Preparation Of High-purity Alumina By Organic Alcohol Elution Method Of Sodium Aluminate Solution

Superior performance and the high purity alumina is a widely used inorganic nonmetallic materials,the preparation methods of more,also on the market at present the mainstream technology means for the improvement of bayer process,but the improvement of the early stage of the bayer process use aluminum hydroxide precursor of the decomposition of sodium aluminate solution process with low decomposition efficiency and add the seed quantity is big,impurity content of the product,there is no guarantee that the subsequent roasting product purity and so on.In order to solve this problem,researchers have used methanol solvent analysis method to improve the efficiency of the early decomposition,can achieve the ideal effect,but methanol belongs to toxic organic alcohols,harm to human body is great,so this point,the author of this paper has carried on the improvement to methanol solvent chromatography,with non-toxic isopropyl alcohol as organic alcohol soluble analysis agent to improve the efficiency of early decomposition of sodium aluminate solution,at the same time with the method of ultrasonic field in combination with organic acids to purification of products,in further to ensure the purity of alumina by using the method of additive roasting.Isopropyl alcohol soluble analysis decomposition of sodium aluminate solution experiments,to study the decomposition temperature,isopropyl alcohol and sodium aluminate solution volume ratio and time of decomposition rate,the influence of the research results show that whether to add or isopropyl alcohol solution,the final breakdown products are sanshui diaspore,when the decomposition temperature of30?,the decomposition of sodium aluminate solution rate up to 72.98%,and highest supersaturation coefficient in the solution;When the volume ratio of isopropanol to sodium aluminate solution reached 1:1,the decomposition rate of sodium aluminate solution reached 75.98%.After the addition of isopropanol,the crystal particles were refined to 2.539?m.On previous preparation of breakdown products in the process of ultrasonic organic acid purification processing,the research results show that the single ultrasound can increase the removal rate of Na₂O in a certain extent,but the effect is not significant,when ultrasonic temperature of 70?for 5 h,penetrating agent,ultrasonic time and decomposition product quality ratio of 1:2,dispersant concentration of 9 mol/L,the removal rate of Na₂O up to 90.1%.After purification of aluminum hydroxide precursor and additive mix roasting,found that some additives could effectively reduce the transition state of alumina calcination temperature,the shift towards steady-state?-Al₂O₃and H₃BO₃,Al F₃additives can get different crystal structure of?-Al₂O₃,and on the basis of guarantee the purity of aluminum oxide have,eventually additive roasting product purity can reach 3 n.