Aluminum hydroxide production method
May 17, 2023
1. In the aluminum sulfate solution, add alkali solution under stirring to form a precipitate. After washing, filtering, and drying at low temperature, the finished product is obtained by crushing. The dehydrated paste can also be directly used as a product. The concentration, temperature, reaction temperature control and drying temperature of the solution in the preparation affect the product quality.
2. React sulfuric acid with aluminum powder or aluminum ash to generate aluminum sulfate, and then carry out metathesis reaction with ammonium bicarbonate to obtain aluminum hydroxide. Or use sodium aluminate solution and aluminum sulfate solution to neutralize to pH 6.5 to form aluminum hydroxide precipitate, wash with water, press filter, dry at 70-80°C, and then pulverize to obtain aluminum hydroxide. Its reaction formula:
3. Aluminum oxide has:
(1) Under the conditions of 40-60°C and pH>12, blow carbon dioxide into the sodium aluminate aqueous solution; place the sodium aluminate aqueous solution at room temperature without adding or adding hydroalumoxy seeds;
(2) Coexistence of Al(OC2H5)3 and 1%-20% ethanolamine NH2C2H4OH, hydrolysis at 20-60°C, aging the resulting gel for several months, etc.
Bayerite has:
(1) Blow carbon dioxide into the sodium aluminate aqueous solution at room temperature;
(2) Aluminum amalgam is hydrolyzed at room temperature;
(3) Al(OC2H5)3 is hydrolyzed below 70°C;
(4) The method of neutralizing the aqueous aluminum chloride solution with alkali metal hydroxide or ammonia, etc. Boehmite can be hydrothermally treated with aluminum hydroxide at 150-300°C in aluminum hydroxide aqueous solution or weakly alkaline aqueous solution; aluminum amalgam can be oxidized with boiling water. The stable area of diaspore is 275～425℃, and the water vapor pressure is above 140atm (1atm=98.066kPa). According to reports, diaspore can be obtained by hydrothermal treatment of aluminum hydroxide, and hydrothermal treatment of ρ alumina and χ alumina produced by vacuum dehydration of hydroalumoxide.
