It is generally believed that the global high-end refractory market requires 98% MgO content of high-grade magnesia, volume density of sintered magnesia 3.40g/cubic centimeter, volume density of fused magnesia 3.50g/cubic centimeter. The annual consumption of high grade magnesia in steel, cement and other high-temperature industrial sectors around the world is about 1 million tons. China's total annual output of sintered magnesia is about 4 million tons. Around 1980, the export volume of cheap Chinese natural magnesia surged, has been occupying the international medium and low end magnesia market.
Generally speaking, the supply of low and medium magnesia exceeds the demand in the market at present, so the output of this part of sintered magnesia should be controlled, especially the production of heavy burned magnesia should be gradually reduced. Due to the decline of ore grade and the increase of fuel and labor price, the quality of medium grade magnesia and high purity magnesia has decreased obviously. In the future, the market demand for medium and high purity magnesia will increase, because the trend of medium sand replacing heavy fired sand downward and high purity sand replacing part of fused sand upward has been obvious. After more than 30 years of disordered mining, it is an indisputable fact that the quality of high quality magnesite ore has decreased and the quality of light fired magnesite ball has declined. At present, relevant enterprises gradually realize the importance of ore flotation purification, and it is an inevitable trend to popularize beneficiation technology. Starting from beneficiation to improve ore grade, with energy-saving and efficient light burning equipment to produce high activity light burning magnesium oxide, through the dry process of high pressure dry ball and clean fuel high temperature calcining production means, improve the quality of high purity sand. More to explore the production of magnesia new technology, new flow, in order to low cost production of MgO content 98%, volume density of 3.40g/cc high grade sintered magnesia. It is in line with the future development direction to build a large production plant integrating mineral processing and production of high purity magnesia.
Improving the technology and equipment of fused magnesia due to the price competitiveness of China's fused magnesia, a large number of western seawater magnesia manufacturers closed down. At present, in the world market of fused magnesia with MgO content >98.5%, China occupies 90% of it, and its application is more extensive. However, the product has high energy consumption and needs to use superior raw materials. Therefore, the comprehensive promotion and improvement of technical equipment measures in the fused magnesia industry will help to reduce energy consumption and control the quality, which is the inevitable trend of future development.
Focus on developing synthetic raw materials
At present, the main synthetic raw materials based on magnesium oxide in Liaoning are electromolten magnesia chrome sand, sintered magnesia calcium sand, sintered magnesia aluminum spinel sand, sintered magnesia aluminum iron sand, with an annual output of more than 200,000 tons. Magnesia calcareous refractory has excellent performance, but its application is limited by the problem of CaO hydration, so the waterproofing of magnesia calcareous refractory should be studied emphatically. It should be pointed out that magnesium-calcium refractory has the effect of removing sulfur and phosphorus impurities in steelmaking due to the presence of CaO; And CaO exists, without hydration is impossible, only to prevent its hydration.
With the increase of environmental protection, chrome refractories will be withdrawn from the market, and the research and production of replacement products are imperative. Therefore, we should further develop and produce MgO-Al2O3, MgO-CaO, MgO-ZrO2, MgO-SiO2, MgO-Fe2O3, Mgo-Cao-Fe2O3, Mgo-Al2o3-Zro2, Mgo-Cao-Zro2, Mgo-Al2o3-Fe2O3 ( FeO) and other high quality synthetic magnesium raw materials.
Generally speaking, as a non-renewable and indispensable strategic resource, restricting and reducing the exploitation of magnesite and improving the utilization rate of its resources will be the focus of all related work in the future. Therefore, the country should greatly reduce the export quota of magnesia, limit the export of low value-added raw materials and ordinary magnesium products.
At the same time, enterprises with mining resources and conditions are encouraged to carry out large-scale technological transformation and equipment renewal, or disperse mining of raw materials, and build several large-scale raw material bases. Mining rock stripping, purification of low-grade ore, construction of large light burning and calcining equipment, and industrialization of new sand making process require a large amount of capital and new technical support, and there are certain risks. We hope that relevant departments of the state can provide support in policy, capital, science and technology, etc.
Only by establishing large raw material bases, adopting systematic and advanced technologies, forming economies of scale, and under the guidance of strong national policies and laws and regulations, can it be possible to eliminate heavily polluting raw material production enterprises and realize the elimination of backward ones in accordance with the principles of market economy. As the largest magnesite refractory raw material production base in the world, China can achieve long-term, stable and sustainable development only by adhering to the effective and rational utilization of magnesite resources, adhering to the business philosophy of low carbon, low energy consumption, low emission and low pollution, integrating economic benefits with resources and environmental protection, adhering to scientific and technological innovation, and adjusting the product structure.