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Method for preparing calcium oxide by using industrial byproduct gypsum

A by-product, calcium oxide technology, applied in the direction of carbon monoxide, chemical instruments and methods, calcium/strontium/barium oxide/hydroxide, etc., can solve the problems of difficult separation of reaction residues, uneven mixing, high reaction temperature, etc., to achieve High convection heat transfer efficiency, improved process economy, and large contact area

Active Publication Date: 2021-11-05
INST OF PROCESS ENG CHINESE ACAD OF SCI
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  • Description
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Problems solved by technology

In the above-mentioned patents, in the process of using industrial by-product gypsum to prepare calcium oxide, the solid raw material is used as the reducing agent to decompose the gypsum, and the solid reducing agent has uneven mixing during the reaction process, and problems such as reaction dead ends are prone to occur; moreover, the solid-state reduction The reagent is also easy to substitute impurities, resulting in more by-products and difficult separation of reaction residues. In addition, the required reaction temperature is high and energy consumption is large.

Method used

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  • Method for preparing calcium oxide by using industrial byproduct gypsum
  • Method for preparing calcium oxide by using industrial byproduct gypsum
  • Method for preparing calcium oxide by using industrial byproduct gypsum

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Embodiment 1

[0053] This embodiment provides a method for preparing calcium oxide by using industrial by-product gypsum, the flow process of the method is as follows figure 2 As shown, the method includes the following steps:

[0054] (1) Reduction treatment: Phosphogypsum is air-dried, crushed, ground and sieved to obtain a solid powder raw material and react with CO introduced at 900°C for 90 minutes to obtain calcium sulfide and CO 2 ;

[0055] (2) Oxidation treatment: the calcium sulfide obtained in CO 2 It is oxidized under gas, heated to 1050°C and reacted for 40 minutes to obtain solid product calcium oxide and gas products CO and SO 2 ;

[0056] (3) Gas separation and recovery treatment: the obtained gas products are separated to obtain independent CO and SO 2 , the CO is used for reduction treatment, the SO 2 For the preparation of sulfur-containing products.

Embodiment 2

[0058] This embodiment provides a method for preparing calcium oxide by using industrial by-product gypsum, the flow process of the method is as follows figure 2 As shown, the method comprises the following steps: except that the temperature described in step (1) is changed to 1100°C, and the reaction time is changed to 30min; the temperature described in step (2) is changed to 1100°C, and the reaction time is changed to 30min; Other conditions are all identical with embodiment 1.

Embodiment 3

[0060] This embodiment provides a method for preparing calcium oxide by using industrial by-product gypsum, the flow process of the method is as follows figure 2 As shown, the method includes the following steps:

[0061] (1) Reduction treatment: Phosphogypsum is air-dried, crushed, ground and sieved to obtain a solid powder raw material and react with CO at 900°C for 150 minutes to obtain calcium sulfide and CO 2 ;

[0062] (2) Oxidation treatment: the calcium sulfide obtained in CO 2 and O 2 It is oxidized under mixed gas, and the temperature is raised to 950°C for 150 minutes to obtain solid product calcium oxide and gas products CO and SO 2 ;

[0063] (3) Gas separation and recovery treatment: the obtained gas products are separated to obtain independent CO and SO 2 , the CO is used for reduction treatment, the SO 2 For the preparation of sulfur-containing products.

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Abstract

The invention provides a method for preparing calcium oxide by using industrial byproduct gypsum, which comprises the following steps: carrying out reduction treatment on the industrial byproduct gypsum, and carrying out oxidation treatment on the obtained calcium sulfide in a CO2 atmosphere. According to the method, two treatment processes of reduction and oxidation are adopted, the initial reaction temperature can be effectively reduced, the decomposition rate and the conversion rate of raw materials can be increased, heat released in oxidation treatment can provide heat for self reaction and can also provide heat for reduction reaction, system energy consumption and operation cost are reduced, and the economical efficiency of the process is improved. No secondary pollutant is discharged in the calcium oxide preparation process, gas generated in the process can be recycled, the gypsum decomposition rate reaches 99%, the calcium oxide conversion rate reaches 97%, and efficient resource utilization of the industrial byproduct gypsum waste residues is achieved.

Description

technical field [0001] The invention belongs to the technical field of solid waste resource utilization, and in particular relates to a method for preparing calcium oxide by utilizing industrial by-product gypsum. Background technique [0002] According to statistics, the current natural gypsum reserves are about 57 billion tons, but only 8% of the reserves are high-quality gypsum (calcium sulfate content greater than 90%) resources, and the content of low-grade ore and anhydrite is relatively large. In addition, the distribution of gypsum resources is extremely uneven, but the market demand for gypsum resources has continued to expand in recent years. Industrial by-product gypsum refers to industrial by-products with calcium sulfate as the main component produced through chemical reactions in industrial production, mainly including phosphogypsum, desulfurization gypsum, titanium gypsum, mirabilite gypsum, fluorine gypsum, salt gypsum and lemon gypsum, among which phosphorus...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F11/02C01F11/08C01F11/10C01B32/40C01B17/50
CPCC01F11/02C01F11/08C01F11/10C01B32/40C01B17/508
Inventor 李松庚郝丽芳何海蔚范垂钢
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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