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Method for producing vitriol and calcium oxide by decomposing gypsum

A technology of calcium oxide and calcium sulfate, which is applied in chemical instruments and methods, sulfur compounds, calcium/strontium/barium oxides/hydroxides, etc., can solve the problem of various production raw materials, large fluctuations in kiln gas concentration, and uneven cement clinker. Stability and other issues, to achieve the effect of large-scale industrial production, easy control of the reaction atmosphere, and stable production process

Inactive Publication Date: 2012-12-26
XIANGFU NEW BUILDING MATERIAL HUNAN
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the complexity of the technology itself: the raw material is ground and preheated and then calcined and decomposed in the rotary kiln. In the rotary kiln, calcium sulfate must be decomposed to produce SO-containing sulfuric acid that meets the requirements for sulfuric acid production. 2 Kiln gas, but also to produce qualified cement clinker, the process has many variable factors, and the operation control is difficult. This is one of them; Ideal; third, due to the many variable factors in the production process control, it is unavoidable to make the kiln gas SO 2 Large concentration fluctuations and unstable cement clinker, resulting in difficult control of sulfuric acid production and unreliable cement labeling
Therefore, there are many problems in the actual production, popularization and application of this technology.

Method used

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  • Method for producing vitriol and calcium oxide by decomposing gypsum
  • Method for producing vitriol and calcium oxide by decomposing gypsum
  • Method for producing vitriol and calcium oxide by decomposing gypsum

Examples

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Embodiment 1

[0031] This embodiment includes the following steps:

[0032] (1) After drying and dehydrating the desulfurized gypsum from a coal power plant with an external moisture content of 10wt%, the moisture content is 6wt%, and the dehydrated desulfurized gypsum and coke powder are mixed according to the mass ratio of 100:5, and then sent to FRMS vertical mill mixed and ground, the fineness is 0.08mm standard sieve, and the sieve residue is 20wt%;

[0033] (2) Send the raw material prepared in step (1) into the suspension preheater, and exchange heat with the 750°C kiln gas from the tail of the rotary kiln, so that the raw material is preheated to 600°C, and the kiln gas leaves the suspension preheater The temperature is 300-350°C;

[0034] (3) Send the preheated raw materials in step (2) into the rotary kiln for calcination and decomposition. At 900-1250°C, control the weak oxidation atmosphere in the kiln, and the air excess coefficient of pulverized coal combustion is 1.04, and c...

Embodiment 2

[0038] The calcium sulfate in this example is derived from phosphogypsum produced in the production of wet-process phosphoric acid, and its external moisture is 15wt%. After drying and dehydration, the mass ratio of phosphogypsum and coke powder is 100:6. Other steps and embodiments 1 is the same.

Embodiment 3

[0040] The raw material used in this embodiment is crushed natural anhydrite, whose lumpiness is less than or equal to 25mm, the natural anhydrite powder is directly compounded, and the crushed natural anhydrite and coke powder are batched according to the mass ratio of 100:8, and coke powder is mixed with coke powder Carry out grinding together, other is with embodiment 1.

[0041] When natural anhydrite is used as raw material, in step (3), the obtained kiln gas has a higher concentration and contains SO 2 10-12wt%, which is beneficial to the preparation of sulfuric acid.

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Abstract

The invention provides a method for producing vitriol and calcium oxide by decomposing gypsum. The method comprises the following steps: (1) preparing materials of gypsum and coke powder based on mass ratio of 100 : (5 to 8), and grinding same; (2) preheating; (3) roasting to decompose; (4) carrying out heat exchange with the gas of a kiln, and then processing by pickling and purifying, drying, converting, and absorbing to obtain the finished product of vitriol; and (5) cooling the solid cinder to obtain the finished product of calcium oxide. According to the method provided by the invention, the coke powder serves as the main component calcium sulfate of the gypsum, which is reduced and decomposed at high temperature so as to obtain the SO2 and the solid calcium oxide; the calcium oxide produced by decomposing limestone is replaced via the calcium oxide produced by decomposing the calcium sulfate, therefore, the calcium oxide resource can be recycled, and the emission of CO2 produced by roasting the limestone at room temperature also can be reduced. The method provided by the invention is simple in material preparing and technology, easy to control the reaction atmosphere, and stable in production, has capacity of making possible the recycling of a large number of industrial by-product gypsum, is environment-friendly, and can save the resource.

Description

technical field [0001] The invention relates to a method for producing sulfuric acid and calcium oxide, in particular to a method for producing sulfuric acid and calcium oxide by using gypsum as raw material. Background technique [0002] With the development of modern industrialization, the discharge of industrial by-product gypsum in my country has also increased greatly. [0003] Industrial by-product gypsum is a waste with calcium sulfate as the main component generated in some industrial production. According to reports, the average sulfur content of coal fired by coal power plants in my country is 1.23%, and the flue gas emitted by coal power plants contains a large amount of SO 2 , if not dealt with, is bound to cause great harm to the environment. Relevant state departments stipulate that coal power plants must desulfurize the exhaust gas. At present, the flue gas desulfurization of coal power plants is mostly the lime-gypsum method, and lime is used to absorb SO ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F11/10C01B17/74
Inventor 刘立文刘珍如宁爱民宁勇宁江天刘勇鲁纪鸣
Owner XIANGFU NEW BUILDING MATERIAL HUNAN
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