Method for oxidizing CaSO3 in desulfurized fly ash in alkaline condition

A technology of oxidative desulfurization and alkaline conditions, applied in the direction of calcium/strontium/barium sulfate, etc., can solve the problems of increasing the cost of oxidation process, equipment corrosion, and adverse effects of comprehensive utilization of desulfurization ash, so as to achieve short oxidation reaction time and avoid corrosion , the effect of high solid-liquid ratio

Inactive Publication Date: 2013-08-07
武汉钢铁有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Desulfurization ash (especially dry and semi-dry) contains a large amount of unconverted alkaline substances CaO or Ca(OH) 2 , if this patented method is adopted, it is necessary to add a large amount of acid to neutralize the CaO or Ca(OH) in the desulfurization ash 2 , will not only increase the cost of the oxidation process, but also cause certain corrosion to the equipment; in addition, the addition of transition metal ion catalysts will introduce new impurities, which will adversely affect the subsequent comprehensive utilization of desulfurization ash

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] A kind of CaSO in oxidative desulfurization ash under alkaline conditions 3 method, including the following steps:

[0027] 1) Take 50g of semi-dry flue gas desulfurization ash (CaSO 3 content of 24.3%), add 100mL of water, stir for 20min to mix evenly (pH 10.7), and obtain desulfurization ash slurry;

[0028] 2) At room temperature, slowly add H with a weight concentration of 10% to the desulfurization ash slurry 2 o 2 solution, the H 2 o 2 with CaSO 3 The molar mass ratio is 1.2:1;

[0029] 3) The above desulfurization ash, H 2 o 2 The mixture of solutions was stirred and reacted for 0.5h.

[0030] Centrifugal separation, determination of CaSO in desulfurization ash after oxidation reaction by iodometric method 3 content, the result is 0.8%, the calculated CaSO 3 The conversion rate reached 96.6%.

Embodiment 2

[0032] A kind of CaSO in oxidative desulfurization ash under alkaline conditions 3 method, including the following steps:

[0033] 1) Take 50g of semi-dry flue gas desulfurization ash (CaSO 3 content of 24.3%), add 300mL of water, stir for 10min to mix evenly, and obtain desulfurization ash slurry;

[0034] 2) At room temperature, slowly add H with a weight concentration of 30% to the desulfurization ash slurry 2 o 2 solution, the H 2 o 2 with CaSO 3 The molar mass ratio is 1:1;

[0035] 3) The above desulfurization ash, H 2 o 2 The mixture of solutions was stirred and reacted for 4h.

[0036] Centrifugal separation, determination of CaSO in desulfurization ash after oxidation reaction by iodometric method 3 content, the result is 1%, and the calculated CaSO 3 The conversion rate reached 95.8%.

Embodiment 3

[0038] A kind of CaSO in oxidative desulfurization ash under alkaline conditions 3 method, including the following steps:

[0039] 1) Take 200g of semi-dry flue gas desulfurization ash (CaSO 3 content of 23.2%), add 800mL of water, stir for 30min to mix evenly, and obtain desulfurization ash slurry;

[0040] 2) At room temperature, slowly add 15% H 2 o 2 solution, the H 2 o 2 with CaSO 3 The molar mass ratio is 2:1;

[0041] 3) The above desulfurization ash, H 2 o 2 The mixture of solutions was stirred and reacted for 1 h.

[0042] Centrifugal separation, determination of CaSO in desulfurization ash after oxidation reaction by iodometric method 3 content, the result is 0, the calculated CaSO 3 The conversion rate is 100%.

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PUM

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Abstract

The invention discloses a method for oxidizing CaSO3 in desulfurized fly ash in an alkaline condition. The method comprises the following steps of: (1) adding 2 to 10 times water by weight to the desulfurized fly ash, and uniformly stirring to obtain desulfurized fly ash slurry; (2) slowly adding H2O2 and / or persulfate solution with weight concentration being 10 to 30% of to the desulfurized fly ash slurry, wherein the molar mass ratio of H2O2 and / or persulfate to CaSO3 is 1- 2: 1; and (3) stirring and reacting mixtures of the desulfurized fly ash slurry, H2O2 and / or persulfate solution for 0.5 to 4 hours. According to the oxidization method, the pH of the solution does not need to be adjusted and metallic ions do not need to add, so that the reaction conditions are mild, and as a result, the oxidization cost is reduced, and the corrosion to the equipment is reduced; and the method has the characteristics of short reaction time, high efficiency, etc.

Description

technical field [0001] The invention relates to CaSO in desulfurization ash 3 Oxidation method, especially a CaSO in the desulfurization ash under alkaline conditions 3 Methods. Background technique [0002] Industrial coal combustion for thermal power generation, metal smelting, etc. produces a large amount of SO 2 , It is easy to cause serious environmental and ecological problems such as air pollution and acid rain. Therefore, flue gas desulfurization has become one of the important links in the production process. Among them, calcium desulfurization technology has been widely implemented due to its advantages of good desulfurization effect, mature process and low operating cost. Sintering flue gas desulfurization technology is divided into wet method, dry method and semi-dry method. The desulfurization process produces a large number of desulfurization by-products - desulfurization ash. The by-product of wet desulfurization is CaSO 4 2H 2 O, whose content is more t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F11/46
Inventor 卢丽君朱丽华薛改凤唐和清张垒余欣雨朱书景王国华付本全
Owner 武汉钢铁有限公司
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