Magnesite resources are very rich in our country, the process of producing light magnesium carbonate by using the method is divided into two kinds according to different ore properties: dolomite carbonization and magnesite carbonization. Dolomite carbonization process is mature, but because of the high calcium content in carbonization leaching process, the production of high purity products is limited by this process. With the continuous development of smelting technology, many special operations in the process of metallurgy tend to use high purity magnesia to greatly improve the life of refractory products, reduce production costs. At the same time, due to the export of high grade magnesite, the comprehensive utilization of magnesite resources becomes more and more obvious. In this paper, low grade magnesite powder ore was carbonized to extract high purity magnesium oxide (wMgO > 99%). In the experiment, the ore properties and light firing properties of magnesite, the digestion process of magnesia and the technological conditions and parameters of carbonation leaching were studied. High purity magnesia was produced from the obtained high soda magnesium carbonate.
The mineral composition of the sample is relatively simple, the main minerals are magnesite and dolomite, and the secondary minerals are talc and chlorite. Trace minerals are quartz, limonite, pyrite, apatite and so on. MgO exists in ore minerals magnesite and gangue minerals dolomite talc and plagiochlorite as a basic form of independent mineral. CaO exists in minerals in two forms: one is in the form of the basic components that form individual minerals, such as dolomite and apatite light burned magnesite, and the other is in the form of fine inclusion of dolomite in magnesite crystals. SiO2 also exists in gangue minerals such as quartz, talc, plagiochlorite, tremolite and alusite in two forms, and in magnesite crystals in the form of fine mechanical inclusions of quartz and silicate minerals.
(1) High purity light magnesium carbonate with wMgO of 99.31% at zero can be obtained by carbonization leaching process of low grade magnesite powder ore. The recovery of magnesium oxide was 80.97%. High purity sintered magnesia with content of 99.21% and volume density of 3.38g/cm can be obtained by sintering process.
(2) The calcium oxide content of light magnesium carbonate produced by atmospheric carbon dioxide leaching process is slightly higher than the CaO grade of the final product of the previous pressure test Z.
(3) Because the grinding process was not adopted in the process of magnesite carbonization leaching, the sample size is large, so the conversion rate and recovery rate of magnesium oxide are not satisfactory. When the particle size is smaller, the conversion index of magnesium oxide in the leaching solution is very ideal.