New method for decolorizing and whitening phosphogypsum

Abstract

The invention discloses method for decolorizing and whitening phosphogypsum. The method comprises the following steps: firstly, removing the organic impurities in the phosphogypsum through a calcination process under a suitable condition; secondly, carrying out decolorizing and whitening to the phosphogypsum by taking sulfuric acid and hydrochloric acid as pickling agents; and finally, carrying out filtering, washing and drying to obtain a whitened phosphogypsum sample. The method has the characteristics of simple operating process, low operating cost and good whitening effect, and opens a new way to the large-scale industrialized treatment and comprehensive utilization of discarded phosphogypsum.

Description

1. Technical field

[0001] The invention relates to the comprehensive utilization of industrial by-product phosphogypsum waste residue, in particular to a new method for decolorization and whitening of phosphogypsum. 2. Background technology

[0002] Phosphogypsum is the solid waste produced in the production process of wet-process phosphoric acid. It takes about 2 tons of sulfuric acid to produce 1 ton of phosphoric acid and produces 4-5 tons of phosphogypsum at the same time. The annual discharge of phosphogypsum in my country's phosphorus chemical industry is about 50 million tons. During the "Eleventh Five-Year Plan" period, the average comprehensive utilization rate of phosphogypsum in domestic enterprises was only 20%, and a considerable amount of phosphogypsum was still disposed of in the form of direct stacking, which not only occupied a large amount of land resources, but also brought heavy burdens to production enterprises. Therefore, from the perspective of environme...