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Method for decomposing semi-hydrated phosphogypsum

A technology of hemihydrate phosphogypsum and phosphogypsum, applied in chemical instruments and methods, solid waste removal, inorganic chemistry and other directions, can solve the problems of low lime quality, low decomposition rate, low thermal efficiency, etc. Decomposition rate, the effect of improving desulfurization rate

Active Publication Date: 2013-07-31
WENGFU (GRP) CO LTD +1
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to overcome the defects existing in the existing phosphogypsum decomposition process, and provide a new decomposition method of hemihydrate phosphogypsum, the technical problem to be solved is to make it solve the thermal efficiency in the existing phosphogypsum decomposition process low, CaSO 4 The decomposition rate is low, and the SO in the tail gas 2 The disadvantages of low concentration and low lime quality make it more suitable for practical use

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  • Method for decomposing semi-hydrated phosphogypsum
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  • Method for decomposing semi-hydrated phosphogypsum

Examples

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Embodiment 1

[0053] Use the waste residue phosphogypsum produced by a phosphate fertilizer factory (the so-called phosphogypsum only refers to the gypsum discharged in the process of phosphating chemical industry, and its main component is still CaSO 4), the chemical composition is shown in Table 1, the fuel composition and industrial analysis are shown in Table 2, and pulverized coal is used as the reducing agent and fuel at the same time.

[0054] Table 1 Main chemical composition of phosphogypsum raw materials

[0055]

[0056] Table 2 Fuel composition and industrial analysis

[0057]

[0058] CaSO in raw material 4 0.5H 2 The O content is about 90% (dry basis), and the free water content is 70% can be discharged. The air flow rate required for normal temperature air is about 1.1-2t, and SO can be obtained. 2 Flue gas with mass percent concentration > 10% 2300Nm 3 .

[0059] like figure 1 As shown, the present invention is concerned with feeding the dried and dehydrated hem...

Embodiment 2

[0072] Use the waste residue phosphogypsum produced by a phosphate fertilizer factory (the so-called phosphogypsum only refers to the gypsum discharged in the process of phosphating chemical industry, and its main component is still CaSO 4 ), its chemical composition, fuel composition and industrial analysis are shown in the above-mentioned Table 1 and Table 2, and coke is used as a reducing agent and a fuel at the same time. For every ton of phosphogypsum residue processed in this process, the amount of coke used is about 10kg. Other process conditions, including process control parameters, are the same as above.

[0073] This is another embodiment of the present invention. In the process of material preheating and dehydration, the five-stage double-series preheater system in Embodiment 1 can be changed to a single-series preheater system.

[0074] see again figure 2 and Figure 4 Shown is a structural schematic diagram of the main reaction system adopted in the decomposit...

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Abstract

The invention relates to a method for decomposing semi-hydrated phosphogypsum, which comprises the following steps of: A. suspended state preheating of the semi-hydrated phosphogypsum: adding a semi-hydrated phosphogypsum material into a suspended state preheating system, carrying out heat exchange with high-temperature smoke in a suspended state, and after dehydrating the semi-dydrated phosphogypsum, forming anhydrous phosphogypsum; B: suspended state thermal decomposition and desulfuration of the anhydrous phosphogypsum: leading the anhydrous phosphogypsum to enter a suspended state thermaldecomposition system connected with an outlet of the suspended state preheating system, simultaneously adding a reducing agent with the weight ratio of (0.01-0.4):1 to the semi-hydrated phosphogypsuminto the suspended state thermal decomposition system and finishing the high-temperature decomposing and desulfurizing process of phosphogypsum; and C. cooling of materials. The method for decomposing the semi-hydrated phosphogypsum can overcome the defects of low decomposing rate and low desulfurizing rate of CaSO4, and the like in the traditional production method and solves the problem of increasing shortage of natural lime and limestone resources while effectively utilizing a sulphur element in the phosphogypsum at high quality.

Description

technical field [0001] The invention relates to a method for treating and utilizing waste residue, in particular to a method for decomposing dried and dehydrated hemihydrate phosphogypsum. Background technique [0002] Phosphogypsum is a solid waste discharged from the industrial production of wet-process phosphoric acid and phosphate fertilizer, and its main component is CaSO 4 .2H 2 O (the general content is above 90%). The production of one ton of phosphoric acid will produce about five tons of phosphogypsum waste residue. The production of phosphate fertilizer in my country will discharge tens of millions of tons of phosphogypsum every year, requiring a large amount of land to be piled up and causing serious pollution to the environment. The environmental protection pressure caused by gypsum discharge has become one of the important restrictive factors for the development of the phosphate fertilizer industry. [0003] Phosphogypsum is both an industrial waste and a va...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B17/74C01F11/04B09B3/00
Inventor 徐德龙何浩明陈延信杨三可李辉解田刘文欢胡宏程福安李文飞范海宏酒少武刘宁昌
Owner WENGFU (GRP) CO LTD
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