Study on Extraction of High Purity Magnesium Oxide from Low-grade Magnesite by Light-burned Magnesium Powder

Magnesium mineral resources are very rich. The process of producing light magnesium carbonate from light burned magnesia powder by carbonization can be divided into two kinds according to the different ore properties: dolomite carbonization and magnesite carbonization. The production process of dolomite carbonization is mature, but the production of high purity products is limited because of the high calcium content in the carbonization leaching process. With the continuous development of smelting technology, many special operations in 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 comprehensive utilization of magnesite resources has become increasingly prominent. For this reason, the author used low-grade magnesite powder to carry out carbonization process to extract high-purity magnesium oxide (wMgO > 99%). In the experiment, the properties of magnesite ore and its light burning property, the digestion process of magnesia and the technological conditions and parameters of carbonation leaching were studied, and high purity magnesia was produced with the obtained high purity alkaline magnesium carbonate.

Its mineral composition is relatively simple, the main minerals are magnesite and dolomite, the secondary minerals are talc and chlorite, and the trace minerals are quartz, limonite, pyrite and apatite. Magnesium oxide in ores mainly exists in magnesite and gangue minerals dolomite, talc and clinochlore as the basic form of independent minerals. CaO exists in minerals in two forms: one is in the basic form of forming independent minerals, such as dolomite and apatite, and the other is in magnesite crystals in the form of dolomite micro-inclusions. SiO 2 also exists in quartz, talc, clinochlore, tremolite and columnar gangue minerals in two forms. The other is in magnesite crystals in the form of micro-mechanical inclusions of quartz and silicate minerals.