Calcium preserving method and system for fly ash washing dechlorination based on carbonation pretreatment

By pretreating fly ash with natural carbonation and washing it with citric acid solution, the problems of dechlorination and retention of Ca-based components in fly ash treatment were solved, achieving efficient dechlorination and improving the resource utilization value of fly ash.

CN120094952BActive Publication Date: 2025-11-28QINGDAO UNIV OF TECH +1
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Patent Information

Application Number
CN202510276226.2
Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Filing Date
2025-03-10
Publication Date
2025-11-28
Estimated Expiration
2045-03-10

AI Technical Summary

Technical Problem

Existing technologies struggle to simultaneously achieve efficient dechlorination and retention of Ca-based components in fly ash treatment, leading to reduced resource utilization value. Furthermore, the washing process generates a large amount of harmful wastewater, increasing subsequent treatment costs.

Method used

Fly ash is pretreated by natural carbonation to ensure its pH value is no higher than 9. Then, it is washed with water using citric acid solution to form stable calcium carbonate, which reduces Ca loss and improves dechlorination efficiency.

Benefits of technology

While meeting dechlorination requirements, it significantly reduces the soluble chlorine content to below 1%, reduces Ca loss rate by 14.32%, reduces mass loss by 8.23%, and improves the resource utilization value of fly ash.

✦ Generated by Eureka AI based on patent content.

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Abstract

The present application relates to a fly ash water washing dechlorination calcium preserving method and system based on carbonation pretreatment, and belongs to the technical field of hazardous solid waste resource utilization. Fly ash with a water content of 10-20% is exposed to air for natural carbonation pretreatment, so that the pH value of the fly ash is not higher than 9; the fly ash after the natural carbonation pretreatment is washed with a citric acid solution. The method provided by the present application overcomes the drawbacks of traditional water washing, can achieve standard chlorine while preserving the Ca-based components in the fly ash, and to a certain extent, reduces the mass loss caused in the fly ash washing process, thereby better preserving the resource properties of the fly ash and improving the value of the fly ash resource utilization.
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Citation Information

Patent Citations

  • Method for preparing sulphoaluminate cement raw material by using incineration fly ash and formula of sulphoaluminate cement

    CN102923978A

  • Water washing pretreatment method for making fly-ash from incineration harmless

    CN1947872A