A method and system for preparing ammonium bifluoride from hydrofluoric acid waste

By combining electrolysis, spray tower conversion, and ammonia water neutralization reaction with microchannel reactors and triple-effect evaporators, the problems of resource waste and high cost of hydrofluoric acid waste liquid have been solved, achieving efficient recovery of ammonium bifluoride and ammonium nitrate, reducing reagent costs and improving recovery rate.

CN122102165APending Publication Date: 2026-05-29JIANGSU ELECTRONIC TECH ENVIRONMENTAL CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
JIANGSU ELECTRONIC TECH ENVIRONMENTAL CO LTD
Filing Date
2025-06-12
Publication Date
2026-05-29

AI Technical Summary

Technical Problem

Existing technologies for treating hydrofluoric acid wastewater suffer from problems such as resource waste, high cost, easy precipitation of fluorosilicates, high cost of ion exchange resins, and inapplicability of membrane separation methods to complex components, making it difficult to effectively recover ammonium bifluoride and ammonium nitrate.

Method used

Metal ions are removed by an electrolytic cell, silicon dioxide is added to generate silicon tetrafluoride, which is then converted into fluorosilicic acid in a spray tower. Ammonium hydrogen fluoride is generated by neutralization reaction with ammonia water. The reaction efficiency is improved by using a microchannel reactor, and evaporation and drying are carried out by a triple-effect evaporator to recover ammonium nitrate and ammonium hydrogen fluoride.

Benefits of technology

This method enables the resource utilization of hydrofluoric acid waste liquid, reduces reagent costs, improves the recovery rate of fluorine and silicon, and produces standard-compliant ammonium bifluoride and ammonium nitrate products. The process is simple and has low energy consumption.

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Abstract

The application discloses a method and system for preparing ammonium bifluoride from hydrofluoric acid waste liquid, which comprises the following steps: (1) adding the hydrofluoric acid waste liquid into an electrolytic cell, transporting the electrolytic cell to a first reaction kettle after electrodepositing treatment, adding silicon dioxide, then stirring and reacting, and returning the generated silicon tetrafluoride and hydrofluoric acid into a spray tower to react and then return to the first reaction kettle, and then adding ammonia water to perform neutralization reaction; (2) filtering the solid-liquid mixture I, evaporating and drying the obtained filtrate I to obtain an ammonium nitrate product, and returning the obtained filter cake I to a second reaction kettle, adding ammonia water to adjust the pH value, and then stirring and reacting; (3) filtering the solid-liquid mixture II, returning the obtained filter cake II to the first reaction kettle for reuse, transporting the obtained filtrate II to a reactor, adding hydrofluoric acid to perform reaction, and then performing evaporation and drying treatment to obtain an ammonium bifluoride product. The method is simple in process, low in energy consumption, convenient to operate and convenient for industrialized production and application.
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