Production Method Of Pseudo Boehmite

Natural or produced alumina monohydrate and alumina trihydrate have the characteristics of small pore volume, small specific surface area and low activity. They cannot be used as boring agents, adsorbents, catalysts and catalyst carriers. Therefore, it is necessary to process alumina monohydrate or alumina trihydrate into pseudo boehmite. This product has the characteristics of high specific surface area, large pore volume, large pore size and high activity. It is suitable for petrochemical, chemical fertilizer, tail gas and other fields as a boring agent, adsorbent, catalyst and catalyst carrier.

One is to prepare pseudo boehmite by carbonization. The carbonization method is based on the sintering method to prepare alumina. NaAlO2 solution and CO2, the central products in the production process, are used as reaction materials. The process is simple, the cost is the lowest, there is basically no waste discharge, and the environmental pollution is small. This is a competitive advantage, but also a way out. The quality of the product prepared by carbonization is related to the production conditions such as material concentration, gelation temperature, pH value, aging temperature and time, and the drying temperature of wet filter cake. The defect of carbonization production is that the product contains impurities, the purity is not high, and the consumption of sodium washing water is large. alpha

The second is to produce the product by alkali method. In order to replace the catalyst used in chemical fertilizer plants, the R & D and production of chemical fertilizer catalysts have been handled. The technical indicators of alumina carrier are: the apparent density is 0.5 ~ 0.65 kg/l, the mass fraction of alumina is 94% ~ 95.5%, the mass fraction of sodium oxide is 0.01% ~ 0.03%, the specific surface area is 175-250m2/g, the pore volume is about 0.50ml/g, and the pore diameter is 3-6nm. The pore diameter of the product is 0.7-1ml/g, and the pore diameter is scattered in 10-50nm. The most suitable pore diameter is 40nm. It is a high-quality product with a wide range of uses.

Third, the product is produced by acid method. The deposition agent ammonia (or sodium hydroxide, sodium carbonate, etc.) is added to the aluminum trichloride (or aluminum sulfate) solution, and then the product is obtained through deposition, filtration, washing and drying. The effects of neutralization temperature, pH value, reactant concentration and aging conditions on pore structure were discussed. This method has the advantages of large pore volume, large specific surface area and high cost.

Fourth, the production of pseudo boehmite by double aluminum method. The so-called "double aluminum method" is the preparation of the product by the parallel reaction of aluminum sulfate and sodium metaaluminate.