Cement kiln bypass exhaust ash resource utilization system and method

A technology of bypass ventilation and cement kiln, applied in the field of solid waste recycling, can solve the problems of high hexavalent chromium content, difficult disposal, short process, etc., achieve low cost, increase investment and disposal costs, and short process

Pending Publication Date: 2021-04-06
BEIJING BUILDING MATERIALS ACADEMY OF SCI RES +1
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  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

[0005] The invention provides a resource utilization method of cement kiln bypass air ash, which has short process, high efficiency and low cost, and solves the pro

Method used

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  • Cement kiln bypass exhaust ash resource utilization system and method
  • Cement kiln bypass exhaust ash resource utilization system and method
  • Cement kiln bypass exhaust ash resource utilization system and method

Examples

Experimental program
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Effect test

Embodiment 1

[0076] In this example, the influence of the amount of water added on the washing effect when washing the bypass blown ash with water was first investigated. After collecting the bypass ash samples with different salt content, and then using different water-cement ratios for water washing and solid-liquid separation, the removal rate of soluble salts in the bypass ash is shown in Table 1 below.

[0077] Table 1 Removal rates of soluble salts with different water-cement ratios in bypass blow-off ash with different salt content

[0078]

[0079] Note: The water-cement ratio in Table 1 refers to the weight ratio of water to bypass ash. The salt content refers to the weight percentage content of soluble salts in the bypass bleed ash.

[0080] The results show that the weight ratio of water and bypass ash is preferably 2-4:1, so that the soluble salts in the bypass ash can be fully dissolved into the water, and the bypass ash only needs to be washed once and then solidified. A...

Embodiment 2

[0082] Add water and bypass ash in a weight ratio of 3:1 into the water washing and stirring tank, and add 5‰ of ferrous sulfate by weight of bypass ash at the same time, and stir for 20 minutes to obtain a slurry. Then, the slurry was pumped into a plate and frame filter press, and subjected to high-pressure pressing for solid-liquid separation, and the moisture content of the obtained filter cake was 51.2%. The chemical composition of the bypass ash before and after washing is shown in Table 2 below. After one washing, the dry weight of the finished ash is reduced to about 60% of the weight of the original ash, and about 80% of the alkali chloride and sulfur in the original ash are removed. The finished ash can be directly used in cement production. Considering the disposal cost and practical application, the bypass ash only needs to be washed once, and there is no need to use multiple washings to pursue a higher alkali chloride and sulfur removal rate.

[0083] The pH of t...

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Abstract

The invention relates to a cement kiln bypass exhaust ash resource utilization system and a cement kiln bypass exhaust ash resource utilization method. The cement kiln bypass vent ash resource utilization method comprises the steps that water and bypass vent ash are prepared into slurry; adding a chromium removing agent to reduce hexavalent chromium into trivalent chromium; after the slurry is subjected to solid-liquid separation, directly adopting a separated solid phase 1 for cement production, introducing CO2 into a separated liquid phase 1 to enable calcium ions to generate calcium carbonate precipitate, and synchronously adjusting the pH; after solid-liquid separation of the liquid phase 1, evaporating, concentrating, cooling and crystallizing the liquid phase 2, and separating out potassium salt to obtain a potash fertilizer; mixing the evaporated water with bypass exhaust ash; returning the obtained liquid phase 3 to continue evaporation and concentration; and when the impurity concentration in the obtained liquid phase 3 is too high, the liquid phase 3 is used for being mixed with bypass exhaust ash. The cement kiln bypass vent ash resource utilization method is short in process, high in efficiency and low in cost, and the problem that bypass vent ash is difficult to dispose due to the fact that the content of harmful elements such as potassium, chlorine and sulfur and heavy metal hexavalent chromium is high is solved.

Description

technical field [0001] The invention relates to the field of solid waste recycling, in particular to a system and a method for recycling ash recycling by bypassing a cement kiln. Background technique [0002] Co-processing of cement kilns has become an important way to dispose of solid wastes such as domestic waste, municipal sludge and hazardous waste. However, due to the complex composition of solid waste, the co-processing of solid waste in cement kilns will increase the content of alkali, chlorine and sulfur in the cement kiln and circulate and enrich in the kiln. And other issues. In order to avoid the cyclic enrichment of alkali, chlorine and sulfur in the kiln system, cement enterprises need to use bypass ventilation technology to release part of the flue gas enriched with high concentration of alkali, chlorine and sulfur from the tail smoke chamber of the cement kiln to alleviate this problem. The bypass ventilation system has gradually become the standard configur...

Claims

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Application Information

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IPC IPC(8): C01F11/18C04B7/26C05D1/00
CPCC01F11/181C05D1/00C04B7/26Y02P40/10Y02P40/18
Inventor 王肇嘉蔡文涛顾军张觊秦玉高鹏飞朱延臣王义春李强邢延更
Owner BEIJING BUILDING MATERIALS ACADEMY OF SCI RES
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