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A seed crystal of sodium aluminate solution decomposition process is one of the important step of the Bayer process production of alumina, the solution decomposition rate, which directly affects the production of alumina, while the decomposition products of aluminum hydroxide particle size, the strength directly affect the quality of the product alumina . Sodium aluminate solution seeded precipitation process additives are added, you can change the course of the crystallization of aluminum hydroxide, improve product yield and quality, and easy to implement, simple operation, low cost, etc.. At present, domestic and foreign additives to improve the sodium aluminate solution precipitation ratio is not much, and the use of additives is generally water-soluble additives, although some success in improving the decomposition rate, but often they give alumina production with to some adverse effects, such as the product alumina particle size, strength decreased cycle decomposition of organic matter accumulation solution. This paper proposes the use of oil-soluble additives to improve the precipitation ratio of sodium aluminate solution. First, the study synthesis of a hydrophobic group the main chain of the Si-C bond-containing anionic surfactant, the amount of the solvent, reaction time and temperature and other factors on the yield, and the product was done Characterization. Second, the surfactant used for the synthesis of the complex of the additive, the preparation of H-type, G type, F type three groups of 11 kinds of oil-soluble additives. Shanxi Branch of China Aluminum sodium aluminate solution to test raw materials, formulated additive preferably in the company's technology development department Research. The results showed that: whether it is in the period of decomposition of a small test in Sec Decomposition test, H1-2 additives can be more stable increase the decomposition rate of 1% or more, and will not give the product of aluminum hydroxide oxide adversely affect the quality of aluminum. Finally, the semi-industrial tests carried out in the Aluminum Corporation of China Shanxi Branch pilot branch of the preferred H1-2 additive. The results showed that the rate of decomposition, product size and strength, the organic content in the solution, aluminum hydroxide, the quality of the analysis of the technical indicators, in the semi-industrial tests, H1-2 additive can improve more stable precipitation ratio of sodium aluminate solution more than 1%, does not adversely affect the quality of the product of aluminum hydroxide, aluminum, and it will not affect other processes in the production of alumina. H1-2 oil-soluble additives above excellent properties, the economic analysis concluded that the use of the additive can bring good income to the alumina business.
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