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

Abstract

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.

Description

technical field [0001] The invention relates to a method for preparing high-purity ultrafine calcium carbonate by utilizing calcium carbide slag. Background technique [0002] Carbide slag is an industrial waste produced after hydration of calcium carbide to produce acetylene gas. Its annual output has exceeded 10 million tons, and the accumulated carbide slag over the years has reached hundreds of millions of tons. Carbide slurry has high water content, high alkalinity, and large flow rate, which is one of the main pollution sources, so it must be treated or transformed and utilized. Since the main component of carbide slag is calcium hydroxide [Ca(OH) 2 ], therefore, in its treatment and conversion utilization, it is mostly used to prepare calcium carbonate (CaCO 3 ), the reason is that different industries have a large demand for various calcium carbonate, so its added value is relatively high. At present, the preparation of calcium carbonate and even superfine calciu...

AI Technical Summary

Problems solved by technology

However, there is an unpleasant smell in the process of leaching in this method, which will cause adverse effects on the environment and the health of operators; and the calcium carbonate product obtained by this method has a larger particle size and a lower purity.

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