Method and system for preparing sulfuric acid from ardealite

By granulating phosphogypsum with a reducing agent and then performing reduction oxidation treatment and flue gas treatment, the problems of low calcium sulfate decomposition rate and low heat recovery rate in existing technologies have been solved, achieving efficient sulfuric acid production and improved product quality.

CN122254440APending Publication Date: 2026-06-23CHINA PETROLEUM & CHEMICAL CORP +2
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Patent Information

Application Number
CN202411880766.3
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2024-12-19
Publication Date
2026-06-23

AI Technical Summary

Technical Problem

Existing technologies for the decomposition and utilization of phosphogypsum suffer from problems such as low calcium sulfate decomposition rate, complex flue gas composition making recovery difficult, low heat recovery rate, complex process flow, and low product quality.

Method used

After granulation by mixing phosphogypsum with a reducing agent, reduction and oxidation treatments are carried out. The flue gas undergoes gas-solid separation and impurity removal, and is converted into sulfur trioxide, which is then absorbed by high-concentration sulfuric acid. The system includes drying, granulation, reduction-oxidation, flue gas treatment, calcium oxide treatment, and sulfuric acid production units, enabling heat recovery and sulfuric acid production.

Benefits of technology

It significantly improved the decomposition rate of calcium sulfate, increased the concentration of sulfur dioxide in flue gas and product quality, reduced production costs, and improved the heat recovery rate.

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Abstract

The invention relates to a method and a system for preparing sulfuric acid from ardealite. The method comprises the following steps: (a) mixing ardealite and a reducing agent, and granulating to obtain raw material granules; (b) carrying out reduction treatment on the raw material particles to obtain a reduced material, and carrying out oxidation treatment on the reduced material to obtain calcium oxide and flue gas; (c) carrying out gas-solid separation on the flue gas, and carrying out heat exchange on a gas phase and an oxygen-containing gas to obtain a preheated oxygen-containing gas and the flue gas subjected to heat exchange; (d) after the flue gas subjected to heat exchange is subjected to impurity removal, sulfur dioxide in the flue gas subjected to impurity removal is converted into sulfur trioxide, and converted flue gas is obtained; (e) the converted flue gas is absorbed by sulfuric acid with the mass fraction of 98% or above, and a sulfuric acid product and absorption tail gas are obtained; wherein the preheated oxygen-containing gas is divided into two streams, and the two streams are respectively introduced into the reduction treatment process and the oxidation treatment process. Through the method, the production cost can be greatly reduced, the decomposition rate of calcium sulfate is improved, and the concentration of sulfur dioxide in flue gas and the product quality are improved.
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