Bauxite actually refers to the ore that can be used in industry and is composed of gibbsite and gibbsite as the main minerals. Bauxite is the best raw material for the production of aluminum metal, and also the most important application field. Its consumption accounts for more than 90% of the total output of bauxite in the world.
The application fields of bauxite include metal and nonmetal. It is the best raw material for producing metal aluminum and also the most important application field. Its consumption accounts for more than 90% of the total output of bauxite in the world. Bauxite accounts for a small proportion of non-metallic consumption, but it is widely used. Mohs hardness is 2.5-3.5.
Bauxite ore has various uses:
(1) Aluminum smelting industry. It is used for national defense, aviation, automobile, electrical appliances, chemical industry, daily necessities, etc.
(2) Precision casting. The bauxite clinker is processed into fine powder and made into casting mould and then precision cast. It is used in military, aerospace, communications, instrumentation, machinery and medical equipment departments.
(3) For refractory products. The refractoriness of high alumina clinker is as high as 1780 ℃, with strong chemical stability and good physical properties.
(4) Aluminum silicate refractory fiber. It has the advantages of light weight, high temperature resistance, good thermal stability, low thermal conductivity, small heat capacity and mechanical vibration resistance. It is used in steel, nonferrous metallurgy, electronics, petroleum, chemical industry, aerospace, atomic energy, national defense and other industries. It is to put the high-alumina clinker into a high-temperature electric arc furnace with a melting temperature of about 2000~2200 ℃, and then melt it at high temperature, inject and cool it with high-pressure high-speed air or steam to form a white "cotton" - aluminum silicate refractory fiber. It can be pressed into fiber blanket, plate or woven cloth to replace the refractory bricks for the lining of high-temperature furnaces in smelting, chemical, glass and other industries. Firefighters can use fire-resistant fiber cloth to make clothes.
(5) Using magnesia and bauxite clinker as raw materials and adding appropriate binder, the effect of pouring the integral lining of steel ladle is very good.
(6) Various compounds that can produce aluminum in the manufacturing of bauxite cement, abrasive materials, ceramic industry and chemical industry.
Among them, the most important uses are: refining metal aluminum in the aluminum industry, as refractory and abrasive materials, and as raw materials for high-alumina cement. The quality requirements of ores vary with different uses.
The industry standard for bauxite ore (YS/T78-94) issued by China Nonferrous Metals Industry Corporation in 1994. According to this standard, bauxite is divided into three types: sedimentary diaspore, accumulative diaspore and laterite gibbsite, and is divided into nine brands according to chemical composition, including LK12-70, LK8-65, LK5-60, LK3-53, LK15-60, LK11-55, LK8-50, LK7-50, LK3-40. In addition to the provisions on the chemical composition of bauxite, the standard also requires that the water content of sedimentary diaspore shall not be greater than 7%, and that of accumulated diaspore and laterite gibbsite shall not be greater than 8%. In addition, the particle size of bauxite ore shall not be greater than 150mm. Bauxite ore shall not be mixed with soil, limestone and other sundries.
The non-metallic uses of bauxite are mainly used as raw materials for refractories, abrasives, chemicals and high-alumina cement. Bauxite accounts for a small proportion of non-metallic consumption, but it is widely used. For example:
1.chemical products such as sulfate, trihydrate and aluminum chloride can be used in papermaking, water purification, ceramics and petroleum refining;
2.Activated alumina can be used as catalyst, catalyst carrier and physical adsorbent for decolorization, dehydration, degassing, deacidification and drying in chemical, oil refining and pharmaceutical industries;
3.The aluminum chloride produced with r-Al2O3 can be used in organic synthesis of dyes, rubber, medicine, petroleum, etc;
4.3%~5% Al2O3 in the glass composition can improve the melting point, viscosity and strength; Abrasive material is the main raw material of high-grade grinding wheel and polishing powder; Refractory is an indispensable furnace building material for industrial departments.
According to the 1996 data of the Mineral Commodity Summaries of the United States Bureau of Mines, the world's bauxite reserves are 23 billion tons, with a reserve base of 28 billion tons. Among them, countries with relatively rich bauxite resources are Australia (with a reserve base of 7.9 billion tons), Guinea (with a reserve base of 5.9 billion tons), Brazil (with a reserve base of 2.9 billion tons), Jamaica (with a reserve base of 2 billion tons), India (with a reserve base of 1.2 billion tons), and Hungary (with a reserve base of 0.9 billion tons). The quantity and quality of bauxite in China are inferior to those of the above countries. For example, compared with the reserves base of these countries, the reserves of grade A+B+C (industrial reserves) are far behind them.
On the whole, China's bauxite resources are relatively rich. The basic reserves of bauxite are the seventh and the eighth in the world. By the end of 2006, the reserve of resources was 2.776 billion tons, including 542 million tons of reserves, 742 million tons of basic reserves, and 2.035 billion tons of resources. It is mainly distributed in Shanxi, Henan, Guangxi, and Guizhou provinces and regions, accounting for 90.9% of the national reserve of resources, including 41.6% in Shanxi, 17.1% in Guizhou, 16.7% in Henan, and 15.5% in Guangxi. In addition, 15 provinces and cities such as Chongqing, Shandong, Yunnan, Hebei, Sichuan and Hainan also have certain resource reserves, but their combined volume only accounts for 9.1% of China's total.
In 1995, China's total communist bauxite ore was 6.4 million tons. In addition to state-owned mining enterprises in the non-ferrous system, China's township collective mining enterprises and individual mining sites also mined a large amount of bauxite, but its output was unstable. The production of alumina and aluminum metal in China has grown rapidly. In 1996, it reached 2.5462 million tons and 1.907 million tons respectively, an increase of nearly 2.5 times and 4 times compared with 1985. The output of aluminum products increased faster, from 310000 tons in 1985 to 16201 tons in 1996, an increase of more than 35 times (Table 3.9.10).
Bauxite is mainly used in alumina industry and high-alumina clinker industry, and the consumption of the two is almost equal in 2003. According to the proportion of bauxite output used for alumina in the main provinces and regions in 2003, the resource reserves that can be used for alumina industry in the bauxite resource reserves can be estimated.
In addition, considering that the best bearing capacity of alumina must be based on reality, that is, the demand for bauxite in industries such as high-alumina clinker must be considered. Therefore, it is appropriate to evaluate the production scale of alumina in each province based on the bearing capacity of bauxite resources used for alumina production. With the excessive expansion of the scale of electrolytic aluminum in China, the contradiction of alumina supply shortage has become increasingly prominent, the import has increased sharply, the price has risen sharply, and the product profit has increased sharply. Driven by economic interests, some provinces with bauxite resources such as Henan and Shanxi have set off a wave of local construction of alumina enterprises. According to statistics, Henan, Shanxi, Shandong and other places have large alumina plants. There are 29 projects under construction and planned, with a total planned scale of more than 20 million tons/year, and the total scale of the existing alumina production scale of more than 30 million tons/year.