CN-122007134-A - Household garbage incineration fly ash granulation and cooperative furnace return recycling method

CN122007134ACN 122007134 ACN122007134 ACN 122007134ACN-122007134-A

Abstract

A method for recycling household garbage incineration fly ash granulation in cooperation with furnace return, belonging to the technical field of hazardous waste treatment and recycling. The method comprises the steps of detecting the contents of heavy metals, dioxin and soluble chloride salt in raw fly ash, dynamically judging and executing water washing pretreatment based on detection results, adding a composite additive consisting of a shaping agent, a heavy metal curing agent, a pore-forming agent and a dioxin resynthesis inhibitor into the treated fly ash, granulating, regulating and controlling the porosity and the diameter of granulated particles according to formulas of the dioxin and the heavy metal content, and finally, putting the particles into an incinerator for co-sintering, and carrying out separation verification on products for recycling. The method directly calculates the technological parameters of each link by using the pollutant concentration which can be measured in a laboratory, so that the fly ash sintered body and the slag can be separated, monitored and traced, and the total amount of heavy metal, dioxin, soluble chloride and leaching toxicity simultaneously meet the relevant standard limit value, thereby having the advantages of strong adaptability, stable effect and good economy.

Inventors

GONG CHEN
HU XUN
XIAO CHENGBIN
HU LIHUA
SHAO ZHERU
Zong xiao
AN JIN
CHEN FANGFANG
WU YONGXIN

Assignees

光大环境科技（中国）有限公司

Dates

Publication Date: 20260512
Application Date: 20260113

Claims (10)

1. A method for recycling household garbage incineration fly ash through granulation and cooperation of furnace return is characterized by comprising the following steps: Step one, fly ash detection, which is to detect and analyze the fly ash generated by a garbage incineration system, wherein detection items comprise total weight metal content, dioxin-like substance content and soluble chloride content; Step two, pretreatment, namely judging whether the fly ash needs to be washed according to the detection result of the step one, if the content of soluble chloride salt in the fly ash exceeds a set threshold value X 1 or the total metal content exceeds a set threshold value X 2 , washing the fly ash, if yes, dynamically determining washing process parameters according to the detection result, and carrying out washing desalination and heavy metal removal treatment to obtain washing ash; step three, compatibility, namely adding additives into the fly ash obtained in the step two for mixing, wherein the additives comprise a shaping agent, a heavy metal curing agent, a pore-forming agent and a dioxin resynthesis inhibitor; granulating, namely granulating the mixture obtained in the step three, wherein the porosity P k of the granulated particles is calculated according to the total metal content C MH and the dioxin content C DN of the fly ash, and the calculation formula is as follows: , Wherein P k is the porosity of the granulated particles, P 0 is the basic porosity, the value range is 0.3-0.5, C MH is the total metal content, mg/kg, C DN is the dioxin-like substance content, ng-TEQ/kg, g and h are empirical coefficients, g is 0.0012-0.0018, and h is 0.003-0.004; The particle size of the granulated particles is calculated according to the total metal content C MH and the dioxin content C DN of the fly ash, and the calculation formula is as follows: , Wherein, D f is the diameter of the granulated fly ash, D 0 is the basic diameter, the value range is 10-15 mm, C MH is the total metal content, mg/kg, C DN is the dioxin content, ng-TEQ/kg, i and j are experience coefficients, i is 0.0008-0.0009, and j is 0.001-0.003; step five, charging into a furnace, namely throwing the granulated particles obtained in the step four into a household garbage incinerator for collaborative sintering treatment; And step six, separating and verifying products, namely separating the sintered products from slag, and detecting and verifying environmental protection indexes and physical properties of the separated fly ash sintered body.
2. The method for recycling household garbage incineration fly ash through granulation in cooperation with furnace returning according to claim 1, wherein in the first step, heavy metals comprise at least one of lead, mercury, cadmium, chromium, nickel and copper, the total metal content is the sum of detection results of single heavy metals, soluble chloride salts comprise at least one of sodium chloride, potassium chloride and calcium chloride, and dioxin substances are 2,3,7,8-PCDD/Fs.
3. The method for recycling household garbage incineration fly ash through granulation in cooperation with furnace returning according to claim 1, wherein in the second step, the set threshold value X 1 of the content of soluble chloride salt is 1.5 wt%, and the set threshold value X 2 of the content of heavy metal is 80 mg/kg.
4. The method for recycling household garbage incineration fly ash granulation in cooperation with a furnace as claimed in claim 1, wherein the water washing process parameters in the step two comprise water washing pH value, water-ash ratio and water washing time, wherein the water washing pH value is determined according to the total metal content C MH of the fly ash, and the calculation formula is as follows: , wherein, C MH is the total weight metal content, mg/kg, a and b are empirical coefficients, the value range of a is 24000-26000, and the value range of b is 0.9-0.96; the water-to-ash ratio is determined according to the content of soluble chloride salt C Cl in the fly ash, and the calculation formula is as follows: , Wherein R WF is water-ash ratio, i.e. mass ratio of water to fly ash, C Cl is mass percent of soluble chloride salt in fly ash, C, d is empirical coefficient, C is 0.48-0.5, d is 0.095-0.098; the water washing time is determined according to the soluble chloride salt content C Cl of the fly ash, and the calculation formula is as follows: , Wherein T w is water washing time, min, T 0 is basic water washing time, min, C Cl is mass percent of soluble chloride in fly ash, e and f are empirical coefficients, the value range of e is 0.16-0.18, and the value range of f is 0.04-0.045.
5. The method for recycling household garbage incineration fly ash granulation in cooperation with furnace returning as claimed in claim 4, wherein the water washing process parameters in the step two further comprise water washing rounds, and the water washing rounds are 2-4 grades.
6. The method for recycling household garbage incineration fly ash through granulation in cooperation with furnace return according to claim 1, wherein the addition amount of the pore-forming agent in the third step is 2-10% of the dry basis weight of the fly ash, and the addition amount of the shaping agent is 5-15% of the dry basis weight of the fly ash.
7. The method for recycling household garbage incineration fly ash through granulation and cooperation of furnace return according to claim 1, wherein the adding amount of the heavy metal curing agent in the third step is 2-15% of the dry basis weight of the fly ash, and the adding amount of the dioxin resynthesis inhibitor is 1-10% of the dry basis weight of the fly ash.
8. The method for recycling household garbage incineration fly ash by granulation in cooperation with furnace return according to claim 1, wherein the limit control range of the porosity of the granulated particles in the fourth step is 0.25-0.45, the limit control range of the diameter D f of the granulated fly ash is 7-15 mm, if the formula calculation result exceeds the process range, the lower limit of the control range is lower, the lower limit of the range is higher, the upper limit of the control range is higher, and the upper limit of the range is higher.
9. The method for recycling the household garbage incineration fly ash by granulating and cooperating with the furnace as claimed in claim 1, wherein the furnace feeding parameters of the co-sintering treatment in the fifth step are as follows, the temperature of a feeding area is controlled to be 400-800 ℃, and the calcination reaction time is controlled to be 0.5-2 h.
10. The method for recycling household garbage incineration fly ash granulation in cooperation with furnace returning according to claim 1, wherein the environmental protection indexes and physical property detection verification in the sixth step comprise heavy metal leaching concentration detection, dioxin content detection, soluble chloride content detection and mechanical strength detection, and if the detection result does not reach the standard, the method returns to the third step to adjust the additive ratio or returns to the fifth step to adjust the furnace entering parameters and then carries out retreatment.

Description

Household garbage incineration fly ash granulation and cooperative furnace return recycling method Technical Field The invention relates to the technical field of hazardous waste treatment and recycling, in particular to a method for recycling household garbage incineration fly ash granulation and cooperation of furnace return. Background The waste incineration fly ash is solid powdery material captured by a bag-type dust collector in the waste incineration process, and comprises grate furnace fly ash and fluidized bed fly ash, wherein the fly ash contains a large amount of soluble salts, easily-leached heavy metals and highly toxic organic pollutants (dioxin, furan and the like). The fly ash from incineration of household garbage is classified as dangerous waste (HW 18) because of the enrichment of heavy metals (such as Pb, cd, cr, etc.), dioxin and soluble chloride salts (Cl-content reaches 15-30%). The incineration treatment capacity of the household garbage rises year by year, and the amount of fly ash generated therewith also presents a faster growing situation. The fly ash has extremely high environmental risk and can be categorized into three types of high chlorine salt content, high heavy metal concentration and high persistent organic pollution. The problem of fly ash becomes a neck problem in the waste incineration industry. At present, the treatment and disposal technology for the waste incineration fly ash at home and abroad presents a diversified development situation, the traditional treatment mode (landfill and stabilization) has the problems of large occupied area, high secondary pollution risk and the like, and the high-temperature melting and sintering technology and cement kiln cooperative treatment can realize harmless treatment, but the traditional treatment mode is dependent on external facilities and has high energy consumption. The return of the fly ash to the incinerator for cooperative heat treatment (cooperative return) is a potential technology, and has the advantages that the existing incineration facilities can be utilized to realize the reduction, harmlessness and recycling of the fly ash. However, the existing fly ash cooperative furnace return technology has common defects. Firstly, fly ash components (heavy metals, chloride salts, dioxins and the like) of different sources and different periods have extremely large fluctuation, but some existing processes adopt relatively fixed pretreatment formulas and operation parameters, and lack of dynamic adjustment capability on fly ash characteristics can cause incomplete pollutant removal or unstable recycling efficiency. Secondly, part of the process directly returns the fly ash which is not dechlorinated or simply treated to the furnace, so that chloride salt is circularly enriched in an incineration system (the chloride salt is condensed in the fly ash after volatilizing) or slag enters into slag to cause the increase of slag chlorine content, and the problems of dilution emission or equipment corrosion are caused. Finally, in terms of dioxin inhibition and heavy metal stabilization, there is a lack of additive regulation means precisely associated with the content of the pollutants of the fly ash itself. For example, chinese patent application publication No. CN 117655071A discloses a method for treating fly ash from incineration of household garbage, which comprises washing fly ash with water to remove chlorine, adding plastic agent into the washing fly ash, granulating, and heat treating in a garbage incinerator to reduce the pollutants in the fly ash, and completely dissolving or utilizing the treated fly ash. The fly ash has larger difference of components and pollutant characteristics in different areas, different projects and different periods, and the method does not provide a dynamically adjustable allocation means according to the real-time component characteristics of the fly ash. The Chinese patent application publication No. CN 117324348A discloses a heat treatment system and a treatment method of the synergic return furnace of fly ash and household garbage, wherein the method is to add water and binder into the fly ash generated by a garbage incineration system, mix, granulate and form, and send the granulated particles and garbage to an incinerator for heat treatment. The method comprises the steps of granulating raw ash, returning the granulated raw ash to a garbage incinerator for heat treatment, enabling chlorine salts such as sodium chloride and potassium chloride in the fly ash in a high temperature zone of the incinerator to be partially volatilized and enter a flue gas system to generate cyclic enrichment, enabling non-volatilized chlorine salts to be combined into slag along with a fly ash treatment product, enabling sodium chloride and potassium chloride to belong to soluble salts, and finally enabling soluble chlorine of the slag to rise, so that the problem of dilution emission exists. The Chinese paten