Study on extraction of high-purity magnesium oxide from low-grade magnesite with light burned magnesium powder

Magnesium ore resources are very rich. The process of producing light magnesium carbonate by carbonation of light burned magnesium powder can be divided into two types according to different ore properties: heavy burned magnesia dolomite carbonation method and magnesite carbonation method. The dolomite carbonation process is mature, but the production of high-purity products is limited due to the high calcium content in the carbonation leaching process. With the continuous development of smelting technology, many special operations in the metallurgical process tend to use high-purity magnesia to greatly improve the life of refractory products and reduce production costs. At the same time, due to the large export of high-grade magnesite, the problem of comprehensive utilization of magnesium ore resources is increasingly significant. Therefore, the author studied the technology of extracting high-purity magnesium oxide (wMgO>99%) by carbonization from low-grade magnesite fines. In the experiment, the properties of magnesite ore and its light burning performance, the digestion process of magnesia and the technological conditions and parameters of carbonation leaching were studied, and high-purity magnesia was produced from the obtained high-purity alkali magnesium carbonate.

The mineral composition is relatively simple. The main minerals are magnesite and dolomite, and the secondary minerals are talc and chlorite; Trace minerals include quartz, limonite, pyrite, apatite, etc. MgO mainly exists in the ore minerals magnesite and gangue minerals dolomite, talc and clinochlore as the basic composition form of independent minerals in the ore. CaO exists in minerals in two forms: one is in the form of basic components forming independent minerals, such as dolomite and apatite, and the other is in the form of dolomite micro inclusions in magnesite crystals. SiO2 also exists in gangue minerals such as quartz, talc, clinochlore, tremolite, and andalusite in two forms, and in magnesite crystals in the form of fine mechanical inclusions of quartz and silicate minerals.