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Process for producing anhydrous gypsum from calcium sulfite hemihydrate

A technology of calcium sulfite hemihydrate and calcium sulfite hydrous, applied in the direction of calcium/strontium/barium sulfate, etc., can solve the problems of large environmental impact, safety risk, difficult to use, etc., to improve performance, improve conversion rate, The effect of increasing the specific surface area

Pending Publication Date: 2021-06-04
SHIJIAZHUANG WUXING MACHINERY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, the semi-dry desulfurization process has attracted more and more attention from all walks of life. However, the main component of desulfurization ash is calcium sulfite hemihydrate, which has become a technical bottleneck for the disposal and comprehensive utilization of desulfurization ash, and is difficult to be used by cement, concrete, and building materials industries. , can only be treated as waste
This method not only needs to invest in the construction of a storage site, occupy land, and pay high solid waste discharge fees, but also has a greater environmental impact and safety risk on the atmospheric environment and groundwater, and has been listed as a key regulatory object by the environmental protection department.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] Gypsum is produced using desulfurized ash as raw material for calcium sulfite hemihydrate.

[0035] (1) Put the raw materials into the calciner, use natural gas as the gas to directly calcinate the calcium sulfite hemihydrate, dehydrate and oxidize the calcium sulfite hemihydrate to form calcium sulfate and form calcium sulfate II crystals; control the calcining temperature to 600 ℃, keep the calcination time for about 30 minutes. In the gas composed of natural gas and oxygen, the content of oxygen is greater than 10% of the total gas, and can be controlled at 15-20%. Calcium sulfate is here present in the form of calcium sulfate II crystals or type II gypsum crystals.

[0036] (2) The generated calcium sulfate II crystals are modified by using a ball mill to increase the specific surface area of ​​the calcium sulfate II crystals. The time control in the ball mill was 25 minutes.

[0037] (3) Using sulfate as an activator to treat the ball-milled calcium sulfate II c...

Embodiment 2

[0040] Gypsum is produced using desulfurized ash as raw material for calcium sulfite hemihydrate.

[0041] (1) Put the raw materials into the calcination furnace, use natural gas as the gas to directly calcine the calcium sulfite hemihydrate, dehydrate and oxidize the calcium sulfite hemihydrate to form calcium sulfate; control the calcination temperature to about 900°C, and keep the calcination time This lasts about 15 minutes. In the gas composed of natural gas and oxygen, the content of oxygen is greater than 10% of the total gas, and can be controlled at 15-20%. Here calcium sulfate exists in the form of type II gypsum crystals.

[0042] (2) Modify the generated calcium sulfate by using a ball mill to increase the specific surface area of ​​type II gypsum crystals. The time control in the ball mill was 32 minutes.

[0043] (3) Using sulfate as an activating agent to treat type II gypsum crystals after ball milling to form anhydrous type II gypsum building material produ...

Embodiment 3

[0046] Gypsum is produced using desulfurized ash as raw material for calcium sulfite hemihydrate.

[0047] (1) Put the raw materials into the calcination furnace, use natural gas as the gas to directly calcine calcium sulfite hemihydrate, dehydrate and oxidize calcium sulfite hemihydrate to form calcium sulfate; control the calcination temperature to about 720°C, and keep the calcination time Lasts about 22 minutes. In the gas composed of natural gas and oxygen, the content of oxygen is greater than 10% of the total gas, and can be controlled at 15-20%. Here calcium sulfate exists in the form of type II gypsum crystals.

[0048] (2) Modify the generated calcium sulfate by using a ball mill to increase the specific surface area of ​​type II gypsum crystals. The time of processing in the ball mill is controlled to be about 40 minutes.

[0049] (3) Using sulfate as an activating agent to treat type II gypsum crystals after ball milling to form anhydrous type II gypsum building...

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Abstract

The invention relates to a process for producing anhydrous gypsum from calcium sulfite hemihydrate, and belongs to the technical field of gypsum production. The process for producing anhydrous gypsum from calcium sulfite hemihydrate comprises the following steps: (1) calcining the calcium sulfite hemihydrate to dehydrate and oxidize the calcium sulfite hemihydrate to form calcium sulfate and form calcium sulfate II crystals; (2) modifying the generated calcium sulfate II by using a ball mill; and (3) treating the calcium sulfate II by using an exciting agent to form an anhydrous type II gypsum building material product. According to the invention, the calcium sulfite hemihydrate can be produced into anhydrous type II gypsum-based self-leveling mortar, anhydrous type II gypsum-based plastering mortar and other products, and can be widely used in building material and building industries. According to the process, the desulfurized fly ash is used as a raw material, so that the problem of desulfurized fly ash stacking is solved, and considerable economic value can be created.

Description

technical field [0001] The invention relates to a process for producing anhydrous gypsum from calcium sulfite hemihydrate, and belongs to the technical field of gypsum production and desulfurization ash treatment. Background technique [0002] At present, there are many flue gas desulfurization methods used in industrial production, mainly in the following categories, wet desulfurization of flue gas washed with absorbent aqueous solution, semi-dry flue gas desulfurization of absorbent slurry spray absorption and drying, and direct injection of calcium-based adsorption The dry method of flue gas desulfurization of agent powder is simply divided into three categories: wet method, semi-dry method and dry method. Among them, the semi-dry flue gas desulfurization process has the advantages of compact results, small footprint, low power and water consumption, small one-time investment, easy maintenance, etc., and has good economy. Therefore, the semi-dry desulfurization process h...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F11/46C04B11/26C04B11/00
CPCC01F11/46C04B11/26C04B11/007
Inventor 吕英强赵保山
Owner SHIJIAZHUANG WUXING MACHINERY
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