Developing Low Cost and High Grade Light Burned Magnesia

It is generally believed that the global high-end refractory market requires high-grade magnesia with a MgO content of 98%, sintered magnesia with a bulk density of 3.40 g/cubic centimeter and fused magnesia with a bulk density of 3.50 g/cubic centimeter. The annual consumption of high-grade magnesia in high-temperature industrial sectors such as steel and cement is about 1 million tons.

The total annual output of sintered magnesia in China is about 4 million tons. Around 1980, the export volume of cheap natural magnesia in China increased sharply, and it has occupied the international middle and low-end magnesia market. Generally speaking, the supply of middle and low-end magnesia in the market exceeds the demand. The output of this part of sintered magnesia should be controlled, especially the production of re-burned magnesia should be gradually reduced. Due to the decline of ore grade and the rise of fuel and labor prices, the quality of mid-grade magnesia and high-purity magnesia has decreased significantly. In the future, the market demand for mid-grade and high-purity magnesia will increase, because the trend of mid-grade sand replacing reburned sand downwards and high-purity sand replacing part of fused sand upwards is obvious.

After more than 30 years of disorderly mining, it is an indisputable fact that the quality of light burnt magnesia decreases and the quality of magnesia decreases. At present, the related enterprises have gradually realized the importance of ore flotation and purification, and it is an inevitable trend to popularize mineral processing technology. Starting from beneficiation, the grade of ore is improved, high activity light-burning magnesia is produced by energy-saving and efficient light-burning equipment, and the quality of high purity sand is improved by means of dry high pressure dry ball and high temperature calcination of clean fuel. It is also necessary to explore new technology and process of magnesia production in order to produce high-grade sintered magnesia with 98% MgO content and 3.40 g/cubic centimeter bulk density at low cost. It is in line with the future development direction to build a large-scale production plant integrating mineral processing and production of high-purity magnesia.