1. What is alumina?
Aluminum oxide, also known as aluminum oxide, is a dehydrated product obtained from bauxite through Bayer process, sintering process, etc., and then heated and decomposed. It is a white powder or sand things.
2. What are the quality indicators of alumina?
The quality indicators of alumina mainly include chemical composition and physical properties. According to the provisions of GB/T24487-2022, the national standard of alumina, the main chemical composition indicators include AL2O3, SiO2, Fe2O3, Na2O, CaO and ignition loss content; the main physical performance indicators include specific surface area and particle size indicators.
3. How to classify alumina?
Alumina is divided into two categories according to different uses: one is used as raw material for electrolytic aluminum, called metallurgical grade alumina; the other is non-metallurgical alumina used in ceramics, chemical, pharmaceutical and other fields, It is called special alumina, also known as chemical alumina. At present, most of the world's alumina is used for electrolytic aluminum smelting and production, while only about 5% is used for other purposes.
4. What quality standard does the alumina industry adopt?
At present, there are two alumina standards promulgated and implemented in my country: one is the national standard "Alumina" (GB/T24487-2022), which is applicable to the production of bauxite, recycled alumina raw materials, etc. It is used as alumina for the production of metal aluminum by molten salt electrolysis, and is also suitable for the production of corundum, ceramics, refractory products and alumina as raw materials for the production of other alumina chemicals; the second is the industry standard "Metallurgical Grade Alumina" (YS/ T803-2012), only applicable to alumina used in the production of electrolytic aluminum by molten salt electrolysis, that is, metallurgical grade alumina.
5. What are the main production costs of alumina?
Alumina production costs mainly include raw material costs and manufacturing costs. Among them, the cost of raw materials mainly includes bauxite, caustic soda and energy, etc., accounting for about 39.7%, 15.6% and 25% respectively in 2022; manufacturing costs mainly include labor costs, depreciation and repair costs, accounting for about was 15.7%.
6. What are the production processes of alumina?
Alumina production processes mainly include Bayer process and sintering process. The technological process of the Bayer process generally has the following main procedures: After the bauxite is crushed, it is mixed with caustic soda to make a qualified raw ore pulp; the raw ore pulp is pre-desiliconized, diluted, and sedimentation and separation of red mud; the sedimentation separation is decomposed by seed crystals Aluminum hydroxide is obtained; aluminum hydroxide is separated, washed and calcined to obtain alumina.
The sintering process has the following main procedures: making fine abrasive slurry from bauxite, limestone and soda ash according to the ratio; after sintering, dissolution and desiliconization procedures, sodium aluminate solution is prepared; the solution is passed through After carbonation and decomposition, the precipitated aluminum hydroxide and sodium carbonate mother liquor are separated; the aluminum hydroxide is roasted to form alumina.
7. What is the relationship between alumina and electrolytic aluminum?
Alumina is the main raw material for the production of electrolytic aluminum. Usually, 4 tons of bauxite can produce 1.92 tons of alumina and then 1 ton of electrolytic aluminum.
微信扫一扫打赏
