Method for preparing nano white carbon black through residues generated after aluminum oxide acid leaching extraction of coal ash and slag

The invention provides a method for preparing nano white carbon black through residues generated after aluminum oxide acid leaching extraction of coal ash and slag. The method comprises the steps that the residues are taken, sodium carbonate solids are added to the residues to be ground and evenly mixed, roasting is carried out for 0.5-4 h at the temperature of 830 DEG C to 930 DEG C, roasting solid products and roasting gas products are collected, the roasting solid products are placed in distilled water to be leached, and a sodium silicate solution and aluminum containing water leaching residues are obtained after soli-liquid separation; the sodium silicate solution is used for adjusting the concentration of SiO2 to range from 0.25 mol/L to 0.35 mol/L, then temperature is controlled to be 60 DEG C to 90 DEG C, surfactant and a dispersing agent are added, the washed and dried roasting gas products are introduced, when the pH value is equal to 7.5 to 8, gas introduction is stopped, still standing and ageing are carried out, filtering and washing are carried out, sediment and n-butyl alcohol are mixed, heating is carried out till azeotropy is achieved, heat preservation is carried out for 10-30 min, and then direct drying is carried out to obtain the nano white carbon black. The process technology economic indexes are advanced, the recovery rate of silicon resources is close to 100%, environment friendliness is achieved, and the resource utilization rate is high.