Innocent treatment method for incineration fly ash

Abstract

The invention provides a harmless treatment method for incineration fly ash, and belongs to the technical field of hazardous waste harmless treatment. According to the method, the mass content of related components in the incineration fly ash is detected firstly, then the incineration fly ash is mixed with an alkaline earth metal additive, a chemical precipitator and water, the alkaline earth metal additive can form a stable physical structure with the fly ash, the chemical precipitator can react with heavy metal in the incineration fly ash to form a chemical stable substance which is insoluble in water, and the chemical stable substance is separated from the incineration fly ash. When the content of selenium in the incineration fly ash is larger than 0.2 mg / kg or the content of cadmium in the incineration fly ash is larger than 0.15 mg / kg, a modified chemical component with the mass ratio of silicon oxide to aluminum oxide being larger than 5 is further added, the stability of heavy metal in the incineration fly ash is further improved, all the components are mixed, then forming and curing are conducted, the stability of the incineration fly ash is further improved, and the stability of the incineration fly ash is further improved. Meanwhile, the harmless treatment method is low in cost, the volume of the incineration fly ash subjected to harmless treatment is not increased, and subsequent landfill or resource utilization is facilitated.

Description

Technical Field

[0001] The invention belongs to the technical field of harmless treatment of hazardous wastes, and in particular relates to a harmless treatment method for incineration fly ash. Background Art

[0002] The incineration of domestic waste in my country has achieved rapid development and great progress, but the treatment of fly ash from waste incineration is not satisfactory, becoming the weakest link in the pollution control and risk management of the whole process of domestic waste incineration. The disposal scheme of fly ash stabilized by organic chelating agents and solidified by cement-based materials and entering hazardous waste safe landfills is the mainstream technical route for fly ash treatment at present, and has been widely recognized and applied. However, such methods usually have problems such as poor stability, large disposal volume, and high treatment costs. With the increase in fly ash emissions year by year, the existing disposal methods for huge amounts of fly ash, on the one hand, have caused great economic pressure on management units and disposal units, and on the other hand, the storage capacity of the built hazardous waste safe landfills is far from meeting the disposal needs of the new fly ash. Poor stability, high disposal costs, and limited disposal capacity have become problems that need to be urgently solved in the existing fly ash disposal.

[0003] Therefore, how to achieve efficient and low-cost harmless disposal of fly ash from the incineration of domestic waste is a technical problem that needs to be solved urgently in this field. Summary of the invention

[0004] The purpose of the present invention is to provide a harmless treatment method for incineration fly ash. After being treated by the harmless treatment method provided by the present invention, the fly ash has good stability, low cost, and the volume of the fly ash does not increase after treatment.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for harmlessly treating incineration fly ash, comprising the following steps:

[0007] (1) Detecting the incineration fly ash to obtain the mass percentage of total silicon oxide TSi, total aluminum oxide TAl, total sulfur trioxide TS, activated alumina AAl, soluble chloride ions SCl and organic matter and the mass content of heavy metals in the incineration fly ash;

[0008] (2) mixing the incineration fly ash with an alkaline earth metal additive, a chemical precipitant and water, and then molding and curing them in sequence to obtain stabilized fly ash; when the selenium content in the incineration fly ash is greater than 0.2 mg / kg or the cadmium content is greater than 0.15 mg / kg, a modified chemical component is also added during the mixing in step (2); the mass ratio of silicon oxide to aluminum oxide in the modified chemical component is greater than 5.

[0009] Preferably, the alkaline earth metal additive in step (2) comprises one or more of calcium oxide, calcium carbonate, calcium acetate, magnesium oxide, magnesium carbonate and magnesium acetate.

[0010] Preferably, when the alkaline earth metal admixture is one or more of calcium oxide, calcium carbonate and calcium acetate, the number of moles of the alkaline earth metal admixture added per 100 g of incineration fly ash in step (2) is the larger value calculated according to formula I or formula II,

[0011] n 碱土金属外加剂 =(0.011~0.015)TS+(0.035~0.048)SCl Formula I,

[0012] n 碱土金属外加剂 =(0.05~0.06)AAl+(0.003~0.007)(TAl-AAl) Formula II,

[0013] In Formula I, n 碱土金属外加剂 is the number of moles of alkaline earth metal additive added to every 100g of incineration fly ash, in mol; TS is the mass percentage of total sulfur trioxide in the incineration fly ash, in %; SCl is the mass percentage of soluble chloride ions in the incineration fly ash, in %; in formula II, n 碱土金属外加剂 is the number of moles of alkaline earth metal admixture added to every 100g of incineration fly ash, in mol; AAl is the mass percentage of activated alumina in the incineration fly ash, in %; TAl is the mass percentage of total alumina in the incineration fly ash, in %.

[0014] Preferably, when the alkaline earth metal additive is one or more of magnesium oxide, magnesium carbonate and magnesium acetate, the molar number of the alkaline earth metal additive added per 100 g of incineration fly ash in step (2) is calculated according to formula III:

[0015] n 碱土金属外加剂 =(0.021~0.036)SCl formula III,

[0016] In formula III, n 碱土金属外加剂 It is the number of moles of alkaline earth metal additive added to every 100g of incineration fly ash, in mol; SCl is the mass percentage of soluble chloride ions in incineration fly ash, in %.

[0017] Preferably, the chemical precipitant in step (2) comprises one or more of hydroxides, ammonium salts, sulfonates and phosphates.

[0018] Preferably, the millimoles of the chemical precipitant added per 1 kg of incineration fly ash in step (2) are calculated according to formula IV:

[0019] n 化学沉淀剂=(0.80~1.25)mFormula IV,

[0020] In Formula IV, n 化学沉淀剂 is the number of millimoles of chemical precipitant added per 1 kg of incineration fly ash, in mmol; m is the sum of the amounts of copper, zinc and lead in the heavy metals in the incineration fly ash, where m = M 铜 / 63.546+M 锌 / 65.38+M 铅 / 207.2,M 铜 、M 锌 and M 铅 They are the mass contents of copper, zinc and lead in the heavy metals in incineration fly ash, respectively, in g / kg.

[0021] Preferably, in step (2), the fluidity of the mixed system obtained by mixing the incineration fly ash with the alkaline earth metal additive, the chemical precipitant and water is ≥180 mm.

[0022] Preferably, the modified chemical components in step (2) include one or both of Y-type molecular sieve and transparent glaze.

[0023] Preferably, the mass of the modified chemical component in step (2) is 20% to 50% of the total mass of the incineration fly ash, alkaline earth metal additive, chemical precipitant and the modified chemical component.

[0024] Preferably, the step (2) further comprises a water reducing agent and / or a defoaming agent.

[0025] The present invention provides a harmless treatment method for incineration fly ash, comprising the following steps: (1) detecting the incineration fly ash to obtain the mass percentage content of total silicon oxide TSi, total aluminum oxide TAl, total sulfur trioxide TS, activated aluminum oxide AAl, soluble chloride ions SCl and organic matter and the mass content of heavy metals in the incineration fly ash; (2) mixing the incineration fly ash with an alkaline earth metal additive, a chemical precipitant and water, and then sequentially forming and curing to obtain stabilized fly ash; when the selenium content in the incineration fly ash is greater than 0.2 mg / kg or the cadmium content is greater than 0.15 mg / kg, a modified chemical component is further added during mixing in the step (2); the mass ratio of silicon oxide to aluminum oxide in the modified chemical component is greater than 5. The present invention first detects the mass content of the relevant components in the incineration fly ash, and then mixes the incineration fly ash with an alkaline earth metal admixture, a chemical precipitant and water. The alkaline earth metal admixture forms a stable physical structure with the fly ash, and the chemical precipitant can react with the heavy metals in the incineration fly ash to form a chemically stable substance that is insoluble in water. When the content of selenium in the incineration fly ash is greater than 0.2 mg / kg or the content of cadmium is greater than 0.15 mg / kg, a modified chemical component with a mass ratio of silicon oxide to aluminum oxide greater than 5 is added to further improve the stability of the heavy metals in the incineration fly ash. After the components are mixed, they are molded and cured to further improve the stability of the incineration fly ash. At the same time, the harmless treatment method has low cost, and the volume of the incineration fly ash after the harmless treatment does not increase, which is more conducive to subsequent landfill or resource utilization. The results of the embodiment show that after being treated by the harmless treatment method of the present invention, the toxic leaching index of the incineration fly ash meets the requirements of GB8978 and also meets the requirements of CJJ / T316. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The theoretical molecular structure diagram of the Al-O-Ca-Cl structure of the present invention;

[0027] Figure 2 The theoretical molecular structure diagram of the Al-O-Ca-SO3 structure of the present invention;

[0028] Figure 3 This is a SEM image of the stabilized fly ash in Example 1 of the present invention. DETAILED DESCRIPTION

[0029] The present invention provides a method for harmlessly treating incineration fly ash, comprising the following steps:

[0030] (1) Detecting the incineration fly ash to obtain the mass percentage of total silicon oxide TSi, total aluminum oxide TAl, total sulfur trioxide TS, activated alumina AAl, soluble chloride ions SCl and organic matter and the mass content of heavy metals in the incineration fly ash;

[0031] (2) mixing the incineration fly ash with an alkaline earth metal additive, a chemical precipitant and water, and then molding and curing them in sequence to obtain stabilized fly ash; when the selenium content in the incineration fly ash is greater than 0.2 mg / kg or the cadmium content is greater than 0.15 mg / kg, a modified chemical component is also added during the mixing in step (2); the mass ratio of silicon oxide to aluminum oxide in the modified chemical component is greater than 5.

[0032] Unless otherwise specified, the present invention has no particular limitation on the sources of the components, and commercially available products known to those skilled in the art may be used.

[0033] The invention detects the incineration fly ash to obtain the mass percentage content of total silicon oxide TSi, total aluminum oxide TAl, total sulfur trioxide TS, activated aluminum oxide AAl, soluble chloride ions SCl and organic matter and the mass content of heavy metals in the incineration fly ash.

[0034] In the present invention, the incineration fly ash is preferably domestic waste incineration fly ash. The present invention has no special limitation on the source of the domestic waste incineration fly ash, and the incineration fly ash obtained by incineration of domestic waste well known to those skilled in the art can be used.

[0035] The present invention has no special limitation on the method for detecting the incineration fly ash to obtain the mass percentage of total silicon oxide TSi, total aluminum oxide TAl, total sulfur trioxide TS, activated aluminum oxide AAl, soluble chloride ions SCl and organic matter and the mass content of heavy metals in the incineration fly ash. The detection method well known to those skilled in the art can be used to obtain the mass percentage of total silicon oxide TSi, total aluminum oxide TAl, total sulfur trioxide TS, activated aluminum oxide AAl, soluble chloride ions SCl and organic matter and the mass content of heavy metals in the incineration fly ash.

[0036] In the present invention, the method for detecting the mass percentage of total silicon oxide TSi, total aluminum oxide TAl and total sulfur trioxide TS in the incineration fly ash is preferably carried out according to GB / T1596-2017; the method for detecting the mass percentage of activated alumina AAl and soluble chloride ions SCl in the incineration fly ash is preferably carried out according to T / CBMF90-2020; the mass content of heavy metals in the incineration fly ash is preferably carried out according to HJ766-2015.

[0037] In the present invention, the heavy metal preferably includes one or more of copper, zinc, cadmium, chromium, mercury, lead, arsenic, selenium, barium, nickel and beryllium.

[0038] In the present invention, the mass percentage of organic matter in the incineration fly ash is preferably detected by:

[0039] a. Dry the incineration fly ash to obtain a dry basis sample;

[0040] b. Test the ignition loss of the dry basis sample obtained in step a under air and nitrogen atmospheres respectively, and then calculate the difference between the ignition loss of the dry basis sample under air and nitrogen atmospheres, which is the mass percentage of organic matter in the incineration fly ash.

[0041] In the present invention, the incineration fly ash is preferably dried to obtain a dry basis sample.

[0042] The present invention has no particular limitation on the drying temperature and time, as long as the free water in the incineration fly ash is fully removed.

[0043] After obtaining the dry basis sample, the present invention preferably tests the ignition loss of the dry basis sample in air and nitrogen atmospheres respectively, and then calculates the difference in ignition loss of the dry basis sample in air and nitrogen atmospheres, which is the mass percentage of organic matter in the incineration fly ash.

[0044] In the present invention, the ignition loss is preferably the mass loss of a dry sample when it is ignited at 600-700° C. to constant weight.

[0045] After obtaining the mass percentage of total silicon oxide TSi, total aluminum oxide TAl, total sulfur trioxide TS, activated aluminum oxide AAl, soluble chloride ions SCl and organic matter and the mass content of heavy metals in the incineration fly ash, the present invention mixes the incineration fly ash with an alkaline earth metal admixture, a chemical precipitant and water, and then sequentially forms and cures them to obtain stabilized fly ash.

[0046] In the present invention, the mass percentage of organic matter in the incineration fly ash is preferably ≤20%.

[0047] When the mass percentage of organic matter in the incineration fly ash is not within the above range, the present invention preferably pre-treats the incineration fly ash to make the mass percentage of organic matter in the incineration fly ash ≤20%.

[0048] The present invention has no special limitation on the method of the pretreatment, and any method known to those skilled in the art that can reduce the content of organic matter in incineration fly ash can be used. In the present invention, the pretreatment preferably includes one or both of biological method or acid-base degradation. The present invention has no special limitation on the operation of the pretreatment, and it is sufficient to ensure that the mass percentage of organic matter in the incineration fly ash after pretreatment is ≤20%. The present invention limits the mass percentage of organic matter in the incineration fly ash to less than 20%, which can further improve its treatment effect.

[0049] In the present invention, the alkaline earth metal admixture preferably includes one or more of calcium oxide, calcium carbonate, calcium acetate, magnesium oxide, magnesium carbonate and magnesium acetate. In the present invention, the alkaline earth metal admixture can form a stable physical structure with fly ash. In the present invention, the stable physical structure refers to an unconfined compressive strength of >1 MPa.

[0050] In the present invention, when the alkaline earth metal additive is one or more of calcium oxide, calcium carbonate and calcium acetate, the molar number of the alkaline earth metal additive added per 100 g of incineration fly ash is preferably the larger value calculated according to Formula I or Formula II.

[0051] n 碱土金属外加剂 =(0.011~0.015)TS+(0.035~0.048)SCl Formula I,

[0052] n 碱土金属外加剂 =(0.05~0.06)AAl+(0.003~0.007)(TAl-AAl) Formula II.

[0053] In Formula I, n 碱土金属外加剂 is the number of moles of alkaline earth metal admixture added to every 100g of incineration fly ash, in mol; TS is the mass percentage of total sulfur trioxide in the incineration fly ash, in %; SCl is the mass percentage of soluble chloride ions in the incineration fly ash, in %.

[0054] In formula II, n 碱土金属外加剂 is the number of moles of alkaline earth metal admixture added to every 100g of incineration fly ash, in mol; AAl is the mass percentage of activated alumina in the incineration fly ash, in %; TAl is the mass percentage of total alumina in the incineration fly ash, in %.

[0055] In the present invention, when the alkaline earth metal additive is one or more of magnesium oxide, magnesium carbonate and magnesium acetate, the molar number of the alkaline earth metal additive added per 100 g of incineration fly ash is preferably calculated according to Formula III:

[0056] n 碱土金属外加剂 =(0.021~0.036)SCl formula III.

[0057] In formula III, n 碱土金属外加剂 is the number of moles of alkaline earth metal admixture added to every 100g of incineration fly ash, in mol; SCl is the mass percentage of soluble chloride ions in the incineration fly ash, in %. The present invention limits the amount of alkaline earth metal admixture to the above range, so that it can form more stable structures with the fly ash, further improving the treatment effect of the incineration fly ash.

[0058] In the present invention, the chemical precipitant preferably includes one or more of hydroxides, ammonium salts, sulfonates and phosphates, and more preferably includes one or more of calcium hydroxide, ammonium nitrate, sodium sulfonate and sodium phosphate.

[0059] In the present invention, the millimoles of the chemical precipitant added per 1 kg of incineration fly ash are preferably calculated according to Formula IV:

[0060] n 化学沉淀剂 =(0.80~1.25)mFormula IV.

[0061] In Formula IV, n 化学沉淀剂 It is the number of millimoles of chemical precipitant added to every 1 kg of incineration fly ash, in units of mmol; m is the sum of the amounts of copper, zinc and lead in the heavy metals in the incineration fly ash.

[0062] In Formula IV, m=M 铜 / 63.546+M 锌 / 65.38+M 铅 / 207.2,M 铜 、M 锌 and M 铅 They are the mass contents of copper, zinc and lead in the heavy metals in incineration fly ash, respectively, in g / kg.

[0063] In the present invention, when the selenium content in the incineration fly ash is greater than 0.2 mg / kg or the cadmium content is greater than 0.15 mg / kg, a modified chemical component is added when the incineration fly ash is mixed with an alkaline earth metal additive, a chemical precipitant and water.

[0064] In the present invention, the mass ratio of silicon oxide to aluminum oxide in the modified chemical component is greater than 5; the modified chemical component preferably includes one or two of a Y-type molecular sieve and a transparent glaze. In the present invention, the modified chemical component can react with heavy metals in the incineration fly ash to improve the stabilization effect of the incineration fly ash.

[0065] In the present invention, when the modified chemical component is added, the mass of the modified chemical component is preferably 20% to 50% of the total mass of the incineration fly ash, alkaline earth metal additive, chemical precipitant and modified chemical component, and more preferably 30% to 40%. In the present invention, when the modified chemical component is added, the mass ratio of silicon oxide to aluminum oxide in the mixed system obtained by mixing the incineration fly ash with the alkaline earth metal additive, chemical precipitant and modified chemical component is preferably greater than 5. The present invention limits the amount of the modified chemical component to the above range, which can further improve the treatment effect of the incineration fly ash.

[0066] In the present invention, a stable chemical structure is formed after adding a chemical precipitant or a modified chemical component; the stable chemical structure includes one or more of a Si-O-Al-Ca-Cl structure, an Al-O-Ca-Cl structure, an Al-O-Ca-SO3 structure, a Si-O-Ca structure and a Mg-OS-Cl structure. The theoretical molecular structure of the Al-O-Ca-Cl structure of the present invention is as follows Figure 1 As shown; the theoretical molecular structure of the Al-O-Ca-SO3 structure is as follows Figure 2 shown.

[0067] In the present invention, the fluidity of the mixed system obtained by mixing the incineration fly ash with the alkaline earth metal additive, the chemical precipitant and water is preferably ≥180 mm.

[0068] In the present invention, when the modified chemical component is added, the fluidity of the mixed system obtained by mixing the incineration fly ash with the alkaline earth metal additive, the chemical precipitant, the modified chemical component and water is preferably ≥180 mm. The present invention limits the fluidity of the mixed system to the above range, which can make each component fully react, further improve the treatment effect of the incineration fly ash, and is also conducive to subsequent molding.

[0069] The present invention has no particular limitation on the amount of water used, as long as the fluidity of the mixed system is within the above range.

[0070] In the present invention, when the incineration fly ash is mixed with the alkaline earth metal additive, the chemical precipitant and water or when the incineration fly ash is mixed with the alkaline earth metal additive, the chemical precipitant, the modified chemical component and water, a water reducing agent and / or a defoaming agent is preferably added.

[0071] The present invention has no particular limitation on the types of the water reducer and defoamer, and water reducers and defoamers well known to those skilled in the art can be used. In the present invention, the water reducer preferably includes one or more of a polycarboxylic acid water reducer and a naphthalene water reducer. The defoamer preferably includes one or more of an organosiloxane and a polyether.

[0072] In the present invention, based on the solid mass in the water reducer, the mass of the water reducer is preferably the total mass of the incineration fly ash, the alkaline earth metal admixture and the chemical precipitant, or the mass of the water reducer is preferably 0.1% to 0.5% of the total mass of the incineration fly ash, the alkaline earth metal admixture, the chemical precipitant and the modified chemical component.

[0073] In the present invention, the mass of the defoamer is preferably 0.1% to 2.5% of the total mass of the incineration fly ash, the alkaline earth metal admixture and the chemical precipitant, or the mass of the defoamer is preferably 0.1% to 2.5% of the total mass of the incineration fly ash, the alkaline earth metal admixture, the chemical precipitant and the modified chemical component, based on the mass of the solid in the defoamer. The present invention limits the amount of the water reducing agent and the defoamer to the above range, which can further improve the treatment effect of the incineration fly ash.

[0074] In the present invention, the molding pressure is preferably 1 to 5 MPa, more preferably 1 to 4 MPa. In the present invention, the molding can further improve the stability of the incineration fly ash.

[0075] In the present invention, the curing temperature is preferably 20 to 30° C., and the curing time is preferably 12 to 72 hours. In the present invention, the curing can further improve the stability of the incineration fly ash.

[0076] The present invention first detects the mass content of relevant components in the incineration fly ash, and then mixes the incineration fly ash with additives to form a stable structure. The harmless treatment method has low cost and the volume of the incineration fly ash does not increase after the harmless treatment, which is more conducive to subsequent landfill or resource utilization.

[0077] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0078] Example 1

[0079] (1) Detecting fly ash from the incineration of domestic waste to obtain the mass percentage content of total silicon oxide TSi, total aluminum oxide TAl, total sulfur trioxide TS, activated alumina AAl, soluble chloride ions SCl and organic matter and the mass content of heavy metals in the fly ash from the incineration of domestic waste;

[0080] The mass percentage of total silicon oxide TSi, total aluminum oxide TAl and total sulfur trioxide TS shall be determined in accordance with GB / T1596-2017; the mass percentage of activated aluminum oxide AAl and soluble chloride ions SCl shall be determined in accordance with T / CBMF90-2020; the mass content of heavy metals shall be determined in accordance with HJ766-2015;

[0081] The mass percentage of organic matter is tested as follows:

[0082] a. Dry the fly ash from the incineration of domestic waste to remove free water and obtain a dry basis sample;

[0083] b. Testing the ignition loss of the dry basis sample obtained in step a at 650° C. in air and nitrogen atmospheres, respectively, and then calculating the difference between the ignition loss of the dry basis sample in air and nitrogen atmospheres, which is the mass percentage of organic matter in the fly ash from the incineration of domestic waste;

[0084] The mass percentage of total alumina in the fly ash from the incineration of domestic waste is 18.21% (TAl), the mass percentage of total sulfur trioxide is 20.83% (TS), the mass percentage of activated alumina is 6.03% (AAl), the mass percentage of soluble chlorine is 12.37% (SCl), the mass percentage of organic matter is 12.3%, and the mass content of heavy metals is: Cu=755.8mg / kg, Zn=8114.4mg / kg, Cd=0.07mg / kg, Cr=79.2mg / kg, Hg=7.6mg / kg, Pb=2577.6mg / kg, As=121.9mg / kg, Se=0.1mg / kg, Ba=507.1mg / kg, Ni=18.8mg / kg, Be=15.0mg / kg;

[0085] (2) The fly ash from the incineration of domestic waste is mixed with calcium oxide, sodium sulfonate, water and polycarboxylate water reducer. The molar number of calcium oxide added to 100 g of the fly ash from the incineration of domestic waste is 0.725 mole calculated by 0.014TS+0.035SCl, and 0.448 mole calculated by 0.06AAl+0.007(TAl-AAl). The larger value of 0.725 mole is added to calcium oxide. The millimole number of sodium sulfonate added to 1 kg of the fly ash from the incineration of domestic waste is 0.185 mmol calculated by 1.25m, where m is the sum of the moles of copper, zinc and lead, and m=M 铜 / 63.546+M 锌 / 65.38+M 铅 / 207.2=0.7558 / 63.546+8.1144 / 65.38+2.5776 / 207.2=0.148, the ratio of the mass of water to the total mass of fly ash from incineration of domestic waste, calcium oxide and sodium sulfonate is 0.42:1, the mass of polycarboxylic acid water reducer is 0.2% of the total mass of fly ash from incineration of domestic waste, calcium oxide and sodium sulfonate, the fluidity of the mixed system is 182mm, and the stabilized fly ash is obtained by molding under a molding pressure of 1.2MPa and curing at room temperature for 24h. The toxic leaching index meets the requirements of GB8978 and also meets the requirements of CJJ / T316.

[0086] The SEM image of the stabilized fly ash in Example 1 is as follows: Figure 3 As shown. Figure 3 In the figure, we can see the flaky Al-O-Ca-Cl (A) and columnar Al-O-Ca-SO3 (B).

[0087] Example 2

[0088] (1) The fly ash from the incineration of domestic waste was tested according to the testing method in Example 1 to obtain the mass percentage contents of total silicon oxide TSi, total aluminum oxide TAl, total sulfur trioxide TS, activated aluminum oxide AAl, soluble chloride ions SCl and organic matter and the mass content of heavy metals in the fly ash from the incineration of domestic waste. The mass percentage content of total aluminum oxide in the fly ash from the incineration of domestic waste was 10.88% (TAl), the mass percentage content of total sulfur trioxide was 25.08% (TS), and the mass percentage content of activated aluminum oxide was 5.25% (AAl). , the mass percentage of soluble chlorine is 16.45% (SCl), the mass percentage of organic matter is 10.11%, and the mass content of heavy metals is: Cu=51.2mg / kg, Zn=101.3mg / kg, Cd=0.11mg / kg, Cr=0mg / kg, Hg=0mg / kg, Pb=84.2mg / kg, As=0mg / kg, Se=0mg / kg, Ba=7.1mg / kg, Ni=10.11mg / kg, Be=2.2mg / kg;

[0089] (2) Mix the fly ash from the incineration of domestic waste with magnesium oxide, ammonium nitrate, water, a polycarboxylate water reducer and a defoaming agent. The molar number of magnesium oxide added per 100 g of the fly ash from the incineration of domestic waste is calculated as 0.592 mol based on 0.036SCl, and the millimole number of ammonium nitrate added per 1 kg of the fly ash from the incineration of domestic waste is calculated as 0.0024 mmol based on 0.8m, where m is the sum of the moles of copper, zinc and lead, m=M 铜 / 63.546+M 锌 / 65.38+M 铅 / 207.2=0.0512 / 63.546+0.1013 / 65.38+0.0842 / 207.2=0.003, the ratio of the mass of water to the total mass of domestic waste incineration fly ash, magnesium oxide and ammonium nitrate is 0.47:1, the mass of the polycarboxylate water reducer is 0.3% of the total mass of domestic waste incineration fly ash, magnesium oxide and ammonium nitrate, the mass of the defoamer is 1% of the total mass of domestic waste incineration fly ash, magnesium oxide and ammonium nitrate, the fluidity of the mixed system is 185mm, and the system is molded at a molding pressure of 2.0MPa and cured at room temperature for 72h to obtain stabilized fly ash, and the toxic leaching index meets the requirements of GB8978 and CJJ / T316.

[0090] Example 3

[0091] (1) The fly ash from the incineration of domestic waste was tested according to the testing method in Example 1, and the mass percentage of total silicon oxide in the fly ash from the incineration of domestic waste was 24.51% (TSi), the mass percentage of total aluminum oxide was 7.42% (TA1), the mass percentage of total sulfur trioxide was 15.16% (TS), the mass percentage of activated alumina was 2.07% (AAl), the mass percentage of soluble chlorine was 12.19% (SCl), the mass percentage of organic matter was 5.67%, and the mass content of heavy metals was: Cu=1.7 mg / kg, Zn=66.8 mg / kg, Cd=4.2 mg / kg, Cr=0 mg / kg, Hg=0.02 mg / kg, Pb=0.77 mg / kg, As=0.02 mg / kg, Se=0.51 mg / kg, Ba=2.5 mg / kg, Ni=0.6 mg / kg, Be=0 mg / kg;

[0092] (2) Mix fly ash from the incineration of domestic waste with calcium oxide, sodium phosphate, transparent glaze (67% silicon oxide, 8% aluminum oxide, the mass ratio of silicon oxide to aluminum oxide is 8.375) and water. The molar number of calcium oxide added per 100 g of fly ash from the incineration of domestic waste is 0.752 mole calculated by 0.011TS+0.048SCl and 0.162 mole calculated by 0.06AAl+0.007(TAl-AAl). The larger value of 0.752 mole is added to calcium oxide. The millimole number of sodium phosphate added per 1 kg of fly ash from the incineration of domestic waste is 0.0014 mmol calculated by 1.25m, where m is the sum of the moles of copper, zinc and lead, and m=M 铜 / 63.546+M 锌 / 65.38+M 铅 / 207.2=0.0017 / 63.546+0.0668 / 65.38+0.00077 / 207.2=0.0011, the mass of the transparent glaze is 32.4% of the total mass of the domestic waste incineration fly ash, calcium oxide, sodium phosphate and the transparent glaze, the mass ratio of silicon oxide to aluminum oxide in the mixed system obtained by mixing the transparent glaze with the domestic waste incineration fly ash, calcium oxide and sodium phosphate is 5.03, the ratio of the mass of water to the total mass of the domestic waste incineration fly ash, calcium oxide, sodium phosphate and the transparent glaze is 0.45:1, the fluidity of the mixed system is 185mm, and the stabilized fly ash is obtained by molding under a molding pressure of 1.0MPa and curing at room temperature for 24h. The toxic leaching index meets the requirements of GB8978 and also meets the requirements of CJJ / T316.

[0093] Comparative Example 1

[0094] (1) The fly ash from the incineration of domestic waste was tested according to the testing method in Example 1, and the mass percentage of total silicon oxide in the fly ash from the incineration of domestic waste was 24.51% (TSi), the mass percentage of total aluminum oxide was 7.42% (TA1), the mass percentage of total sulfur trioxide was 15.16% (TS), the mass percentage of activated alumina was 2.07% (AAl), the mass percentage of soluble chlorine was 12.19% (SCl), the mass percentage of organic matter was 5.67%, and the mass content of heavy metals was: Cu=1.7 mg / kg, Zn=66.8 mg / kg, Cd=4.2 mg / kg, Cr=0 mg / kg, Hg=0.02 mg / kg, Pb=0.77 mg / kg, As=0.02 mg / kg, Se=0.51 mg / kg, Ba=2.5 mg / kg, Ni=0.6 mg / kg, Be=0 mg / kg;

[0095] (2) The fly ash from the incineration of domestic waste is mixed with calcium oxide, sodium phosphate, a naphthalene-based water reducer and water. The molar number of calcium oxide added per 100 g of the fly ash from the incineration of domestic waste is 0.752 mole as calculated by 0.011TS+0.048SCl and 0.162 mole as calculated by 0.06AAl+0.007(TAl-AAl). The larger value of 0.752 mole is taken and added to calcium oxide. The millimole number of sodium phosphate added per 1 kg of the fly ash from the incineration of domestic waste is 0.0014 mmol as calculated by 1.25m, where m is the sum of the moles of copper, zinc and lead, and m=M 铜 / 63.546+M 锌 / 65.38+M 铅 / 207.2=0.0017 / 63.546+0.0668 / 65.38+0.00077 / 207.2=0.0011, the ratio of the mass of water to the total mass of fly ash from incineration of domestic waste, calcium oxide and sodium phosphate is 0.45:1, the mass of naphthalene-based water reducer is 3.5% of the total mass of fly ash from incineration of domestic waste, calcium oxide and sodium phosphate, the fluidity of the mixed system is 185mm, and after molding at a molding pressure of 1.0MPa and curing at room temperature for 168h, the toxic leaching index still does not meet the requirements of CJJ / T316.

[0096] It can be seen from Examples 1 to 3 and Comparative Example 1 that the treatment method provided by the present invention can make the treated incineration fly ash have excellent stability.

[0097] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for harmless treatment of incineration fly ash, comprising the following steps: (1) Detecting the incineration fly ash to obtain the mass percentage of total silicon oxide TSi, total aluminum oxide TAl, total sulfur trioxide TS, activated alumina AAl, soluble chloride ions SCl and organic matter and the mass content of heavy metals in the incineration fly ash; (2) mixing the incineration fly ash with an alkaline earth metal additive, a chemical precipitant and water, and then molding and curing them in sequence to obtain stabilized fly ash; when the selenium content in the incineration fly ash is greater than 0.2 mg / kg or the cadmium content is greater than 0.15 mg / kg, a modified chemical component is also added during the mixing in step (2); the mass ratio of silicon oxide to aluminum oxide in the modified chemical component is greater than 5.

2. The harmless treatment method according to claim 1, characterized in that: The alkaline earth metal additive in step (2) includes one or more of calcium oxide, calcium carbonate, calcium acetate, magnesium oxide, magnesium carbonate and magnesium acetate.

3. The harmless treatment method according to claim 2, characterized in that: When the alkaline earth metal additive is one or more of calcium oxide, calcium carbonate and calcium acetate, the number of moles of the alkaline earth metal additive added per 100 g of the incineration fly ash in step (2) is the larger value calculated according to formula I or formula II, n 碱土金属外加剂 =(0.011~0.015)TS+(0.035~0.048)SCl Formula I, n 碱土金属外加剂 = (0.05 - 0.06)AAl + (0.003 - 0.007)(TAl - AAl), Formula II In Formula I, n 碱土金属外加剂 is the number of moles of alkaline earth metal additive added to every 100g of incineration fly ash, in mol; TS is the mass percentage of total sulfur trioxide in the incineration fly ash, in %; SCl is the mass percentage of soluble chloride ions in the incineration fly ash, in %; in formula II, n 碱土金属外加剂 is the number of moles of alkaline earth metal admixture added to every 100g of incineration fly ash, in mol; AAl is the mass percentage of activated alumina in the incineration fly ash, in %; TAl is the mass percentage of total alumina in the incineration fly ash, in %.

4. The harmless treatment method according to claim 2, characterized in that: When the alkaline earth metal additive is one or more of magnesium oxide, magnesium carbonate and magnesium acetate, the molar number of the alkaline earth metal additive added per 100 g of the incineration fly ash in step (2) is calculated according to formula III: n 碱土金属外加剂 =(0.021~0.036)SCl formula III, In formula III, n 碱土金属外加剂 It is the number of moles of alkaline earth metal additive added to every 100g of incineration fly ash, in mol; SCl is the mass percentage of soluble chloride ions in incineration fly ash, in %.

5. The harmless treatment method according to claim 1, characterized in that: The chemical precipitating agent in step (2) includes one or more of hydroxides, ammonium salts, sulfonates and phosphates.

6. The harmless treatment method according to claim 1 or 5, characterized in that: The millimoles of chemical precipitant added per 1 kg of incineration fly ash in step (2) are calculated according to formula IV: n 化学沉淀剂 =(0.80~1.25)mFormula IV, In Formula IV, n 化学沉淀剂 is the number of millimoles of chemical precipitant added per 1 kg of incineration fly ash, in mmol; m is the sum of the amounts of copper, zinc and lead in the heavy metals in the incineration fly ash, where m = M 铜 / 63.546+M 锌 / 65.38+M 铅 / 207.2,M 铜 、M 锌 and M 铅 They are the mass contents of copper, zinc and lead in the heavy metals in incineration fly ash, respectively, in g / kg.

7. The harmless treatment method according to claim 1, characterized in that: In the step (2), the fluidity of the mixed system obtained by mixing the incineration fly ash with the alkaline earth metal additive, the chemical precipitant and water is ≥180 mm.

8. The harmless treatment method according to claim 1, characterized in that: The modified chemical components in step (2) include one or two of Y-type molecular sieve and transparent glaze.

9. The harmless treatment method according to claim 8, characterized in that: The mass of the modified chemical component in step (2) is 20% to 50% of the total mass of the incineration fly ash, alkaline earth metal additive, chemical precipitant and the modified chemical component.

10. The harmless treatment method according to claim 1, characterized in that: The step (2) also includes a water reducing agent and / or a defoaming agent.

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