A method for screening and reducing stock garbage

Abstract

The present invention relates to a method for screening and reducing stock waste, and belongs to the technical field of stock waste screening. A method for screening and reducing stock waste comprises the following steps: (1) mixing the biochemically dried stock waste with powder; (2) screening through a first drum screen to obtain a first oversize and a first undersize; (3) mixing with fine sand and sending to a second drum screen for screening to obtain a second oversize and a second undersize; (4) subjecting the pretreated first oversize and second oversize to a first air separation and a second air separation, respectively, to obtain a first light material, a first heavy material, a second light material, and a second heavy material; (5) obtaining combustible RDF through a baler; and obtaining metal material and aggregate after magnetic separation and separation through a magnetic separator. The drum screening efficiency and screening quality are improved by adding sodium carboxymethyl cellulose, micropowder silica gel, and fine sand; and vegetable oil is added before air separation to reduce solid inclusions on the surface of the waste, thereby improving the efficiency and quality of air separation.

Description

Technical Field

[0001] The invention belongs to the technical field of stock garbage screening and relates to a method for screening and reducing stock garbage. Background Art

[0002] With the annual increase in garbage volume and the fact that many landfills are already or about to reach saturation, the contradiction between the rapidly growing amount of garbage and land resources has become increasingly prominent. Therefore, it is necessary to treat the stale domestic waste in landfills to free up landfill space. Currently, the mainstream landfill stock waste management technologies at home and abroad include excavation screening and aerobic rapid stabilization technology. Excavation screening technology involves excavating the existing garbage from the landfill and screening it using equipment such as drum screens, magnetic separators, and air separators. The garbage is then treated according to different resource recovery methods based on its composition and particle size.

[0003] Due to the high humidity in the garbage, it is difficult to dehydrate it in a short time. Therefore, some garbage tends to form clumps under the action of drum screening, which are difficult to separate, resulting in problems such as clogging, adhesion and poor vibration of the drum. In addition, due to the presence of a small amount of humus and sand on the surface of the material after the secondary drum screening process, the combustible RDF selected by the air is adhered to more granular impurities, which need to be separated in the later stage, increasing the complexity of the garbage screening process. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for screening and reducing the amount of existing garbage. The scheme of the present invention can make the particles in the garbage evenly dispersed by adding sodium carboxymethyl cellulose, and the micropowder silica gel can enhance the dispersion effect between the particles, making it easier for solid particles to pass through the screen, improving screening efficiency and screening quality, greatly reducing the screening amount of subsequent air separation processes and reducing waste of resources; adding fine sand to the garbage material before the second drum screen to increase the friction between the garbage particles, can better control the specific gravity and viscosity properties of the garbage, and have a better screening effect; adding vegetable oil before air separation, during air separation, the humus, sand and other impurities attached to the surface of the material are removed, and the vegetable oil can reduce the surface tension of the garbage, making the mixed garbage more susceptible to wind blowing, reducing the solid inclusions on the surface of the garbage, thereby improving the efficiency and quality of air separation, effectively reducing the screening amount of magnetic separation, and increasing the effective utilization of resources.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A method for screening and reducing stock waste comprises the following steps:

[0007] (1) Evenly mixing the biochemically dried waste with the powder to obtain a waste mixture;

[0008] (2) sending the garbage mixture to a first drum screen for screening to obtain a first oversize material and a first undersize material;

[0009] (3) After the first undersize material is evenly mixed with fine sand, it is sent to the second drum screen for screening to obtain the second oversize material and the second undersize material;

[0010] (4) performing a first air separation and a second air separation on the pretreated first oversize material and the second oversize material, respectively, to obtain a first light material, a first heavy material, a second light material, and a second heavy material;

[0011] (5) The first light material and the second light material are mixed and packaged by a baler to obtain combustible RDF; the first heavy material and the second heavy material are mixed and magnetically separated and separated by a magnetic separator to obtain metal material and aggregate.

[0012] As can be seen from the above scheme, the separated metal materials can be used as recycled resources; the aggregates can be prepared into bone meal materials for feed and fertilizer; and the combustible RDF can be used as an environmentally friendly alternative fuel for users who need heat sources in waste incineration power plants and coal-fired power plants.

[0013] As a preferred technical solution of the present invention, in step (1), the mass ratio of the stock garbage to the powder is 100:0.07-0.09, and the powder is a mixture of sodium carboxymethyl cellulose and micropowder silica gel in a mass ratio of 2.5-3.0:1.

[0014] As a preferred technical solution of the present invention, in step (2), the aperture of the first drum screen is 55-60 mm.

[0015] As a preferred technical solution of the present invention, in step (3), the mass ratio of the first undersize material to the fine sand is 100:0.05-0.08.

[0016] As a preferred technical solution of the present invention, in step (3), the fine sand is quartz sand or natural river sand, or a combination of the two, and the particle size of the fine sand is 6-7 mm.

[0017] As a preferred technical solution of the present invention, in step (3), the aperture of the second drum screen is 28-30 mm.

[0018] As a preferred technical solution of the present invention, after step (3), the second undersize obtained in step (3) is further processed into humus soil for use in plant cultivation, backfilling, covering of landfills, and comprehensive utilization of soil resources for non-food chain landscaping.

[0019] As a preferred technical solution of the present invention, in step (4), the pretreatment is to stir and mix the first oversize material and the second oversize material with vegetable oil respectively.

[0020] As a preferred technical solution of the present invention, the mass ratio of the first oversize material to the vegetable oil is 300-400:2-3; the mass ratio of the second oversize material to the vegetable oil is 150-200:2-3.

[0021] As a preferred technical solution of the present invention, the vegetable oil is a combination of one or more of rapeseed oil, palm oil, soybean oil and peanut oil.

[0022] Beneficial effects of the present invention:

[0023] (1) Sodium carboxymethyl cellulose can form a highly stable dispersant with the water in the garbage, and through the electrostatic repulsion between the molecular chains, the particles are evenly dispersed, the water solubility of the particle surface is increased, the precipitation and agglomeration of the particles on the garbage surface are avoided, and the screening efficiency is improved; micropowder silica gel has extremely strong water absorption, and has an extremely high specific surface area, excellent adsorption and dispersibility. When the water absorption of micropowder silica gel is high, it can still maintain a powder state and can still effectively thicken in non-polar and low-polar media. The scheme of the present invention can promote the dispersion state of various materials in the garbage by adding micropowder silica gel, thereby reducing the agglomeration and binding effect between particles; therefore, when sodium carboxymethyl cellulose and micropowder silica gel are used at the same time, the scheme of the present invention can synergize with each other through their different action mechanisms, that is, sodium carboxymethyl cellulose can make the particles in the garbage evenly dispersed, and micropowder silica gel can enhance the dispersion effect between the particles, making it easier for solid particles to pass through the screen, improving the screening efficiency and screening quality, greatly reducing the screening amount of the subsequent air separation process and reducing the waste of resources.

[0024] (2) The present invention adds fine sand to the garbage material before the second drum screen to increase the friction between the garbage particles and improve the effect of screening debris. It can better control the specific gravity and viscosity properties of the garbage, have a better screening effect, and further reduce the screening amount of the subsequent air separation process.

[0025] (3) The present invention adds vegetable oil before air separation. During air separation, impurities such as humus and sand attached to the surface of the material are removed. Vegetable oil can reduce the surface tension of the garbage, making the mixed garbage more susceptible to wind and reducing the solid inclusions on the surface of the garbage, thereby improving the efficiency and quality of air separation, effectively reducing the screening amount of magnetic separation, and increasing the effective utilization of resources. In addition, vegetable oil can also reduce the adhesion and binding of impurities (such as fine powder, weeds, etc.) to the garbage, thereby reducing the adhesion rate of garbage during the air separation process, making it easier for impurities to be screened out; adding an appropriate amount of vegetable oil can moisten the surface of the garbage, reduce the friction and wear of garbage particles, prevent the generation of dust, and at the same time avoid the flying and harm of dust and particulate matter, ensuring the hygiene and safety of the air separation environment. Vegetable oil itself has good adsorption properties and can adsorb harmful gases such as VOCs, reduce the degree of air pollution, and can play a certain role in purification and deodorization. DETAILED DESCRIPTION

[0026] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with the embodiments.

[0027] Example 1

[0028] A method for screening and reducing stock waste comprises the following steps:

[0029] (1) mixing the biochemically dried stock garbage and powder at a mass ratio of 100:0.07 to obtain a garbage mixture; wherein the powder is prepared by mixing sodium carboxymethyl cellulose and micropowder silica gel at a mass ratio of 2.5:1;

[0030] (2) sending the garbage mixture to a first drum screen for screening to obtain a first oversize material and a first undersize material; wherein the aperture of the first drum screen is 55 mm;

[0031] (3) After the first undersize material is evenly mixed with fine sand, it is sent to a second drum screen for screening to obtain a second oversize material and a second undersize material; wherein the mass ratio of the first undersize material to the natural river sand is 100:0.05; the particle size of the natural river sand is 6 mm; wherein the aperture of the second drum screen is 28 mm; the second undersize material is made into humus soil;

[0032] (4) performing a first air separation and a second air separation on the pretreated first oversize material and the second oversize material, respectively, to obtain a first light material, a first heavy material, a second light material, and a second heavy material; wherein the pretreatment comprises stirring and mixing the first oversize material and the second oversize material with peanut oil, respectively; the mass ratio of the first oversize material to the peanut oil is 300:2; the mass ratio of the second oversize material to the peanut oil is 150:2;

[0033] (5) The first light material and the second light material are mixed and packaged by a baler to obtain combustible RDF; the first heavy material and the second heavy material are mixed and magnetically separated and separated by a magnetic separator to obtain metal material and aggregate.

[0034] Example 2

[0035] A method for screening and reducing stock waste comprises the following steps:

[0036] (1) mixing the biochemically dried stock garbage and powder at a mass ratio of 100:0.08 to obtain a garbage mixture; wherein the powder is prepared by mixing sodium carboxymethyl cellulose and micropowder silica gel at a mass ratio of 2.8:1;

[0037] (2) sending the garbage mixture to a first drum screen for screening to obtain a first oversize material and a first undersize material; wherein the aperture of the first drum screen is 58 mm;

[0038] (3) After the first undersize material is evenly mixed with fine sand, it is sent to a second drum screen for screening to obtain a second oversize material and a second undersize material; wherein the mass ratio of the first undersize material to the natural river sand is 100:0.065; the particle size of the natural river sand is 7 mm; wherein the aperture of the second drum screen is 29 mm; and the second undersize material is made into humus soil;

[0039] (4) performing a first air separation and a second air separation on the pretreated first oversize material and the second oversize material, respectively, to obtain a first light material, a first heavy material, a second light material, and a second heavy material; wherein the pretreatment comprises stirring and mixing the first oversize material and the second oversize material with peanut oil, respectively; the mass ratio of the first oversize material to the peanut oil is 350:2.5; the mass ratio of the second oversize material to the peanut oil is 170:2.5;

[0040] (5) The first light material and the second light material are mixed and packaged by a baler to obtain combustible RDF; the first heavy material and the second heavy material are mixed and magnetically separated and separated by a magnetic separator to obtain metal material and aggregate.

[0041] Example 3

[0042] A method for screening and reducing stock waste comprises the following steps:

[0043] (1) mixing the biochemically dried stock garbage and powder at a mass ratio of 100:0.3 to obtain a garbage mixture; wherein the powder is prepared by mixing sodium carboxymethyl cellulose and micropowder silica gel at a mass ratio of 3.0:1;

[0044] (2) sending the garbage mixture to a first drum screen for screening to obtain a first oversize material and a first undersize material; wherein the aperture of the first drum screen is 60 mm;

[0045] (3) After the first undersize material is evenly mixed with fine sand, it is sent to a second drum screen for screening to obtain a second oversize material and a second undersize material; wherein the mass ratio of the first undersize material to the natural river sand is 100:0.08; the particle size of the natural river sand is 7 mm; wherein the aperture of the second drum screen is 30 mm; the second undersize material is made into humus soil;

[0046] (4) performing a first air separation and a second air separation on the pretreated first oversize material and the second oversize material, respectively, to obtain a first light material, a first heavy material, a second light material, and a second heavy material; wherein the pretreatment comprises stirring and mixing the first oversize material and the second oversize material with peanut oil, respectively; the mass ratio of the first oversize material to the peanut oil is 400:3; the mass ratio of the second oversize material to the peanut oil is 200:3;

[0047] (5) The first light material and the second light material are mixed and packaged by a baler to obtain combustible RDF; the first heavy material and the second heavy material are mixed and magnetically separated and separated by a magnetic separator to obtain metal material and aggregate.

[0048] Comparative Example 1

[0049] Step (1) mixing the biochemically dried stock garbage and powder at a mass ratio of 100:0.08 to obtain a garbage mixture; wherein the powder is sodium carboxymethyl cellulose;

[0050] Compared with Example 2, the difference is that Comparative Example 1 does not use micropowder silica gel, and the other components, preparation steps and parameters are the same.

[0051] Comparative Example 2

[0052] Step (1) mixing the biochemically dried stock garbage and powder at a mass ratio of 100:0.08 to obtain a garbage mixture; wherein the powder is micropowder silica gel;

[0053] Compared with Example 2, the difference is that sodium carboxymethyl cellulose is not used in Comparative Example 2, and the other components, preparation steps and parameters are the same.

[0054] Comparative Example 3

[0055] Compared with Example 2, the difference is that no powder is added in Comparative Example 3, and the other components, preparation steps and parameters are the same.

[0056] Comparative Example 4

[0057] Step (3) sending the first undersize material to a second drum screen for screening to obtain a second oversize material and a second undersize material; wherein the aperture of the second drum screen is 9 mm; and making the second undersize material into humus soil;

[0058] Compared with Example 2, the difference is that Comparative Example 4 does not use natural river sand, and the other components, preparation steps and parameters are the same.

[0059] Comparative Example 5

[0060] Step (4) performing a first air separation and a second air separation on the first oversize material and the second oversize material, respectively, to obtain a first light material, a first heavy material, a second light material, and a second heavy material;

[0061] Compared with Example 2, the difference is that peanut oil is not used in Comparative Example 5, and the other components, preparation steps and parameters are the same.

[0062] Performance testing

[0063] The effective utilization rates of the stock garbage of Examples 1-3 and Comparative Examples 1-5 were observed, recorded, and calculated. The results are shown in Table 1.

[0064] Table 1

[0065] Effective utilization rate (%) Example 1 96.77 Example 2 96.33 Example 3 96.45 Comparative Example 1 76.94 Comparative Example 2 80.32 Comparative Example 3 68.25 Comparative Example 4 82.47 Comparative Example 5 78.33

[0066] As shown in Table 1, compared with Comparative Examples 1-5, Examples 1-3 achieve an effective utilization rate of 96% for the stock of garbage by adopting the scheme of the present invention, which is significantly higher than that of Comparative Examples 1-5. The scheme of the present invention improves the drum screening efficiency and screening quality by adding sodium carboxymethyl cellulose, micropowder silica gel and fine sand. The addition of vegetable oil reduces solid inclusions on the surface of the garbage, thereby improving the efficiency and quality of air separation.

[0067] Specifically, by comparing Examples 1-3 with Comparative Examples 1-3, it can be seen that, through their different mechanisms of action, sodium carboxymethyl cellulose and micropowdered silica gel can synergize with each other. That is, sodium carboxymethyl cellulose can evenly disperse the particles in the garbage, while micropowdered silica gel can enhance the dispersion effect between the particles, making it easier for solid particles to pass through the screen, improving screening efficiency and screening quality, greatly reducing the amount of screening required in the subsequent air separation process, and reducing resource waste. Regardless of whether sodium carboxymethyl cellulose or micropowdered silica gel is lacking, the effective utilization rate of the existing garbage is not as good as that of Examples 1-3. This is particularly evident in Comparative Example 3, which lacks both sodium carboxymethyl cellulose and micropowdered silica gel.

[0068] As can be seen from the comparison of Examples 1-3 with Comparative Example 4, the scheme of the present invention increases the friction between the garbage particles and improves the effect of screening debris by adding fine sand to the garbage material before the second drum screen. It can better control the specific gravity and viscosity properties of the garbage, has a better screening effect, and further reduces the screening amount of the subsequent air separation process.

[0069] It can be seen from the comparison of Examples 1-3 with Comparative Example 5 that the scheme of the present invention adds vegetable oil before air separation. During air separation, impurities such as humus and sand attached to the surface of the material are removed. The vegetable oil can reduce the surface tension of the garbage, making the mixed garbage more susceptible to wind blowing, reducing solid inclusions on the surface of the garbage, thereby improving the efficiency and quality of air separation, effectively reducing the screening amount of magnetic separation, and increasing the effective utilization of resources.

[0070] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, make some changes or modifications to equivalent embodiments using the technical contents disclosed above. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for screening and reducing stock waste, characterized in that: The following steps are involved: (1) Evenly mixing the biochemically dried waste with the powder to obtain a waste mixture; (2) sending the garbage mixture to a first drum screen for screening to obtain a first oversize material and a first undersize material; (3) After the first undersize material is evenly mixed with fine sand, it is sent to the second drum screen for screening to obtain the second oversize material and the second undersize material; (4) performing a first air separation and a second air separation on the pretreated first oversize material and the second oversize material, respectively, to obtain a first light material, a first heavy material, a second light material, and a second heavy material; (5) mixing the first light material and the second light material with a baler to obtain combustible RDF; The first heavy material and the second heavy material are mixed and subjected to magnetic separation and separation in a magnetic separator to obtain metal material and aggregate; In step (1), the mass ratio of the stock garbage to the powder is 100:0.07-0.09, and the powder is prepared by mixing sodium carboxymethyl cellulose and micropowder silica gel at a mass ratio of 2.5-3.0:1; In step (4), the pretreatment is to stir and mix the first oversize material and the second oversize material with vegetable oil respectively.

2. The method for screening and reducing stock waste according to claim 1, characterized in that: In step (2), the aperture of the first drum screen is 55-60 mm.

3. The method for screening and reducing stock waste according to claim 1, characterized in that: In step (3), the mass ratio of the first undersize material to the fine sand is 100:0.05-0.

08.

4. A method for screening and reducing stock waste according to claim 1 or 3, characterized in that: In step (3), the fine sand is quartz sand or natural river sand, or a combination of the two, and the particle size of the fine sand is 6-7 mm.

5. The method for screening and reducing stock waste according to claim 1, characterized in that: In step (3), the aperture of the second drum screen is 28-30 mm.

6. The method for screening and reducing stock waste according to claim 1, characterized in that: After step (3), the method further includes preparing the second undersize material obtained in step (3) into humus soil.

7. The method for screening and reducing stock waste according to claim 1, characterized in that: The mass ratio of the first oversize material to the vegetable oil is 300-400:2-3; the mass ratio of the second oversize material to the vegetable oil is 150-200:2-3.

8. The method for screening and reducing stock waste according to claim 1, characterized in that: The vegetable oil is a combination of one or more of rapeseed oil, palm oil, soybean oil and peanut oil.