KR20030038914A - A heavy metal-fixing agent stabilizing heavy metals contained in scattering wastes - Google Patents

Abstract

PURPOSE: Provided is a heavy metal-fixing agent capable of stably solidifying and stabilizing harmful heavy metals contained in fly ash and preventing release of the heavy metals. CONSTITUTION: The heavy metal-fixing agent is consisted of at least two kinds of chelating agents with specificity, wherein the chelating agent is consisted of derivatives of iminodiacetic acid, derivatives of 8-hydroxyquinoline, derivatives of polyamines and derivatives of dithiocarbamate.

Description

Heavy metal fixative to stabilize heavy metals in waste fly ash {A HEAVY METAL-FIXING AGENT STABILIZING HEAVY METALS CONTAINED IN SCATTERING WASTES}

The present invention relates to a composition of a heavy metal fixative to stably trap and fix various harmful heavy metals contained in fly ash generated when incineration of various industrial wastes to prevent re-elution of heavy metals.

With the development of the industry, the economic scale grows and the quality of life of human beings increases, the proper disposal of various hazardous wastes inevitably arises as a problem of groundwater and soil resource ozone, not limited to the surrounding living environment problems. have.

Conventionally, the final treatment of waste has been mainly reliant on landfill, but there are many questions about the economic and technical satisfaction of the treatment method, and it is difficult to complete the treatment.

Incineration and recycling have been proposed as a new alternative. However, incineration residues, especially fly ash captured by hazardous gas treatment facilities, contain various harmful heavy metals. Many environmental problems, such as environmental pollution, has become a new environmental problem.

That is, the above fly ash treatment methods include cement solidification method, asphalt solidification method, plaster solidification method, fire extinguishing solidification method and pyrolysis melt solidification method. In Korea, it is mainly treated by cement solidification method, but there are many problems such as progressive dissolution of harmful components, increase in volume of solid body after solidification, and breakage of solid body due to decrease in compressive strength.

In particular, the cement solidification method causes various harmful heavy metals which are gradually eluted when the leachate occurs in the landfill where the solids are finally disposed of not only increase the treatment cost of the leachate, but also cause secondary pollution to the ecosystem due to groundwater contamination. have.

As a countermeasure against the increase in the volume of solidified substances and the gradual dissolution of heavy metals due to cement solidification, the addition of a chemical insolubilizer (chelating agent), which is not eluted by chemically stably fixing heavy metals in fly ash, has been proposed. Materials having a dithiocarbamate bond group are mainly used.

However, dithiocarbamate alone is insufficient to stably handle various harmful heavy metals contained in fly ash, which shows high reactivity with Hg, Cd, Zn, Pb, etc. It is difficult to apply to the containing fly ash.

The present invention is to solve the above problems, the specificity of the reaction of the chemical insolubilizing agent (chelating agent) of various types of harmful heavy metals contained in the fly ash among various incineration residues generated from municipal waste incineration ash, thermal power plant, coal ash mill, etc. The purpose of the present invention is to provide a composition of a heavy metal fixative composed of a chemical insolubilizer that can stably collect and immobilize using to inhibit re-dissolution of heavy metal.

The present invention provides a heavy metal fixative to stably collect and fix various harmful heavy metals contained in fly ash generated by incineration of various industrial wastes with a chemical insolubilizer (chelating agent) to prevent re-elution of harmful heavy metals. to provide.

That is, it stabilizes heavy metal waste by adding water and heavy metal fixative of the present invention to fly ash containing harmful heavy metal.

Chemical insolubilizers (chelating agents) used in the heavy metal fixative composition are iminodiacetic acid derivatives, hydroxyquinoline derivatives, polyamines derivatives, dithiocarbamate It consists of derivatives.

The chemical insolubilizer is composed of two or more kinds of reaction specificity to exhibit a high reactivity to a variety of heavy metals, heavy metal reaction of the insolubilizer is shown in Table 1.

<Table 1>

Chelate derivatives Active area Target metals Iminodoacetic acid Most polyvalent heavy metals Hirogishquinoline (8-hydroxy guinoline) Cu, Ni, Zn, Co Polyamines NH ₂ CH ₂ CH ₂ NH ₂ CH ₂ CH ₂ NH ₂ Cu, Ni, Zn, Co Dithiocarbamate Hg, Cd, Zn, Pb

In other words, since there are various kinds of harmful heavy metals in fly ash according to their origin and season and there are many changes in concentration, one kind of insolubilizing agent (chelating agent) can play an effective heavy metal fixative role. The measurement results of the analysis of heavy metals contained in these fly ashes are shown in Table 2.

<Table 2>

Therefore, the composition of the heavy metal fixative of the present invention is capable of stabilizing various harmful heavy metals by using two or more kinds of imino diacetic acid derivatives, hydroxyquinoline derivatives, polyamine derivatives and dithiocarbamate derivatives.

When the heavy metal fixative according to the present invention is added to fly ash generated in an incinerator, an example in which harmful heavy metals are collected and stabilized will be described.

<Example>

Water and this heavy metal fixative were mixed with 30% and 3.0% by weight of fly ash, respectively, and then analyzed by the dissolution test of the waste process test method. As a comparative example, 3% of the dialkyl dachiogarbamate-based heavy metal fixative currently used was used.

As a result, as shown in Table 3, it can be seen that the present invention compared with the existing comparative example, stably traps and fixes various harmful heavy metals.

<Table 3>

Hazardous Substances in Designated Waste

As described above, the composition of the heavy metal fixative according to the present invention can stably collect and fix various harmful heavy metals, and prevent the secondary environmental pollution by preventing the heavy metal re-elution by leachate from the final landfill with excellent stability and reactivity. And, compared to the conventional cement solidification method can be fixed to the heavy metal without using cement has the advantage of minimizing the discharge of the final waste.

Claims (2)

Heavy metal stabilizers to stabilize the heavy metals contained in the waste fly ash, characterized in that the fixing agent for stabilizing harmful heavy metals contained in the waste fly ash is composed of two or more chemical insolubilizing agents (chelating agents) The method of claim 1, wherein the chemical insolubilizer (chelating agent) stabilizes the heavy metals contained in the waste fly ash, characterized in that consisting of amino diacetic acid, derivatives, hydroxyquinoline derivatives, polyamine derivatives, dithiocarbamate derivatives Heavy metal fixative