Besides brown fused alumina, bauxite also contains SiO2, Fe2O3, TiO2, Ca0 and other impurities. According to the world bauxite output (130-150 million tons / year), the static guarantee period is more than 200 years. In 2002, the proven bauxite reserves in the world were about 25 billion tons, and the reserve base was about 34 billion tons. With the continuous expansion of aluminum consumption, the mining volume of bauxite is also increasing.

 

Different types of bauxite have different crystal states due to their alumina, so the reaction ability with sodium aluminate solution will naturally be different. Even if the same type of bauxite has different crystal integrity due to different places of origin, its dissolution performance will be different. The dissolution performance of different types of bauxite will be discussed below. In gibbsite type bauxite, alumina mainly exists in the form of gibbsite (Al2O3 · 3H2O).

 

As we all know, special refractories are a group of new refractories developed on the basis of traditional ceramics and refractories, also known as high temperature ceramics. Ceramic is named after technology. Usually, brown aluminum oxide products made by powder making, molding, sintering and other processes are called ceramics. It can also be said that special refractories are refractory products made of ceramic production process. The slurry shall have good suspension and fluidity.

 

For this reason, some factories are committed to the production of sintered corundum directly by one-step grinding of industrial alumina. After the material is crushed to a certain fineness, a grinding aid is added. After the material is adsorbed on the particle surface, it can not only de coagulate, but also improve the grinding efficiency due to the reduction of the particle surface energy. The addition of grinding aid can reduce the water consumption, improve the dispersibility and the fluidity of mud, which is conducive to the smooth progress of ultrafine grinding.

 

Generally, adjust according to the actual stick color. It is characterized by adding excessive carbon reduction in the middle stage and decarburizing agent in the later stage. That is to say, the former and the brown aluminium oxide middle stage are reduction smelting period, and the later stage is oxidation refining period. After the reduction smelting period, it enters into the oxidation refining period. During the oxidation refining period, the unmelted layer on the upper surface of the furnace pool shall not be too thick, and the material shall not be added any more. At this time, decarburization begins.

 

Generally, silica balls are not used as abrasives, and some SiO2 impurities will be grinded into the materials. Silica balls and silica linings are allowed only when clay or SiO2 containing materials are added. In one-step production, water, liquid grinding aids, dense additives, industrial alumina, etc. are uniformly added into the continuous vibration mill, and the slurry after vibration grinding is fully stirred in the slurry tank, and then screened, iron absorbed and pressure filtered.

 

This is because the pulverized fine powder forms aggregates under the action of molecular cohesion and prevents further pulverization; at the same time, the fine powder acts as a buffer for large particles Effect, making larger unpulverized particles difficult to further pulverize. Al2O3 is the main component in bauxite. The higher the content, the better. At present, the brown fused aluminum oxide production of industrial alumina requires an aluminum-silicon ratio of not less than 3.0 to 3.5. Other oxides are regarded as impurities. SiO2 is a harmful impurity in the production of alumina by the alkaline method.