CN109675910B - Treatment method for heavy metals such as dioxin, mercury and the like in fly ash - Google Patents

Abstract

The invention relates to a method for treating heavy metals such as dioxin, mercury and the like in fly ash, belonging to the technical field of fly ash treatment. Fly ash generated in industries such as garbage incineration, medical waste incineration, industrial waste incineration and the like contains dioxin and heavy metals (such as mercury, cadmium, lead, chromium, metalloid arsenic and the like with remarkable biological toxicity), belongs to dangerous solid waste, and needs to be subjected to harmless treatment. In order to simultaneously and thoroughly solve the pollution problem of heavy metals such as dioxin, mercury and the like in the fly ash, the invention adopts the coupling technology of high-temperature plasma and low-temperature plasma and the adsorption and regeneration technology of ceramic nano materials, and realizes the resource recovery of mercury salt, mercury soot and other wastes generated in the disposal process through a wet extraction device.

Description

Treatment method for heavy metals such as dioxin, mercury and the like in fly ash

Technical Field

The invention relates to a method for treating heavy metals such as dioxin, mercury and the like in fly ash, belonging to the technical field of fly ash treatment.

Background

Fly ash generated in industries such as garbage incineration, medical waste incineration, industrial waste incineration and the like contains dioxin and heavy metals (such as mercury, cadmium, lead, chromium, metalloid arsenic and the like with remarkable biological toxicity), belongs to dangerous solid waste, and needs to be subjected to harmless treatment.

There are some patents relating to the treatment of heavy metals, dioxins and mercury etc. in fly ash. Patent CN101797572A discloses a method for treating waste incineration by plasma, which removes mercury vapor in tail gas through an activated carbon adsorption tower, and the activated carbon adsorbing mercury vapor is still dangerous waste, and the treatment of mercury is not thorough. Patent CN 1632376a discloses a method for melting waste incineration fly ash at high temperature in a cyclone furnace, which mentions that dioxin is decomposed at high temperature and fly ash containing dioxin and heavy metals is subjected to complete melting treatment in the cyclone furnace, and obviously the method is not suitable for the treatment of mercury pollution. Patent CN 102531389a discloses a method for preparing glass ceramics by melting waste incineration fly ash in an electric arc furnace, which does not relate to the treatment of mercury pollutants. Patent CN201711321111 discloses a method for removing dioxin and metallic mercury in fly ash, which includes adsorbing the mercury-containing tail gas to adsorb mercury elements in the mercury-containing tail gas, and preferably performing adsorption treatment by using activated carbon, which also does not completely treat mercury. Therefore, a solution capable of removing dioxin and common heavy metals in the fly ash and thoroughly treating mercury pollution is needed in the prior art to simultaneously solve the pollution problem of heavy metals such as dioxin and mercury in the fly ash.

In order to simultaneously and thoroughly solve the pollution problem of heavy metals such as dioxin, mercury and the like in the fly ash, the invention adopts the coupling technology of high-temperature plasma and low-temperature plasma and the adsorption and regeneration technology of ceramic nano materials, and realizes the resource recovery of mercury salt, mercury soot and other wastes generated in the disposal process through a wet extraction device.

Disclosure of Invention

The invention mainly aims to provide a method for treating heavy metals such as dioxin, mercury and the like in fly ash, so as to solve the problem of pollution of the heavy metals such as the dioxin, the mercury and the like in the fly ash at the same time.

The method for treating the heavy metals such as dioxin, mercury and the like in the fly ash is characterized by comprising the following steps:

step 1, mixing fly ash and a component regulator, and under the action of high-temperature plasma at 1300-1800 ℃, thoroughly decomposing dioxin in the fly ash into harmless gas, and stably solidifying heavy metals except mercury in the fly ash in a molten glass body to obtain flue gas containing mercury vapor;

2, firstly, the flue gas containing mercury vapor passes through a condensing device to reduce the gas temperature; then, a water removal system is adopted to reduce the water content of the flue gas (the water vapor content is reduced to 3% at room temperature); the dust content of the cooled flue gas is further reduced; then oxidizing and decomposing pollutants by a low-temperature plasma system;

step 3, to realize Hg²⁺And other pollutants are deeply purified, and the flue gas treated by the low-temperature plasma system enters a ceramic nano material adsorption and regeneration system to achieve standard emission of the flue gas.

And 4, recycling the mercury salt, mercury soot and the like generated in the treatment process by using a wet extraction device.

The method for treating the heavy metals such as dioxin, mercury and the like in the fly ash is characterized by comprising the following steps: the high-temperature plasma coupling technology and the low-temperature plasma coupling technology are adopted, and the problem of pollution of heavy metals such as dioxin, mercury and the like in the fly ash is solved;

the method for treating the heavy metals such as dioxin, mercury and the like in the fly ash is characterized by comprising the following steps: in the process of solving the pollution problem of heavy metals such as dioxin, mercury and the like in the fly ash, a low-temperature plasma system is adopted to oxidize and decompose pollutants, and a wet extraction device is used for realizing resource recovery of wastes such as mercury salt, mercury soot and the like.

The invention has the beneficial effects that:

the invention relates to a method for treating heavy metals such as dioxin, mercury and the like in fly ash, which adopts the coupling technology of high-temperature plasma and low-temperature plasma, simultaneously thoroughly solves the pollution problem of the heavy metals such as the dioxin, the mercury and the like in the fly ash, and realizes the resource recovery of wastes such as mercury salt, mercury soot and the like in the process of treating the heavy metals such as the dioxin, the mercury and the like in the fly ash.

Drawings

Fig. 1 is a diagram illustrating steps of a method for treating heavy metals such as dioxin and mercury in fly ash.

In the figure: 1. briquetting machine, 2, high-temperature plasma furnace, 3, low-temperature plasma reactor, 4, ceramic nanometer adsorption tower, 5, nanometer ceramic regeneration tower, 6, wet extraction device, 7, mercury salt, mercury soot, 8, dioxin, 9, vitreous body, 10 and flue gas which reaches the discharge standard.

Detailed Description

The present invention will be described with reference to examples, but the present invention is not limited to the examples.

Example 1:

as shown in figure 1 of the drawings, in which,

(1) adding SiO-containing₂Mixing the modifier into the fly ash, and then adding the adjusted fly ash into a briquetting machine 1 for briquetting pretreatment;

(2) heating and melting the pressed fly ash in the high-temperature plasma furnace 2, completely decomposing dioxin 8 into harmless flue gas at the stage, and stably solidifying heavy metals except mercury in a glass body 9 formed by cooling the molten mass;

(3) the mercury-containing flue gas passes through a condensing device to reduce the temperature of the gas; then, a water removal system is adopted to reduce the water content of the flue gas (the water vapor content is reduced to 3% at room temperature); the cooled flue gas enters the flue gas to further reduce the dust content; then the pollutants in the flue gas entering the low-temperature plasma reactor 3 are oxidized and decomposed;

(4) from low temperature plasmaThe flue gas from the reactor 3 enters a ceramic nano adsorption tower 4, and Hg contained in the flue gas²⁺And other pollutants are adsorbed and then discharged after reaching the standard 10;

(5) and the ceramic nano material adsorbed and saturated in the adsorption tower enters a regeneration system of a nano ceramic regeneration tower 5, and the mercury salt, mercury soot 7 and other wastes are recycled through a wet extraction device 6.

Claims (1)

1. A method for treating dioxin and heavy metals in fly ash adopts a high-temperature plasma coupling technology and a low-temperature plasma coupling technology, and simultaneously solves the pollution problem of the dioxin and the heavy metals including mercury in the fly ash, and is characterized by comprising the following steps:

step 1, mixing fly ash and a component regulator, and under the action of high-temperature plasma at 1300-1800 ℃, thoroughly decomposing dioxin in the fly ash into harmless gas, and stably solidifying heavy metals except mercury in the fly ash in a molten glass body to obtain flue gas containing mercury vapor;

2, making the flue gas containing mercury vapor pass through a condensing device to reduce the gas temperature; then, reducing the water content of the flue gas by adopting a water removal system to reduce the water vapor content to 3% at room temperature; the dust content of the cooled flue gas is further reduced; then oxidizing and decomposing pollutants by a low-temperature plasma system;

step 3, to realize Hg²⁺And other pollutants are deeply purified, and the flue gas treated by the low-temperature plasma system enters a ceramic nano adsorption tower to realize the standard-reaching emission of the flue gas; the ceramic nano material which is adsorbed and saturated in the ceramic nano adsorption tower enters a nano ceramic regeneration tower;

and 4, recycling the mercury salt and the mercury soot produced in the treatment process through a wet extraction device.