Novel process for producing high-purify magnesium oxide from salt lake brine

Abstract

The invention discloses a novel process for producing high-purify magnesium oxide from salt lake brine, belongs to the technical field of comprehensive utilization of brine and aims to provide a process for coproducing high-purify magnesium oxide, sodium sulfate and sodium chloride by taking natural salt lake brine and sodium hydrogen carbonate as raw materials. The process comprises the following steps of: blending according to an equivalence ratio of magnesian ions to bicarbonate ions, being (1:2.02)-(1:2.05); separating after reaction to obtain intermediate products, i.e. basic magnesium carbonate and mother liquid I; washing the basic magnesium carbonate with deionized water; calcining the washed basic magnesium carbonate to obtain the high-purify magnesium oxide; evaporating and concentrating the mother liquid I, and then centrifugally separating to obtain the basic magnesium carbonate and mother liquid II; evaporating and concentrating the mother liquid II, and then centrifugingto obtain anhydrous sodium sulfate and mother liquid III; and cooling and crystallizing the mother liquid III to obtain sodium chloride and mother liquid IV. The process has the advantages of realization of comprehensive utilization of brine, simplicity of operation in a reaction process, easiness for industrialized mass production, high magnesium conversion ratio, good product quality, no three-waste emission in the reaction process and favorable environment and societal benefits.

Description

technical field [0001] The invention belongs to the technical field of comprehensive utilization of salt lake brine, and in particular relates to a new process for producing high-purity magnesium oxide from salt lake brine. Background technique [0002] At present, there are several methods for producing magnesium oxide using brine (sea) water as raw materials: ①. Emulsion method, including limestone emulsion method and dolomite emulsion method, that is, magnesium chloride and lime milk in sea (brine) water Slurry (prepared by adding water after calcining limestone or dolomite) reacts to generate magnesium hydroxide, which is then calcined to generate magnesium oxide. The raw material cost of this method is low, and it is the most widely used method abroad. For example, Japan and the United Kingdom generally use this method to produce high-purity seawater magnesia. The main disadvantage is that the product contains high calcium and boron. ②. Ammonia method, using ammonia o...

AI Technical Summary

Problems solved by technology

A significant advantage of the carbonization method over the milk slurry method is that the intermediate product is basic magnesium carbonate, and its filtration performance is better than that of magnesium hydroxide. The disadvantages are: huge equipment, large investment, unstable composition of basic magnesium carbonate, and calcium content in the product High (this problem exists when dolomite or magnesite is used as raw material)

[0003] Sulfate salt lake brine is Na + , Mg 2+ / / SO 4 2- , Cl - -H 2 O Quaternary interactive system, taking Yuncheng Salt Lake in Shanxi as an example, for many years, has been following the process of raising brine in summer and analyzing nitrate in winter, and using Glauber's salt decahydrate as raw material to produce Yuanming powder. Due to the single extraction of sodium sulfate, magnesium salts are enriched , not only affects the product quality of sodium sulfate, but also causes a waste of magnesium resources

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