Comprehensive utilization method of wastewater containing phosphorus and fluorine

Abstract

The invention relates to the field of wastewater comprehensive utilization, and particularly relates to a comprehensive utilization method of wastewater containing phosphorus and fluorine. The comprehensive utilization method comprises the following steps: carrying out twice neutralization on the wastewater containing phosphorus and fluorine, and controlling the final pH value after each time of neutralization; separating calcium fluoride from wastewater according to the solubility product of calcium fluoride and calcium orthophosphate, so as to enable the main ingredients of wastewater to be calcium orthophosphate and silica gel; separating silica gel by centrifugal separation to obtain a waste liquid containing phosphorus; carrying out secondary neutralization on the waste liquid containing phosphorus to enable the pH value to be 4-7; after generating calcium hydrophosphate, carrying out cooling crystallization treatment; separating calcium hydrophosphate to obtain a clear liquid, so as to realize treatment on wastewater containing phosphorus and fluorine. By adopting the comprehensive utilization method, maximal reutilization of the phosphorus fluorine resource is realized, the by-product silica gel is generated, the product additional value is increased, and the cost of treatment on wastewater containing phosphorus and fluorine is reduced.

Description

technical field [0001] The invention relates to the technical field of comprehensive utilization of wastewater, in particular to a method for comprehensive utilization of wastewater containing phosphorus and fluorine. Background technique [0002] Phosphorous and fluorine-containing wastewater is the unavoidable acidic wastewater produced by phosphoric acid production enterprises; the discharge of this wastewater in the environment will cause serious pollution to the environment. After the waste water is neutralized to neutral treatment, solid-liquid separation technology is combined, and the solid waste residue formed in it is filtered, and the treated clear liquid is discharged; in phosphoric acid production enterprises, phosphate rock and inorganic acid, and phosphate rock contains a variety of impurity elements, such as fluorine, silicon, calcium, etc., so in the production process, it will not only lead to a large amount of waste residue, but also lead to a large amount...

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Problems solved by technology

[0002] Phosphorous and fluorine-containing wastewater is the unavoidable acidic wastewater produced by phosphoric acid production enterprises; the discharge of this wastewater in the environment will cause serious pollution to the environment. After the waste water is neutralized to neutral treatment, solid-liquid separation technology is combined, and the solid waste residue formed in it is filtered, and the treated clear liquid is discharged; in phosphoric acid production enterprises, phosphate rock and inorganic acid, and phosphate rock contains a variety of impurity elements, such as fluorine, silicon, calcium, etc., so in the production process, it will not only lead to a large amount of waste residue, but also lead to a large amount of waste In the waste liquid, due to the high impurity content and low concentration of part of the fluorosilicic acid, it is difficult to be separated from the mixture with part of the low-concentration phosphoric acid, and then forms phosphorus and fluorine-containing waste water that coexists with phosphorus and fluorine.

[0003] In the above-mentioned prior art, for the treatment method of wastewater containing phosphorus and fluorine, although it can treat the pollution degree ...