Method for controlling dioxin in sintering co-treatment process of waste incineration fly ash

Abstract

The invention discloses a method for controlling dioxin in a sintering co-treatment process of waste incineration fly ash. The method comprises the following steps of firstly, mixing the waste incineration fly ash, lime milk and thiourea, and granulating to obtain fly ash pellets; then uniformly mixing the fly ash pellets with iron ore sintering raw materials to obtain a mixture, distributing materials, igniting on the material surface of the mixture at the ignition temperature of 1000-1150 DEG C, sintering under the condition of air draft at the bottom of the mixture at the highest sintering temperature of 1200-1350 DEG C, and controlling the heating rate in the sintering process to be not lower than 220 DEG C / min. According to the method, on the premise that the quality and the yield of the sintered ore are guaranteed, effective treatment of the fly ash and efficient degradation of dioxin in the fly ash are achieved, efficient cleaning treatment of the waste incineration fly ash is achieved, meanwhile, de novo synthesis of dioxin in the sintering process is inhibited, and harmless recycling treatment of the fly ash is achieved in the true sense.

Description

technical field [0001] The invention belongs to the field of fly ash disposal, and in particular relates to a method for controlling dioxin in the process of sintering cooperative disposal of waste incineration fly ash. Background technique [0002] According to the China Statistical Yearbook, in 2017, the volume of domestic waste removal in my country was as high as 215.2 million tons, an increase of 5.69% compared with 2016, and the harmless treatment rate of domestic waste reached 97.7%. The annual incineration capacity increased significantly from 25.99 million tons per year to 84.63 million tons per year. The ratio of waste incineration and disposal will continue to rise. With the continuous expansion of the scale of construction and proposed construction, while solving the problem of "garbage siege", the problem of fly ash cannot be ignored. Because fly ash contains easily leached heavy metals and traces of persistent organic pollutants dioxin, my country has included ...

AI Technical Summary

Problems solved by technology

Because fly ash contains easy-to-leach heavy metals and traces of persistent organic pollutant dioxins, my country has included fly ash in the "National Hazardous Waste List", which belongs to HW18 hazardous waste. If it is not treated effectively, it will cause air pollution. Air pollution has adverse effects on human beings and restricts the development of waste incineration power generation

[0003] At present, fly ash disposal mainly relies on cement chelation solidification and cement kiln synergy. Although cement solidification can inhibit the leaching of heavy metals in fly ash, it cannot degrade dioxins in fly ash. It is conducive to transportation and landfill, and does not have the conditions for subsequent resource utilization

Cement kiln co-processing is the main way of resource utilization of fly ash, but due to the strict control of chlorine in cement, the amount of fly ash added is very low, so cement kilns can only achieve limited resource utilization of fly ash; my country's policy level It actively encourages domestic waste incineration to generate power, but the lack of reasonable fly ash disposal technology has become one of the important factors restricting the development of waste incineration power generation industry

[0004] Chinese patent CN 107159678 B discloses a dioxin control method in the iron ore sintering co-processing waste incineration fly ash process, the four components of waste fly ash, lime milk, flammable solid fuel and sludge are mixed, granulated, and dried Finally, it is made into small balls, and then evenly mixed with the sintering raw materials that are made into balls, and then the cloth is ignited and sintered; although this method realizes the efficient degradation of dioxins in fly ash, it ensures the effective consolidation of garbage fly ash, and realizes garbage fly ash. However, during the sintering process, Cl and Cu in the fly ash are introduced, and dioxins will be re-synthesized during the sintering process. Total emission of dioxins in sintering flue gas

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