Soil-like matrix prepared from solid waste and preparation method thereof

Abstract

The invention discloses a soil-like matrix prepared from solid wastes and a preparation method of the soil-like matrix, and belongs to the field of solid waste resource utilization and agriculture. The soil-like matrix comprises a smoldering product of the solid waste and a flue gas treatment product in the smoldering process of the solid waste. The preparation method comprises the steps that inorganic solid waste and organic solid waste are pretreated and then mixed, open fire is extinguished after the solid waste mixture is ignited, and smoldering combustion is conducted on the mixture by means of oxygen deficit and intermittent blowing-in of air; ash generated in the smoldering combustion process is collected, water is added for stirring, slurry is obtained and used for adsorbing flue gas generated in the smoldering combustion process, and a flue gas treatment product is obtained; after smoldering combustion is completed, a smoldering product and a flue gas treatment product are fully mixed, and the soil-like matrix is obtained. The method for preparing the soil-like matrix from the solid waste is simple, local materials are used, in-situ treatment is achieved, high-added-value resource utilization of the solid waste can be achieved, cyclic utilization of resources is achieved, and the method has wide development prospects.

Description

Technical Field

[0001] The invention belongs to the field of solid waste resource utilization and agriculture, and specifically relates to a soil-like matrix prepared from solid waste and a preparation method thereof. Background Art

[0002] In today's society, inorganic solid waste treatment is of vital necessity. With the acceleration of industrialization and the increasing frequency of human activities, a large amount of inorganic solid waste such as tailings and industrial waste is constantly generated. If not properly handled, these inorganic solid wastes will occupy a large amount of land resources, affect the ecological landscape, and cause waste and destruction of land resources. At the same time, some inorganic solid wastes may contain harmful substances such as heavy metals. If they are randomly piled up or improperly disposed of, they will infiltrate into the soil and water bodies under the action of rainwater erosion, causing serious environmental pollution problems and posing a huge threat to the ecosystem and human health. In addition, effective treatment and resource utilization of inorganic solid waste can save natural resources, reduce dependence on primary resources, promote the development of circular economy, and achieve sustainable development of economy, society and environment. At present, the main treatment methods of inorganic solid waste are concentrated in building materials, filling, roadbed materials and harmless storage, but due to the sluggish building materials market and high costs, large quantities of inorganic solid waste cannot be treated, so new inorganic solid waste batch treatment technology needs to be studied.

[0003] On the other hand, the resource processing of organic solid waste is extremely necessary. With the rapid economic development and the continuous growth of population, various types of organic solid waste such as kitchen waste, agricultural waste, sludge, etc. are generated in large quantities. If not properly treated, these organic solid wastes will not only occupy a large amount of land for stacking, but also release unpleasant odors and harmful gases due to corruption and fermentation, polluting the air environment. At the same time, harmful substances in organic solid waste may penetrate into the soil and water, destroy the ecological balance, and threaten human health. At present, the main methods of organic solid waste treatment are composting, landfill, incineration and pyrolysis, all of which are ex situ treatment technologies with high treatment costs, low value, and easy to cause secondary pollution.

[0004] So far, there are no reports on the use of organic and inorganic solid wastes to prepare soil-like matrices. How to combine the resource utilization of organic and inorganic solid wastes, while solving the problems caused by adverse effects in the existing agricultural development process and avoiding high costs and secondary pollution during the utilization process is a new challenge facing researchers. Summary of the invention

[0005] The technical problem to be solved by the present invention is that the existing organic solid waste and inorganic solid waste have high treatment costs, are difficult to promote and apply, are prone to secondary pollution, have small resource processing scales, and have complex processing processes.

[0006] The technical solution adopted by the present invention to solve its technical problem is:

[0007] In a first aspect, the present invention provides a soil-like matrix prepared using solid waste, including smoldering products of the solid waste and flue gas treatment products during the smoldering of the solid waste.

[0008] In the above-mentioned soil matrix, the carbon content of the smoldering products of the solid waste is greater than 35%, the N content is 0.5% to 0.8%, the P content is 0.5% to 1.2%, the K content is 2.8% to 3.2%, the water retention rate is greater than 80%, and the density is 3.5 to 4.1 g / cm 3 .

[0009] In the above-mentioned soil matrix, the carbon content of the flue gas treatment product during the smoldering of the solid waste is greater than 40%, the N content is 0.9% to 1.8%, the P content is 1.1% to 2.2%, and the K content is 3.4% to 4.2%. The water retention rate is greater than 85%, and the density is 4.5 to 4.9 g / cm 3 .

[0010] In the above-mentioned soil-like matrix, the solid waste is inorganic solid waste and organic solid waste.

[0011] Furthermore, the inorganic solid waste is at least one of tin tailings, phosphogypsum, flue gas desulfurization gypsum, titanium gypsum, phosphate tailings, vanadium-titanium magnetite tailings, iron tailings, copper tailings, lead-zinc tailings, coal gangue, fly ash, steel slag, and antimony tailings.

[0012] Furthermore, the organic solid waste is at least one of domestic sludge, kitchen waste, agricultural straw, and dead branches and leaves.

[0013] In a second aspect, the present invention provides a method for preparing the above-mentioned soil-like matrix:

[0014] Pre-treating inorganic solid waste and organic solid waste, mixing them, igniting the solid waste mixture and then extinguishing the open flame, using the lack of oxygen and intermittent blowing of air to make the mixture smolder, and obtaining smoldering products and ash;

[0015] Collect ash produced during the smoldering combustion process, add water and stir to obtain a slurry, which is used to adsorb and treat the flue gas produced during the smoldering combustion process to obtain a flue gas treatment product;

[0016] After the smoldering combustion is completed, the smoldering products and the flue gas treatment products are fully mixed to obtain a soil-like matrix.

[0017] Furthermore, in the above preparation method, the pretreatment of the inorganic solid waste and the organic solid waste is: drying the inorganic solid waste and the organic solid waste and then crushing them respectively.

[0018] Furthermore, the mixture is dried at 60-90° C. to a moisture content of less than 5%, and then crushed to a particle size of less than 50 mesh.

[0019] Furthermore, in the above preparation method, the inorganic solid waste and the organic solid waste are mixed in a mass ratio of 1:2 to 5.

[0020] Furthermore, in the above preparation method, igniting the solid waste mixture and then extinguishing the open flame is: igniting the solid waste mixture at 200-500° C., burning the open flame for 1-5 minutes, and then extinguishing the open flame.

[0021] Furthermore, in the above preparation method, 5% to 20% of water is added to the ash and stirred to obtain slurry.

[0022] Furthermore, in the above preparation method, when the smoke generated during the smoldering process is adsorbed and treated, the amount of slurry used is 2-5 kg / cm 3 .

[0023] The beneficial effects of the present invention are as follows: in the preparation method of the soil-like matrix of the present invention, the lignin, cellulose and other components contained in the pre-treated organic solid waste are extremely easy to ignite, and the solid waste mixture is ignited and then the open flame is extinguished to smolder. During the smoldering process, the fluffy solid waste will introduce a trace amount of air to keep the smoldering from extinguishing. The high temperature generated by the smoldering will continue to kill the pests in the solid waste, the heavy metals in the inorganic solid waste will be solidified and stabilized at high temperature, and the plant-usable elements will be released, providing the necessary element composition for the soil-like matrix; at the same time, the biochar generated by the smoldering of the organic solid waste provides a porous carbon structure for the soil-like matrix, improves the water retention rate of the soil-like matrix, and provides a storage place for the attachment of microorganisms and the slow release of nutrients.

[0024] From the perspective of environmental protection: this method is not only used for the treatment of large quantities of inorganic and organic solid wastes, but also the smoke generated during the smoldering process is treated with smoldering ash. The ash already has soil properties, which mainly exhibits weak alkaline properties. Under the condition of a certain moisture content, the aggregated soil colloids will be able to treat particulate matter, NOx, SO 2 , VOCs, CO and CO 2 Adsorption is carried out to achieve the interception of nutrients in the flue gas, and at the same time the smoldering flue gas is purified. The weakly acidic smoldering gas and the weakly alkaline smoldering product ash react to achieve a neutralization effect, further ensuring the effect of the soil-like matrix.

[0025] From the perspective of sustainable development: This method has important strategic significance. On the one hand, this method can realize the resource utilization of organic and inorganic solid wastes and reduce pollution to the environment. On the other hand, this method provides a new source of healthy soil matrix, realizing the true meaning of turning waste into treasure, providing nutrients for agricultural production, and realizing the recycling of resources. In addition, this method can also drive the development of related industries, such as solid waste treatment industry and agriculture, and create more employment opportunities and economic benefits.

[0026] The method for preparing a soil-like matrix from solid waste is simple, uses local materials, and performs in-situ processing, can achieve high-value-added resource utilization of solid waste, realize the recycling of resources, and has broad development prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic flow chart of a method for preparing a soil-like matrix using solid waste according to the present invention;

[0028] Figure 2 To implement Case 1, phosphogypsum and domestic sewage sludge were used to prepare soil-like matrix using smoldering treatment technology;

[0029] Figure 3 To implement Case 2, vanadium-titanium magnetite tailings and agricultural straw were treated with smoldering technology to prepare a soil-like matrix;

[0030] Figure 4 In order to implement Case 3, coal gangue and litter were treated with smoldering technology to prepare a soil-like matrix. DETAILED DESCRIPTION

[0031] The technical solution of the present invention can be specifically implemented in the following manner.

[0032] A method for preparing a soil-like matrix using solid waste, the specific process is as follows Figure 1 As shown, the specific steps are as follows:

[0033] A. Dry the organic solid waste and inorganic solid waste at 60°C to 90°C to reduce the moisture content to below 5%, and then crush them to select solid waste with a particle size of less than 50 mesh;

[0034] B. Compounding the organic solid waste and the inorganic solid waste treated in step A at a mass ratio of 2 to 5:1, and fully mixing to obtain a solid waste mixture;

[0035] C. Ignite the compounded solid waste mixture at an open flame temperature of 200-500°C, extinguish the open flame after burning for 1-5 minutes, and then burn without open flame (smoldering) in an environment of self-deficient oxygen and intermittent oxygen blowing;

[0036] D. Collect the ash produced during the smoldering process, add 5% to 20% water and stir to form a wet mixture (slurry), which is used to purify the flue gas during the smoldering process. The usage is 2 to 5 kg / cm 3 ;

[0037] E. After the smoldering is completed, the smoldering products and the flue gas treatment products are fully mixed to obtain a soil-like matrix.

[0038] The technical solution and effects of the present invention are further illustrated below through practical examples.

[0039] Example

[0040] 1. Using solid waste to prepare soil-like matrix

[0041] (1) Pretreatment of organic solid waste and inorganic solid waste: Dry the organic solid waste and inorganic solid waste at 60°C to 90°C to reduce the moisture content to less than 5%, crush them, and screen out solid waste with a particle size of less than 50 mesh; compound the organic solid waste and inorganic solid waste at a mass ratio of 2 to 5:1 and mix them thoroughly; the specific process is shown in Table 1.

[0042] Table 1 Pretreatment process

[0043] Example 1 Example 2 Example 3 Inorganic solid waste Phosphogypsum Vanadium Titanium Magnetite Tailings Coal Gangue Drying temperature 60℃ 90℃ 80℃ Moisture content 5％ 3％ 2％ Solid waste particle size 50 mesh 100 mesh 200 mesh Organic solid waste Domestic sludge Agricultural straw Dead branches and leaves Drying temperature 90℃ 70℃ 60℃ Moisture content 2％ 3％ 5％ Solid waste particle size 200 mesh 100 mesh 50 mesh Ratio of organic and inorganic solid waste 2:1 3:1 5:1

[0044] (2) Smoldering: Ignite the compounded organic and inorganic solid wastes at an open flame temperature of 200-500°C, extinguish the open flame after 1-5 minutes, and use the oxygen-deficient and intermittent oxygen-blowing environment to burn without open flames. The specific process is shown in Table 2.

[0045] Table 2 Smoldering parameters

[0046] Ignition temperature Ignition time Intermittent oxygenation flow Example 1 200℃ 5min 1 minute every 30 minutes <![CDATA[0.1m 3 / s]]> Example 2 500℃ 3min 2 minutes every 40 minutes <![CDATA[0.9m 3 / s]]> Example 3 300℃ 1min 0.5min every 35min <![CDATA[0.5m 3 / s]]>

[0047] (3) Smoldering flue gas treatment: Add 5% to 20% water to the ash produced by smoldering and stir to form a wet mixture, which is used to purify the flue gas during the smoldering process. The usage amount is 2 to 5 kg / cm 3 ; The solid waste after smoldering treatment and the ash after flue gas treatment are fully mixed to obtain a soil-like matrix; the specific process is shown in Table 3.

[0048] Table 3 Smoldering flue gas treatment parameters

[0049] Example 1 Example 2 Example 3 Ash water content 5％ 20％ 10％ Usage <![CDATA[2kg / cm 3 ]]> <![CDATA[5kg / cm 3 ]]> <![CDATA[3kg / cm 3 ]]>

[0050] 2. Performance test of soil-like matrix

[0051] Example 1 Performance test results of preparing soil-like matrix using smoldering treatment technology of phosphogypsum Figure 2As shown in the figure, it can be seen that the carbon content in the smoldering product is 35%, the water retention rate is 80%, and the soil density is 3.5g / cm 3 , N content is 0.5%, P content is 0.5%, K content is 2.8%; the carbon content in the flue gas treatment product is 40%, the water retention rate is 85%, and the soil density is 4.5g / cm 3 , N content is 0.9%, P content is 1.1%, and K content is 3.4%, all of which meet the healthy soil standards.

[0052] Example 2 Performance test results of preparing soil-like matrix using smoldering treatment technology of vanadium-titanium magnetite tailings Figure 3 As shown in the figure, the carbon content in the smoldering product is 38%, the water retention rate is 82%, and the soil density is 3.9g / cm 3 , N content is 0.7%, P content is 1%, K content is 3.1%; the carbon content in the flue gas treatment product is 42%, the water retention rate is 89%, and the soil density is 4.9g / cm 3 , N content is 1.5%, P content is 1.9%, and K content is 3.9%; all meet the healthy soil standards.

[0053] Example 3 Performance test results of preparing soil-like matrix using coal gangue smoldering treatment technology Figure 4 As shown in the figure, the carbon content in the smoldering product is 40%, the water retention rate is 85%, and the soil density is 4.1g / cm 3 , N content is 0.8%, P content is 1.2%, K content is 3.2%; the carbon content in the flue gas treatment product is 45%, the water retention rate is 90%, and the soil density is 4.5g / cm 3 , N content is 1.8%, P content is 2.2%, and K content is 4.2%; all meet the healthy soil standards.

Claims

1. A soil-like matrix prepared from solid waste, characterized in that: Including smoldering products of solid waste and flue gas treatment products during the smoldering of solid waste; The smoldering product of the solid waste has a carbon content of more than 35%, a N content of 0.5% to 0.8%, a P content of 0.5% to 1.2%, a K content of 2.8% to 3.2%, a water retention rate of more than 80%, and a density of 3.5 to 4.1 g / cm 3 ; The carbon content of the flue gas treatment product during the smoldering of the solid waste is greater than 40%, the N content is 0.9% to 1.8%, the P content is 1.1% to 2.2%, the K content is 3.4% to 4.2%, the water retention rate is greater than 85%, and the density is 4.5 to 4.9 g / cm 3 ; The solid waste includes inorganic solid waste and organic solid waste.

2. The soil-like matrix prepared from solid waste according to claim 1, characterized in that: The inorganic solid waste is at least one of tin tailings, phosphogypsum, flue gas desulfurization gypsum, titanium gypsum, phosphate tailings, vanadium-titanium magnetite tailings, iron tailings, copper tailings, lead-zinc tailings, coal gangue, fly ash, steel slag, and antimony tailings.

3. The soil-like matrix prepared from solid waste according to claim 1, characterized in that: The organic solid waste is at least one of domestic sludge, kitchen waste, agricultural straw, and dead branches and leaves.

4. The method for preparing a soil-like matrix according to any one of claims 1 to 3, characterized in that: Pre-treating inorganic solid waste and organic solid waste, mixing them, igniting the solid waste mixture and then extinguishing the open flame, using the lack of oxygen and intermittent blowing of air to make the mixture smolder, and obtaining smoldering products and ash; collecting the ash produced during the smoldering combustion process, adding water and stirring to obtain a slurry, and using it to absorb and treat the flue gas produced during the smoldering process to obtain a flue gas treatment product; After the smoldering combustion is completed, the smoldering products and the flue gas treatment products are fully mixed to obtain a soil-like matrix.

5. The method for preparing the soil-like matrix according to claim 4, characterized in that: The pretreatment of inorganic solid waste and organic solid waste is as follows: drying and crushing the inorganic solid waste and organic solid waste respectively.

6. The method for preparing the soil-like matrix according to claim 5, characterized in that: Dry at 60-90°C to a moisture content of <5%, and then crush to a particle size of <50 mesh.

7. The method for preparing a soil-like matrix according to claim 4, characterized in that: Inorganic solid waste and organic solid waste are mixed in a mass ratio of 1:2 to 5.

8. The method for preparing a soil-like matrix according to claim 4, characterized in that: After igniting the solid waste mixture, the open flame is extinguished: ignite the solid waste mixture at 200-500°C, and extinguish the open flame after burning for 1-5 minutes.

9. The method for preparing a soil-like matrix according to claim 4, characterized in that: 5% to 20% of water is added to the ash and stirred to obtain slurry.

10. The method for preparing a soil-like matrix according to claim 4, characterized in that: When the smoke generated during the smoldering process is adsorbed, the amount of slurry used is 2-5 kg / cm 3 .

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