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Recycling method for fly-ash building materials

A technology for fly ash and building materials, applied in sustainable waste treatment, solid waste management, climate sustainability, etc., can solve problems such as poor solidification of heavy metals, carbon dioxide gas emissions, and difficulty in finding chemicals, to ensure long-term The effect of stability, reducing leaching concentration and solving environmental safety hazards

Inactive Publication Date: 2015-07-08
CHINESE RES ACAD OF ENVIRONMENTAL SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In recent years, countries such as Japan, Europe and the United States have generally adopted this method as the final disposal method of some hazardous solid wastes, but it generally has the following problems: the addition of cement can easily lead to an increase in the volume of the processed product; some heavy metals (such as cadmium, hexavalent chromium, etc.) , molybdenum and zinc, etc.) have poor curing effects; the production of cement required for curing can easily lead to a large amount of carbon dioxide gas emissions, which is contrary to relevant carbon emission reduction policies
However, chemical agents generally have certain selectivity, and it is difficult to find a broad-spectrum chemical agent

Method used

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  • Recycling method for fly-ash building materials

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] The fly ash sample comes from a waste incineration plant in Beijing. The heavy metal content in the sample is shown in Table 1-1, and the Cl content is 14.06%. From Table 1-2, it can be seen that the leaching concentration of Pb in fly ash is relatively high, which exceeds the standard limit of Pb in the "Identification Standard for Leach Concentration of Hazardous Wastes" (GB5085.3-2007), so the fly ash is judged as Hazardous waste with leaching toxicity characteristics.

[0034] Table 1-1 Content of heavy metal elements in incineration fly ash (mg / kg)

[0035]

[0036] Table 1-2 Leaching characteristics of heavy metal elements in incineration fly ash

[0037]

[0038] This fly ash building material reuse method is as follows, and can perform dechlorination and solidification and stabilization of heavy metals at the same time.

[0039] (1) Add 15% NaOH to the fly ash, add 75% water by mass percentage, and make primary mud under the condition of 25°C.

[0040] ...

Embodiment 2

[0047] The fly ash sample comes from a waste incineration plant in Chongqing. The heavy metal content in the sample is shown in Table 2-1, and the Cl content is 17.24%. It can be seen from Table 2-2 that the leaching concentration of Pb in fly ash is relatively high, which exceeds the standard limit of Pb in the "Identification Standard for Leach Concentration of Hazardous Wastes" (GB5085.3-2007), so the fly ash is judged as Hazardous waste with leaching toxicity characteristics.

[0048] Table 2-1 Content of heavy metal elements in incineration fly ash (mg / kg)

[0049]

[0050] Table 2-2 Leaching characteristics of heavy metal elements in incineration fly ash

[0051]

[0052] This fly ash building material reuse method is as follows, and can perform dechlorination and solidification and stabilization of heavy metals at the same time.

[0053] (1) Add 20% NaOH to fly ash, add 100% water by mass percentage, and make primary mud under the condition of 25°C.

[0054] (2...

Embodiment 3

[0061] The fly ash sample comes from a waste incineration plant in Beijing. The heavy metal content in the sample is shown in Table 3-1, and the Cl content is 14.06%. It can be seen from Table 3-2 that the leaching concentration of Pb in fly ash is relatively high, which exceeds the standard limit of Pb in the "Identification Standard for Leach Concentration of Hazardous Wastes" (GB5085.3-2007), so the fly ash is judged as Hazardous waste with leaching toxicity characteristics.

[0062] Table 3-1 Content of heavy metal elements in incineration fly ash (mg / kg)

[0063]

[0064] Table 3-2 Leaching characteristics of heavy metal elements in incineration fly ash

[0065]

[0066] This fly ash building material reuse method is as follows, and can perform dechlorination and solidification and stabilization of heavy metals at the same time.

[0067] (1) Add 6% Na to the fly ash 2 SiO 3 , add water with a mass percentage of 50%, and make primary mud under the condition of 25...

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Abstract

The invention provides a recycling method for fly-ash building materials. The recycling method comprises the following steps: a primary pulping process, a stirring process, a digesting process, a crushing process, a mixture preparing process, a secondary pulping process and a maintaining process, wherein a time interval between the primary pulping process and the digesting process does not exceeds 18 hours; shaping is performed by adopting different moulds according to the end use of the product, and the product is maintained, so that the compressive strength of the final product obtained is higher than or equal to 10 MPa. According to the recycling method for the fly-ash building materials, fly ash which is hazardous waste can be simultaneously subjected to dechloridation and heavy metal solidification stabilization treatment, so that the fly ash can be recycled as building material and is mainly used as aggregate of concrete and ceramsite for building material.

Description

technical field [0001] The invention relates to hazardous waste treatment technology, in particular to a method for reusing fly ash building materials, which can simultaneously dechlorinate fly ash and solidify and stabilize heavy metals, and reuse fly ash as building materials. Background technique [0002] Landfill is the main treatment method for domestic waste in my country. However, due to the continuous growth of domestic waste production, landfill is gradually difficult to meet the growing processing requirements, and a series of municipal and environmental problems such as "garbage siege" have arisen. [0003] Incineration technology can relieve the pressure of domestic waste treatment and complete the reduction of domestic waste. Waste incineration power generation technology can also complete the recycling of waste. In 2010, there were 104 waste incineration plants in China, with a processing capacity of 23.17 million tons, accounting for 18.2% of the amount of har...

Claims

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Application Information

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IPC IPC(8): C04B18/08B09B3/00
CPCY02W30/91
Inventor 李扬高兴保王琪黄启飞何洁
Owner CHINESE RES ACAD OF ENVIRONMENTAL SCI
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