Method for preparing high-purity magnesium oxide

Abstract

The invention discloses a method for preparing high-purity magnesium oxide. The method comprises the following steps: 1) detecting iron content in a magnesium hydrogen carbonate solution, adding an excessive strong oxidant, performing oxidation on Fe2+ to Fe3+ under condition that a pH value is 6-8, and precipitating the material to obtain iron hydroxide precipitate; 2) after oxidation is completed, according to an excessive value of the strong oxidant, adding a weak reducing agent for a neutralization reaction, 3) adding active carbon to absorb the iron hydroxide precipitate, filtering the iron hydroxide precipitate to obtain low-iron magnesium hydrogen carbonate solution with an iron content being less than or equal to 0.6 mg / L; and 4) performing pyrolysis, filtering and calcining on thelow-iron magnesium hydrogen carbonate solution in order to obtain the high-purity magnesium oxide. The method has the advantages of stable operation and high iron removal rate, iron hydroxide precipitated during whole process flow cannot be easily re-dissolved, the iron content of a magnesium product is low, and quality of the product can be increased to analytically pure by an industrial article.

Description

technical field [0001] The invention belongs to the technical field of inorganic salt production, and in particular relates to a method for preparing high-purity magnesium oxide. Background technique [0002] High-purity magnesium oxide refers to samples with MgO content greater than 98%. It has excellent alkali resistance and electrical insulation at high temperatures, good light transmission, high thermal conductivity, and large thermal expansion coefficient. It is widely used in electronics, optics, instrumentation, metallurgy, and national defense. and other fields have a wide range of applications. At present, my country's annual demand for high-purity iron oxide is more than 100,000 tons, but my country's production is far from enough, and the gap mainly relies on imported products to supplement. [0003] At present, the methods for preparing high-purity magnesium oxide at home and abroad include seawater lime method and salt lake brine method. The seawater lime meth...

AI Technical Summary

Problems solved by technology

Although this method does not need to change the original production process or build additional treatment facilities, and can remove some iron ions, the added sodium sulfide itself is unstable and easy to decompose hydrogen sulfide gas that pollutes the environment; itself has a large amount of H 2 CO 3 , it is easy to decompose the black ferrous sulfide generated by the reaction into hydrogen sulfide gas and ferrous ions, so that the iron ions re-enter the solution

The stability of the whole reaction process is relatively poor, which is not conducive to large-scale industrial production

Images