Fly ash brightening method

A technology of fly ash and calcium hydroxide, applied in the direction of climate sustainability, sustainable waste treatment, solid waste management, etc., can solve the problems of secondary pollution, unsuitable promotion, high cost, etc.

Inactive Publication Date: 2005-03-16
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although strong acid or strong alkali can roughen the surface of fly ash, it cannot improve the whiteness of fly ash, and the follow-up treatment is difficult, high cost,

Method used

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Embodiment 1

[0018] 200g fly ash, 735ml concentration is 9% Ca(OH) 2 The solution was thoroughly mixed with 2750 ml of tap water in the reactor. Heating at normal pressure and 100° C. for 1 hour with a stirring speed of 410 rpm. After the reaction is finished, cool the slurry to 30° C., and pass in carbon dioxide gas for neutralization, filtration, and drying. The whiteness of the final fly ash product is 68.66 (the raw material whiteness is 36.86), and the specific surface area is 25.03m 2 / g (the specific surface area of ​​the raw material is 3.07m 2 / g), bulk density 0.38g / cm 3 (The bulk density of the raw material is 1.10g / cm 3 ).

Embodiment 2

[0020] 150g fly ash, 735ml concentration is 9% Ca(OH) 2 The solution was thoroughly mixed with 1533 ml of tap water in the reactor. Heating at normal pressure and 95° C. for 4 hours with a stirring speed of 320 rpm. After the reaction is finished, cool the slurry to 33° C., and pass in carbon dioxide gas for neutralization, filtration, and drying. The whiteness of the final fly ash product is 69.43 (the raw material whiteness is 35.99), and the specific surface area is 23.95m 2 / g (the specific surface area of ​​the raw material is 3.07m 2 / g), bulk density 0.42g / cm 3 (The bulk density of the raw material is 1.10g / cm 3 ).

Embodiment 3

[0022] 200g fly ash, 833ml concentration is 8% Ca(OH) 2 The solution was thoroughly mixed with 3700 ml of tap water in the reactor. Heating at normal pressure and 80° C. for 7 hours with a stirring speed of 470 rpm. After the reaction is finished, cool the slurry to 28° C., and pass in carbon dioxide gas for neutralization, filtration, and drying. The whiteness of the final fly ash product is 65.15 (the raw material whiteness is 33.54), and the specific surface area is 34.83m 2 / g (the specific surface area of ​​the raw material is 3.07m 2 / g), bulk density 0.45g / cm 3 (The bulk density of the raw material is 1.10g / cm 3 ).

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Abstract

The invention provides a fly ash brightening method which comprises, mixing fly ash with calcium hydroxide solution, heating, stirring for modifying the surface of the fly ash, then cooling down the slurry, and letting in carbon dioxide to neutralize the remaining calcium hydroxide.

Description

technical field [0001] The invention relates to a treatment method of fly ash, in particular to a treatment method of fly ash discharged outside by wet method. It belongs to the technical field of solid waste recycling engineering in the discipline of environmental engineering. Background technique [0002] Fly ash, also known as "fly ash", is thin and light, and it is inconvenient to collect, discharge, transport, and store, and it is even more difficult to manage and utilize it. In 2001, the national production of fly ash was 168 million tons, and the utilization rate was only 52%. If it is not developed and utilized, it will not only occupy a large amount of fertile land and increase the storage cost of fly ash, but also easily form public nuisance and pollute the environment. Since the 1950s, my country's building materials department has begun to try to use fly ash in the production of building materials and concrete. In the 1960s, a fly ash utilization pattern based ...

Claims

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Application Information

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IPC IPC(8): C04B18/06C04B18/08
CPCY02W30/91
Inventor 盖国胜杨玉芬郝向阳蔡振芳
Owner TSINGHUA UNIV
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