Invention of Alumina Production Technology to Solve Worldwide Concerns

Alumina is the basic materials in the production of aluminum, but also used as organic reaction catalyst, abrasives, polishes, refractory materials, etc. in ceramics, medicines, electronics, machinery and other industries, whose correlation degree is more than 90% of national economy. The production of alumina is about 50 million tons each year in our country, accounting for 50% of the world, and we are the world's largest producer of alumina. Innovation and breakthrough of alumina production technology are particularly important. Traditional Bayer Process of alumina production(utilization rate is as high as 99%) has two basic flaws: One is that it has high requirements for bauxite, and the other is that it will produce a large number of high alkalinity of red mud. Among them, the production of 1 ton alumina will bring 1 ~ 2 tons of red mud, which not only harms the environment, but also takes up a lot of space. The use of red mud is a worldwide difficult concern.

Recently, China Nonferrous Metals Industry Association have organized some experts to identify "Large-scale Low-cost Bayer Process Red Mud Technology" completed by the team of Professor Zhang from Northeast University, and they agreed that the technologies have reached the international leading level. For example, using the technology to handle bauxite of 3.29 aluminum and silicon, whose alumina dissolution rate is as high as 86%, compared with the traditional method.

70% of bauxite resources in China belong to the low grade ore, and a large number of imports are needed, which can reach more than 50%. How to effectively utilize low grade bauxite in our country? It has been the technology bottleneck problem of alumina industry in China. The special metallurgy innovation team led by the professor Tingan Zhang put forward a new structure red mud without alkali and containing no aluminum in theory from changing the balance solid phase structure in red mud, after years of painstaking research. Thus, the above technologies not only get away theoretically from the limits of Bayer Process on alumina production, but also reduce the content of sodium and aluminum in the red mud, fundamentally solving large-scale, harmless, resource recovery and low cost of red mud, which is a disruptive technology of alumina production.

The success  of technology research and development is of great significance for the alumina industry in China, which is equivalent to make our bauxite resources expanded about 2 ~ 3 times, prolongs the service life of more than 30 years, and can get rid of the dependence on imported mineral of alumina industry. At the same time, using the technology to process low and medium grade bauxite can reduce the production cost per ton about 400 ~ 500 RMB than the existing methods. The application of the technology can also reduce the alkali content of red mud from 4% ~ 6% to 0.12% ~ 0.20%,. The economic benefit of red mud per ton can reach 150 RMB, and the maintenance cost of red mud yard each year is more than 60 million RMB. If the technology is widely used in our country, the economic benefit in the production of alumina can be extra improved about 50 billion RMB every year, which has significant social benefits and economic benefits.