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Process for removing dioxin in fly ash

A fly ash and process technology, applied in gas treatment, calcium carbonate/strontium/barium, electrolysis process, etc., can solve the problems of high infrastructure construction cost, high temperature requirements of incineration process, unfavorable energy saving and emission reduction, etc., and meet the reaction conditions Easy to meet, reduce operating costs, and easy to build

Pending Publication Date: 2022-01-21
JIANGXI GAIA ENVIRONMENTAL SCI & TECH CO LTD +1
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In order to overcome the above-mentioned deficiencies in the prior art, the present invention provides a process for removing dioxins in fly ash. The main technical problems to be solved are: the traditional high-temperature incineration method for removing dioxins requires strict reaction conditions, and the incineration process The temperature requirement is high, so the infrastructure construction cost is high, and the removal of dioxins requires a continuous high temperature environment of 850 ° C, and the removal of dioxin precursors requires a continuous high temperature environment of 1200 ° C, so the energy consumption is particularly high, which is not conducive to energy saving and emission reduction , reduce operating costs

Method used

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  • Process for removing dioxin in fly ash
  • Process for removing dioxin in fly ash
  • Process for removing dioxin in fly ash

Examples

Experimental program
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Effect test

Embodiment 1

[0024] Example 1, such as figure 1 As shown, it includes the following steps:

[0025] Step 1, washing the fly ash with water, mixing the fly ash and water to prepare a slurry, and then using a suction filter to filter the prepared slurry to obtain a washing solution and solid residue;

[0026] Step 2, carbon dioxide high-pressure leaching, washing the solid slag with water to prepare a slurry, and placing the prepared slurry in a high-pressure container, while passing an excessive amount of carbon dioxide into the slurry, and using carbon dioxide high-pressure leaching to extract the The calcium contained in the solid slag is converted into calcium bicarbonate and dissolved in water, and the slurry that has been leached by carbon dioxide under high pressure is suction-filtered with a suction filter to obtain the leaching residue and filtrate. Decompose to generate calcium carbonate; and, the calcium carbonate can be calcined to obtain quicklime and carbon dioxide gas, the qu...

Embodiment 2

[0030] Example 2, such as figure 1 , 2 As shown, it includes the following steps:

[0031] Step 1. Washing of fly ash by using multi-stage reverse pulping fly ash washing method,

[0032] 1) Mix fly ash and water according to the solid-to-liquid ratio of 1:3-5 to prepare slurry, and at the same time, pass carbon dioxide gas into the slurry to adjust the pH value to 6-8, which is conducive to the precipitation of heavy metals and calcium ions;

[0033] 2) Suction filter the slurry prepared in 1) with a suction filter to obtain washing liquid and primary solid residue;

[0034] 3) Mix the primary solid slag obtained in 2) with water at a solid-to-liquid ratio of 1:3-5 to prepare a slurry;

[0035] 4) Suction filter the slurry prepared in 3) with a suction filter to obtain washing liquid and secondary solid residue;

[0036]5) Mix the secondary solid slag obtained in 4) with water at a solid-to-liquid ratio of 1:3-5 to prepare a slurry;

[0037] 6) Suction filter the slurry ...

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Abstract

A process for removing dioxin in fly ash is based on carbon dioxide high-pressure extraction of solid residues obtained after washing of the fly ash, then the extraction residues are washed with water and placed in a stainless steel reaction kettle under the high-temperature and high-pressure conditions, NaClO is added as an oxidizing agent for a reaction at the same time, and the dioxin is removed through a hydrothermal oxidation method. Compared with conventional high-temperature incineration, the hydrothermal oxidation method for removing dioxin saves more energy consumption, the washing liquid is subjected to evaporative crystallization and separation through an MVR evaporator to obtain sylvite and mixed salt waste liquid, NaClO can be obtained by electrolyzing the mixed salt waste liquid, an oxidizing agent does not need to be purchased additionally, on one hand, reagents are saved, on the other hand, NaClO has strong oxidizing property, the degradation efficiency on the dioxin is higher than the degradation efficiency of a common oxidizing agent, the hydrothermal oxidation effect is good, the recycling product of the fly ash is reused in the process link, the problem of product treatment such as export sales does not need to be considered, and the resynthesis of the dioxin can be effectively prevented.

Description

technical field [0001] The invention belongs to the technical field of harmless treatment of fly ash produced by garbage incineration, and in particular relates to a process for removing dioxins in fly ash. Background technique [0002] The output of fly ash from waste incineration in my country is huge. With the increase in the volume of domestic waste removal and the increase in the proportion of incineration, the waste incineration industry will grow explosively. By the end of 2020, the total amount of waste incineration will reach 591,400 tons per day. During the process of waste incineration, many harmful substances will be produced, such as dioxins, acid gases (such as hydrogen chloride, sulfur dioxide), nitrogen oxides, heavy metal dust, etc. Most of these pollutants will be trapped by the dust removal system to form fly ash during flue gas purification, and the annual production of fly ash is about 10 million tons. Large and medium-sized cities generate a large amou...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F11/18C25B1/26C25B1/14C25B1/50C04B2/10C04B2/02A62D3/38A62D3/33B01D53/81A62D101/08A62D101/22A62D101/28
CPCC01F11/18C25B1/26C25B1/14C25B1/50C04B2/10C04B2/02A62D3/33A62D3/38B01D53/81A62D2101/22A62D2101/08A62D2101/28B01D2258/0283
Inventor 高锦创徐丽琴罗成
Owner JIANGXI GAIA ENVIRONMENTAL SCI & TECH CO LTD
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