Household garbage incineration fly ash wet-method mold bag treatment method and system

Abstract

The invention discloses a household garbage incineration fly ash wet-method mold bag treatment method. By means of three links of fly ash slurrying, fly ash slurry conveying and fly ash slurry dewatering / hydrating solidification, fly ash homogenizing, heavy metal and dioxin detoxifying, desalting and spontaneous hydrating solidification forming are achieved sufficiently at the same time; fly ash in mold bags after solidification meets related national standard requirements, solidified mold bag bodies can be subjected to landfill disposal, and fly ash can be taken out of the mold bags to be subjected to resource utilization; and liquid drained out of the mold bags is subjected to natural evaporation and concentration through a landfill space, after heavy metal and dioxin are recycled and impurities are filtered and removed, the liquid is recycled, or after further salt removing is carried out, the liquid is recycled. The invention further discloses a household garbage incineration fly ash wet-method mold bag treatment system. The household garbage incineration fly ash wet-method mold bag treatment method and system can overcome the defects of traditional fly ash dry-method landfill and a water washing pretreatment technology in large-scale industrial application, fly ash homogenizing, detoxifying, desalting, spontaneous hydrating solidification and landfill integrated treatment can be achieved, a basis is laid for follow-up fly ash resource utilization, the treatment cost is low, and the household garbage incineration fly ash wet-method mold bag treatment method and system can be applied to large-scale industrial production.

Description

technical field [0001] The invention belongs to the technical field of solid waste treatment and disposal, and in particular relates to a method and system for treating domestic waste incineration fly ash by a wet mold bag. Background technique [0002] Domestic waste incineration fly ash is a kind of off-white or dark gray fine powder, with low moisture content, generally rod-shaped, polygonal, cotton-like, spherical and other irregular shapes, uneven particle size, high porosity and large specific surface area specialty. Fly ash is rich in high concentration of chlorine salts, high content of heavy metals and dioxins that are easily leached, and is listed as hazardous waste by countries all over the world (China, code HW18). Therefore, fly ash must undergo strict disposal before landfill and resource utilization. In recent years, research on various fly ash disposal technologies has been carried out at home and abroad, including solidification and stabilization, separati...

AI Technical Summary

Problems solved by technology

The dry landfill disposal of fly ash has the following problems: (1) The composition of fly ash fluctuates greatly, dry mixing cannot achieve a better homogenization effect, the effect of chelating agent cannot be effectively exerted, the dosage is not easy to control stably, and the detoxification effect is unstable ; or in order to ensure the chelating effect, adding excessive chelating agent will increase the cost of the medicament; (2) fly ash contains a large amount of fine dust, which can easily form PM 2.5 pollution sources when exposed to the environment. Although the conventional dry landfill treatment has water spray Humidification, mechanical rolling, preforming and other dust suppression measures, but still can not avoid the impact on the surrounding environment of the landfill; (3) The new ash landfill is often accompanied by a pungent ammonia smell, which can easily cause dissatisfaction among nearby residents. Even lead to mass incidents; (4) Due to the strength of the stabilized fly ash, only the space below the ground can be used for landfill disposal in pits, and the space above the ground cannot be used, resulting in low utilization of storage capacity; (5) Summer and autumn rainy seasons , mud may be formed in the landfill pit, making the landfill operation impossible; (6) There are inevitably problems with the treatment of landfill leachate, which will increase additional treatment costs

The problem is that the concentration of the supernatant liquid entering the evaporative crystallization system has not been concentrated, resulting in large equipment investment and high operating costs in the evaporative crystallization salt extraction process; if the supernatant liquid entering the evaporative crystallization system is concentrated by natural evaporation, There is basically no treatment cost, and it is technically feasible, but this method occupies a large amount of land. The implementation site of the water washing pretreatment technology is generally in the cement factory, which cannot provide the land area required for the natural evaporation and concentration of the supernatant, so the actual implementation is not feasible; If the chlorine salt is not extracted and recycled directly, the cost of evaporation crystallization can be saved, but the removal effect of fly ash washing chlorine salt is extremely poor, and the effect of fly ash washing pretreatment cannot be exerted

[0007] Since municipal sludge and tailings are general solid wastes, while domestic waste incineration fly ash is hazardous waste (China, code HW18), if the above technology is simply transplanted to the field of disposal of domestic waste incineration fly ash, it will The following problems arise: (1) Environmental protection issues: the products after hazardous waste disposal and the waste residue and waste water generated during the disposal process have strict standard requirements, which are strictly different from general solid waste such as sludge and tailings; (2 ) Technical issues: 1) Sludge and tailings contain 50-95% water, which are water-containing materials. They are treated with mold bags, and only need to consider the problem of dehydration and capacity reduction; while fly ash contains 1-2% water, which belongs to dry materials, and mold bags are used. Pulping and dehydration treatment must be considered at the same time, and the pulping process has a greater impact on the subsequent dehydration effect, and it is required to complete the harmless disposal of fly ash as hazardous waste during the entire treatment process; 2) Sludge Mold bags used for solid waste treatment such as or tailings are vulnerable to rainwater penetration, which affects the strength of sludge or tailings consolidation in the mold bag

[0008] Due to the above-mentioned defects and deficiencies in the large-scale industrial application of the traditional dry landfill of fly ash and the pretreatment technology of fly ash washing, and the simple transplantation of mold bags to the field of domestic waste incineration fly ash disposal will lead to technical and environmental protection problems. The problem

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