Method for preparing high-purity magnesium fluoride by using magnesite

Abstract

The invention discloses a method for preparing high-purity magnesium fluoride by using magnesite. The method is characterized by comprising the following steps: (1) calcining the magnesite, thus obtaining light calcined magnesia mineral powder; (2) taking and adding the light calclined magnesia mineral powder in an ammonium salt solution to remove soluble calcium, and filtering, thus obtaining filter cake, wherein ammonium salt is one or several of ammonium chloride, ammonium nitrate, ammonium sulfate, ammonium oxalate or ammonium acetate; (3) adding the obtained filter cake in an organic acid solution for reacting, and filtering after reacting, thus obtaining leachate, wherein an organic acid is one or several of a formic acid, an acetic acid, a propanoic acid, a lactic acid, a citric acid, a glycolic acid, a malonic acid, a succinic acid or an adipic acid; (4) adding a hydrofluoric acid in the leachate, generating a precipitate, filtering, washing, and drying, thus obtaining the high-purity magnesium fluoride. According to the method disclosed by the invention, the source of raw materials is wide, the cost is low, the requirements of a device are low, the high-purity magnesium fluoride can be obtained by utilizing cheap magnesite, and the production cost of the high-purity magnesium fluoride is reduced to a large extent.

Description

technical field [0001] The invention belongs to the technical field of mineral processing, and in particular relates to a method for preparing high-purity magnesium fluoride from magnesite. Background technique [0002] my country's magnesite resource reserves rank first in the world, accounting for one-third of the world's total reserves, mainly distributed in Liaoning, Hebei, Shandong and other provinces and cities. Magnesite has a wide range of uses and can be used in many fields such as refractory materials, ironmaking additives, magnesium oxychloride cement, flue gas desulfurization, acid wastewater treatment, etc. However, it is widely used in these industries and the product price is low. Magnesium fluoride is an important chemical raw material and optical material. High-purity magnesium fluoride has excellent optical properties, thermal stability and chemical stability, and is widely used in optical film materials, catalyst carriers, infrared optics, etc. High-end t...

AI Technical Summary

Problems solved by technology

The preparation method of magnesia and basic magnesium carbonate is to use high-purity magnesium oxide or basic magnesium carbonate as raw material to react with hydrogen fluoride to prepare magnesium fluoride, while the raw materials of high-purity magnesium oxide or basic magnesium carbonate are expensive and cost high

The brine preparation method uses ammonia water or ammonium bicarbonate as raw materials to prepare magnesium hydroxide or basic magnesium carbonate, and neutralizes it with hydrogen fluoride to obtain magnesium fluoride. The process needs to consume a large amount of ammonia water, and the precipitation of magnesium ions is not complete, so the cost is also high

[0005] The method of patent application CN103214012A is that hydrogen fluoride gas reacts with high-purity magnesium oxide, magnesium carbonate, magnesium hydroxide or magnesium chloride to obtain high-purity magnesium fluoride through gas phase reaction. In this process, the cost of high-purity magnesium compound raw materials is relatively high, and the reaction temperature is 400 ~ 500 ℃, high requirements for corrosion resistance of equipment, resulting in high investment costs

Patent applications CN105776260A and CN101100303A all have the same principle as the preparation of magnesium fluoride from brine, and the methods are that magnesium hydroxide is reacted with ammonia water to prepare magnesium hydroxide, and then magnesium hydroxide is reacted with hydrofluoric acid, dried and calcined to obtain high Pure magnesium fluoride, this method needs to consume a large amount of ammonia water, and the precipitation is not complete when magnesium ions prepare magnesium hydroxide, so the cost is higher

The current existing methods are expensive in terms of raw material sources and equipment requirements

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