Method for preparing high-purity calcium carbonate superfine powder from carbide slag

The invention relates to a method for preparing high-purity calcium carbonate superfine powder from carbide slag. The method comprises the following steps of: crushing, screening, and heating and combusting the carbide slag in a microwave-assisted mode to preprocess the carbide slag; mixing the carbide slag and 1.2 to 2.0 mol/L solution of ammonium chloride or solution of ammonium nitrate to perform leaching; filtering the mixture to obtain a filtrate; adding water-soluble ionic liquid into the filtrate to obtain mixed solution; mixing the mixed solution and solution of ammonium bicarbonate; stirring the mixture under action of microwave radiation, and filtering the mixture to obtain a calcium carbonate solid; washing the calcium carbonate solid with distilled water for 2 to 3 times; and finally drying the calcium carbonate solid at the temperature of between 95 and 105 DEG C to obtain powdery calcium carbonate. The method does not cause secondary pollution to environment, the dispersibility of the calcium carbonate superfine powder is high, the grain diameter is between 30 and 200nm, the purity is over 99.2 percent, and the calcium carbonate superfine powder fully meets the requirements of industrial production of rubber, plastic and coating. The method realizes recycling of leaching agents and water in the process of preparing the calcium carbonate and reduces production cost.