Method for purifying quartz sand through gradient calcination after acid leaching

Abstract

The invention particularly discloses a method for purifying quartz sand through gradient calcination after acid leaching. The method comprises the steps of pretreatment, primary calcination, primary acid leaching, secondary gradient calcination, secondary acid leaching, washing and drying. According to the method, impurities on the surface of the quartz sand are removed through pretreatment, quartz lattices are induced to expand through primary calcination so that metal impurities can be deintercalated, then residual hydrofluoric acid and silicon dioxide wrapping the lattice impurities are promoted to react through secondary gradient calcination to generate volatile silicon fluoride, and the removal effect of special impurities in the quartz sand is effectively improved; and finally, trace metal impurities remaining on the surface of the quartz sand are removed through normal-temperature acid leaching, and the impurity removal effect is further improved. Therefore, the gradient calcination purification method after acid leaching of the quartz sand can effectively remove special impurities in the quartz sand, and has the characteristics of simple process and high purification efficiency.

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