Method for stabilizing heavy metals in waste incineration fly ash through combination of coal gangue and calcium oxide

A waste incineration fly ash and domestic waste incineration technology, which is applied in the field of domestic waste incineration fly ash disposal, can solve the problems of low solidification efficiency of heavy metals, low cost, high energy consumption of high-temperature calcination, etc., and achieves good industrial application prospects and capacity reduction Good effect and high curing efficiency

Active Publication Date: 2021-09-28
POWERCHINA HEBEI ELECTRIC POWER SURVEY & DESIGN INST CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005]The main components of coal gangue are SiO2 and Al2O3, Many previous studies used high-temperature calcination to stimulate its pozole reactivity to prepare geopolymers. At the same time, high-temperature calcination can also remove carbon impurities contained in coal gangue, but high-temperature calcination consumes high energy, high carbon emissions, and low environmental benefits. In the face of the increasing fly ash production, the cost of high-temperature calcination is not advantageous, and the economy is still not good enough to achieve large-scale industrial application; the calcium content in coal gangue is very low, and it can be solidified during curing Hydration products such as calcium silicate hydrate and calcium aluminosilicate hydrate of heavy metals are difficult to form, and the curing efficiency of heavy metals is lower than that of cement curing methods

Method used

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  • Method for stabilizing heavy metals in waste incineration fly ash through combination of coal gangue and calcium oxide
  • Method for stabilizing heavy metals in waste incineration fly ash through combination of coal gangue and calcium oxide
  • Method for stabilizing heavy metals in waste incineration fly ash through combination of coal gangue and calcium oxide

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045] Raw material: domestic waste incineration fly ash to be treated, the original leaching concentration of excessive heavy metals in the fly ash is as follows: Cd1.65mg / L, Cr1.46mg / L, Cu8.19mg / L, Ni0.93mg / L, Pb3.70mg / L, Zn77.64mg / L.

[0046] Approach:

[0047] Step 1, according to domestic waste incineration fly ash: coal gangue: the ratio of calcium oxide=6:1:3 is fully mixed to obtain 100g material one;

[0048] Step 2, the NaOH of 50mL10% mass fraction and NaOH 2 SiO 3 Compound alkali solution (NaOH:Na 2 SiO 3 =1:2) was added to material 1, stirred for 0.5 hours to make it fully react, and obtained homogeneous slurry material 2;

[0049] Step 3: Inject material 2 into a 40*40*40mm mold with constant temperature and humidity (80°C, 80% relative humidity) for 1 day of curing, and after demoulding, indoor curing for 7 days to obtain fly ash-coal gangue-calcium oxide polymerization cured body.

[0050] The solid waste leaching toxic leaching method-acetic acid buffe...

Embodiment 2

[0056] Raw material: domestic waste incineration fly ash to be treated, the original leaching concentration of excessive heavy metals in the fly ash is as follows: Cd1.65mg / L, Cr1.46mg / L, Cu8.19mg / L, Ni0.93mg / L, Pb3.70mg / L, Zn77.64mg / L.

[0057] Approach:

[0058] Step 1, according to domestic waste incineration fly ash: coal gangue: the ratio of calcium oxide=6:1:3 is fully mixed to obtain 100g material one;

[0059] Step 2, 75mL15% mass fraction NaOH and NaOH 2 SiO 3 Compound alkali solution (NaOH:Na 2 SiO 3 =1:2.5) was added to material 1, stirred for 0.5 hours to make it fully react, and obtained homogeneous slurry material 2;

[0060] Step 3: Inject material 2 into a 40*40*40mm mold with constant temperature and humidity (85°C, 90% relative humidity) for 1 day of curing, and after demoulding, indoor curing for 14 days to obtain fly ash-coal gangue-calcium oxide polymerization cured body.

[0061] The solid waste leaching toxic leaching method-acetic acid buffer so...

Embodiment 3

[0067] Raw materials: domestic waste incineration fly ash to be treated, the original leaching concentration of excessive heavy metals in the fly ash is as follows: Cd1.65mg / L, Cr1.46mg / L, Cu8.19mg / L, Ni0.93mg / L, Pb3.70mg / L L, Zn77.64mg / L.

[0068] Approach:

[0069] Step 1, according to domestic waste incineration fly ash: coal gangue: the ratio of calcium oxide=6:2:2 is fully mixed to obtain 100g material one;

[0070] Step 2, 50mL10% mass fraction NaOH and NaOH 2 SiO 3 Compound alkali solution (NaOH:Na 2 SiO 3 =1:2) was added to material 1, stirred for 0.5 hours to fully react among them, and obtained homogeneous slurry material 2;

[0071] Step 3: Inject material 2 into a 40*40*40mm mold with constant temperature and humidity (90°C, 95% relative humidity) for 1 day of curing, and after demoulding, indoor curing for 28 days to obtain fly ash-coal gangue-calcium oxide polymerization cured body.

[0072] The solid waste leaching toxic leaching method-acetic acid buffer...

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Abstract

The invention discloses a method for stabilizing heavy metals in waste incineration fly ash through combination of coal gangue and calcium oxide, and belongs to the field of household waste incineration fly ash treatment. Coal gangue and amorphous SiO2 and Al2O3 in household waste incineration fly ash are subjected to a geological polymerization reaction under the condition of an alkali activator, an inorganic polymer of a three-dimensional net structure is formed, meanwhile, calcium oxide is added, a large quantity of hydrated calcium silicate, hydrated calcium aluminosilicate and hydrated sodium aluminosilicate gel are formed in a cured body during maintenance and react with the heavy metals in manners of physical encapsulation, physical adsorption and ion exchange, so that the heavy metals in the fly ash are harmlessly treated, and it is guaranteed that the heavy metal leaching concentration of the fly ash-coal gangue-calcium oxide polymerization cured body meets the landfill safety standard. The heavy metals in the waste incineration fly ash are stabilized and produced though combination of coal gangue and calcium oxide, the curing efficiency of the heavy metals in the fly ash is further improved, the curing cost is reduced, and the environment-friendly concept of treating wastes with wastes is met.

Description

technical field [0001] The invention relates to the technical field of domestic waste incineration fly ash disposal, in particular to a method for compounding and stabilizing heavy metals in waste incineration fly ash by using coal gangue and calcium oxide. Background technique [0002] At present, the harmless disposal methods of domestic waste are mainly divided into landfill, incineration and composting. Heat supply and power generation, so as to achieve the purpose of resource utilization. However, the fly ash produced by waste incineration contains harmful substances such as dioxins and heavy metals, and is listed as hazardous waste, which requires harmless disposal before being safely landfilled. [0003] Fly ash treatment technologies mainly include dielectric material solidification technology, high temperature treatment technology and chelating agent stabilization technology. In my country, chemical agent stabilization combined with cement solidification is general...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09B3/00B09B5/00
CPCB09B3/00B09B5/00Y02P40/10
Inventor 李智孔莉倓蒋旭光龙凌赵晓利武洋齐建召董舟赵奕萌吕国钧陆胜勇
Owner POWERCHINA HEBEI ELECTRIC POWER SURVEY & DESIGN INST CO LTD
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