Silicon steel grade magnesia is a relatively economical magnesia coating material, and it is also a high value-added magnesia product.
China is a big producer of magnesium compounds, ranking first in the world, but the product grade is low, the production scale is generally small, the automation control level is low, the energy consumption is high, and the research, preparation and application of high-purity, high-quality, high-value-added magnesium oxide Application is still far behind developed countries. It is very important to speed up the research and application of the preparation of silicon steel grade magnesium oxide.
Adopt advanced technology and equipment, improve production level, develop high-purity magnesium series products, and transform China from a large magnesium oxide production country to a magnesium oxide production power.
In the production process of silicon steel grade magnesia, due to the strict requirements on the purity, particle size and hydration rate of magnesia, the ore resources are less and less, and the grade is getting lower and lower, the impurity content is high, and the product quality is unstable; Seawater or salt lake brine resources are huge and cheap, with low production cost and low impurity content, and are suitable for the production of silicon steel grade magnesium oxide. In China, the reserves of magnesium salt in salt lake brine alone are as high as 4.816 billion tons.
A large number of magnesium resources in salt lake brine cannot be comprehensively utilized. Cause huge waste, but also affect potash fertilizer production. Therefore, the production of high-purity silicon steel grade magnesium oxide with seawater or salt lake brine as raw material has great advantages and will be an inevitable trend in the development of this industry.
Lime is used as a precipitant. Although the production cost is low, it has high requirements for lime purity and activity.
At the same time, it will introduce calcium ions that are very harmful to the quality of silicon steel. It is difficult to remove impurities, the product quality cannot be guaranteed, and there is still a large amount of slag. Serious environmental pollution and other problems; using sodium carbonate, sodium hydroxide, etc.
Precipitating agent, due to its wide range of sources, is relatively cheap, and does not introduce impurity ions, the product has high purity, and can also realize the recycling of ammonia water and carbon dioxide.
Therefore, in the future, ammonia water, ammonium carbonate or ammonium bicarbonate will be used as Precipitating agent, the use of basic magnesium carbonate as an intermediate product will be a development trend.