Preparation Of Oil-soluble Additives And Their Effects On The Precipitation Ratio Of Seed Precipitation From The Sodium Aluminate Liquor

The seed precipitation from the sodium aluminate liquor is a very important working procedure in the production of alumina. The precipitation ratio decide the yield of alumina, and the granularity,strength of aluminum hydroxide decide the quality of alumina. Using organic additive in the seed precipitation process can increase the yield and do good for the quality of alumina, and it else have several advantages, for example, coming true easily,operating briefly,low costing and so on. At present, the study on the additives which can increase the precipitation ratio is few, and the additives are water-solubility generally. The additives can make good effect on the precipitation ratio sometimes, but they also take some bad effects too, for example, doing harm for the granularity and strength of alumina,the organic compounds cumulating in the circle liquor seriously. In this thesis, it's first time to using oil-soluble additive in the seed precipitation process to increase the precipitation ratio.First of all, an anion surfactant which contains Si-C bond in the chain backbone was synthesized. During this process, the influence of solvent dose, time and temperature on the yield ware reviewed, then the compound was test by IR.Secondly, we confect eleven oil-soluble additives of three types H, G and F using the above anion surfactant and the other oil-soluble materials.Thirdly, using the sodium aluminate liquor of Shanxi branch of China Aluminum Industry as material, we pick out the best additive; in the whole experiment, the additive H1-2 can increase the precipitation ratio above 1% steadily, and it can't take bad effect to the quality of aluminum hydroxide and alumina.Finally, we do semi-industry experiment with the additive H1-2 in test dispart factory of Shanxi branch of China Aluminum Industry. In this part, we analyse several factors, for example, precipitation ratio,the granularity and intensity of alumina,the concentration of organic materials,the quality of aluminum hydroxide, and so on, the results show that the additive H1-2 can increase the precipitation ratio above 1% steadily, don't take bad effect to the quality of aluminum hydroxide and alumina, and don't take bad effect to the other working procedure in the production of alumina. All above results show that the oil-soluble additive H1-2 has good properties, and it can take good economy benefit to the alumina enterprise, so it could be used in the industry of alumina production.