A method for co-disposing waste incineration fly ash using cement kiln

Abstract

The present invention relates to the field of building materials, and specifically to a method for co-disposing waste incineration fly ash in a cement kiln; pneumatic conveying is used to transport the waste incineration fly ash into the kiln head, a five-stage Z-shaped air intake facility is installed in the smoke chamber at the end of the cement kiln, the fifth stage is connected to the smoke chamber, a Roots blower is installed in the first stage, the air outlet is connected to the temporary storage bin A, a cold air blower is installed at the bottom of the temporary storage bin for blowing, a cyclone dust removal facility B is installed on the top, the dust collected by B is sent to a phosphoric acid solution reaction tank, a slag pump is installed at the bottom of the phosphoric acid solution reaction tank, the precipitate is pumped to a plate and frame filter press, the material is obtained after filtration, and after drying, cement raw materials are mixed in proportion and calcined to obtain cement clinker. The present invention realizes the transformation of waste into treasure and the green and environmentally friendly treatment of incineration fly ash.

Description

Technical Field

[0001] The invention relates to the technical field of printing and dyeing sludge treatment, in particular to a method for co-disposing waste incineration fly ash with a cement kiln. Background Art

[0002] Incineration fly ash is produced during the incineration of municipal domestic waste. During the incineration process of waste, organic matter in the waste is mainly discharged in the form of gaseous substances; while inorganic matter mainly forms solid particles, among which larger solid particles are deposited at the bottom of the incinerator and on the grate, which is called bottom ash, and those fine particles float in the flue gas and enter the flue gas purification system with the flue gas. These particles constitute 50% of the incineration fly ash, and the remaining incineration fly ash comes from the limestone or activated carbon added during the flue gas purification process. They are captured together in the dust collector (electrostatic precipitator, bag filter, etc.), and some fine particles also settle at the bottom of the flue and chimney. These captured and settled fine particles are called incineration fly ash.

[0003] For example, Chinese patent CN105585288A discloses a stabilizing and curing agent for waste incineration fly ash and a method for treating municipal solid waste incineration fly ash; the stabilizing and curing agent is composed of a heavy metal stabilizer, water and cement. The raw materials in the stabilizing and curing agent are easily available, the cost of the agent is low, the amount of cement used is small, the solidified body is stable, and no secondary pollution is caused to the environment. It is used to treat municipal solid waste incineration fly ash, and has the dual effects of stabilization and curing. The physical and chemical properties of the obtained solidified block are stable, and the amount of cement used and the volume increase ratio of the solidified block are reduced, effectively solving the harm caused by incineration fly ash to the human body and the ecological environment.

[0004] Another example is a Chinese patent CN108687115B that discloses a method for the coordinated treatment of waste incineration fly ash and desulfurization wastewater, in which the waste incineration fly ash is dried and then evenly mixed with desulfurization wastewater in a certain proportion to complete the modification, and the Ca in the waste incineration fly ash is 2+ SO4 in desulfurization wastewater 2- Combined with the formation of CaSO4 on the surface of waste incineration fly ash to solidify the heavy metals in the waste incineration fly ash, the porous structure of the waste incineration fly ash selectively adsorbs the heavy metals and impurities in the desulfurization wastewater, and at the same time enriches the Cl- in the waste incineration fly ash in the desulfurization wastewater for unified treatment. This method follows the concept of "waste treatment with waste", improves the reuse quality of waste incineration fly ash without the need for external chemicals, realizes the pretreatment of desulfurization wastewater, and gives full play to the reuse value of desulfurization wastewater. This method uses waste to treat waste, has low treatment cost, wide application range, and has good application prospects.

[0005] For another example, Chinese patent CN201610135700.0 discloses a method for secondary treatment of fly ash from the incineration of domestic waste and cement granulation, and realizes its resource-based clean application in asphalt pavement in engineering. First, the fly ash from the incineration of domestic waste is granulated with cement, and then the surface of the particles is coated with silane waterproofing agent, diluted asphalt, etc. for secondary treatment to obtain pre-treated particles of fly ash from the incineration of domestic waste, and then the pre-treated particles of fly ash from the incineration of domestic waste are added to the asphalt mixture. In the present invention, the obtained pre-treated particles of fly ash from the incineration of domestic waste are added to the asphalt mixture instead of part of the mineral powder or aggregate for pavement paving, which can be used for the surface layer and base layer of asphalt pavement. The leaching toxicity of heavy metals and their compounds in the fly ash from the incineration of domestic waste in the paved pavement is qualified, and no secondary pollution is caused to the environment. In addition, various indicators of road performance meet the requirements of the specifications, and the resource-based clean application of fly ash is realized in engineering.

[0006] The leaching toxicity of heavy metals in waste incineration fly ash far exceeds the admission control standard of hazardous waste landfills. Phosphoric acid washing is used to improve the treatment characteristics of incineration fly ash. Although this method can better separate heavy metals in incineration fly ash, amphoteric metals Pb and Zn are easily dissolved in large quantities in high pH water washing liquid, causing secondary pollution, which needs further improvement.

[0007] In view of the deficiencies of the prior art, the present invention proposes a method for co-disposing waste incineration fly ash with a cement kiln. Summary of the invention

[0008] The present invention aims to solve at least one of the above technical problems to a certain extent. To this end, one object of the present invention is to propose an economically reasonable and environmentally friendly method for co-disposing waste incineration fly ash in cement kilns.

[0009] In one aspect of the present invention, the present invention proposes a method for co-disposing waste incineration fly ash in a cement kiln, and the specific steps are as follows:

[0010] Step 1: Use pneumatic conveying to transport the fly ash from the garbage incineration into the kiln head, install a five-stage Z-shaped air intake facility in the smoke chamber at the tail of the cement kiln, the fifth stage is connected to the smoke chamber, a Roots blower is installed in the first stage, the diameter of the air duct at the first stage outlet is 20 to 30 times the diameter of the air intake duct, the air outlet is connected to the temporary storage bin A, a cold air blower is installed at the bottom of the temporary storage bin, and a cyclone dust removal facility B is installed on the top;

[0011] Step 2: The dust collected in B is sent to a phosphoric acid solution reaction tank. A slag pump is installed at the bottom of the phosphoric acid solution reaction tank to pump the precipitate to a plate and frame filter press for filtration to obtain a material (a) with a water content of 30-40%;

[0012] Step 3: Send material (a) to a belt dryer for drying, and dry material (a) to a moisture content of about 8-10%. The heat source of the dryer comes from the waste heat of the temporary storage bin A;

[0013] Step 4: The dried material (a) is mixed with cement raw material at a ratio of 10%-15%, and is fed into a rotary kiln as a raw material for producing cement clinker, and is calcined at 1200-1400° C. to obtain cement clinker.

[0014] According to an embodiment of the present invention, the amount of fly ash injected in step 1 is 3 to 5 tons / hour.

[0015] According to an embodiment of the present invention, in the step 1, the first-stage Roots blower is installed to extract an air volume of 3,000 to 5,000 cubic meters per hour.

[0016] According to an embodiment of the present invention, the filter press pressure in step 2 is 8-12 kg / cm 2 , the filtration time is 30 to 40 minutes.

[0017] According to an embodiment of the present invention, in step 2, the reaction time of the dust in the phosphoric acid pool is 0.5-2h.

[0018] According to an embodiment of the present invention, in step 2, a phosphoric acid solution is added to the phosphoric acid solution reaction tank, and its composition is: phosphoric acid: water: metal chelating accelerator = 1: 10-30: 0.001-0.02 (wt%), and the mass percentage concentration of the phosphoric acid solution is 50-85%.

[0019] According to an embodiment of the present invention, in step 2, the dust is added to the phosphoric acid solution reaction tank, and the liquid-to-solid ratio RL / S is controlled to be 10-20 mL / g.

[0020] Another aspect of the present invention discloses a method for preparing a metal chelating accelerator:

[0021] S1: Add 300-400 parts of distilled water and 20-50 parts of carboxymethyl starch in a three-necked flask by mass, stir magnetically to evenly disperse the starch, place in a water bath at 60-75°C for gelatinization for 20-60 minutes, add 1-3 parts of potassium persulfate solution to activate the starch hydroxyl groups to generate free radicals, activate at 50-60°C for 20-60 minutes, and dry;

[0022] S2: Continue to add 2-5 parts of unsaturated monomer, 0.002-0.05 parts of N-allyl-O-isobutylthiocarbamate, 300-400 parts of water, 2-4 parts of potassium persulfate, introduce nitrogen to eliminate oxygen interference, and heat the reaction; after the reaction, the product is distilled to remove water, and the product is dried to obtain a metal chelating accelerator.

[0023] According to an embodiment of the present invention, the unsaturated monomer is selected from 1-vinylimidazole, N-allylimidazole, 4-vinylpyridine, 4-methyl-5-vinylthiazole, 2-methyl-1-vinylimidazole, 3-methyl-1-vinylpyrazole, N-vinylpurine, N-vinylpiperazine and combinations thereof.

[0024] According to an embodiment of the present invention, the reaction temperature is 60-70° C., and the reaction time is 3-6 hours.

[0025] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention.

[0026] Technical effects:

[0027] Based on the above, the method for co-disposal of waste incineration fly ash by cement kiln of the present invention has the following beneficial effects:

[0028] (1) Cement kilns have the characteristics of high calcination temperature, long process time and strong alkaline atmosphere. At high temperature, dioxins in fly ash can be completely decomposed and most of the harmful heavy metals in fly ash can be solidified.

[0029] (2) Adding phosphoric acid for washing can effectively inhibit the dissolution of heavy metals in incineration fly ash and fix most of the heavy metals in the fly ash in a more stable form. In addition, adding phosphoric acid for washing can also improve the thermal stability of incineration fly ash.

[0030] (3) Phosphoric acid washing combined with sintering technology can effectively fix heavy metals in fly ash, thereby improving the long-term environmental safety of resource utilization of sintered products. DETAILED DESCRIPTION

[0031] The embodiments of the present invention are described in detail below, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The following embodiments are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0032] The composition of the untreated incineration fly ash in the specific embodiment of the present invention is shown in the table below: it is mainly enriched with heavy metal elements such as Pb, Zn, Cd, Cr, Ni, and Cu.

[0033] Table 1 Chemical composition and heavy metal content of incineration fly ash

[0034] composition 100w composition 100w composition <![CDATA[10 6 in]]> <![CDATA[SiO2]]> 10.23 <![CDATA[Fe2O3]]> 4.18 Zn 5408 CaO 39.34 <![CDATA[SO3]]> 6.46 Pb 1351 <![CDATA[Al2O3]]> 3.9 <![CDATA[TiO2]]> 1.35 Cu 418 MgO 3.71 <![CDATA[P2O5]]> 1.85 Cd 469 <![CDATA[Na2O]]> 6.44 Cl 15.18 Cr 222 <![CDATA[K2O]]> 4.93 other 2.44 Ni 60.4

[0035] The toxicity of incineration fly ash is tested according to GB 5086.1 / 2-1997 "Toxicity leaching method for solid waste". The heavy metal leaching concentration of untreated incineration fly ash is shown in the following table:

[0036] Table 2 Heavy metal leaching concentrations from incineration fly ash

[0037] Leaching elements d / (mg / L) Leaching elements d / (mg / L) Pb 35.840 Cr 0.538 Zn 5.983 Ni Not detected Cd 0.005 Cu 0.117

[0038] Example 1

[0039] A method for co-disposing waste incineration fly ash in a cement kiln, the specific steps are as follows:

[0040] Step 1: Use pneumatic conveying to transport the fly ash from the garbage incineration into the kiln head, install a five-stage Z-shaped air intake facility in the smoke chamber at the tail of the cement kiln, the fifth stage is connected to the smoke chamber, a Roots blower is installed in the first stage, the diameter of the air duct at the first stage outlet is 20 times the diameter of the air intake duct, the air outlet is connected to the temporary storage bin A, a cooling fan is installed at the bottom of the temporary storage bin, and a cyclone dust removal facility B is installed on the top;

[0041] Step 2: The dust collected in B is sent to a phosphoric acid solution reaction tank. A slag pump is installed at the bottom of the phosphoric acid solution reaction tank to pump the precipitate to a plate and frame filter press for filtration to obtain a material (a) with a water content of 40%;

[0042] Step 3: Send material (a) to a belt dryer for drying, and dry material (a) to a moisture content of about 10%. The heat source of the dryer comes from the waste heat of the temporary storage bin A;

[0043] Step 4: The dried material (a) is mixed with cement raw material at a ratio of 10%, and is fed into a rotary kiln as a raw material for producing cement clinker, and is calcined at 1200° C. to obtain cement clinker.

[0044] The fly ash injection rate in step 1 is 3 tons / hour.

[0045] In the step 1, the first stage Roots blower is installed to extract an air volume of 3,000 cubic meters per hour.

[0046] In step 2, the filter press pressure is 8kg / cm 2 , filtration time 30 minutes.

[0047] In step 2, the dust reacts in the phosphoric acid pool for 0.5 h.

[0048] In the step 2, a phosphoric acid solution is added to the phosphoric acid solution reaction tank, wherein the composition is: phosphoric acid: water: metal chelating accelerator = 1:10:0.01 (wt%), and the mass percentage concentration of the phosphoric acid solution is 50%.

[0049] In the step 2, the dust is added into the phosphoric acid solution reaction tank, and the liquid-to-solid ratio RL / S is controlled to be 10 mL / g.

[0050] A method for preparing a metal chelating accelerator is as follows:

[0051] S1: Add 300g of distilled water and 20g of carboxymethyl starch into a three-necked flask, stir magnetically to evenly disperse the starch, place in a water bath at 60°C for gelatinization for 20 minutes, add 1g of potassium persulfate solution to activate the starch hydroxyl groups to generate free radicals, activate at 50°C for 20 minutes, and dry;

[0052] S2: Continue to add 2g of unsaturated monomer, 0.01g of N-allyl-O-isobutylthiocarbamate, 300g of water, and 2g of potassium persulfate, introduce nitrogen to eliminate oxygen interference, and heat the reaction; after the reaction, the product is distilled to remove water, and the product is dried to obtain a metal chelating accelerator.

[0053] The unsaturated monomer is selected from 1-vinylimidazole.

[0054] The reaction temperature is 60° C. and the reaction time is 3 h.

[0055] In this example, the heavy metal leaching concentration of fly ash after treatment is:

[0056]

[0057]

[0058] Example 2

[0059] A method for co-disposing waste incineration fly ash in a cement kiln, the specific steps are as follows:

[0060] Step 1: Use pneumatic conveying to transport the fly ash from the garbage incineration into the kiln head, install a five-stage Z-shaped air intake facility in the smoke chamber at the tail of the cement kiln, the fifth stage is connected to the smoke chamber, a Roots blower is installed in the first stage, the diameter of the air duct at the first stage outlet is 25 times the diameter of the air intake duct, the air outlet is connected to the temporary storage bin A, a cold air blower is installed at the bottom of the temporary storage bin, and a cyclone dust removal facility B is installed on the top;

[0061] Step 2: The dust collected in B is sent to a phosphoric acid solution reaction tank. A slag pump is installed at the bottom of the phosphoric acid solution reaction tank to pump the precipitate to a plate and frame filter press for filtration to obtain a material (a) with a water content of 35%;

[0062] Step 3: Send material (a) to a belt dryer for drying, and dry material (a) to a moisture content of about 9%. The heat source of the dryer comes from the waste heat of the temporary storage bin A;

[0063] Step 4: The dried material (a) is mixed with cement raw material at a ratio of 12%, and is fed into a rotary kiln as a raw material for producing cement clinker, and is calcined at 1300° C. to obtain cement clinker.

[0064] The fly ash injection rate in step 1 is 4 tons / hour.

[0065] In the step 1, the first stage Roots blower is installed to extract an air volume of 4,000 cubic meters per hour.

[0066] In step 2, the filter press pressure is 10 kg / cm 2 , filtration time 35 minutes.

[0067] In step 2, the dust reacts in the phosphoric acid pool for 1 hour.

[0068] In the step 2, a phosphoric acid solution is added to the phosphoric acid solution reaction tank, wherein the composition is: phosphoric acid: water: metal chelating accelerator = 1:20:0.15 (wt%), and the mass percentage concentration of the phosphoric acid solution is 70%.

[0069] In the step 2, the dust is added into the phosphoric acid solution reaction tank, and the liquid-to-solid ratio RL / S is controlled to be 15 mL / g.

[0070] A method for preparing a metal chelating accelerator is as follows:

[0071] S1: Add 350g of distilled water and 35g of carboxymethyl starch into a three-necked flask, stir magnetically to evenly disperse the starch, place in a water bath at 70°C for gelatinization for 40 minutes, add 2g of potassium persulfate solution to activate the starch hydroxyl groups to generate free radicals, activate at 55°C for 40 minutes, and dry;

[0072] S2: Continue to add 3g of unsaturated monomer, 0.03g of N-allyl-O-isobutylthiocarbamate, 350g of water, and 3g of potassium persulfate, introduce nitrogen to eliminate oxygen interference, and heat the reaction; after the reaction, the product is distilled to remove water, and the product is dried to obtain a metal chelating accelerator.

[0073] The unsaturated monomer is selected from N-allylimidazole.

[0074] The reaction temperature is 65° C. and the reaction time is 4.5 h.

[0075] In this example, the heavy metal leaching concentration of fly ash after treatment is:

[0076] Leaching elements d / (mg / L) Leaching elements d / (mg / L) Pb 15.211 Cr 0.228 Zn 2.545 Ni Not detected Cd 0.002 Cu 0.045

[0077] Example 3

[0078] A method for co-disposing waste incineration fly ash in a cement kiln, the specific steps are as follows:

[0079] Step 1: Use pneumatic conveying to transport the fly ash from the garbage incineration into the kiln head, install a five-stage Z-shaped air intake facility in the smoke chamber at the tail of the cement kiln, the fifth stage is connected to the smoke chamber, a Roots blower is installed in the first stage, the diameter of the air duct at the first stage outlet is 30 times the diameter of the air intake duct, the air outlet is connected to the temporary storage bin A, a cold air blower is installed at the bottom of the temporary storage bin, and a cyclone dust removal facility B is installed on the top;

[0080] Step 2: The dust collected in B is sent to a phosphoric acid solution reaction tank. A slag pump is installed at the bottom of the phosphoric acid solution reaction tank to pump the precipitate to a plate and frame filter press for filtration to obtain a material (a) with a water content of 30%;

[0081] Step 3: Send material (a) to a belt dryer for drying, and dry material (a) to a moisture content of about 8%. The heat source of the dryer comes from the waste heat of the temporary storage bin A;

[0082] Step 4: The dried material (a) is mixed with cement raw material at a ratio of 15%, and is fed into a rotary kiln as a raw material for producing cement clinker, and is calcined at 1400° C. to obtain cement clinker.

[0083] The fly ash injection rate in step 1 is 5 tons / hour.

[0084] In the step 1, the first stage Roots blower is installed to extract an air volume of 5,000 cubic meters per hour.

[0085] In step 2, the filter press pressure is 12 kg / cm 2 , filtration time 40 minutes.

[0086] In step 2, the dust reacts in the phosphoric acid pool for 2 hours.

[0087] In the step 2, a phosphoric acid solution is added to the phosphoric acid solution reaction tank, wherein the composition is: phosphoric acid: water: metal chelating accelerator = 1:30:0.02 (wt%), and the mass percentage concentration of the phosphoric acid solution is 85%.

[0088] In the step 2, the dust is added into the phosphoric acid solution reaction tank, and the liquid-to-solid ratio RL / S is controlled to be 20 mL / g.

[0089] A method for preparing a metal chelating accelerator is as follows:

[0090] S1: Add 400g of distilled water and 50g of carboxymethyl starch into a three-necked flask, stir magnetically to evenly disperse the starch, place in a water bath at 75°C for gelatinization for 60 minutes, add 3g of potassium persulfate solution to activate the starch hydroxyl groups to generate free radicals, activate at 60°C for 60 minutes, and dry;

[0091] S2: Continue to add 5g of unsaturated monomer, 0.05g of N-allyl-O-isobutylthiocarbamate, 400g of water, and 4g of potassium persulfate, introduce nitrogen to eliminate oxygen interference, and heat the reaction; after the reaction, the product is distilled to remove water, and the product is dried to obtain a metal chelating accelerator.

[0092] The unsaturated monomer is selected from 4-vinylpyridine.

[0093] The reaction temperature is 70° C. and the reaction time is 6 h.

[0094] In this example, the heavy metal leaching concentration of fly ash after treatment is:

[0095] Leaching elements d / (mg / L) Leaching elements d / (mg / L) Pb 14.011 Cr 0.195 Zn 2.224 Ni Not detected Cd 0.002 Cu 0.038

[0096] Comparative Example 1

[0097] A method for co-disposing waste incineration fly ash in a cement kiln, the specific steps are as follows:

[0098] Step 1: Use pneumatic conveying to transport the fly ash from the garbage incineration into the kiln head, install a five-stage Z-shaped air intake facility in the smoke chamber at the tail of the cement kiln, the fifth stage is connected to the smoke chamber, a Roots blower is installed in the first stage, the diameter of the air duct at the first stage outlet is 20 times the diameter of the air intake duct, the air outlet is connected to the temporary storage bin A, a cooling fan is installed at the bottom of the temporary storage bin, and a cyclone dust removal facility B is installed on the top;

[0099] Step 2: The dust collected in B is sent to a phosphoric acid solution reaction tank. A slag pump is installed at the bottom of the phosphoric acid solution reaction tank to pump the precipitate to a plate and frame filter press for filtration to obtain a material (a) with a water content of 40%;

[0100] Step 3: Send material (a) to a belt dryer for drying, and dry material (a) to a moisture content of about 10%. The heat source of the dryer comes from the waste heat of the temporary storage bin A;

[0101] Step 4: The dried material (a) is mixed with cement raw material at a ratio of 10%, and is fed into a rotary kiln as a raw material for producing cement clinker, and is calcined at 1200° C. to obtain cement clinker.

[0102] The fly ash injection rate in step 1 is 3 tons / hour.

[0103] In the step 1, the first stage Roots blower is installed to extract an air volume of 3,000 cubic meters per hour.

[0104] In step 2, the filter press pressure is 8kg / cm 2 , filtration time 30 minutes.

[0105] In step 2, the dust reacts in the phosphoric acid pool for 0.5 h.

[0106] In the step 2, a phosphoric acid solution is added to the phosphoric acid solution reaction tank, wherein the composition is: phosphoric acid: water: metal chelating accelerator = 1:10:0.01 (wt%), and the mass percentage concentration of the phosphoric acid solution is 50%.

[0107] In the step 2, the dust is added into the phosphoric acid solution reaction tank, and the liquid-to-solid ratio RL / S is controlled to be 10 mL / g.

[0108] A method for preparing a metal chelating accelerator is as follows:

[0109] S1: Add 300g of distilled water and 20g of carboxymethyl starch into a three-necked flask, stir magnetically to evenly disperse the starch, place in a water bath at 60°C for gelatinization for 20 minutes, add 1g of potassium persulfate solution to activate the starch hydroxyl groups to generate free radicals, activate at 50°C for 20 minutes, and dry;

[0110] S2: Continue to add 0.01g N-allyl-O-isobutylthiocarbamate, 300g water, and 2g potassium persulfate, introduce nitrogen to eliminate oxygen interference, and heat the reaction; after the reaction, the product is distilled to remove water, and the product is dried to obtain a metal chelating accelerator.

[0111] The reaction temperature is 60° C. and the reaction time is 3 h.

[0112] In this example, the heavy metal leaching concentration of fly ash after treatment is:

[0113] Leaching elements d / (mg / L) Leaching elements d / (mg / L) Pb 22.504 Cr 0.315 Zn 3.012 Ni Not detected Cd 0.004 Cu 0.075

[0114] Comparative Example 2

[0115] A method for co-disposing waste incineration fly ash in a cement kiln, the specific steps are as follows:

[0116] Step 1: Use pneumatic conveying to transport the fly ash from the garbage incineration into the kiln head, install a five-stage Z-shaped air intake facility in the smoke chamber at the tail of the cement kiln, the fifth stage is connected to the smoke chamber, a Roots blower is installed in the first stage, the diameter of the air duct at the first stage outlet is 20 times the diameter of the air intake duct, the air outlet is connected to the temporary storage bin A, a cooling fan is installed at the bottom of the temporary storage bin, and a cyclone dust removal facility B is installed on the top;

[0117] Step 2: The dust collected in B is sent to a phosphoric acid solution reaction tank. A slag pump is installed at the bottom of the phosphoric acid solution reaction tank to pump the precipitate to a plate and frame filter press for filtration to obtain a material (a) with a water content of 40%;

[0118] Step 3: Send material (a) to a belt dryer for drying, and dry material (a) to a moisture content of about 10%. The heat source of the dryer comes from the waste heat of the temporary storage bin A;

[0119] Step 4: The dried material (a) is mixed with cement raw material at a ratio of 10%, and is fed into a rotary kiln as a raw material for producing cement clinker, and is calcined at 1200° C. to obtain cement clinker.

[0120] The fly ash injection rate in step 1 is 3 tons / hour.

[0121] In the step 1, the first stage Roots blower is installed to extract an air volume of 3,000 cubic meters per hour.

[0122] In step 2, the filter press pressure is 8kg / cm 2 , filtration time 30 minutes.

[0123] In step 2, the dust reacts in the phosphoric acid pool for 0.5 h.

[0124] In the step 2, a phosphoric acid solution is added to the phosphoric acid solution reaction tank, wherein the composition is: phosphoric acid: water: metal chelating accelerator = 1:10:0.01 (wt%), and the mass percentage concentration of the phosphoric acid solution is 50%.

[0125] In the step 2, the dust is added into the phosphoric acid solution reaction tank, and the liquid-to-solid ratio RL / S is controlled to be 10 mL / g.

[0126] A method for preparing a metal chelating accelerator is as follows:

[0127] S1: Add 300g of distilled water and 20g of carboxymethyl starch into a three-necked flask, stir magnetically to evenly disperse the starch, place in a water bath at 60°C for gelatinization for 20 minutes, add 1g of potassium persulfate solution to activate the starch hydroxyl groups to generate free radicals, activate at 50°C for 20 minutes, and dry;

[0128] S2: Continue to add 2g of unsaturated monomer, 300g of water, and 2g of potassium persulfate, introduce nitrogen to eliminate oxygen interference, and heat the reaction; after the reaction, the product is distilled to remove water, and the product is dried to obtain a metal chelating accelerator.

[0129] The unsaturated monomer is selected from 1-vinylimidazole.

[0130] The reaction temperature is 60° C. and the reaction time is 3 h.

[0131] In this example, the heavy metal leaching concentration of fly ash after treatment is:

[0132] Leaching elements d / (mg / L) Leaching elements d / (mg / L) Pb 23.145 Cr 0.339 Zn 3.117 Ni Not detected Cd 0.004 Cu 0.078

[0133] Comparative Example 3

[0134] A method for co-disposing waste incineration fly ash in a cement kiln, the specific steps are as follows:

[0135] Step 1: Use pneumatic conveying to transport the fly ash from the garbage incineration into the kiln head, install a five-stage Z-shaped air intake facility in the smoke chamber at the tail of the cement kiln, the fifth stage is connected to the smoke chamber, a Roots blower is installed in the first stage, the diameter of the air duct at the first stage outlet is 20 times the diameter of the air intake duct, the air outlet is connected to the temporary storage bin A, a cooling fan is installed at the bottom of the temporary storage bin, and a cyclone dust removal facility B is installed on the top;

[0136] Step 2: The dust collected in B is sent to a phosphoric acid solution reaction tank. A slag pump is installed at the bottom of the phosphoric acid solution reaction tank to pump the precipitate to a plate and frame filter press for filtration to obtain a material (a) with a water content of 40%;

[0137] Step 3: Send material (a) to a belt dryer for drying, and dry material (a) to a moisture content of about 10%. The heat source of the dryer comes from the waste heat of the temporary storage bin A;

[0138] Step 4: The dried material (a) is mixed with cement raw material at a ratio of 10%, and is fed into a rotary kiln as a raw material for producing cement clinker, and is calcined at 1200° C. to obtain cement clinker.

[0139] The fly ash injection rate in step 1 is 3 tons / hour.

[0140] In the step 1, the first stage Roots blower is installed to extract an air volume of 3,000 cubic meters per hour.

[0141] In step 2, the filter press pressure is 8kg / cm 2 , filtration time 30 minutes.

[0142] In step 2, the dust reacts in the phosphoric acid pool for 0.5 h.

[0143] In the step 2, a phosphoric acid solution is added to the phosphoric acid solution reaction tank, wherein the composition is: phosphoric acid: water = 1:10 (wt%), and the mass percentage concentration of the phosphoric acid solution is 50%.

[0144] In this example, the heavy metal leaching concentration of fly ash after treatment is:

[0145] Leaching elements d / (mg / L) Leaching elements d / (mg / L) Pb 28.501 Cr 0.399 Zn 3.987 Ni Not detected Cd 0.004 Cu 0.084

[0146] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0147] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and intent of the present invention.

Claims

1. A method for co-disposing waste incineration fly ash in a cement kiln, the operating steps of which are as follows: Step 1: Use pneumatic conveying to transport the fly ash from the garbage incineration into the kiln head, install a five-stage Z-shaped air intake facility in the smoke chamber at the tail of the cement kiln, the fifth stage is connected to the smoke chamber, a Roots blower is installed in the first stage, the diameter of the air duct at the first stage outlet is 20 to 30 times the diameter of the air intake duct, the air outlet is connected to the temporary storage bin A, a cold air blower is installed at the bottom of the temporary storage bin, and a cyclone dust removal facility B is installed on the top; Step 2: The dust collected by the cyclone dust removal facility B is sent to the phosphoric acid solution reaction tank. A slag pump is installed at the bottom of the phosphoric acid solution reaction tank to pump the precipitate to a plate and frame filter press for filtration to obtain material a with a moisture content of 30-40%; Step 3: Send material a to the belt dryer for drying, and dry material a to a moisture content of 8-10%. The heat source of the dryer comes from the waste heat of the temporary storage bin A; Step 4: The dried material a is mixed with cement raw material at a ratio of 10%-15%, and the raw material is put into a rotary kiln as a raw material for producing cement clinker, and calcined at 1200-1400° C. to obtain cement clinker; In the step 2, a phosphoric acid solution is added to the phosphoric acid solution reaction tank, wherein the composition is: phosphoric acid: water: metal chelating accelerator = 1: 10-30: 0.001-0.02, wt%, and the mass percentage concentration of the phosphoric acid solution is 50-85%; The preparation method of the metal chelating accelerator in step 2 is: S1: Add 300-400 parts of distilled water and 20-50 parts of carboxymethyl starch in a three-necked flask by mass, stir magnetically to evenly disperse the starch, place in a water bath at 60-75°C for gelatinization for 20-60 minutes, add 1-3 parts of potassium persulfate solution to activate the starch hydroxyl groups to generate free radicals, activate at 50-60°C for 20-60 minutes, and dry; S2: Continue to add 2-5 parts of unsaturated monomer, 0.002-0.05 parts of N-allyl-O-isobutylthiocarbamate, 300-400 parts of water, 2-4 parts of potassium persulfate, introduce nitrogen to eliminate oxygen interference, and heat the reaction; after the reaction, distill the product to remove water, and dry the product to obtain a metal chelating accelerator; The unsaturated monomer is selected from 1-vinylimidazole, N-allylimidazole, 4-vinylpyridine, 4-methyl-5-vinylthiazole, 2-methyl-1-vinylimidazole, 3-methyl-1-vinylpyrazole, N-vinylpurine, N-vinylpiperazine and combinations thereof.

2. The method for co-disposal of waste incineration fly ash by cement kiln according to claim 1, characterized in that: In step 1, the amount of fly ash injected is 3 to 5 tons per hour.

3. The method for co-disposal of waste incineration fly ash by cement kiln according to claim 1, characterized in that: In the step 1, the first stage Roots blower is installed to extract air at a volume of 30,000 to 50,000 cubic meters per hour.

4. The method for co-disposal of waste incineration fly ash by cement kiln according to claim 1, characterized in that: In step 2, the filter press pressure is 8-12 kg / cm 2 , filtration time is 30 to 40 minutes.

5. The method for co-disposal of waste incineration fly ash by cement kiln according to claim 1, characterized in that: In step 2, the dust reacts in the phosphoric acid pool for 0.5-2 hours.

6. The method for co-disposal of waste incineration fly ash by cement kiln according to claim 1, characterized in that: In the step 2, the dust is added into the phosphoric acid solution reaction tank, and the liquid-to-solid ratio RL / S is controlled to be 10-20 mL / g.

7. The method for co-disposal of waste incineration fly ash by cement kiln according to claim 1, characterized in that: The reaction temperature is 60-70°C and the reaction time is 3-6h.

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