,cooling,evaporation,cooling process,explore the suitable process conditions of evaporative cooling: cooling temperature 0~10,time is no less than 12h;the evaporation temperature of evaporation at room temperature 20~35?,time to solution proportion at or close to the raw liquid proportion is appropriate.Two methods of filtration,washing and pulping and washing were used to wash coarse Mg products.It was found that the quality of products after pulping and washing was good,Cl<0.30%,which achieved the quality requirement of impurity Cl for Mg products.The total yield of Mg process was 69.89%.The quality of magnesium sulfate heptahydrate products reached first-class grade of chemical industrial in HG/T2680-2009;The quality of Magnesium Sulfate monohydrate products reached first-class grade of chemical industrial in Q/NFJ-03-022-2001.Study on the by-product generated in the process of recovery and purification of sodium chloride,the process of crude NaCl.The recovery rate of NaCl was 68.90%.The recovery rate of purification was 91.95%,and the total recovery rate was 63.34%.Dissolution of solid phase after treatment the quality of refining industrial grade salt,solid phase evaporation by two times after the treatment the quality of the products reached two grade.The quality of the two is a grade of refined salt product according to the ratio of output.In this study,three products of magnesium sulfate heptahydrate,Magnesium Sulfate monohydrate and sodium chloride were prepared by using the main components of the resource.The following two goals are achieved:(1)the whole process basically has little discharge from waste residue and liquid,(2)which is in line with the requirements of developing new projects without polluting the environment.By preliminary estimation,the economic benefit of the process was better.