Saline-alkali soil repairing agent and preparation method thereof
Through the comprehensive utilization of saline-alkali land surface soil, modified organic matter and inorganic coal-based solid waste, combined with hydrothermal reaction and biomass binder, a low-cost saline-alkali land repair agent was prepared, which solved the high cost of saline-alkali land repair agent and heavy metal pollution. The problem of soil structure and improvement effect has significantly improved.
Patent Information
- Application Number
- CN202411263429.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-10
- Publication Date
- 2024-12-13
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The existing saline-alkali land repair agents are costly and have heavy metal pollution problems, and the improvement effect is limited, especially in the arid and rainy areas in the northwest, with fewer methods.
Salt-alkali land surface soil, modified organic matter and inorganic coal-based solid waste are prepared through hydrothermal reaction and biomass binder, and combined with anaerobic fermentation and oxalic acid loading technology to achieve the comprehensive utilization of a variety of solid wastes and soil improvement.
It reduces the saline content of saline-alkali soil in saline-alkali soil, improves the soil structure, increases the soil's water and fertilizer retention ability, reduces the risk of heavy metal pollution, and reduces production costs and environmental pollution.
Smart Images
Figure CN119120034A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of saline-alkali land restoration, and in particular to a saline-alkali land restoration agent and a preparation method thereof. Background Art
[0002] Saline-alkali land is very common in my country's Huanghuaihai Plain, Northeast Plain and arid areas in the northwest. Its high salt-alkali content greatly restricts crop growth and is one of the important factors affecting agricultural production and the ecological environment. Existing saline-alkali land treatment technologies include physical methods such as deep plowing and loosening the soil, laying an isolation layer; biological methods such as selecting salt-tolerant crops and cultivating green manure; agricultural system optimization methods such as irrigation and drainage, crop rotation and optimizing the use of chemical fertilizers; application of chemical improvers, etc. In the arid and rainy northwest regions, due to geographical and climatic limitations, there are relatively fewer saline-alkali land restoration methods available. Soil remediation agents and organic fertilizers are a relatively reliable and feasible means of improving saline-alkali land. However, most of the existing soil remediation agents are composts of straw and livestock and poultry manure, and fly ash and tailings are directly used. In addition, they use relatively expensive polymer binders and various microbial agents, which have the problems of high cost, ignoring heavy metal pollution and limited improvement effect.
[0003] Therefore, developing a low-cost, significantly improved saline-alkali land remediation agent and a corresponding production process has important economic and social value. Summary of the invention
[0004] In view of the above problems, the present invention discloses a saline-alkali land remediation agent and a preparation method thereof. The saline-alkali land remediation agent is prepared based on saline-alkali land surface soil, modified organic matter, inorganic coal-based solid waste and biomass binder, providing a new process for the production of saline-alkali land remediation agents and realizing the comprehensive utilization of various coal-based solid wastes and agricultural solid wastes.
[0005] A method for preparing a saline-alkali land repair agent according to the purpose of the present invention comprises the following steps:
[0006] Step 1: adding clean water and saline-alkali surface soil into a desalination pool for leaching and desalination treatment; the remaining desalinated soil after desalination treatment is stored in a desalination soil bin as an inorganic substance; and the produced saline-alkali water is stored in a saline-alkali water pool as a pore-forming promoter for hydrothermal reaction;
[0007] Step 2: add the saline water stored in the saline water pool in step 1 into the hydrothermal reactor through a saline water pump, and at the same time, mix the tail coal slime and gasified ash in a certain proportion and add them into the hydrothermal reactor. Under the promotion of the saline water, the tail coal slime and gasified ash react in the hydrothermal reactor to generate three types of substances: gas phase, liquid phase and solid phase; the liquid phase and solid phase components are separated by a plate and frame filter press to obtain porous tail coal slime and hydrothermal reaction mixed liquid, the porous tail coal slime is stored in a porous tail coal slime bin, and the hydrothermal reaction mixed liquid enters a separator for oil-water separation, and coal tar and hydrothermal reaction liquid are generated after separation, the coal tar is retained for use, and the hydrothermal reaction liquid is stored in a tail liquid pool;
[0008] Step 3: Put the crop straw into a grinder and grind it. The resulting straw grinds and livestock and poultry manure are added to an anaerobic fermentation tank. Anaerobic bacteria are added at the same time. Fermentation gas and a fermentation solid-liquid mixture are obtained through anaerobic fermentation. The fermentation solid-liquid mixture is put into a vibrating arc sieve and solid-liquid separation is performed through the vibrating arc sieve to obtain fermentation solids and fermentation liquid. Part of the fermentation liquid is returned to the anaerobic fermentation tank as a strain.
[0009] Step 4: The gaseous substances generated by the reaction in the hydrothermal reactor and the fermentation gas obtained after anaerobic fermentation are introduced into the absorption tower, and appropriate amounts of clean water and oxalic acid are added at the same time. After purification by the absorption tower, clean fuel gas and nitrogen-containing absorption tower waste liquid are obtained. The clean fuel gas is used for life production, and the nitrogen-containing absorption tower waste liquid is stored in the tail liquid pool;
[0010] Step 5: Add the mixed tail liquid in the tail liquid pool into the first agitator through the mixed tail liquid pump, and add appropriate amount of plant ash, porous tail coal slime in the porous tail coal slime bin, and fermentation solids and part of the fermentation liquid obtained by the vibrating arc screen. After mixing the components in the first agitator, put them into the composting bin for composting to obtain organic matter compost;
[0011] Step 6: Add the crusher discharge obtained after the coal gangue is crushed by the crusher into the vibrating screen, and after screening by the vibrating screen, return the material on the vibrating screen to the crusher for further crushing, and screen out the fine coal gangue as inorganic matter;
[0012] Step seven: put fine-grained coal gangue, desalinated soil, organic matter, calcium-based clay minerals and biomass binder into a second mixer, mix them in the second mixer to obtain a granulation matrix mixture, add it into a granulator, and granulate it in the granulator to obtain a saline-alkali land repair agent.
[0013] Preferably, the proportions of the raw material components are 2-6% of saline-alkali surface soil, 25-35% of tailings slime, 3-7% of gasification ash, 25-35% of livestock and poultry manure, 10-15% of straw, 3-6% of coal gangue, 3-6% of wood ash, 5-9% of calcium-based clay minerals, 1-5% of oxalic acid, and 2-4% of biomass binder.
[0014] Preferably, in step 1, clean water and surface soil from saline-alkali land are added to a desalination tank in a liquid-to-solid ratio of 2:1-5:1 for leaching and desalination treatment.
[0015] Preferably, in step 2, the hydrothermal reactor is a horizontal reactor with continuous airflow or a vertical intermittent reactor, each reaction time is 60-180 min, the pressure of the hydrothermal reactor is 1-3 MPa, and the temperature is 100-950°C.
[0016] Preferably, in step three, the straw is crushed to less than 10 mm; and anaerobic bacteria are added at a ratio of 500-800 g anaerobic bacteria: 1 t of a mixture of straw and livestock and poultry manure.
[0017] Preferably, in step 4, the amount of clean water added is 200-500 times the mass of oxalic acid.
[0018] Preferably, in step six, the aperture of the vibrating screen is 2 mm.
[0019] The invention further discloses a saline-alkali land repair agent prepared by the preparation method.
[0020] Compared with the prior art, the saline-alkali land repair agent and the preparation method thereof disclosed in the present invention have the following advantages:
[0021] (1) The present invention realizes the production of saline-alkali land repair agent with the functions of retaining water and fertilizer, passivating soil heavy metals, and alleviating further salinization of saline-alkali soil through desalination of surface saline-alkali soil, hydrothermal reaction pore formation of tailings sludge, anaerobic fermentation of biomass, oxalic acid loading modification and inorganic compounding, thereby realizing the comprehensive utilization of various coal-based solid wastes and agricultural solid wastes, generating good social and economic benefits, and reducing environmental pollution and environmental pressure.
[0022] (2) The present invention uses residual carbon in low-quality tailings to perform hydrothermal pore formation, and at the same time uses saline water extracted from the salt- and alkali-rich soil on the surface of saline-alkali land to promote the efficiency of hydrothermal pore formation; because the saline ions required for hydrothermal reaction pore formation come from the surface soil of saline-alkali land, on the one hand, the surface soil with the richest salt and alkali in the saline-alkali land is utilized to reduce the salt and alkali content of the soil, and on the other hand, the amount of industrial salt and alkali required for hydrothermal reaction is also reduced.
[0023] (3) The present invention comprehensively treats the waste gas generated in the production process, produces fuel gas, fixes the water-soluble nitrogen in the waste gas, increases the fertility of the saline-alkali soil repair agent, and reduces external emissions.
[0024] (4) The present invention provides minerals and trace elements such as calcium, magnesium, potassium, silicon, and iron required for plant growth in free and fixed forms by hydrothermal reaction and compounding of minerals in tailing coal slime, gasification ash, coal gangue, and plant ash. Fine-grained coal gangue is also beneficial for improving the soil pore structure of saline-alkali land and reducing the deterioration rate of saline-alkali land.
[0025] (5) The porous tailings slime and calcium-based clay minerals in the present invention are both hydrophilic porous materials, which provide hydrophilic pores of various shapes and sizes, improve the pore composition of the saline-alkali land repair agent, and increase the ability of soil ion adsorption and exchange. A large number of hydrophilic surfaces and pores provide adsorption sites for water and nutrients, which helps to retain water and fertilizer in saline-alkali land.
[0026] (6) The present invention loads oxalic acid in a porous matrix, and after repair and application, chelates with heavy metal ions in the soil to passivate the heavy metals in the soil and reduce the risk of uncontrolled heavy metal pollution in the soil. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0028] Figure 1 It is a process flow chart of the present invention.
[0029] Figure 2 This is a diagram showing the connection between a method and equipment for preparing a saline-alkali land repair agent disclosed in the present invention.
[0030] In the figure: 1-surface soil of saline-alkali land; 2-clean water; 3-desalinated soil; 4-saline-alkali water; 5-tail coal slime; 6-gas phase; 7-liquid phase and solid phase; 8-hydrothermal reaction mixture; 9-porous tail coal slime; 10-coal tar; 11-hydrothermal reaction liquid; 12-gasification ash; 13-oxalic acid; 14-fuel gas; 15-nitrogen-containing absorption tower waste liquid; 16-mixed tail liquid; 17-livestock and poultry manure; 18-straw; 19-straw crushed material; 20-fermentation gas; 21-fermentation solid-liquid mixture; 22-fermentation solid; 23-second stage fermentation liquid; 24-first stage fermentation liquid; 25-wood ash; 26-organic mixture; 27-organic mature matter; 28-coal gangue; 29-crusher discharge material; 30-vibrating screen oversize; 31-fine-grained coal gangue; 32-calcium-based clay minerals; 33-biomass binder; 34-granulation matrix mixture; 35-saline-alkali land repair agent; 36-desalting tank; 37-desalting soil bin; 38-saline-alkali water pool; 39-hydrothermal reactor; 40-plate and frame filter press; 41-absorption tower; 42-separator; 43-porous tailings slime bin; 44-tailings pool; 45-crusher; 46-anaerobic fermentation tank; 47-vibrating arc screen; 48-first agitator; 49-composting bin; 50-crusher; 51-vibrating screen; 52-second agitator; 53-granulator; 54-saline-alkali water pump; 55-mixed tailings pump; 56-clear water pool. DETAILED DESCRIPTION
[0031] The specific implementation of the present invention is briefly described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0032] Figure 1 , Figure 2 The preferred embodiments of the present invention are shown and analyzed in detail.
[0033] like Figure 1 , 2 A method for preparing a saline-alkali land repair agent is shown, comprising the following steps:
[0034] Step 1: add the clean water 2 in the clean water tank 56 and the surface soil 1 of the saline-alkali land into the desalination tank 36 at a liquid-to-solid ratio of 4:1 for leaching and desalination treatment. The remaining desalinated soil 3 after desalination treatment is stored in the desalination soil bin 37 as an inorganic matter for standby use. The produced saline-alkali water 4 is stored in the saline-alkali water tank 38 as a pore-forming promoter for the hydrothermal reaction.
[0035] Step 2: The saline water 4 stored in the saline water pool 38 in step 1 is added to the hydrothermal reactor 39 through the saline water pump 54. At the same time, the tail coal slime 5 and the gasified ash 12 are mixed in a certain proportion and added to the hydrothermal reactor 39. Under the promotion of the saline water 4, the tail coal slime 5 and the gasified ash 12 react in the hydrothermal reactor 39 to generate three types of substances: gas phase 6, liquid phase, and solid phase; the liquid phase and solid phase 7 components are separated into solid and liquid by a plate and frame filter press 40 to obtain porous tail coal slime 9 and a hydrothermal reaction mixture 8. The porous tail coal slime 9 is stored in a porous tail coal slime bin 43, and the hydrothermal reaction mixture 8 enters a separator 42 for oil-water separation. After separation, coal tar 10 and a hydrothermal reaction liquid 11 are generated. The coal tar 10 can be used as a coal slime flotation agent or other industrial raw materials. The hydrothermal reaction liquid 11 is stored in a tail liquid pool 44. The hydrothermal reactor 39 is a horizontal reactor with continuous airflow. The reaction time for each reaction is 120 minutes. The pressure of the hydrothermal reactor 39 is 2 MPa and the temperature is 550°C.
[0036] Step 3: Put the crop straw 18 into the pulverizer 45 and grind it to less than 10 mm. The resulting straw grind 19 is added to the anaerobic fermentation tank 46 together with the livestock and poultry manure 17. At the same time, anaerobic bacteria are added at a ratio of 600g anaerobic bacteria: 1t of the mixed material of the straw 18 and the livestock and poultry manure 17. After anaerobic fermentation, fermentation gas 20 and a fermentation solid-liquid mixture 21 are obtained. The fermentation solid-liquid mixture 21 is put into a vibrating arc screen 47, and the solid-liquid separation is performed by the vibrating arc screen 47 to obtain fermentation solids 22 and fermentation liquid. The fermentation liquid is divided into a first-stage fermentation liquid 24 and a second-stage fermentation liquid 23. The first-stage fermentation liquid 24 is returned to the anaerobic fermentation tank 46 as a strain for subsequent production use.
[0037] Step 4: The gas phase 6 generated by the reaction in the hydrothermal reactor 39 and the fermentation gas 20 obtained after anaerobic fermentation are introduced into the absorption tower 41, and clean water 2 and oxalic acid 13 are added at the same time. The amount of clean water 2 added is 300 times the mass of oxalic acid 13. After purification by the absorption tower 41, clean fuel gas 14 and nitrogen-containing absorption tower waste liquid 15 are obtained. The clean fuel gas 14 is used for life production, and the nitrogen-containing absorption tower waste liquid 15 is stored in the tail liquid pool 44.
[0038] Step 5: Add the mixed tail liquid 16 in the tail liquid pool 44 into the first agitator 48 through the mixed tail liquid pump 55, and at the same time add an appropriate amount of wood ash 25, the porous tail coal slime 9 in the porous tail coal slime bin 43, and the fermentation solids 22 and the second-stage fermentation liquid 23 obtained by the vibrating arc screen 47. After the components are mixed and stirred in the first agitator 48, they are put into the composting bin 49 for composting treatment to obtain the organic compost 27.
[0039] Step 6: Add the crusher discharge 29 obtained after the coal gangue 28 is crushed by the crusher 50 into a vibrating screen 51 with a pore size of 2 mm. After screening by the vibrating screen 51, return the vibrating screen oversize 30 to the crusher 50 for further crushing, and screen out the fine coal gangue 31 as inorganic matter.
[0040] Step 7: Put fine coal gangue 31, desalinated soil 3, organic matter 27, calcium-based clay mineral 32 and biomass binder 33 into the second agitator 52, mix them in the second agitator 52 to obtain a granulation matrix mixture 34, add it into the granulator 53, and granulate it in the granulator 53 to obtain a saline-alkali land restoration agent 35. The calcium-based clay mineral 32 is bentonite, kaolin, etc., and the biomass binder 33 is starch, lignin sulfonate, carboxymethyl cellulose salt, tannic acid, pectin, etc.
[0041] In the above method, the proportions of the raw material components are 13% of saline-alkali surface soil, 530% of tailings slime, 126% of gasification ash, 1728% of livestock and poultry manure, 1815% of straw, 285% of coal gangue, 255% of plant ash, 325% of calcium-based clay minerals, 131% of oxalic acid, and 332% of biomass binder.
[0042] The porous tailings slime 9 and hydrothermal reaction liquid 11 produced by hydrothermal reaction are generally alkaline, the wood ash 25 is weakly alkaline, the waste liquid from the absorption tower 41 is weakly acidic, the fermentation solids 22 and the fermentation liquid are weakly acidic. Under comprehensive preparation, the saline-alkali land remediation agent 35 is adjusted to neutral or weakly acidic.
[0043] The above description is only a preferred embodiment of the present invention and does not impose any form of limitation on the present invention. Any simple modification, change and modification made to the above embodiment based on the technical essence of the present invention, such as adding or reducing water pumps, improving dehydration equipment, modifying the aperture of the vibrating screen, etc., are all within the scope of the technical solution of the present invention.
Claims
1. A method for preparing a saline-alkali land repair agent, characterized in that: The following steps are involved: Step 1: adding clean water (2) and saline-alkali surface soil (1) into a desalination pool (36) for leaching and desalination treatment; the remaining desalinated soil (3) after the desalination treatment is stored in a desalination soil bin (37) as an inorganic substance; and the produced saline-alkali water (4) is stored in a saline-alkali water pool (38) as a pore-forming promoter for a hydrothermal reaction; Step 2: The saline water (4) stored in the saline water pool (38) in step 1 is added to the hydrothermal reactor (39) through the saline water pump (54), and the tail coal slime (5) and the gasified ash (12) are mixed in a certain proportion and added to the hydrothermal reactor (39). Under the promotion of the saline water (4), the tail coal slime (5) and the gasified ash (12) react in the hydrothermal reactor (39) to generate three types of substances: gas phase (6), liquid phase, and solid phase; The liquid phase and the solid phase (7) components are separated into a porous tail coal slime (9) and a hydrothermal reaction mixture (8) by a plate and frame filter press (40). The porous tail coal slime (9) is stored in a porous tail coal slime bin (43). The hydrothermal reaction mixture (8) enters a separator (42) for oil-water separation. After separation, coal tar (10) and a hydrothermal reaction liquid (11) are generated. The coal tar (10) is retained for use, and the hydrothermal reaction liquid (11) is stored in a tail liquid pool (44). Step 3: Put the crop straw (18) into a pulverizer (45) for pulverization, and add the resulting straw pulverizer (19) and livestock and poultry feces (17) into an anaerobic fermentation tank (46), and add anaerobic bacteria at the same time. After anaerobic fermentation, fermentation gas (20) and a fermentation solid-liquid mixture (21) are obtained. The fermentation solid-liquid mixture (21) is put into a vibrating curved screen (47), and solid-liquid separation is performed by the vibrating curved screen (47) to obtain fermentation solid (22) and fermentation liquid, and part of the fermentation liquid is returned to the anaerobic fermentation tank (46) as a strain; Step 4: The gas phase (6) substance generated by the reaction in the hydrothermal reactor (39) and the fermentation gas (20) obtained after anaerobic fermentation are introduced into the absorption tower (41), and appropriate amounts of clean water (2) and oxalic acid (13) are added at the same time. After purification by the absorption tower (41), clean fuel gas (14) and nitrogen-containing absorption tower waste liquid (15) are obtained. The clean fuel gas (14) is used for life production, and the nitrogen-containing absorption tower waste liquid (15) is stored in the tail liquid pool (44); Step 5: Add the mixed tail liquid (16) in the tail liquid pool (44) to the first agitator (48) through the mixed tail liquid pump (55), and at the same time add an appropriate amount of plant ash (25), porous tail coal slime (9) in the porous tail coal slime bin (43), and fermentation solids (22) obtained by the vibrating arc screen (47) and part of the fermentation liquid. After the components are mixed in the first agitator (48), they are placed in the composting bin (49) for composting to obtain organic matter (27); Step 6: Add the crusher discharge (29) obtained after the coal gangue (28) is crushed by the crusher (50) into the vibrating screen (51), and after screening by the vibrating screen (51), return the vibrating screen screen material (30) to the crusher (50) for further crushing, and screen out the fine coal gangue (31) as inorganic matter; Step 7: Place fine-grained coal gangue (31), desalinated soil (3), organic matter (27), calcium-based clay minerals (32) and biomass binder (33) into a second agitator (52), mix them in the second agitator (52) to obtain a granulation matrix mixture (34), add it to a granulator (53), and granulate it in the granulator (53) to obtain a saline-alkali land repair agent (35).
2. The method for preparing a saline-alkali land repair agent according to claim 1, characterized in that: The proportions of the raw material components are as follows: saline-alkali surface soil (1) 2-6%, tailings slime (5) 25-35%, gasification ash (12) 3-7%, livestock and poultry manure (17) 25-35%, straw (18) 10-15%, coal gangue (28) 3-6%, wood ash (25) 3-6%, calcium-based clay minerals (32) 5-9%, oxalic acid (13) 1-5%, and biomass binder (33) 2-4%.
3. The method for preparing a saline-alkali land repair agent according to claim 1, characterized in that: In step 1, clean water (2) and saline-alkali surface soil (1) are added to a desalination tank (36) at a liquid-to-solid ratio of 2:1-5:1 for leaching and desalination treatment.
4. The method for preparing a saline-alkali land repair agent according to claim 1, characterized in that: In step 2, the hydrothermal reactor (39) is a horizontal reactor with continuous airflow or a vertical intermittent reactor, each reaction time is 60-180 min, the pressure of the hydrothermal reactor (39) is 1-3 MPa, and the temperature is 100-950°C.
5. The method for preparing a saline-alkali land repair agent according to claim 1, characterized in that: In step three, the straw (18) is crushed to less than 10 mm; anaerobic bacteria are added in a ratio of 500-800 g anaerobic bacteria: 1 t of the mixture of straw (18) and livestock and poultry excrement (17).
6. The method for preparing a saline-alkali land repair agent according to claim 1, characterized in that: In step 4, the amount of clean water (2) added is 200-500 times the mass of oxalic acid (13).
7. The method for preparing a saline-alkali land repair agent according to claim 1, characterized in that: In step six, the aperture of the vibrating screen (51) is 2 mm.
8. A saline-alkali land repair agent (35) prepared using the preparation method described in claim 1.