A method for preparing high-performance artificial wetland filler using tailings

Abstract

The invention discloses a preparation method of high-performance artificial wetland filler by using tailings, belongs to the technical field of wetland fillers, and comprises the following steps: grinding tailings, preparing sawdust powder, preparing binder aqueous solution, mixing, granulating, drying and roasting. The invention uses tailings, sawdust powder, water, polyvinyl alcohol or sodium carboxymethyl cellulose, aluminum hydroxide and the like as main raw materials, and prepares tailings artificial wetland filler through grinding, mixing, granulating, drying, roasting and the like processes. The invention has the advantages of low preparation cost, high hydraulic conductivity, large specific surface area, relatively uniform pore distribution, fast organic matter accumulation speed, high ability to remove phosphorus in water and the like, is suitable for various artificial wetland water treatment processes, and has good development prospects and practical significance.

Description

Technical Field

[0001] The invention belongs to the technical field of artificial wetland fillers, and in particular relates to a method for preparing high-performance artificial wetland fillers by utilizing tailings. Background Art

[0002] Tailings are solid waste discharged during the mining process.

[0003] At present, the comprehensive utilization of tailings at home and abroad mainly includes: production of building materials (cement, building ceramics, bricks and tiles, refractory materials, lightweight aggregates, unburned bricks, microcrystalline glass, wood-plastic panels, etc.), glass products, production of polymer fillers, recovery of valuable metals, production of mineral fertilizers, soil reclamation improvers, covering soil to create fields, and backfilling of mines and mine goafs. Using tailings as mine backfill seems to be the best disposal method, but they still need to be piled up in tailings ponds during the mineral development cycle, and not all tailings can be used as backfill. In addition, tailings as backfill need to go through screening, adding binders and stirring, which not only increases the backfill cost, but also reduces the backfill efficiency. Several other disposal methods have high requirements on tailings composition and limited consumption capacity. There is still a long way to go to solve the tailings problem.

[0004] Wetland is an important and multifunctional ecosystem. It plays an extremely important role in the global ecological balance and is known as the "kidney of the earth". Artificial wetland is a wastewater treatment system similar to natural wetlands that is artificially built and operated with reference to naturally formed wetlands. It is an emerging sewage treatment process in recent years. It has the characteristics of low investment and operation costs, simple system maintenance, stable treatment effect, etc., integrating environmental landscape benefits and economic benefits. Artificial wetland water treatment technology has developed rapidly in my country due to its obvious advantages, and has been widely used in the process of urban domestic sewage treatment. Artificial wetlands are composed of fillers, plants, water distribution systems and other units. The fillers are the matrix and carrier of artificial wetlands. They are generally composed of one or more of the media such as soil, fine sand, coarse sand, gravel, natural crushed stone or other rock mineral materials. They not only provide support for wetland plants, but also provide nutrition for plants and microorganisms. The physical and chemical properties of the fillers play a very important role in the smooth start-up of the wetland and the sewage treatment effect.

[0005] At present, the fillers used in artificial wetland systems have problems such as high cost, low hydraulic conductivity, small specific surface area, and slow accumulation of organic matter. Therefore, improving the performance of artificial wetland fillers and reducing the cost of fillers are of great significance to the promotion of artificial wetland water treatment technology.

[0006] Therefore, in order to address the problems of tailings resource utilization and existing artificial wetland fillers such as high price, low hydraulic conductivity, small specific surface area, and slow accumulation of nutrients such as organic matter, the present invention proposes a preparation method for high-performance artificial wetland fillers using tailings, which opens up a new path for the comprehensive utilization of tailings. Compared with other tailings utilization methods, it has the advantages of low requirements on tailings types and components, simple preparation process, etc. Summary of the invention

[0007] The technical problem to be solved by the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a method for preparing high-performance artificial wetland filler using tailings, which has low preparation cost, high hydraulic conductivity, large specific surface area, relatively uniform pore distribution, and high ability to remove phosphorus in water.

[0008] The technical solution adopted to solve the above technical problems is: a method for preparing high-performance artificial wetland filler using tailings comprises the following steps:

[0009] S1, grinding tailings: adding clean water to the tailings for washing, placing them in a drying oven at a temperature of 110±5°C for 2 hours, grinding the dried tailings, and sieving them through a standard sieve to obtain tailings;

[0010] S2, preparing sawdust powder: placing the sawdust powder in a drying oven at a temperature of 110±5° C. for 2 hours, and sieving through a standard sieve to obtain sawdust powder;

[0011] S3, preparing an aqueous binder solution: adding 1 to 7 g of a binder to 99 to 93 mL of distilled water, stirring, heating to a temperature of 85 to 95° C., and then keeping the temperature for 2 hours to allow the binder to completely swell, and cooling to obtain an aqueous binder solution;

[0012] S4, mixing: weigh 100g of tailings, 18-42g of sawdust powder, 5-10g of aluminum hydroxide, and 28-61g of 1%-7% binder aqueous solution, mix them evenly into mud, and make filler mud embryos;

[0013] S5, granulation, drying and calcination: the filler mud embryo is made into spherical particles and then dried, and then placed in a muffle furnace at a temperature of 1000-1300°C for sintering for 20min-1h, and high-performance tailings artificial wetland filler is obtained after cooling in the furnace.

[0014] Furthermore, the volume ratio of tailings to clean water in step S1 is 1:2.

[0015] Furthermore, the standard sieves in step S1 are 200 mesh and 400 mesh respectively, and the tailings with a particle size of 200-400 mesh are retained.

[0016] Furthermore, the standard sieves in step S1 are 250 mesh and 300 mesh respectively, and the tailings with a particle size of 250-300 mesh are retained.

[0017] Furthermore, the standard sieves in step S1 are 300 mesh and 350 mesh respectively, and the tailings with a particle size of 300-350 mesh are retained.

[0018] Furthermore, in step S2, the standard sieves are 200 mesh and 400 mesh respectively, and the sawdust powder with a particle size of 200-400 mesh is retained.

[0019] Furthermore, in step S2, the standard sieves are 250 mesh and 300 mesh respectively, and the sawdust powder with a particle size of 250-300 mesh is retained.

[0020] Furthermore, in step S2, the standard sieves are 300 mesh and 350 mesh respectively, and the sawdust powder with a particle size of 300-350 mesh is retained.

[0021] Furthermore, in step S3, the binder is polyvinyl alcohol or sodium carboxymethyl cellulose.

[0022] Furthermore, in step S5, the diameter of the spherical particles is 1 to 3 cm.

[0023] The beneficial effects of the present invention are as follows: (1) The present invention adopts tailings, sawdust powder, water, polyvinyl alcohol or sodium carboxymethyl cellulose, aluminum hydroxide and the like as main raw materials, and prepares tailings artificial wetland filler through processes such as grinding, mixing, granulating, drying and roasting. The tailings artificial wetland filler has the advantages of low preparation cost, high hydraulic conductivity, large specific surface area, relatively uniform pore distribution, and high ability to remove phosphorus in water. The tailings artificial wetland filler is suitable for various artificial wetland water treatment processes and has good development prospects and practical significance.

[0024] (2) The present invention uses tailings waste as the main raw material, which has the advantages of low preparation cost, low requirements on the type and composition of tailings, and simple preparation process. Various tailings such as iron tailings, molybdenum tailings, lead-zinc tailings, etc. can be used to achieve the purpose of "treating waste with waste". DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0026] Example 1

[0027] This embodiment uses iron tailings, and the preparation method of high-performance artificial wetland filler using tailings includes the following steps:

[0028] S1, grinding tailings: add clean water to the iron tailings for three times, with the volume ratio of tailings to clean water being 1:2, and put them into a drying oven at a temperature of 110±5℃ for 2 hours. Grind the dried tailings with a ball mill, and sieve them with 200 mesh and 400 mesh standard sieves in turn, and retain tailings with a particle size of 200-400 mesh.

[0029] S2, preparing sawdust powder: placing the sawdust powder in a drying oven at a temperature of 110±5° C. for 2 hours, sieving using 200-mesh and 400-mesh standard sieves in turn, and retaining sawdust powder with a particle size of 200-400 mesh.

[0030] Sawdust powder can be purchased or you can clean the wood and crush it with a crusher.

[0031] S3, aqueous binder solution: add 5 g of polyvinyl alcohol to 99 mL of distilled water, stir, heat to 85-95°C and keep warm for 2 hours to allow the polyvinyl alcohol to completely swell, and cool to obtain a polyvinyl alcohol aqueous solution.

[0032] S4, mixing: 100 g of iron tailings, 26.6 g of sawdust powder, 8 g of aluminum hydroxide, and 46.2 g of 5% polyvinyl alcohol aqueous solution are weighed respectively, and mixed evenly into mud to make a filler mud embryo.

[0033] Among them, sawdust powder is a pore-forming agent, which has a pore-forming effect and can improve the permeability coefficient of the filler. Polyvinyl alcohol solution is a binder and has a microporous effect. The role of aluminum hydroxide is to strengthen the phosphate adsorption effect and small pores, which can improve the filler's adsorption effect on pollutants. Therefore, due to the different molecular sizes of sawdust powder, polyvinyl alcohol solution, and aluminum hydroxide, the pore sizes of the pores are also different. The order of pores from large to small is: sawdust powder, polyvinyl alcohol solution, aluminum hydroxide.

[0034] S5, granulation, drying and roasting: Use a pellet machine to make the filler mud embryo into spherical particles with a diameter of 1 cm and then dry them. Put them into a muffle furnace at a temperature of 1180°C and sinter them for 30 minutes. After cooling in the furnace, gray spherical iron tailings artificial wetland filler is obtained.

[0035] The physical and chemical properties of the iron tailings artificial wetland filler were measured. The results showed that it was a gray sphere with a diameter of about 1 cm and a porosity of 48.26%. The specific surface area was 133.79 m 2 / g, the pores are relatively transparent and evenly distributed, and the adsorption capacity of phosphate in water is 56.44 mg / g. The prepared filler is subjected to a static adsorption test, and the results are shown in Table 1.

[0036] Table 1 Treatment effect of 50mg / L phosphate wastewater

[0037]

[0038] Example 2

[0039] This embodiment uses iron tailings, and the preparation method of high-performance artificial wetland filler using tailings includes the following steps:

[0040] S1, grinding tailings: add clean water to the iron tailings for three times, with the volume ratio of tailings to clean water being 1:2, and put them into a drying oven at a temperature of 110±5℃ for 2 hours. Grind the dried tailings with a ball mill, and sieve them with 250-mesh and 300-mesh standard sieves in turn, and retain tailings with a particle size of 250-300 mesh.

[0041] S2, preparing sawdust powder: placing the sawdust powder in a drying oven at a temperature of 110±5° C. and drying for 2 hours, sieving using 250-mesh and 300-mesh standard sieves in turn, and retaining sawdust powder with a particle size of 250-300 mesh.

[0042] Sawdust powder can be purchased or you can clean the wood and crush it with a crusher.

[0043] S3, aqueous binder solution: add 4 g of polyvinyl alcohol to 96 mL of distilled water, stir, heat to 85-95°C and keep warm for 2 hours to allow the polyvinyl alcohol to completely swell, and cool to obtain a polyvinyl alcohol aqueous solution.

[0044] S4, mixing: 100 g of iron tailings, 28.1 g of sawdust powder, 7.5 g of aluminum hydroxide, and 46.5 g of 4% polyvinyl alcohol aqueous solution were weighed respectively, and mixed evenly into mud to prepare filler mud embryos.

[0045] Among them, sawdust powder is a pore-forming agent, which has a pore-forming effect and can improve the permeability coefficient of the filler. Polyvinyl alcohol solution is a binder and has a microporous effect. The role of aluminum hydroxide is to strengthen the phosphate adsorption effect and small pores, which can improve the filler's adsorption effect on pollutants. Therefore, due to the different molecular sizes of sawdust powder, polyvinyl alcohol solution, and aluminum hydroxide, the pore sizes of the pores are also different. The order of pores from large to small is: sawdust powder, polyvinyl alcohol solution, aluminum hydroxide.

[0046] S5, granulation, drying and roasting: the filler mud embryos are made into spherical particles with a diameter of 1.5 cm by a pellet rolling machine, and then dried in the air, and sintered in a muffle furnace at a temperature of 1150°C for 40 minutes. After cooling in the furnace, gray spherical iron tailings artificial wetland filler is obtained.

[0047] The physical and chemical properties of the iron tailings artificial wetland filler were measured. The results showed that it was a gray sphere with a diameter of about 1.5 cm and a porosity of 49.49%. The specific surface area was 125.81 m 2 / g, the pores are relatively transparent and evenly distributed, and the adsorption capacity of phosphate in water is 50.06 mg / g. The prepared filler is subjected to a static adsorption test, and the results are shown in Table 2.

[0048] Table 2 Treatment effect of 50mg / L phosphate wastewater

[0049]

[0050] Example 3

[0051] This embodiment uses molybdenum tailings, and the preparation method of high-performance artificial wetland filler using tailings includes the following steps:

[0052] S1, grinding tailings: add clean water to the molybdenum tailings for three times, with the volume ratio of tailings to clean water being 1:2, put it into a drying oven at a temperature of 110±5℃ and dry it for 2 hours, grind the dried tailings with a ball mill, and sieve them with 300 mesh and 350 mesh standard sieves in turn, and retain the tailings with a particle size of 300-350 mesh.

[0053] S2, preparing sawdust powder: placing the sawdust powder in a drying oven at a temperature of 110±5° C. and drying for 2 hours, sieving using 300-mesh and 350-mesh standard sieves in turn, and retaining sawdust powder with a particle size of 300-350 mesh.

[0054] Sawdust powder can be purchased or you can clean the wood and crush it with a crusher.

[0055] S3, prepare the binder aqueous solution: add 5.5g of sodium carboxymethyl cellulose to 94.5mL of distilled water, stir, heat to 85-95°C and keep warm for 2 hours to make the sodium carboxymethyl cellulose completely swell, and cool to obtain the sodium carboxymethyl cellulose aqueous solution.

[0056] S4, mixing: weigh 100g of molybdenum tailings, 25g of sawdust powder, 9g of aluminum hydroxide, and 46.5g of 5.5% sodium carboxymethyl cellulose aqueous solution respectively, mix them evenly into mud, and then make a filler mud embryo.

[0057] Among them, sawdust powder is a pore-forming agent, which has a pore-forming effect and can improve the permeability coefficient of the filler. Sodium carboxymethyl cellulose is a binder and has a microporous effect. The role of aluminum hydroxide is to strengthen the phosphate adsorption effect and small pores, which can improve the filler's adsorption effect on pollutants. Therefore, due to the different molecular sizes of sawdust powder, sodium carboxymethyl cellulose solution, and aluminum hydroxide, the pore sizes of the pores are also different. The order of pores from large to small is: sawdust powder, sodium carboxymethyl cellulose, and aluminum hydroxide.

[0058] S5, granulation, drying and calcination: Use a pelletizing machine to make the filler mud embryo into spherical particles with a diameter of 1 cm and then dry them. Put them into a muffle furnace at a temperature of 1150°C and sinter them for 40 minutes. After cooling in the furnace, gray spherical molybdenum tailings artificial wetland filler is obtained.

[0059] The physical and chemical properties of the molybdenum tailings artificial wetland filler were measured. The results showed that it was a gray sphere with a diameter of about 1 cm and a porosity of 46.81%. The specific surface area was 189.33 m 2 / g, the pores are relatively transparent and evenly distributed, and the adsorption capacity of phosphate in water is 16.19 mg / g. The prepared filler is subjected to a static adsorption test, and the results are shown in Table 3.

[0060] Table 3 Treatment effect of 50mg / L phosphate wastewater

[0061]

[0062] Example 4

[0063] This embodiment uses molybdenum tailings, and the preparation method of high-performance artificial wetland filler using tailings includes the following steps:

[0064] S1, grinding tailings: add clean water to the molybdenum tailings for three times, with the volume ratio of tailings to clean water being 1:2, put it into a drying oven at a temperature of 110±5℃ and dry it for 2 hours, grind the dried tailings with a ball mill, and sieve them with 200 mesh and 250 mesh standard sieves in turn, and retain the tailings with a particle size of 200-250 mesh.

[0065] S2, preparing sawdust powder: placing the sawdust powder in a drying oven at a temperature of 110±5° C. and drying for 2 hours, sieving using 200-mesh and 250-mesh standard sieves in turn, and retaining sawdust powder with a particle size of 200-250 mesh.

[0066] Sawdust powder can be purchased or you can clean the wood and crush it with a crusher.

[0067] S3, prepare the binder aqueous solution: add 7g of sodium carboxymethyl cellulose to 93mL of distilled water, stir, heat to 85-95°C and keep warm for 2 hours to make the sodium carboxymethyl cellulose completely swell, and cool to obtain the sodium carboxymethyl cellulose aqueous solution.

[0068] S4, mixing: respectively weigh 100g of molybdenum tailings, 18g of sawdust powder, 5g of aluminum hydroxide, and 28g of 7% sodium carboxymethyl cellulose aqueous solution, mix them evenly into mud, and then make a filler mud embryo.

[0069] Among them, sawdust powder is a pore-forming agent, which has a pore-forming effect and can improve the permeability coefficient of the filler. Sodium carboxymethyl cellulose is a binder and has a microporous effect. The role of aluminum hydroxide is to strengthen the phosphate adsorption effect and small pores, which can improve the filler's adsorption effect on pollutants. Therefore, due to the different molecular sizes of sawdust powder, sodium carboxymethyl cellulose solution, and aluminum hydroxide, the pore sizes of the pores are also different. The order of pores from large to small is: sawdust powder, sodium carboxymethyl cellulose, and aluminum hydroxide.

[0070] S5, granulation, drying and calcination: the filler mud embryo is made into spherical particles with a diameter of 3 cm by a pellet rolling machine and then dried, and then placed in a muffle furnace at a temperature of 1100°C for sintering for 20 minutes. After cooling in the furnace, gray spherical molybdenum tailings artificial wetland filler is obtained.

[0071] The physical and chemical properties of the molybdenum tailings artificial wetland filler were measured. The test results showed that it was a gray sphere with a diameter of about 3 cm and a porosity of 38.55%. The specific surface area was 89.67 m 2 / g, the pores are relatively transparent and evenly distributed, and the adsorption capacity of phosphate in water is 8.77 mg / g. The prepared filler is subjected to a static adsorption test, and the results are shown in Table 4.

[0072] Table 4 Treatment effect of 50mg / L phosphate wastewater

[0073]

[0074] Example 5

[0075] This embodiment uses iron tailings, and the preparation method of high-performance artificial wetland filler using tailings includes the following steps:

[0076] S1, grinding tailings: add clean water to the iron tailings for three times, with the volume ratio of tailings to clean water being 1:2, and put them into a drying oven at a temperature of 110±5℃ for 2 hours. Grind the dried tailings with a ball mill, and sieve them with 350 mesh and 400 mesh standard sieves in turn, and retain tailings with a particle size of 350-400 mesh.

[0077] S2, preparing sawdust powder: placing the sawdust powder in a drying oven at a temperature of 110±5° C. and drying for 2 hours, sieving using 350-mesh and 400-mesh standard sieves in turn, and retaining sawdust powder with a particle size of 350-400 mesh.

[0078] Sawdust powder can be purchased or you can clean the wood and crush it with a crusher.

[0079] S3, prepare the binder aqueous solution: add 1g of polyvinyl alcohol to 99mL of distilled water and stir, heat to 85-95°C and keep warm for 2 hours to make the polyvinyl alcohol completely swell, and then cool to obtain the polyvinyl alcohol aqueous solution.

[0080] S4, mixing: respectively weigh 100g of iron tailings, 42g of sawdust powder, 10g of aluminum hydroxide, and 61g of 1% polyvinyl alcohol aqueous solution, mix them evenly into mud, and then make filler mud embryos.

[0081] Among them, sawdust powder is a pore-forming agent, which has a pore-forming effect and can improve the permeability coefficient of the filler. Polyvinyl alcohol is a binder and has a microporous effect. The role of aluminum hydroxide is to strengthen the phosphate adsorption effect and small pores, which can improve the adsorption effect of the filler on pollutants. Therefore, due to the different molecular sizes of sawdust powder, polyvinyl alcohol solution, and aluminum hydroxide, the pore sizes of the pores are also different. The order of pores from large to small is: sawdust powder, polyvinyl alcohol, and aluminum hydroxide.

[0082] S5, granulation, drying and calcination: Use a pellet machine to make the filler mud embryo into spherical particles with a diameter of 1 cm and then dry them. Put them into a muffle furnace at a temperature of 1000°C and sinter them for 1 hour. After cooling in the furnace, gray spherical iron tailings artificial wetland filler is obtained.

[0083] The physical and chemical properties of the iron tailings artificial wetland filler were measured. The results showed that it was a gray sphere with a diameter of about 1 cm and a porosity of 57.34%. The specific surface area was 196.71 m 2 / g, the pores are relatively transparent and evenly distributed, and the adsorption capacity of phosphate in water is 58.73 mg / g. The prepared filler is subjected to a static adsorption test, and the results are shown in Table 5.

[0084] Table 5 Treatment effect of 50mg / L phosphate wastewater

[0085]

[0086] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention.

Claims

1. A method for preparing high-performance artificial wetland filler using tailings, characterized in that: The following steps are involved: S1, grinding tailings: adding clean water to the iron tailings for washing, the volume ratio of iron tailings to clean water is 1:2, and drying in a drying oven at a temperature of 110±5℃ for 2 hours, grinding the dried tailings, sieving them with 250 mesh and 300 mesh standard sieves in turn, and retaining tailings with a particle size of 250-300 mesh; S2, preparing sawdust powder: placing the sawdust powder in a drying oven at a temperature of 110±5°C for 2 hours, sieving using a 250-mesh and a 300-mesh standard sieve in turn, and retaining sawdust powder with a particle size of 250-300 mesh; S3, preparing a binder aqueous solution: adding 4 g of polyvinyl alcohol to 96 mL of distilled water, stirring, heating to a temperature of 85-95° C., and then keeping the temperature for 2 hours to allow the polyvinyl alcohol to completely swell, and cooling to obtain a polyvinyl alcohol aqueous solution; S4, mixing: weigh 100g of iron tailings, 28.1g of sawdust powder, 7.5g of aluminum hydroxide, and 46.5g of 4% polyvinyl alcohol aqueous solution, mix them evenly into mud, and then prepare filler mud embryo; S5, granulation, drying and calcination: the filler mud embryo is made into spherical particles with a diameter of 1.5 cm and then dried, and then placed in a muffle furnace at a temperature of 1150°C for sintering for 40 minutes. After cooling in the furnace, gray spherical iron tailings artificial wetland filler is obtained.

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