An analytical review of various methods of carbonization of aluminate solutions was performed. As a result, the most important factors affecting the coarseness of aluminum hydroxide were selected: the concentration of CO₂ in the gas-air mixture, the temperature of the carbonization process and the value of the addition of hydroxide seed. In subsequent experiments we determined the specific dependencies of the influence of these factors on the disperse composition of the obtained Al(OH)₃. It was found that with increasing temperature increases the value of the average particle size, and with increasing the concentration of CO₂ the size of the hydroxide particles decreases. The dependences of changes in the concentration of Na₂O_gen and Na₂O_caust, Al₂O₃ and the coarseness of the obtained aluminum hydroxide during the carbonization process were investigated. The obtained results make it possible to create a technological scheme for obtaining alumina of any size.