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Method for cooperative activation of fly ash and decomposition of gypsum for recovery of sulfur resource

A fly ash and sulfur recovery technology, applied in chemical instruments and methods, aluminum chloride, aluminum halide, etc., can solve problems such as environmental threats, technology in the research and development stage, and low utilization rate

Inactive Publication Date: 2016-07-20
INST OF PROCESS ENG CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

These industrial by-products of gypsum contain a certain amount of harmful impurities, and the low utilization rate leads to a large amount of stockpiling, which poses a serious threat to the environment.
At the same time, the sulfur resource rich in gypsum has gradually become a research hotspot in recent years by using gypsum to produce sulfuric acid. Patents CN101708826A, CN102786035A, CN1040009, CN102530889A, CN201896071U, and CN101343047 all report methods and processes for producing sulfuric acid using gypsum as a raw material, but For now, most technologies are still in the research and development stage

Method used

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  • Method for cooperative activation of fly ash and decomposition of gypsum for recovery of sulfur resource
  • Method for cooperative activation of fly ash and decomposition of gypsum for recovery of sulfur resource

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] The fly ash and desulfurized gypsum of the coal-fired power plant are selected in this embodiment, wherein the content of alumina in the fly ash is 47.8%, and the content of calcium sulfate in the desulfurized gypsum is 65.4%. The specific process is as follows:

[0030] (1) Fly ash and gypsum are mixed in a certain proportion so that the calcium-aluminum molar ratio (Ca / Al) is 1.05 / 1 to obtain a mixture of fly ash and gypsum;

[0031] (2) ball milling the solid mixture obtained in step (1) so that its particle size is less than 100 mesh;

[0032] (3) Calcining the mixture obtained in (2) for 120 minutes at 1300° C.;

[0033] (4) The sulfur content of the (3) product after calcination was detected to be 0.36%, indicating that the desulfurization gypsum was almost completely decomposed; XRD analysis showed that the mullite phase in the fly ash had transformed into an anorthite and anorthite phase;

[0034] (5) Leach the clinker after calcined in (3), and use 0.5mol / L hy...

Embodiment 2

[0036] In this embodiment, the fly ash from a coal-fired power plant and the phosphogypsum from a phosphorus chemical enterprise are selected, wherein the alumina content in the fly ash is 40.3%, and the calcium sulfate content in the phosphogypsum is 73.8%. The specific process is as follows:

[0037] (1) Fly ash and gypsum are mixed in a certain proportion so that the calcium-aluminum molar ratio (Ca / Al) is 2.1 / 1 to obtain a mixture of fly ash and gypsum;

[0038] (2) ball milling the solid mixture obtained in step (1) so that its particle size is less than 300 mesh;

[0039] (3) calcining the mixture obtained in (2) at 1450° C. for 100 min;

[0040] (4) The sulfur content of the (3) product after calcination was detected to be 0.49%, indicating that the desulfurization gypsum was almost completely decomposed; XRD analysis showed that the mullite phase in the fly ash had transformed into a calcium alumina feldspar phase;

[0041] (5) Leach the calcined clinker in (3), and u...

Embodiment 3

[0043] In this embodiment, the fly ash from a coal-fired power plant and the phosphogypsum from a certain phosphorus chemical enterprise are selected, wherein the alumina content in the fly ash is 35.3%, and the calcium sulfate content in the phosphogypsum is 70.8%. The specific process is as follows:

[0044] (1) Fly ash and gypsum are mixed in a certain proportion so that the calcium-aluminum molar ratio (Ca / Al) is 0.4 / 1 to obtain a mixture of fly ash and gypsum;

[0045] (2) ball milling the solid mixture obtained in step (1) so that its particle size is less than 200 mesh;

[0046] (3) calcining the mixture obtained in (2) for 180 min at 950° C.;

[0047] (4) The sulfur content of the (3) product after calcination was detected to be 1.08%, indicating that the desulfurized gypsum was almost completely decomposed; XRD analysis showed that the mullite phase in the fly ash had transformed into an anorthite phase;

[0048] (5) Leach the calcined clinker in (3) with 0.5mol / L su...

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Abstract

The invention provides a method for cooperative activation of fly ash and decomposition of gypsum for recovery of a sulfur resource. According to the method, solid waste, i.e., fly ash, discharged by a coal-fired power plant or coal-fired boiler is used as a raw material, a certain proportion of desulfurized gypsum discharged by the coal-fired power plant or waste phosphogypsum produced in the phosphorus chemical industry is added and mixed with the fly ash, then the obtained mixture is subjected to ball milling, and activation and calcination at a temperature of 950 to 1450 DEG C are carried out for 5 to 180 min; calcium sulfate in the gypsum are almost totally decomposed after calcination, and produced gas contains sulfur dioxide or sulfur trioxide which can be used as feed gas for preparation of sulfuric acid; and calcination enables solid fly ash to be activated, leaching with a sulfuric acid or hydrochloric acid solution is carried out at a temperature of 50 to 100 DEG C, and the leaching rate of alumina is greater than 80%. The method provided by the invention has the advantages that since all the raw materials are solid waste, the purpose of treating the waste by using the waste is achieved; elemental sulphur in the gypsum can be recovered; and the fly ash can be activated and activity of the fly ash can be improved, so a high alumina recovery rate at a low temperature can be realized. With the method, high-efficiency extraction of alumina in the fly ash is realized; the sulfur resource in the gypsum is recovered; shortage in industrial sulphur in the sulfuric acid industry in China is compensated; and the method has good economic benefits and wide industrial application prospects.

Description

technical field [0001] The invention belongs to the field of resource utilization of bulk solid waste, and particularly relates to a method of using fly ash discharged from coal-fired power plants or coal-fired boilers and desulfurized gypsum from coal-fired power plants or phosphogypsum, a solid waste of phosphorus chemical industry, as raw materials, and adopts calcining A method for activating fly ash and simultaneously decomposing gypsum for recovering sulfur resources. Background technique [0002] The annual discharge of fly ash in my country has reached 500 million tons, and the cumulative amount has reached 3.5 billion tons. Among them, the discharge of fly ash from coal-fired power plants is the largest, mainly in ash yard storage and open-air accumulation, which occupy a large amount of land. There is a greater potential threat to the human environment. Fly ash is generally rich in aluminum, silicon, gallium and other elements, and it is also an important valuable ...

Claims

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Application Information

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IPC IPC(8): C01B17/74C01F7/74C01F7/56
Inventor 李会泉许德华包炜军王小方
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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