Method for extracting potassium from fly ash hydrolysate

Abstract

A method for extracting potassium from fly ash hydrolysate comprises the following steps: step A, carrying out front-section filtration on the fly ash hydrolysate and removing suspended matters, thenadding sulfuric acid to regulate pH value, then feeding sodium sulfate, and carrying out clarification and sludge filtration to obtain clarified water; step B, concentrating the clarified water obtained from step A, adding the sodium sulfate in a concentrated solution, then carrying out freezing crystallization, and separating out glaserite solid; and step C, adding the glaserite solid obtained instep B in a potassium chloride regulating solution to obtain potassium sulfate salt mixture slurry, and separating the potassium sulfate salt mixture slurry to obtain potassium sulfate crystallized salt. Compared with an existing process, the method for extracting the potassium from the fly ash hydrolysate has the advantages that the pretreatment process is greatly simplified, and the running cost is greatly reduced; and co-products with high value can be obtained, and therefore, the cost-effectiveness of a treatment process is greatly increased.

Description

technical field [0001] The invention relates to the technical field of recycling of environmental protection resources, in particular to a method for extracting potassium from fly ash washing liquid. Background technique [0002] Garbage fly ash refers to the residues collected in the flue gas purification system of waste incineration power plants. It usually contains organic pollutants such as dioxins and furans and soluble heavy metals such as Pb and Cr. It is harmful to the environment and human health and must be cleaned. Safe and effective disposal. According to the composition characteristics of waste fly ash, sintering cement as raw material is an effective method to dispose of waste fly ash, but the content of chloride ion in waste fly ash is high, and directly used as cement raw material will cause skinning and blockage, which will affect the normal operation of cement kiln. Therefore, it is necessary to pretreat the fly ash to control the chloride ion content with...

AI Technical Summary

Problems solved by technology

The equipment used mainly includes preheaters, evaporators, flash crystallizers and steam mechanical compressors, etc. However, due to these existing pretreatment processes, the salt contained in the garbage fly ash washing liquid treated in the technology mainly includes Sodium chloride, potassium chloride, sodium sulfate, calcium chloride, etc. have complex components and high salt concentration, which makes it difficult to separate sodium and potassium salts in subsequent evaporative desalination operations, unstable equipment operation, and low salt quality.

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