Production method of aluminum hydroxide
In aluminum sulfate solution, alkali solution is added to agitation, and then the precipitates are washed, filtered and dried at low temperature. The dried paste can also be used as a product directly. In the process of preparation, the concentration of solution, temperature, control of reaction temperature and drying temperature affect the quality of products.
Aluminum sulfate and aluminum ash were used to produce aluminum sulfate and then decomposed with ammonium bicarbonate to produce aluminum hydroxide. Or the sodium aluminate solution and aluminum sulfate solution are neutralized to pH6.5, and the aluminum hydroxide is precipitated. After water washing and pressure filtration, it is dried at 70~80 C and then crushed to produce aluminum hydroxide. Its reaction formula:
Water al oxygen has:
(1) under the condition of 40~60 C, pH>12, the sodium aluminate aqueous solution is blown into carbon dioxide, and the sodium aluminate aqueous solution is not added or added to the normal temperature at normal temperature.
(2) Al (OC2H5) 3 and 1% ~ 20% ethanolamine NH2C2H4OH coexist and hydrolyze at 20~60 C, and the gel is cured for several months.
Three hydroxybauxite has:
1) blowing carbon dioxide into aqueous sodium aluminate solution at room temperature.
2) the aluminum amalgam was hydrolyzed at normal temperature.
(3) Al (OC2H5) 3 is hydrolyzed below 70 C;
(4) the method of neutralizing aluminum chloride solution with alkali hydroxide or ammonia. A water bauxite is treated by hydrothermal treatment of aluminum hydroxide at 150~300 C in aqueous aluminum hydroxide solution or weak alkaline aqueous solution, and the aluminum amalgam is oxidized by boiling water. The stable area of the bauxite is 275~425 degrees, and the water vapor pressure is above 140atm (1atm=98.066kPa). It is reported that bauxite can be obtained by hydrothermal treatment of aluminum hydroxide and hydrothermic treatment of alumina and X alumina produced by vacuum dehydration of bauxite.