A method for producing sulfuric acid 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: 2014-10-15
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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  • A method for producing sulfuric acid and calcium oxide by decomposing gypsum
  • A method for producing sulfuric acid and calcium oxide by decomposing gypsum
  • A method for producing sulfuric acid and calcium oxide by decomposing gypsum

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Embodiment 1

[0031] This embodiment includes the following steps:

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

[0033] (2) The raw materials prepared in step (1) are sent to the suspension preheater and exchange heat with the 750℃ kiln gas from the tail of the rotary kiln to preheat the raw materials to 600℃, and the kiln gas leaves the suspension preheater. The temperature is 300-350℃;

[0034] (3) The raw materials preheated in step (2) are sent to the rotary kiln for calcination and decomposition. At 900-1250°C, the kiln is controlled to have a weak oxidizing atmosphere, and the pulverized coal combustion air excess coefficient is 1.04, and the kiln tail gas ...

Embodiment 2

[0038] The calcium sulfate in this embodiment is derived from the phosphogypsum produced in the production of wet-process phosphoric acid, and its external moisture is 15wt%. The mass ratio of the phosphogypsum to the coke powder after drying and dehydration 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 with a lumpiness ≤25mm. The natural anhydrite powder is directly blended. The crushed natural anhydrite and coke powder are blended with a mass ratio of 100:8, and the coke powder The grinding was carried out together, and the others were the same as in Example 1.

[0041] When natural anhydrite is used as the raw material, in step (3), the obtained kiln gas has a higher concentration and contains SO 2 10-12wt%, 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 a raw material. Background technique [0002] With the development of modern industrialization, the emission of industrial by-product gypsum has also increased greatly. [0003] Industrial by-product gypsum is a waste product with calcium sulfate as the main component generated in some industrial production. According to reports, the average sulfur content of coal-fired 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 it is not handled, it will inevitably cause great harm to the environment. Relevant national departments stipulate that coal power plants must desulfurize the exhaust flue gas. At present, the flue gas desulfurization of coal power plants is mostly lime-gypsum method, and lime is used to absorb SO in t...

Claims

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Application Information

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Patent Type & Authority Patents(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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