A method for resource utilization of cement kiln co-processing stale garbage undersize

Abstract

The application provides a method for cement kiln co-processing stale garbage undersize for resource utilization, which comprises using a cement kiln to co-process stale garbage undersize into cement clinker. The cement clinker comprises the following raw materials in parts by weight: 0.5-10 parts of modified undersize, 85-95 parts of limestone, 2-5 parts of phyllite, 8-12 parts of iron tailings, 10-15 parts of bauxite, and 1-4 parts of fly ash. The undersize is modified to better combine with limestone, phyllite, iron tailings, bauxite and fly ash, improve the adhesion and bonding force between materials, and significantly enhance the performance of cement. The undersize screening comprises manual primary selection, primary vibration screening, magnetic separation, wet screening, secondary vibration screening and tertiary vibration screening. The wet screening uses modified adsorption resin to adsorb chlorine elements and heavy metal substances in the undersize, so that the undersize meets the kiln entry standard, and the peculiar smell of the undersize can be removed.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of waste treatment, in particular to a cement kiln collaborative disposal of stale garbage under-screen material resource utilization method. BACKGROUND

[0002] The landfill built in the early days of the founding of our country is mostly a simple landfill without lining, which causes the later environmental protection requirements to be substandard, and has a bad influence on the surrounding soil and water environment pollution. At the same time, with the continuous improvement of urbanization level, the amount of domestic waste continues to grow, and a large number of operating landfills are out of capacity. The land resources of cities and surrounding areas are gradually scarce, so it is urgent to re-excavate, separate and utilize or standardize the old and simple garbage landfill that has been stopped, so as to realize the reduction of landfill pollution sources, the resource utilization of landfill gas and landfill gas. Therefore, a large amount of stale garbage needs to be screened and utilized.

[0003] Cement kiln collaborative disposal technology is a process of putting the under-screen material that meets or meets the requirements of cement kiln after pretreatment into the cement kiln to realize the harmless disposal of waste while producing cement clinker. Using cement kiln collaborative disposal of stale garbage under-screen material can realize waste treatment and reduction, recycle waste, and avoid potential harm of harmful substances to the environment, contributing to environmental protection and sustainable development. At present, the selection of the ratio of under-screen material to other cement clinker and how to effectively combine with other cement clinker is a difficulty, which will have a great influence on the strength of cement clinker. At present, the screening technology, the main destination of the screen material is to enter the waste incineration plant for incineration power generation, and the main material of the screen material is humus. The under-screen material is extremely complex in composition and contains a variety of toxic and harmful substances such as chlorine and heavy metals. The high amount of chlorine in the under-screen material is difficult to remove effectively, which becomes a bottleneck for the resource utilization of the under-screen material. SUMMARY

[0004] In view of this, the present application provides a cement kiln collaborative disposal of stale garbage under-screen material resource utilization method to solve the above problems.

[0005] The technical scheme of the present application is as follows:

[0006] A cement kiln collaborative disposal of stale garbage under-screen material resource utilization method, using cement kiln collaborative disposal to make stale garbage under-screen material into cement clinker; the cement clinker comprises the following raw materials by weight: 0.5-10 parts of modified under-screen material, 85-95 parts of limestone, 2-5 parts of phyllite, 8-12 parts of iron tailings, 10-15 parts of bauxite, and 1-4 parts of fly ash.

[0007] Further, the modified undersize, limestone, phyllite, iron tailings, bauxite, fly ash are crushed, dried, and then ground to obtain raw meal. The raw meal is metered and then gradually preheated and decomposed in a preheater. After most of the carbonates are decomposed, the material is introduced into a rotary kiln for calcination. The pre-decomposed material is further decomposed and undergoes a series of chemical and physical reactions in the rotary kiln to generate cement clinker mainly composed of silicates.

[0008] Further, the flue gas discharged during the calcination process is dusted by a bag filter and then discharged after desulfurization by a desulfurization system using lime slurry.

[0009] Further, the modified undersize is prepared as follows: 1-2 parts of polyacrylamide is dissolved in 15-20 parts of pure water to obtain a polyacrylamide solution; the undersize is placed in the polyacrylamide solution, soaked for 2-3 hours, and then placed in an ultrasonic generator for ultrasonic treatment for 1-2 hours. The ultrasonic power is controlled at 1000-1500 W, and the ultrasonic frequency is controlled at 15-20 Hz. The undersize is filtered out and introduced into a moisture adjusting device to adjust the moisture content to ≤30% to obtain the modified undersize.

[0010] Further, the undersize includes the following screening steps:

[0011] S1: manual primary selection: manually select and classify large pieces of plastic, stones, and metals for recycling and placement;

[0012] S2: primary vibration screening: evenly spread the decomposed garbage after preliminary screening on a vibration screen with a screen hole diameter of 150-200 mm, and set the vibration frequency to 10-50 Hz and the amplitude to 1-5 mm;

[0013] S3: magnetic separation: place the undersize from step S2 into a magnetic induction machine with a magnetic induction intensity of 0.8-1.0 T to screen out magnetic substances;

[0014] Further, after the magnetic separation in step S3, an inductively coupled plasma spectrometer is used to determine the content of heavy metals and chlorine elements in accordance with HJ 662-2013 "Technical Code for Environmental Protection of Cement Kiln Collaborative Disposal of Solid Waste". If the content of heavy metals and chlorine elements in the undersize exceeds the standard, the following steps S4 are performed in sequence. If the content of heavy metals and chlorine elements in the undersize meets the standard, the following steps S6 are performed in sequence.

[0015] S4: wet screening: the undersize after magnetic separation in S3 is transported to an adsorption tank, tap water and modified adsorption resin are added, the mass / volume ratio of undersize, modified adsorption resin and tap water is (1.0-1.2):(0.2-0.3):(2.5-3.0) kg / L; a stirring paddle is arranged at the bottom of the adsorption tank, and the stirring paddle is operated at 50-60 r / min for 8-10 min, and then is left standing for 20-30 min, and the tap water and light substances are discharged from the upper layer to a water collecting tank;

[0016] S5: moisture adjustment: the undersize and adsorption resin precipitated at the bottom in S4 are put into a moisture adjustment device, and the moisture is adjusted to ≤20%;

[0017] S6: secondary vibrating screening: the undersize treated in S3 or S5 is evenly laid on a vibrating screen with a screen hole diameter of 90-100 mm, the vibrating frequency is set to 20-30 Hz, and the amplitude is set to 2-3 mm, and undersize with a diameter of 90-100 mm is obtained;

[0018] S7: the undersize treated in S6 is evenly laid on a vibrating screen with a screen hole diameter of 20-30 mm, the vibrating frequency is set to 20-30 Hz, and the amplitude is set to 2-3 mm, and undersize with a diameter of 20.1-100 mm is obtained.

[0019] Further, the modified adsorption resin comprises the following raw materials by weight: 45-50 parts of polystyrene resin with a particle size of 100-300 mesh, 25-30 parts of 30-50 wt% chloromethylation reagent, 50-70 parts of 5-10 wt% sodium hydroxide solution, and 0.5-1.5 parts of catalyst.

[0020] Further, the preparation method of the modified adsorption resin comprises the following steps:

[0021] (1): preparation of polystyrene resin suspension: the polystyrene resin is put into a stirrer, the sodium hydroxide solution is added, the pH is adjusted to 8-9, the stirring speed of the stirrer is 300-500 r / min, and the stirring time is 30-60 min, to obtain polystyrene resin suspension A for standby;

[0022] (2): preparation of preliminary modified suspension: the chloromethylation reagent is added dropwise to the suspension A, the stirring speed of the stirrer is 50-100 r / min, the stirring time is 20-40 min, and the reaction temperature is controlled at 30-40℃, to obtain preliminary modified suspension B for standby;

[0023] (3): preparation of modified suspension: the catalyst is added to the suspension B, the stirring speed of the stirrer is 50-100 r / min, the stirring time is 10-20 min, and the reaction temperature is controlled at 30-40℃, to obtain modified suspension C;

[0024] (4) Preparation of modified adsorption resin: filter the suspension C using a 20-120 mesh screen to obtain a residue; rinse the residue with purified water for 3-5 times, and then place it into a drying machine to dry at 60-80℃ for 3-4h to obtain the modified adsorption resin.

[0025] Further, the chloromethylation reagent is one of chloromethyltrichlorosilane solution or chloromethyl dimethylchlorosilane solution.

[0026] Further, the catalyst is one of 20-30wt% sodium carbonate solution, sodium bicarbonate solution.

[0027] Compared with the prior art, the present application has the following beneficial effects:

[0028] The present application introduces chlorine atoms on the surface of polystyrene resin by using chloromethylation reagent to modify the polystyrene resin. The chlorine atoms on the surface of the modified adsorption resin exchange ions with the chloride ions in the undersize, thereby realizing the adsorption of chloride ions. The chlorine atoms on the surface of the modified adsorption resin have high negative charge, which strongly interacts with the heavy metal ions in the undersize through electrostatic interaction, thereby effectively adsorbing these metal ions. The benzene ring structure inside the modified adsorption resin acts as a coordination group, forming a stable complex with heavy metal ions, thereby further enhancing the adsorption effect.

[0029] The present application uses wet screening to effectively remove odor substances in the undersize. In water, odor molecules are dispersed and dissolved, so that they are eluted and removed. The modified adsorption resin has better dispersibility in water, and the adsorption efficiency is further improved.

[0030] The present application uses polyacrylamide solution to modify the undersize, introduces hydrophobic groups in the polyacrylamide into the undersize, further interacts with the surface of limestone, phyllite, iron tailings, bauxite, fly ash materials, forms surface wetting phenomenon, improves the adhesion and bonding force between materials, thereby significantly enhances the performance of cement. At the same time, these interactions can also improve the hydration reaction kinetics of clinker, improve the early strength and long-term performance of cement. At the same time, the addition proportion of the modified undersize in the present application is accurately controlled, ensuring that the chemical composition and physical properties of the cement clinker meet the requirements, and obtaining cement clinker with higher strength. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is the process flow chart of the present application. DETAILED DESCRIPTION

[0032] In order to better understand the technical content of the present application, the following specific examples are provided to further illustrate the present application.

[0033] The experimental methods used in the embodiments of the present application are all conventional methods unless otherwise specified.

[0034] The materials, reagents, etc. used in the embodiments of the present application can be obtained from commercial channels unless otherwise specified.

[0035] Example 1

[0036] A cement kiln collaborative disposal of stale garbage undersize material recycling method, the stale garbage undersize material screening includes the following steps:

[0037] S1: manual preliminary selection: manually select large pieces of plastic, stone, metal, and classify and recycle and place;

[0038] S2: first-stage vibration screening: uniformly spread the stale garbage after preliminary screening on a vibration screen with a screen hole diameter of 150 mm, set the vibration frequency to 10 Hz and the amplitude to 1 mm;

[0039] S3: magnetic separation: put the undersize material in the S2 step into a magnetic induction machine with a magnetic induction intensity of 0.8 T, and screen out magnetic substances;

[0040] S4: wet screening: deliver the undersize material after magnetic separation in the S3 step to an adsorption tank, and add tap water and modified adsorption resin, with a mass-volume ratio of the undersize material, modified adsorption resin, and tap water being 1.0:0.2:2.5 kg / L; a stirring paddle is arranged at the bottom of the adsorption tank, and is operated at 50 r / min for 8 min, and then is left to stand for 20 min, and the tap water and light substances are discharged from the upper layer to a water collection tank; the modified adsorption resin comprises the following raw materials in parts by weight: 45 parts of polystyrene resin with a particle size of 100 mesh, 25 parts of 30 wt% chloromethyltrichlorosilane solution, 50 parts of 5 wt% sodium hydroxide solution, and 0.5 parts of sodium carbonate solution;

[0041] The preparation method of the above modified adsorption resin comprises the following steps:

[0042] (1): preparation of polystyrene resin suspension: put the polystyrene resin into a stirrer, add the sodium hydroxide solution, adjust the pH to 8, the stirrer speed is 300 r / min, and the stirring time is 30 min, to obtain polystyrene resin suspension A for standby;

[0043] (2): preparation of preliminary modified suspension: add the chloromethyltrichlorosilane solution drop by drop to the suspension A, the stirrer speed is 50 r / min, the stirring time is 20 min, and the reaction temperature is controlled at 30℃, to obtain preliminary modified suspension B for standby;

[0044] (3): preparation of modified suspension: add the sodium carbonate solution to the suspension B, the stirrer speed is 50 r / min, the stirring time is 10 min, and the reaction temperature is controlled at 30℃, to obtain modified suspension C;

[0045] (4) Preparation of modified adsorption resin: filter the suspension C using a 20 mesh screen to obtain a residue; rinse the residue with purified water three times, and then place it in a drying machine at 60°C for 3h to obtain a modified adsorption resin.

[0046] S5: moisture adjustment: put the undersize and adsorption resin precipitated in the S4 step into a moisture adjustment device to adjust the moisture to 20%;

[0047] S6: secondary vibration screening: evenly spread the undersize treated in the S5 step on a vibration screen with a screen hole diameter of 100mm, set the vibration frequency to 20Hz and the amplitude to 2mm to obtain 100mm undersize.

[0048] S7: evenly spread the undersize treated in the S6 step on a vibration screen with a screen hole diameter of 20mm, set the vibration frequency to 20Hz and the amplitude to 2mm to obtain 20.1-100mm undersize.

[0049] Next, the undersize obtained in the S7 step is modified as follows: take 1 part of polyacrylamide and dissolve it in 15 parts of purified water to obtain a polyacrylamide solution; then put the undersize obtained in the S7 step into the polyacrylamide solution, soak for 2h, and then put it into an ultrasonic generator for ultrasonic treatment for 1h, with the ultrasonic power controlled at 1000W and the ultrasonic frequency controlled at 15Hz; filter out the undersize and put it into a moisture adjustment device to adjust the moisture to 30% to obtain modified undersize.

[0050] Next, the obtained modified undersize is made into cement clinker; the cement clinker includes the following raw materials by weight: 0.5 parts of modified undersize, 85 parts of limestone, 2 parts of phyllite, 8 parts of iron tailings, 10 parts of bauxite, and 1 part of fly ash.

[0051] Example 2

[0052] A method for resource utilization of stale garbage undersize by cement kiln co-processing, the stale garbage undersize screening includes the following steps:

[0053] S1: manual primary screening: manually screen out large pieces of plastic, stone, and metal, and classify and recycle them;

[0054] S2: primary vibration screening: evenly spread the stale garbage treated by primary screening on a vibration screen with a screen hole diameter of 175mm, set the vibration frequency to 30Hz and the amplitude to 3mm;

[0055] S3: magnetic separation: put the undersize in the S2 step into a magnetic induction machine with a magnetic induction intensity of 0.9T to screen out magnetic materials;

[0056] S4: wet screening: the undersize after magnetic separation in S3 is transported to an adsorption tank, tap water and modified adsorption resin are added, the mass / volume ratio of undersize, modified adsorption resin and tap water is 1.1:0.25:2.7 kg / L; a stirring paddle is arranged at the bottom of the adsorption tank, and is operated at 55 r / min for 9 min, and then is statically placed for 15 min, and the tap water and light substances are discharged from the upper layer to a water collecting tank; the modified adsorption resin comprises the following raw materials in parts by weight: 47 parts of polystyrene resin with a particle size of 200 mesh, 27 parts of 40 wt% chloromethyl dimethyl chlorosilane solution, 60 parts of 7 wt% sodium hydroxide solution, 1.0 part of sodium bicarbonate solution;

[0057] The preparation method of the modified adsorption resin comprises the following steps:

[0058] (1): preparing a polystyrene resin suspension: the polystyrene resin is put into a stirrer, the sodium hydroxide solution is added, the pH is adjusted to 8.5, the stirring speed of the stirrer is 400 r / min, and the stirring time is 45 min, to obtain a polystyrene resin suspension A for standby;

[0059] (2): preparing a preliminary modified suspension: the chloromethyl methyl dichlorosilane solution is added dropwise to the suspension A, the stirring speed of the stirrer is 75 r / min, the stirring time is 30 min, and the reaction temperature is controlled at 35°C, to obtain a preliminary modified suspension B for standby;

[0060] (3): preparing a modified suspension: the sodium bicarbonate solution is added to the suspension B, the stirring speed of the stirrer is 75 r / min, the stirring time is 10-20 min, and the reaction temperature is controlled at 35°C, to obtain a modified suspension C;

[0061] (4): preparing a modified adsorption resin: the suspension C is filtered by using a 70-mesh screen, to obtain a filter residue; the filter residue is washed with pure water for 4 times, and then is placed into a drying machine for drying at 70°C for 3.5 h, to obtain a modified adsorption resin.

[0062] S5: moisture adjustment: the undersize and the adsorption resin precipitated at the bottom in S4 are put into a moisture adjustment device, and the moisture is adjusted to 10%;

[0063] S6: secondary vibrating screening: the undersize treated in S5 is evenly laid on a vibrating screen with a screen hole diameter of 95 mm, the vibrating frequency is set to 25 Hz, and the amplitude is set to 2.5 mm, to obtain 95 mm undersize;

[0064] S7: the undersize treated in S6 is evenly laid on a vibrating screen with a screen hole diameter of 25 mm, the vibrating frequency is set to 25 Hz, and the amplitude is set to 2.5 mm, to obtain 25-95 mm undersize.

[0065] Then the undersize obtained in step S7 is subjected to a modification treatment, the process being as follows: 1.5 parts of polyacrylamide is dissolved in 17 parts of pure water to obtain a polyacrylamide solution; then the undersize obtained in step S7 is placed in the polyacrylamide solution, soaked for 2.5 h, and then placed in an ultrasonic generator for ultrasonic treatment for 1.5 h, with the ultrasonic power being controlled at 1250 W and the ultrasonic frequency being controlled at 17 Hz; the undersize is filtered out and put into a moisture adjusting device, and the moisture is adjusted to 20% to obtain modified undersize.

[0066] Next, the obtained modified undersize is made into cement clinker; the cement clinker comprises the following raw materials in parts by weight: 5 parts of modified undersize, 90 parts of limestone, 3.5 parts of phyllite, 10 parts of iron tailings, 12.5 parts of bauxite, and 2.5 parts of fly ash.

[0067] Example 3

[0068] A method for resource utilization of stale garbage undersize by cement kiln co-processing, the screening of stale garbage undersize comprising the following steps:

[0069] S1: manual preliminary selection: manually select out large pieces of plastic, stone, metal, and classify and recycle them;

[0070] S2: primary vibration screening: the preliminarily screened stale garbage is evenly laid on a vibration screen with a screen hole diameter of 200 mm, and the vibration frequency is set to 50 Hz and the amplitude is set to 5 mm;

[0071] S3: magnetic separation: the undersize in step S2 is placed in a magnetic induction machine with a magnetic field induction intensity of 1.0 T to screen out magnetic substances;

[0072] S4: wet screening: the undersize after magnetic separation in step S3 is conveyed to an adsorption tank, and tap water and modified adsorption resin are added, with the mass / volume ratio of the undersize, modified adsorption resin, and tap water being 1.2:0.3:3.0 kg / L; a stirring paddle is provided at the bottom of the adsorption tank, and is operated at 60 r / min for 10 min, and then is left to stand for 30 min, and the tap water and light substances are discharged from the upper layer to a water collection tank; the modified adsorption resin comprises the following raw materials in parts by weight: 50 parts of polystyrene resin with a particle size of 300 mesh, 30 parts of 50 wt% chloromethyl dimethyl chlorosilane solution, 70 parts of 10 wt% sodium hydroxide solution, and 1.5 parts of sodium bicarbonate solution;

[0073] The preparation method of the above modified adsorption resin comprises the following steps:

[0074] (1): preparation of polystyrene resin suspension: polystyrene resin is placed in a stirrer, sodium hydroxide solution is added, the pH is adjusted to 9, the stirrer speed is 500 r / min, and the stirring time is 60 min to obtain polystyrene resin suspension A for standby;

[0075] (2): Preparation of the preliminary modified suspension: drop by drop add chloromethyl dimethyl chlorosilane solution to the suspension A, the stirring speed is 100 r / min, the stirring time is 40 min, the reaction temperature is controlled at 40℃, to obtain the preliminary modified suspension B for standby;

[0076] (3): Preparation of the modified suspension: add sodium bicarbonate solution to the suspension B, the stirring speed is 100 r / min, the stirring time is 20 min, the reaction temperature is controlled at 40℃, to obtain the modified suspension C;

[0077] (4): Preparation of the modified adsorption resin: filter the suspension C using 120 mesh screen, to obtain the filter residue; the filter residue is washed with pure water for 5 times, and then is placed in the drying machine at 80℃ for 4h, to obtain the modified adsorption resin.

[0078] S5: Moisture adjustment: put the undersize and the adsorption resin precipitated in the S4 step into the moisture adjustment device, to adjust the moisture to 5%;

[0079] S6: Secondary vibrating screen selection: evenly spread the undersize treated in the S5 step on the vibrating screen with the screen hole diameter of 90mm, set the vibration frequency at 30Hz and the amplitude at 3mm, to obtain the undersize of 90mm.

[0080] S7: Evenly spread the undersize treated in the S6 step on the vibrating screen with the screen hole diameter of 30mm, set the vibration frequency at 30Hz and the amplitude at 3mm, to obtain the undersize of 30-90mm.

[0081] Then, the undersize obtained in the S7 step is subjected to modification treatment, the process is as follows: take 2 parts of polyacrylamide to dissolve in 20 parts of pure water, to obtain the polyacrylamide solution; then, put the undersize obtained in the S7 step into the polyacrylamide solution, soak for 3h, and then is placed in the ultrasonic generator for ultrasonic treatment for 2h, the ultrasonic power is controlled at 1500W, and the ultrasonic frequency is controlled at 20Hz, filter out the undersize and put it into the moisture adjustment device, to adjust the moisture to ≤10%, to obtain the modified undersize.

[0082] Next, the obtained modified undersize is made into cement clinker; the cement clinker comprises the following raw materials by weight: 10 parts of the modified undersize, 95 parts of limestone, 5 parts of phyllite, 12 parts of iron tailings, 15 parts of bauxite, and 4 parts of fly ash.

[0083] The cement clinker of the above-mentioned embodiment 1, embodiment 2 and embodiment 3 is prepared by the following method: the modified undersize, limestone, phyllite, iron tailings, bauxite and fly ash are crushed, dried, and then ground to obtain raw meal, and the raw meal is homogenized and metered to enter a preheater for gradual preheating and decomposition, and after most of the carbonates are decomposed, the raw meal enters a rotary kiln for calcination, and the pre-decomposed material is further decomposed and a series of chemical and physical reactions occur in the rotary kiln to generate cement clinker with silicates as the main component; the flue gas discharged in the calcination process is dusted by a bag-type dust collector, and then discharged after reaching the standard by desulfurization system using lime slurry desulfurization.

[0084] Comparative example 1

[0085] Comparative example 1 and embodiment 2 are compared, and the difference is that equal mass of polystyrene adsorption resin is used instead of modified adsorption resin.

[0086] Comparative example 2

[0087] Comparative example 2 and embodiment 2 are compared, and the difference is that air separation is used instead of wet screening, and the air separation process is as follows: the undersize after magnetic separation in step S3 is transported to an air separator, and under the action of 300 Pa wind for 30 s, light and heavy materials are obtained respectively. Then the heavy material is put into a stirrer, and at the same time, modified adsorption resin is added, and the mass ratio of undersize to modified adsorption resin is 1.1:0.25, and the stirrer is operated at 55 r / min for 9 min.

[0088] I. Determination of heavy metal and chlorine content in undersize

[0089] The undersize screened out by the present application embodiments 1-3 and comparative examples 1-2 is used to determine the heavy metal and chlorine (Cl) content by inductively coupled plasma spectrometer, and the heavy metal determination indexes are mercury (Hg), thallium + cadmium + lead + 15x arsenic (Tl+Cd+Pb+15As), beryllium + chromium + 10x tin + 50x antimony + copper + manganese + nickel + vanadium (Be+Cr+10Sn+50Sb+Cu+Mn+Ni+V), and the determination results are as shown in the following table 1:

[0090] Table 1

[0091]

[0092] As can be seen from Table 1, the method of the present application has good heavy metal removal and chlorine element removal effects, especially the effect of Example 2 is the best. The present application modifies the polystyrene resin by using a chloromethylating agent, thereby introducing chlorine atoms on the surface of the polystyrene resin. The chlorine atoms on the surface of the modified adsorption resin are ion exchanged with the chloride ions in the undersize, thereby realizing the adsorption of the chloride ions. The chlorine atoms on the surface of the modified adsorption resin have high electronegativity, and they have strong electrostatic interaction with the heavy metal ions in the undersize which have high polarity, thereby effectively adsorbing these metal ions. The benzene ring structure inside the modified adsorption resin acts as a coordination group, forming a stable complex with heavy metal ions, thereby further enhancing the adsorption effect. Therefore, the undersize treated by the method of the present application meets the requirements of HJ 662-2013 “Technical Code for Environmental Protection of Cement Kiln Co-processing Solid Waste” 6.67 and 6.68 chapters for heavy metals and chlorine elements.

[0093] Comparative Example 3

[0094] Comparative Example 3 and Example 2 are compared, the difference is that the undersize is not modified, and the same mass of undersize is used instead of modified undersize.

[0095] Comparative Example 4

[0096] Comparative Example 4 and Example 2 are compared, the difference is that the cement clinker includes the following raw materials by weight: 15 parts of modified undersize, 90 parts of limestone, 3.5 parts of phyllite, 10 parts of iron tailings, 12.5 parts of bauxite, and 2.5 parts of fly ash.

[0097] II. Determination of heavy metal and chlorine element content of undersize

[0098] The cement clinker made by the present application Examples 1-3 and Comparative Example 3 is taken according to the provisions of GB175-2007 “General Portland Cement”, and the method specified in GB / T17671-2021 “Cement Mortar Strength Test Method (ISO Method)” is used to make standard test pieces, and the 3d and 28d flexural strength and compressive strength are measured under standard curing conditions according to the specified method.

[0099] Table 2

[0100]

[0101] As can be seen from Table 2, the cement clinker prepared by the method of the present application has good compressive strength and flexural strength, especially the effect of Example 2 is the best. Compared with Comparative Example 3, the present application uses polyacrylamide solution to modify undersize, introduces hydrophobic groups in polyacrylamide into undersize, further interacts with the surface of limestone, phyllite, iron tailings, bauxite and fly ash materials, forms surface wetting phenomenon, improves the adhesion and bonding force between materials, thereby significantly enhances the performance of cement.

[0102] Compared with Comparative Example 4, the addition ratio of modified undersize is higher than the formula ratio of the present application. Since the modified undersize is a kind of waste with high organic matter content, the ash content and harmful impurities are higher than other raw materials. Too high addition ratio of undersize leads to the destruction of some crystal structures in the cement clinker, thereby reducing the strength of the cement.

[0103] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for cement kiln co-processing of resource utilization of stale refuse undersize, characterized in that: The cement kiln is used for co-processing to produce cement clinker from stale refuse undersize; the cement clinker comprises the following raw materials by weight: 0.5-10 parts of modified undersize, 85-95 parts of limestone, 2-5 parts of phyllite, 8-12 parts of iron tailings, 10-15 parts of bauxite, and 1-4 parts of fly ash; The preparation method of the modified undersize is as follows: 1-2 parts of polyacrylamide is dissolved in 15-20 parts of pure water to obtain a polyacrylamide solution; the undersize is soaked in the polyacrylamide solution for 2-3 hours, and then is placed in an ultrasonic generator for ultrasonic treatment for 1-2 hours, with the ultrasonic power being controlled at 1000-1500 W and the ultrasonic frequency being controlled at 15-20 Hz; the undersize is filtered out and is fed into a moisture adjusting device, and the moisture is adjusted to ≤30% to obtain the modified undersize; The undersize comprises the following screening steps: S1: manual primary selection: manually selecting out large pieces of plastic, stones and metals for classified recycling and placement; S2: primary vibration screening: uniformly laying the stale refuse after the preliminary screening on a vibration screen with a screen hole diameter of 150-200 mm, and setting the vibration frequency at 10-50 Hz and the amplitude at 1-5 mm; S3: magnetic separation: placing the undersize in the S2 step in a magnetic induction machine with a magnetic field induction intensity of 0.8-1.0 T to screen out magnetic substances; S4: wet screening: feeding the undersize after the magnetic separation in the S3 step to an adsorption tank, and adding tap water and modified adsorption resin, with the mass / volume ratio of the undersize, the modified adsorption resin and the tap water being (1.0-1.2):(0.2-0.3):(2.5-3.0) kg / L; the adsorption tank is provided with a stirring paddle which is operated at 50-60 r / min for 8-10 min, and then is statically placed for 20-30 min, and the tap water and light substances are discharged from the upper layer to a water collecting tank; S5: moisture adjustment: feeding the undersize and the adsorption resin which are precipitated at the bottom in the S4 step into a moisture adjusting device to adjust the moisture to ≤20%; S6: secondary vibration screening: uniformly laying the undersize treated in the S5 step on a vibration screen with a screen hole diameter of 90-100 mm, and setting the vibration frequency at 20-30 Hz and the amplitude at 2-3 mm to obtain undersize with a size of 90-100 mm; S7: tertiary vibration screening: uniformly laying the undersize treated in the S6 step on a vibration screen with a screen hole diameter of 20-30 mm, and setting the vibration frequency at 20-30 Hz and the amplitude at 2-3 mm to obtain undersize with a size of 20.1-100 mm; The modified adsorption resin comprises the following raw materials by weight: 45-50 parts of polystyrene resin with a particle size of 100-300 mesh, 25-30 parts of 30-50 wt% chloromethylation reagent, 50-70 parts of 5-10 wt% sodium hydroxide solution, and 0.5-1.5 parts of catalyst.

2. A method for cement kiln co-processing of resource recovery of stale garbage undersize according to claim 1, characterized in that: The cement clinker is prepared by the following method: modified undersize, limestone, phyllite, iron tailings, bauxite, fly ash are crushed, dried, and then ground to obtain raw meal, the raw meal is homogenized and metered, and then gradually preheated and decomposed in a preheater, most of the carbonates are decomposed, and then enter a rotary kiln for calcination, the pre-decomposed material is further decomposed in the rotary kiln and a series of chemical and physical reactions occur to generate a cement clinker mainly composed of silicates.

3. A method for cement kiln co-processing of resource recovery of stale garbage undersize according to claim 2, characterized in that: The flue gas discharged in the calcination process is dusted by a bag-type dust collector, and then discharged after desulfurization by a desulfurization system using lime slurry.

4. A method for cement kiln co-processing of resource recovery of stale garbage undersize according to claim 1, characterized in that: The preparation method of the modified adsorption resin comprises the following steps: (1): preparing a polystyrene resin suspension: placing polystyrene resin into a stirrer, adding sodium hydroxide solution, adjusting the pH to 8-9, the stirrer speed is 300-500 r / min, the stirring time is 30-60 min, and a polystyrene resin suspension A is obtained for standby; (2): preparing a preliminary modified suspension: adding chloromethylation reagent dropwise to the suspension A, the stirrer speed is 50-100 r / min, the stirring time is 20-40 min, the reaction temperature is controlled at 30-40℃, and a preliminary modified suspension B is obtained for standby; (3): preparing a modified suspension: adding a catalyst to the suspension B, the stirrer speed is 50-100 r / min, the stirring time is 10-20 min, the reaction temperature is controlled at 30-40℃, and a modified suspension C is obtained; (4): preparing a modified adsorption resin: filtering the suspension C using a 20-120 mesh screen to obtain a residue; the residue is washed with pure water for 3-5 times, and then placed in a drying machine at 60-80℃ for 3-4 h to obtain a modified adsorption resin.

5. A method for cement kiln co-processing of resource recovery of stale garbage undersize according to claim 1, characterized in that: The chloromethylation reagent is one of chloromethyltrichlorosilane solution or chloromethyldimethylchlorosilane solution.

6. A method for cement kiln co-processing of resource recovery of stale garbage undersize according to claim 1, characterized in that: The catalyst is one of 20-30 wt% sodium carbonate solution or sodium bicarbonate solution.

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