CN111454008A

CN111454008A - Zero-landfill technical method for waste incineration fly ash

Info

Publication number: CN111454008A
Application number: CN202010282168.1A
Authority: CN
Inventors: 赵洁
Original assignee: Qingdao Hui Cheng Environmental Technology Co ltd
Current assignee: Qingdao Hui Cheng Environmental Technology Co ltd
Priority date: 2020-04-11
Filing date: 2020-04-11
Publication date: 2020-07-28

Abstract

The invention provides the technical field of zero landfill treatment of waste incineration fly ash, and particularly relates to a technical method for zero landfill of waste incineration fly ash. The method comprises two steps of chemical pretreatment and preparation of high-end cement by dechlorination residues. The method comprises the following specific steps: (1) adding metal ions into the fly ash in the water washing process for stabilization to remove chloride and heavy metals; (2) the pretreated fly ash is pneumatically conveyed to the tail of a cement kiln with higher temperature through a sealed pipeline, and then enters into melting with higher temperature for disposal. Meanwhile, when clinker is melted and calcined, organic matters such as dioxin and the like which are difficult to remove are thoroughly decomposed into carbon dioxide and water vapor. Heavy metals can be effectively fixed in the crystal lattice of the cement clinker, thereby ensuring the realization of harmless and recycling of the fly ash.

Description

Zero-landfill technical method for waste incineration fly ash

Technical Field

The invention relates to a zero-landfill technical method for waste incineration fly ash.

Background

Along with the rapid development of urbanization, the garbage output of China increases year by year, and the garbage incineration industry increases explosively, but a new problem, namely the treatment of the garbage incineration fly ash, is generated. The waste incineration fly ash refers to residue collected in a flue gas purification system of a waste incineration plant, and generally comprises dust collector fly ash and absorption tower fly ash, wherein the dust collector fly ash and the absorption tower fly ash contain flue ash, added chemical agents, chemical reaction products and the like. The waste fly ash is a substance with high specific surface area, not only enriches a large amount of toxic heavy metals such as mercury, lead and cadmium, but also enriches a large amount of dioxin-like substances, so the waste incineration fly ash belongs to dangerous waste, and is numbered HWl 8.

At present, the fly ash treatment modes at home and abroad mainly comprise the following modes:

the cement solidification-hazardous waste landfill is the main fly ash disposal mode in China at present, the process is mature, the system is simple, the operation is easy, the solidification treatment cost is low, but the landfill site pressure is increased sharply along with the increase of the yield of the fly ash, the service life of the landfill site is limited, the safe landfill disposal cost of a solidified body is high, and the long-term stability of heavy metal is poor.

The second step is that the fly ash melting treatment technology has the advantages of high volume reduction rate which can be generally reduced to 1/2-1/3 (volume), stable quality of the obtained slag, no dissolution of heavy metals, renewable utilization, complete decomposition of dioxin and other organic pollutants, generation of waste gas containing volatile heavy metals such as Pb, Zn, Cd and the like under a high temperature condition, need of a subsequent flue gas treatment device, complex process, high energy consumption and high treatment cost.

The fly ash cement kiln co-disposal technology has the advantages that the fly ash can replace raw materials, the cement kiln rotary kiln is suitable for treating the hazardous waste, the operation process is easy to control, the pollutant treatment is thorough, and the resource utilization can be realized.

The invention patent CN103771695A discloses a harmless treatment and utilization method of waste incineration fly ash. The method comprises the steps of mixing fly ash, silicate, borate and a reducing agent according to a certain proportion, pressing the mixture into pellets, putting the pellets into a molybdenum electrode furnace, introducing electric energy into materials in the furnace by using a molybdenum electrode, taking a material melt as a resistor, converting the electric energy into heat energy to heat the materials, melting the materials at 1300-1600 ℃ for 11-15 hours, and introducing the materials into a forming device to prepare plates, cotton or continuous fibers. It integrates the electric melting solidification, reduction smelting and low-temperature plasma technology to carry out harmless treatment on the waste incineration fly ash, and simultaneously produces usable products by utilizing fly ash molten slurry. However, the method has the problems that the types of the disposable fly ash are few, the disposable fly ash is only used for the fly ash of a power plant, the disposal effect of the fly ash with other components is not good, the efficiency is low in the disposal process, fly ash flying is easy to occur, and secondary pollution and incomplete disposal are caused.

The invention is based on the fly ash cement pit disposal technology, adopts the methods of inorganic chloride removal, heavy metal chemistry and high-temperature lattice stabilization, and comprehensively utilizes the main components of the fly ash as the cement raw material, thereby realizing the thorough resource treatment of the fly ash.

Disclosure of Invention

The invention provides the technical field of zero landfill treatment of waste incineration fly ash, and particularly relates to a zero landfill technical method of waste fly ash. The method comprises two steps of chemical pretreatment and preparation of high-end cement by dechlorination residues. The method comprises the following specific steps:

(1) washing the fly ash with water, and adding a chemical agent in the washing process to remove chlorine and heavy metal ions; (2) the pretreated fly ash is pneumatically conveyed to the tail of a cement kiln with higher temperature through a sealed pipeline, and then enters into melting with higher temperature for disposal. Meanwhile, when clinker is melted and calcined, organic matters such as dioxin and the like which are difficult to remove are thoroughly decomposed into carbon dioxide and water vapor. Heavy metals can be effectively fixed in the crystal lattice of the cement clinker, thereby ensuring the realization of harmless and recycling of the fly ash.

Detailed Description

The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

In the present invention, the raw materials and equipment used are commercially available or commonly used in the art, unless otherwise specified.

The methods in the following examples are conventional in the art unless otherwise specified.

Example 1:

a zero landfill technical method of waste incineration fly ash comprises the following steps: comprises the steps of washing fly ash with water and calcining at high temperature. Chelating agents are added in the washing process, heavy metal ions are directly changed into inorganic mineral substances through chemical reaction for a period of time, the mineral substances are insoluble in water, and the mass ratio of the washing fly ash to the water is 1: 2; after washing, solid-liquid separation is carried out, and the solid (the content of chloride ions is about 1 percent by dry weight) is sent to a cement kiln for cooperative treatment.

Example 2:

Claims

1. A zero landfill technical method for waste incineration fly ash is characterized by comprising the following steps:

(1) the chemical pretreatment part removes harmful chlorine, sulfur and alkali compounds in the fly ash by a washing dechlorination process, the removal rate reaches more than 80 percent, and controls metal ions in the fly ash washing liquid to reach the discharge standard by a metal chemical stabilization method, and the solid quality requirement after inorganic chloride removal is as follows: na2O + K2O is less than or equal to 1 percent, and Cl is less than or equal to 1 percent;

(2) the dechlorination remainder can be used for preparing high-end cement, the temperature in a cement kiln can reach about 1400 ℃, organic matters such as dioxin and the like which are difficult to remove can be directly and thoroughly decomposed into carbon dioxide and water vapor, and main components such as CaO and SiO in fly ash₂、Al₂O₃Etc. are fully utilized as a part of the cement raw material.

2. A method according to claim 1, characterized in that an inorganic chloride removal process is added to the process.

3. The method of claim 1, wherein the control of dioxin phase and separation thereof during dechlorination of fly ash.