Industrial Requirements for Magnesite Ore
(1) Refractory material: The fused stone is a dense block mainly composed of microcrystalline periclase in which CO2 almost completely escapes and chemical activity is lowered. Magnesia refractory products such as magnesia bricks, metallurgical magnesia and magnesia refractory clay are produced from calcinite. The higher the MgO content in the ore, the more magnesite in the product and the better the fire resistance. The main impurities in the ore are CaO, SiO2, A12O3 and Fe2O3. After calcination at high temperature, some new minerals will be formed, which have different effects on the quality of the magnesia brick. For ordinary magnesia bricks, CaO and SiO2 are harmful impurities. When the content of CaO is large, the formation of homomorphic transformation of dicalcium silicate (2CaO·SiO2) will occur at a certain temperature, and the volume will increase, which will cause cracking or scattering of the magnesia brick. More calcium peridotite (CaO·MgO·SiO2) is formed to reduce the load softening point and slag resistance of the product. In addition, the presence of free CaO can also crack the product due to hydration. When the content of SiO2 is too large, a large amount of forsterite (2MgO·SiO2) is formed, which is disadvantageous for sintering into a dense structure. A small amount of Fe2O3 is not considered as a harmful impurity in ordinary magnesia bricks. Fe2O3 can form magnesium ferrite (MgO·Fe2O3) with MgO, which will promote the growth of the magnesite crystal and promote the sintering of the magnesia brick. However, the solubility of magnesium ferrite in periclase varies drastically with temperature, affecting the thermal stability of the product. A12O3 can form aluminum-magnesium spinel (MgO·Al2O3) during the processing of the product, which improves the thermal stability of the product. Therefore, ordinary magnesium brick does not require A12O3 content.
(2) Magnesium cement (magnesium chloride cement) If CaO in the ore is present in carbonate, it will form free lime during light burning, which will cause expansion and dry cracking of magnesium cement products during solidification (silicate CaO has no harm). CaO ≤ 2 - 4% is required in the ore. In the calcined magnesite, even if the SiO2 content is 15-20%, the cementation property is not affected, so the SiO2 content in the ore can be higher. If the Fe2O3 content is too high, the magnesium binder will turn red and its content should be low. A12O3 is generally not high in ore and does not affect the quality of magnesium cement.
(3) Magnesium metal
The production of magnesium metal from magnesite mainly uses magnesium chloride molten salt electrolysis method, but there are various methods for preparing anhydrous magnesium chloride. In China, magnesium chloride is directly chlorinated to produce magnesium chloride, and then the temperature is about 700 °C. The molten magnesium chloride is electrolyzed to obtain crude magnesium. In the preparation of magnesium chloride, oxides of calcium, silicon, aluminum and iron are harmful impurities.
(4) Other aspects
The requirements for other applications of magnesite ore are different. The chemical industry and the paper industry require high MgO. The ceramics and glass industries require low levels of Fe2O3 and TiO2 to avoid affecting the color of the product. When making natural rubber fillers, it is required to be free of manganese, which causes premature aging of rubber products.
FENGCHENG CITY HEQI BRUCITE MINING CO., LTD is registered in Dandong city, Liaoning province. Sufficient talent reserves, proper environmental governance, convenient transportation and communication.We are mainly engaged in the purchase, processing and sales of mineral products.
Main products: magnesium hydroxide flame retardant and brucite powder. Complete specifications of products, welcome to visit our factory guidance.
Since its inception, with "business integrity, standard services, sustainable development, commitment to the community" is the principle of the company. Our company has a good reputation, which is oriented by customers' demands, strives for survival by quality reputation, relying on high-quality products and good services.
