Phosphorus gypsum purification treatment method

Abstract

The invention provides a phosphorus gypsum purification treatment method, which comprises the following steps: (1) adding washing water into a phosphorus gypsum raw material, performing standing demixing to remove an organic matter layer floating at the top after uniform stirring, and performing solid-liquid separation on a residual material to obtain washed phosphorus gypsum solids and washing wastewater; (2) neutralizing the washing wastewater by virtue of a saturated calcium hydroxide solution, and performing standing demixing to obtain upper-layer clear water used as the washing water in step (1) and precipitates used as a raw material for preparing phosphoric acid. Preferably, between steps (1) and (2), the method further comprises the following step: (11) adding cleaning water into the washed phosphorus gypsum solids, and performing solid-liquid separation to obtain cleaned phosphorus gypsum solids and cleaning wastewater after uniform mixing. In step (2), the cleaning wastewater is mixed with the washing wastewater, and the upper-layer clear water is further used as the cleaning water in step (11). According to the method, impurities can be efficiently removed or reduced, and the method is economical, environment-friendly, high in treatment capacity, ingenious in design, easy to operate and suitable for large-scale popularization and application.

Description

technical field [0001] The invention relates to the technical field of impurity removal, in particular to the technical field of impurity removal methods, in particular to a method for removing impurities from phosphogypsum. Background technique [0002] Phosphogypsum is an industrial waste produced in the wet-process phosphoric acid production process, and its main component is calcium sulfate dihydrate (CaSO 4 2H 2 O), its mass fraction is usually more than 85%. The free water content in phosphogypsum is relatively high, the mass fraction is about 20-30%, and the pH value is generally between 2-6. Phosphogypsum contains soluble phosphoric acid and its salts, fluoride, organic matter and other harmful substances that are harmful to human health and biological growth. Soluble phosphorus is converted into Ca when the building gypsum hardens. 3 (PO 4 ) 2 Precipitation covers the surface of gypsum crystals, delaying the setting time and reducing the strength; soluble fluor...

AI Technical Summary

Problems solved by technology

The lime neutralization method can eliminate the influence of soluble phosphorus and fluorine, but it is only suitable for the situation where the quality of phosphogypsum is relatively stable, and the treatment efficiency is low; the water washing method can effectively remove soluble impurities and organic matter, but the sewage discharge after treatment will cause Secondary pollution; flotation treatment can effectively remove organic matter, thereby eliminating the harmful effects of organic matter, but flotation treatment equipment, reagents, etc. are expensive; flash burning method is a new heat treatment process that has emerged to eliminate eutectic phosphorus The only effective way to affect, and its secondary pollution is small, the energy consumption of equipment production is low, but the current processing capacity is small

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