Attached base and method of preparation based on deep sea mining tailings and shipboard in-situ smelting slag

Abstract

This invention provides an adhesion substrate based on deep-sea mining tailings cement and shipborne in-situ smelting slag, and its preparation method. The raw materials consist of 600-700 parts of tailings cement, 300-400 parts of shipborne smelting slag, 0-300 parts of kaolin, 0-300 parts of pore-forming agent, 400-1100 parts of binder, 1000-1500 parts of modifier I, and 1000-1500 parts of modifier II. The particle size ranges of mixture I and mixture II are 10-20 μm and 0-10 μm, respectively. Mixture I accounts for 0-30% of the total of the two by mass percentage, with the remainder being mixture II. The waste heat from the shipborne smelting process is used to preheat the raw materials to 100-600 °C after heat exchange, and held at this temperature for 2-6 h. In the second stage, the raw materials are calcined at high temperature to 900-1500 °C and held for 0.5-3 h. After acid washing, sol impregnation, and treatment with attached microorganisms, the resulting substrate has a diameter of 0–11 cm, a porosity of 20%–65%, a pore size of 1–60 nm, and a hydrostatic pressure resistance of 60–80 MPa. It can be placed in situ in the mining area to provide the necessary hard matrix and microbial support for the ecosystem and to repair the environmental damage caused by deep-sea mining.

Description

Technical Field

[0001] This invention relates to the field of deep-sea mining, and more particularly to an attachment substrate based on deep-sea mining tailings cement and shipborne in-situ smelting slag, and its preparation method. Background Technology

[0002] Deep-sea mining, as a crucial means of obtaining resources such as cobalt, manganese, and nickel, has garnered significant global attention. However, the environmental hazards associated with deep-sea mining activities cannot be ignored. Deep-sea mining permanently removes porous nodules that provide habitats for deep-sea organisms, along with the organisms attached to them. These nodules contain numerous narrowly endemic species and species with extremely slow life cycles. Once removed, ecosystem recovery can take hundreds of years or even longer, and may never return to its pre-mining state. Sediments generated during nodule collection are brought to the surface and then discharged into the ocean, forming widespread and difficult-to-manage mid-water plumes that harm the upper marine ecosystem. Therefore, a method is urgently needed to reduce the environmental damage caused by deep-sea mining and to effectively restore marine ecosystems after mining activities.

[0003] Economic assessments of deep-sea polymetallic nodule development, both domestically and internationally, indicate that under traditional systems, nodules must be transported back to land for smelting, incurring high transportation costs, sometimes reaching 21% of the total cost. Integrating some smelting and preliminary reduction processes directly onto the mining vessel can significantly shorten the supply chain and save over 50% in transportation costs, making it one of the most promising solutions for future commercial deep-sea mining. However, shipboard smelting processes are energy-intensive, increasing the load on the ship's power and cooling systems and posing a potential risk of localized thermal disturbances. Furthermore, direct discharge of smelting slag into the sea will cause environmental pollution; transporting it all back to land will significantly increase return loads and transportation costs, reducing economic efficiency. Therefore, how to efficiently utilize waste heat and slag from the smelting process has become a key research topic.

[0004] However, existing deep-sea mining technologies have many shortcomings in these aspects. For example, current technologies still mainly rely on direct discharge to treat deep-sea mining tailings cement, ignoring its resource attributes and causing resource waste and economic losses; some proposed shipborne smelting methods do not reuse the waste heat generated during smelting, which may lead to energy waste; some proposed shipborne smelting methods fail to effectively treat in-situ smelting slag, which may lead to resource waste and environmental damage; some methods for treating smelting slag, although proposing recycling and reuse methods, cannot be reused in marine ecosystem restoration; and some proposed substrate remediation technologies have certain differences in the composition and structure of the substrate compared to the original nodular hard substrate, which may result in poor remediation effects. Summary of the Invention

[0005] The purpose of this invention is to provide an attachment substrate based on deep-sea mining tailings cement and shipborne in-situ smelting slag, and its preparation method. This method is compatible with deep-sea mining shipborne smelting systems, utilizing the waste heat generated during the deep-sea mining shipborne smelting process to co-prepare the tailings cement and smelting slag into an attachment substrate. This provides a feasible technical approach for the comprehensive utilization of tailings cement generated from deep-sea mining, as well as smelting slag and waste heat generated during shipborne smelting. The treated and microbially attached substrate can be placed in situ in the post-mining mining area to simulate the ecological function of polymetallic nodules in the deep-sea ecosystem, thereby achieving the protection and restoration of the deep-sea ecosystem.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A substrate for deep-sea mining tailings cement and shipborne in-situ smelting slag, and its preparation method, are characterized in that the invention is adapted to deep-sea mining shipborne smelting systems. The required raw materials are composed of the following parts by weight: 600-700 parts tailings cement, 300-400 parts shipborne smelting slag, 0-300 parts kaolin, 0-300 parts pore-forming agent, 400-1100 parts binder, 1000-1500 parts modifier I, and 1000-1500 parts modifier II, with sufficient desalinated water. The raw materials are dried, mixed, ground, and sieved to obtain mixture I with a particle size of 10-20 μm and mixture II with a particle size of 0-10 μm. Mixture I accounts for 0-30% of the total of the two by mass percentage, with the remainder being mixture II. The silicon-aluminum ratio of mixtures I and II is 1-3. The firing process is divided into two stages. In the first stage, the waste heat from the shipborne smelting is exchanged to preheat the raw materials to 100-600 °C. The raw materials are first heated to 900-1500 ℃ and kept at that temperature for 2-6 hours. In the second stage, the raw materials are calcined at 900-1500 ℃ and kept at that temperature for 0.5-3 hours. After acid washing, sol impregnation, and treatment with attached microorganisms, the resulting substrate has a diameter of 0-11 cm, a porosity of 20%-65%, and a pore size of 1-60 nm. It has hydrostatic pressure resistance of 60-80 MPa and provides the hard substrate and microorganisms required for deep-sea ecosystems at depths of 4000-6000 m, making it suitable for deep-sea ecological restoration.

[0007] An adhesion substrate based on deep-sea mining tailings cement and shipborne in-situ smelting slag, and its preparation method, specifically including the following steps: S1. Mix the dried tail cement, ship-borne in-situ smelting slag, kaolin, and pore-forming agent, and then perform ultrafine grinding to obtain mixture I with a particle size of 10-20 μm and mixture II with a particle size of 0-10 μm. Mixture I accounts for 0-30% of the total amount of the two by mass percentage, and the remainder is mixture II. S2. Place mixture I, mixture II, and binder in a mixer and stir at a speed of 200-300 r / min for 15-20 min. After mixing evenly, control the moisture content to be between 5-10% and semi-dry press it into a calcined mixture with a diameter of 0-11 cm. S3. Preheat the mixture to be calcined using waste heat, control the temperature of the calcining furnace at 100~600 ℃, and keep it at that temperature for 2~6 h. Then control the temperature of the calcining furnace to rise to 900~1500 ℃ at 2~5 ℃ / min and keep it at that temperature for 0.5~3 h. S4. After calcination, allow the substrate to cool naturally to room temperature to obtain the attached substrate. Test its porosity. If the porosity is between 20% and 65%, proceed to the next step. Otherwise, adjust the amount of pore-forming agent and prepare it again. S5. Immerse the substrate in modifier I and sonicate it for 0.5-2 hours. After the treatment, remove the substrate and rinse it with desalinated water to remove any residual solution. S6. Immerse the treated substrate in a vacuum-sealed container containing modifier II, vacuum the container to reduce pressure, and ensure that modifier II fully enters the pores of the substrate. Then remove, dry, and remove excess components to obtain the microbial substrate intermediate. S7. Test the porosity, pore size and compressive strength of the microbial attachment substrate intermediate. If the porosity is between 20% and 65%, the pore size is between 1 and 60 nm, and the hydrostatic pressure resistance is between 60 and 80 MPa, the next step can be carried out. Otherwise, the dosage of pore-forming agent and the composition of modifier need to be adjusted and the substrate needs to be prepared again. S8. Microbial attachment substrate intermediates are immersed in microbial culture medium for 1-3 days to obtain microbial attachment substrate.

[0008] Furthermore, the shipborne in-situ smelting slag is the tailings produced after valuable metals are extracted from deep-sea minerals such as polymetallic nodules, cobalt-rich crusts, or polymetallic sulfides through shipborne smelting.

[0009] Furthermore, the tailings cement is obtained by filtering and separating a solid-liquid mixture that is extracted to the sea surface along with deep-sea minerals such as polymetallic nodules, cobalt-rich crusts, or polymetallic sulfides.

[0010] Furthermore, the desalinated water is seawater that has been filtered and desalinated.

[0011] Furthermore, the pore-forming agent includes, but is not limited to, one or more of starch, polyethylene spheres, ammonium bicarbonate, and calcium carbonate.

[0012] Furthermore, the preparation of the adhesive includes the following steps: S1. Weigh out 25-35 parts of sodium carboxymethyl cellulose, 15-25 parts of polyethylene glycol, 3-7 parts of polyacrylamide, and 800-1400 parts of desalinated water by weight. S2. Place the desalinated water into a mixer and stir continuously at a speed of 300~800 r / min. Slowly and evenly add sodium carboxymethyl cellulose and stir for 30~60 min. After it is fully hydrated, heat it to 40~50 ℃ and add polyethylene glycol. Stir for 10~20 min. After it is dissolved, add polyacrylamide and stir at a speed of 200~500 r / min for 60~120 min. S3. Pass the slurry obtained in step S2 through an 800-mesh sieve and collect the slurry that passes through the sieve, which is the binder.

[0013] Furthermore, the modifier I is used to remove impurities, adjust surface roughness and chemical activity, thereby improving subsequent adhesion performance, and is prepared by the following steps: S1. Weigh out 50-150 parts of oxalic acid dihydrate and 950-1350 parts of desalinated water by mass. S2. Mix oxalic acid dihydrate and desalinated water, stir at a rate of 300~600 r / min for 2~5 min, remove undissolved or coarse solids from the mixture through an 800 mesh sieve, and collect the permeate through the sieve as modifier I.

[0014] Furthermore, the modifier II is mainly based on silicon source and may introduce elements such as iron, magnesium, calcium, and phosphorus, or add organic components such as polyethylene glycol, polyvinyl alcohol, and citric acid to form a composite sol system, which is used to construct a stable nanoscale pore layer on the surface of the attached substrate pore wall to improve specific surface area and surface activity.

[0015] Furthermore, the microbial culture medium is characterized in that the microorganisms in the microbial culture medium originate from the local microbial community attached to the surface of polymetallic nodules in the mining area.

[0016] Compared with the prior art, the present invention brings the following beneficial technical effects: (1) The damage to the deep-sea ecosystem caused by deep-sea mining mainly comes from the permanent removal of specific hard substrates and specific microorganisms attached to the hard substrates, which reduces biodiversity and harms the ecological environment. The present invention obtains a microbial substrate by soaking the substrate in a microbial culture solution for 1-3 days. The obtained microbial substrate is similar to polymetallic nodules in diameter, porosity and pore size, and is attached with in-situ microbial communities. After placement, it can provide the hard substrate and microorganisms required for the operation of the original deep-sea ecosystem, promote the restoration of the deep-sea ecosystem and reduce the damage to the ecological environment caused by deep-sea mining; (2) Currently, the mineral mud generated from deep-sea mining is directly discharged back into the ocean. This method generates sediment plumes, which affect the marine ecosystem and cause problems such as bottom material migration, environmental water migration, light and noise generation, release of toxic substances, seawater acidification, and depletion of dissolved oxygen. This invention uses tailings cement as the main raw material to prepare an attachment substrate, which solves the problem of sediment plumes generated by tailwater discharge and makes it possible to utilize tailings cement that is difficult to recover. (3) Smelting slag, as a solid residue left after extracting valuable metals from deep-sea minerals, is only partially recycled. Moreover, the recycling of low-grade metals from smelting slag is economically unfeasible and costly. In addition, transporting smelting slag back to land from ships will significantly increase the return load and transportation costs. This invention uses smelting slag as one of the raw materials to burn it into an attachment substrate, which fully realizes the utilization of solid waste, greatly reduces the cost of harmless treatment and transportation of smelting slag, and reduces the possibility of harmful substances leaching out. (4) The shipboard smelting process consumes a lot of energy. If the waste heat generated is not recovered and is directly discharged, it will not only lead to energy waste, but also increase the heat dissipation load of the ship and the energy consumption of the cooling system, and cause thermal disturbance in local sea areas. The present invention utilizes the waste heat during shipboard smelting to complete the preheating, which reduces the cost of waste heat treatment and the consumption of shipboard fuel, and improves economic and environmental benefits; (5) The present invention uses a method of preheating, slow heating, and segmented heat preservation to prepare the substrate. In the first stage of the substrate firing process, the high-temperature air used in the smelting of polymetallic nodules is used to preheat to 100~600 ℃ and the heat preservation is maintained for 2~6 h. In the second stage, the high-temperature air is used to assist heating to 900~1500 ℃ and the heat preservation is maintained for 0.5~3 h. Through preheating and slow heating, the internal moisture and organic matter are gradually discharged, reducing thermal stress and preventing defects such as cracks, blistering and bursting. Through segmented heat preservation, the reaction at each stage is fully carried out, promoting the uniform densification of particles and grain growth, thereby improving the structural uniformity and mechanical properties of the substrate. (6) The present invention uses two types of raw materials with particle sizes of 10-20 μm and 0-10 μm to prepare the adhesion substrate, which makes the pore distribution between particles more uniform and the gas discharge path more continuous, which helps to suppress sintering defects such as bubbles, cracks or warping caused by pore retention. At the same time, the large particle skeleton can resist deformation caused by non-uniform shrinkage. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings: Figure 1 This is a process flow diagram for preparing the microbial attachment substrate according to the present invention. Specific implementation methods To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be described in detail below with reference to specific embodiments. It should be noted that the embodiments provided by this invention represent only a part of the examples of this invention and do not represent all the examples. Based on the examples provided by this invention, those skilled in the art can develop other embodiments without departing from the spirit and scope of this invention.

[0018] Example 1 A substrate for deep-sea mining tailings cement and shipborne in-situ smelting slag, and its preparation method, are characterized in that the invention is adapted to deep-sea mining shipborne smelting systems. The required raw materials are composed of the following parts by weight: 600-700 parts (preferably 700 parts) of tailings cement, 300-400 parts (preferably 300 parts) of shipborne smelting slag, 0-300 parts (preferably 300 parts) of kaolin, 0-300 parts (preferably 200 parts) of pore-forming agent, 400-1100 parts of binder, 1000-1500 parts of modifier I and 1000-1500 parts of modifier II, and sufficient desalination water. The raw materials are dried, mixed, ground, and sieved to obtain mixture I with a particle size of 10-20 μm and mixture II with a particle size of 0-10 μm. Mixture II, with a mass percentage of 0-30% for mixture I and the remainder being mixture II, has a silicon-to-aluminum ratio of 1-3 for both mixtures I and II. The calcination process is divided into two stages: in the first stage, the waste heat from the shipboard smelting is used to preheat the raw material to 100-600 °C and hold it for 2-6 h; in the second stage, the raw material is calcined at a high temperature to 900-1500 °C and held for 0.5-3 h. After acid washing, sol impregnation, and treatment with attached microorganisms, the resulting substrate has a diameter of 0-11 cm (preferably 5 cm), a porosity of 20%-65%, a pore size of 1-60 nm, and a hydrostatic pressure resistance of 60-80 MPa. It provides the hard substrate and microorganisms required for deep-sea ecosystems at depths of 4000-6000 m and is suitable for deep-sea ecological restoration.

[0019] To achieve the above objectives, the technical solution adopted by the present invention is as follows: S1. Mix the dried tail cement, ship-borne in-situ smelting slag, kaolin, and pore-forming agent, and then perform ultrafine grinding to obtain mixture I with a particle size of 10-20 μm and mixture II with a particle size of 0-10 μm. Mixture I accounts for 0-30% of the total amount of the two by mass percentage, and the remainder is mixture II. S2. Place mixture I, mixture II, and binder in a mixer and stir at a speed of 200-300 r / min for 15-20 min. After mixing evenly, control the moisture content to be between 5-10% and semi-dry press it into a calcined mixture with a diameter of 0-11 cm. S3. Preheat the mixture to be calcined using waste heat, control the temperature of the calcination furnace at 100~600 ℃, and keep it at that temperature for 2~6 h. Then control the temperature of the calcination furnace to rise to 900~1500 ℃ at 2~5 ℃ / min (preferably 2 ℃ / min), and keep it at that temperature for 0.5~3 h. S4. After calcination, allow the substrate to cool naturally to room temperature to obtain the attached substrate. Test its porosity. If the porosity is between 20% and 65%, proceed to the next step. Otherwise, adjust the amount of pore-forming agent and prepare it again. S5. Immerse the substrate in modifier I and sonicate it for 0.5-2 hours. After the treatment, remove the substrate and rinse it with desalinated water to remove any residual solution. S6. Immerse the treated substrate in a vacuum-sealed container containing modifier II, vacuum the container to reduce pressure, and ensure that modifier II fully enters the pores of the substrate. Then remove, dry, and remove excess components to obtain the microbial substrate intermediate. S7. Test the porosity, pore size and compressive strength of the microbial attachment substrate intermediate. If the porosity is between 20% and 65%, the pore size is between 1 and 60 nm, and the hydrostatic pressure resistance is between 60 and 80 MPa, the next step can be carried out. Otherwise, the dosage of pore-forming agent and the composition of modifier need to be adjusted and the substrate needs to be prepared again. S8. Microbial attachment substrate intermediates are immersed in microbial culture medium for 1-3 days to obtain microbial attachment substrate.

[0020] Furthermore, the shipborne in-situ smelting slag is the tailings produced after valuable metals are extracted from deep-sea minerals such as polymetallic nodules, cobalt-rich crusts, or polymetallic sulfides through shipborne smelting.

[0021] Furthermore, the tailings cement is obtained by filtering and separating a solid-liquid mixture that is extracted to the sea surface along with deep-sea minerals such as polymetallic nodules, cobalt-rich crusts, or polymetallic sulfides.

[0022] Furthermore, the desalinated water is seawater that has been filtered and desalinated.

[0023] Furthermore, the pore-forming agent includes, but is not limited to, one or more of starch, polyethylene spheres, ammonium bicarbonate, and calcium carbonate.

[0024] Furthermore, the preparation of the adhesive includes the following steps: S1. Weigh out 25-35 parts of sodium carboxymethyl cellulose, 15-25 parts of polyethylene glycol, 3-7 parts of polyacrylamide, and 800-1400 parts of desalinated water by weight. S2. Place the desalinated water into a mixer and stir continuously at a speed of 300~800 r / min. Slowly and evenly add sodium carboxymethyl cellulose and stir for 30~60 min. After it is fully hydrated, heat it to 40~50 ℃ and add polyethylene glycol. Stir for 10~20 min. After it is dissolved, add polyacrylamide and stir at a speed of 200~500 r / min for 60~120 min. S3. Pass the slurry obtained in step S2 through an 800-mesh sieve and collect the slurry that passes through the sieve, which is the binder.

[0025] Furthermore, the modifier I is used to remove impurities, adjust surface roughness and chemical activity, thereby improving subsequent adhesion performance, and is prepared by the following steps: S1. Weigh out 50-150 parts of oxalic acid dihydrate and 950-1350 parts of desalinated water by mass. S2. Mix oxalic acid dihydrate and desalinated water, stir at a rate of 300~600 r / min for 2~5 min, remove undissolved or coarse solids from the mixture through an 800 mesh sieve, and collect the permeate through the sieve as modifier I.

[0026] Furthermore, the modifier II is mainly based on silicon source and may introduce elements such as iron, magnesium, calcium, and phosphorus, or add organic components such as polyethylene glycol, polyvinyl alcohol, and citric acid to form a composite sol system, which is used to construct a stable nanoscale pore layer on the surface of the attached substrate pore wall to improve specific surface area and surface activity.

[0027] Furthermore, the microbial culture medium is characterized in that the microorganisms in the microbial culture medium originate from the local microbial community attached to the surface of polymetallic nodules in the mining area.

[0028] The table below shows the test results of the adhesion substrates designed according to the preferred values ​​in Example 1: project diameter Porosity hydrostatic pressure resistance index 5cm 44.3% 72.9MPa Example

[0029] The difference from Example 1 is that: A substrate for deep-sea mining tailings cement and shipborne in-situ smelting slag, and its preparation method, are characterized in that the invention is adapted to deep-sea mining shipborne smelting systems. The required raw materials are composed of the following parts by weight: 600-700 parts (preferably 600 parts) of tailings cement, 300-400 parts (preferably 400 parts) of shipborne smelting slag, 0-300 parts (preferably 200 parts) of kaolin, 0-300 parts (preferably 200 parts) of pore-forming agent, 400-1100 parts of binder, 1000-1500 parts of modifier I and 1000-1500 parts of modifier II, and sufficient desalination water. The raw materials are dried, mixed, ground, and sieved to obtain mixture I with a particle size of 10-20 μm and mixture II with a particle size of 0-10 μm. Mixture II, with a mass percentage of 0-30% for mixture I and the remainder being mixture II, has a silicon-to-aluminum ratio of 1-3 for both mixtures I and II. The calcination process is divided into two stages: in the first stage, the waste heat from the shipboard smelting is used to preheat the raw material to 100-600 °C and hold it for 2-6 h; in the second stage, the raw material is calcined at a high temperature to 900-1500 °C and held for 0.5-3 h. After acid washing, sol impregnation, and treatment with attached microorganisms, the resulting substrate has a diameter of 0-11 cm (preferably 5 cm), a porosity of 20%-65%, a pore size of 1-60 nm, and a hydrostatic pressure resistance of 60-80 MPa. It provides the hard substrate and microorganisms required for deep-sea ecosystems at depths of 4000-6000 m and is suitable for deep-sea ecological restoration.

[0030] The table below shows the test results of the adhesion substrates designed according to the preferred values ​​in Example 2: project diameter Porosity hydrostatic pressure resistance index 5cm 43.7% 65.9MPa Comparing Examples 1 and 2, it can be seen that increasing the amount of shipborne in-situ smelting slag during the preparation of the substrate reduces the hydrostatic pressure resistance of the substrate.

[0031] Example 3 The difference from Example 1 is that: A substrate for deep-sea mining tailings cement and shipborne in-situ smelting slag, and its preparation method, are characterized in that the invention is adapted to deep-sea mining shipborne smelting systems. The required raw materials are composed of the following parts by weight: 600-700 parts (preferably 700 parts) of tailings cement, 300-400 parts (preferably 300 parts) of shipborne smelting slag, 0-300 parts (preferably 300 parts) of kaolin, 0-300 parts (preferably 200 parts) of pore-forming agent, 400-1100 parts of binder, 1000-1500 parts of modifier I and 1000-1500 parts of modifier II, and sufficient desalination water. The raw materials are dried, mixed, ground, and sieved to obtain mixture I with a particle size of 10-20 μm and mixture II with a particle size of 0-10 μm. Mixture II, with a mass percentage of 0-30% for mixture I and the remainder being mixture II, has a silicon-to-aluminum ratio of 1-3 for both mixtures I and II. The calcination process is divided into two stages: in the first stage, the waste heat from the shipboard smelting is used to preheat the raw material to 100-600 °C and hold it for 2-6 h; in the second stage, the raw material is calcined at a high temperature to 900-1500 °C and held for 0.5-3 h. After acid washing, sol impregnation, and treatment with attached microorganisms, the resulting substrate has a diameter of 0-11 cm (preferably 5 cm), a porosity of 20%-65%, a pore size of 1-60 nm, and a hydrostatic pressure resistance of 60-80 MPa. It provides the hard substrate and microorganisms required for deep-sea ecosystems at depths of 4000-6000 m and is suitable for deep-sea ecological restoration.

[0032] To achieve the above objectives, the technical solution adopted by the present invention is as follows: S1. Mix the dried tail cement, ship-borne in-situ smelting slag, kaolin, and pore-forming agent, and then perform ultrafine grinding to obtain mixture I with a particle size of 10-20 μm and mixture II with a particle size of 0-10 μm. Mixture I accounts for 0-30% of the total amount of the two by mass percentage, and the remainder is mixture II. S2. Place mixture I, mixture II, and binder in a mixer and stir at a speed of 200-300 r / min for 15-20 min. After mixing evenly, control the moisture content to be between 5-10% and semi-dry press it into a calcined mixture with a diameter of 0-11 cm (preferably 5 cm). S3. Preheat the mixture to be calcined using waste heat, control the temperature of the calcination furnace at 100~600 ℃, and keep it at that temperature for 2~6 h. Then control the temperature of the calcination furnace to rise to 900~1500 ℃ at 2~5 ℃ / min (preferably 5 ℃ / min), and keep it at that temperature for 0.5~3 h. S4. After calcination, allow the substrate to cool naturally to room temperature to obtain the attached substrate. Test its porosity. If the porosity is between 20% and 65%, proceed to the next step. Otherwise, adjust the amount of pore-forming agent and prepare it again. S5. Immerse the substrate in modifier I and sonicate it for 0.5-2 hours. After the treatment, remove the substrate and rinse it with desalinated water to remove any residual solution. S6. Immerse the treated substrate in a vacuum-sealed container containing modifier II, vacuum the container to reduce pressure, and ensure that modifier II fully enters the pores of the substrate. Then remove, dry, and remove excess components to obtain the microbial substrate intermediate. S7. Test the porosity, pore size and compressive strength of the microbial attachment substrate intermediate. If the porosity is between 20% and 65%, the pore size is between 1 and 60 nm, and the hydrostatic pressure resistance is between 60 and 80 MPa, the next step can be carried out. Otherwise, the dosage of pore-forming agent and the composition of modifier need to be adjusted and the substrate needs to be prepared again. S8. Microbial attachment substrate intermediates are immersed in microbial culture medium for 1-3 days to obtain microbial attachment substrate.

[0033] The table below shows the test results of the adhesion substrates designed according to the preferred values ​​in Example 3: project diameter Porosity hydrostatic pressure resistance index 5cm 48.7% 63.9MPa Examples 1 and 3 show that increasing the heating rate of the calcining furnace during the preparation of the substrate increases the porosity of the substrate and reduces its hydrostatic pressure resistance.

[0034] In summary, considering that the diameter of polymetallic nodules in the ocean is usually between 2 and 10 cm, the average porosity is about 40%, and the pore size is mainly distributed in the range of 1.7 to 58.0 nm, and that the substrates obtained in each embodiment of the present invention can withstand the water pressure of 4000 to 6000 m deep sea, the obtained substrates can effectively promote the restoration of deep-sea ecosystems.

[0035] The above embodiments of the present invention are only used to illustrate the technical solutions and features of the present invention, and are intended to enable those skilled in the art to clearly understand the essence of the present invention and to serve as a reference for implementing the present invention. They should not be construed as limiting the scope of protection of the present invention. Any equivalent substitutions, modifications, or variations made by those skilled in the art to the present invention without departing from the spirit and essence of the present invention should be included within the scope of protection of the present invention.

Claims

1. An adhesion substrate based on deep-sea mining tailings cement and shipborne in-situ smelting slag, and its preparation method, characterized in that, This invention is adapted to a deep-sea mining vessel-borne smelting system. The required raw materials are composed of the following parts by weight: 600-700 parts tailings cement, 300-400 parts ship-borne smelting slag, 0-300 parts kaolin, 0-300 parts pore-forming agent, 400-1100 parts binder, 1000-1500 parts modifier I and 1000-1500 parts modifier II, with sufficient desalinated water. The raw materials are dried, mixed, ground, and sieved to obtain mixture I with a particle size of 10-20 μm and mixture II with a particle size of 0-10 μm. Mixture I accounts for 0-30% of the total of the two by weight, with the remainder being mixture II. The silicon-aluminum ratio of mixtures I and II is 1-3. The calcination process is divided into two stages. In the first stage, the waste heat from the ship-borne smelting is used to preheat the raw materials to 100-600 °C after heat exchange, and the temperature is maintained for 2-6 hours. In the second stage, the raw materials are calcined at high temperature to 900-1500 °C. The substrate is heated to ℃ and kept at that temperature for 0.5-3 hours. After acid washing, sol impregnation, and treatment with attached microorganisms, the resulting substrate has a diameter of 0-11 cm, a porosity of 20%-65%, a pore size of 1-60 nm, and a hydrostatic pressure resistance of 60-80 MPa. It provides the hard substrate and microorganisms required for deep-sea ecosystems at depths of 4000-6000 m and is suitable for deep-sea ecological restoration.

2. The adhesion substrate and preparation method based on deep-sea mining tailings cement and shipborne in-situ smelting slag according to claim 1, characterized in that, Includes the following steps: S1. Mix the dried tail cement, ship-borne in-situ smelting slag, kaolin, and pore-forming agent, and then perform ultrafine grinding to obtain mixture I with a particle size of 10-20 μm and mixture II with a particle size of 0-10 μm. Mixture I accounts for 0-30% of the total amount of the two by mass percentage, and the remainder is mixture II. S2. Place mixture I, mixture II, and binder in a mixer and stir at a speed of 200-300 r / min for 15-20 min. After mixing evenly, control the moisture content to be between 5-10% and semi-dry press it into a calcined mixture with a diameter of 0-11 cm. S3. Preheat the mixture to be calcined using waste heat, control the temperature of the calcining furnace at 100~600 ℃, and keep it at that temperature for 2~6 h. Then control the temperature of the calcining furnace to rise to 900~1500 ℃ at 2~5 ℃ / min and keep it at that temperature for 0.5~3 h. S4. After calcination, allow the substrate to cool naturally to room temperature to obtain the attached substrate. Test its porosity. If the porosity is between 20% and 65%, proceed to the next step. Otherwise, adjust the amount of pore-forming agent and prepare it again. S5. Immerse the substrate in modifier I and sonicate it for 0.5-2 hours. After the treatment, remove the substrate and rinse it with desalinated water to remove any residual solution. S6. Immerse the treated substrate in a vacuum-sealed container containing modifier II, vacuum the container to reduce pressure, and ensure that modifier II fully enters the pores of the substrate. Then remove, dry, and remove excess components to obtain the microbial substrate intermediate. S7. Test the porosity, pore size and compressive strength of the microbial attachment substrate intermediate. If the porosity is between 20% and 65%, the pore size is between 1 and 60 nm, and the hydrostatic pressure resistance is between 60 and 80 MPa, the next step can be carried out. Otherwise, the dosage of pore-forming agent and the composition of modifier need to be adjusted and the substrate needs to be prepared again. S8. Microbial attachment substrate intermediates are immersed in microbial culture medium for 1-3 days to obtain microbial attachment substrate.

3. The shipborne in-situ smelting slag according to claim 1, characterized in that, The shipborne in-situ smelting slag is the tailings produced after valuable metals are extracted from deep-sea minerals such as polymetallic nodules, cobalt-rich crusts, or polymetallic sulfides through shipborne smelting.

4. The tailings cement according to claim 1, characterized in that, The tailings cement is obtained by filtering and separating a solid-liquid mixture that is extracted to the sea surface along with deep-sea minerals such as polymetallic nodules, cobalt-rich crusts, or polymetallic sulfides.

5. The desalinated water according to claim 1, characterized in that, The desalinated water is seawater that has been filtered and desalinated.

6. The pore-forming agent according to claim 1, characterized in that, The pore-forming agent includes, but is not limited to, one or more of starch, polyethylene balls, ammonium bicarbonate, and calcium carbonate.

7. The adhesive according to claim 1, characterized in that, The preparation of the adhesive includes the following steps: S1. Weigh out 25-35 parts of sodium carboxymethyl cellulose, 15-25 parts of polyethylene glycol, 3-7 parts of polyacrylamide, and 800-1400 parts of desalinated water by weight. S2. Place the desalinated water into a mixer and stir continuously at a speed of 300~800 r / min. Slowly and evenly add sodium carboxymethyl cellulose and stir for 30~60 min. After it is fully hydrated, heat it to 40~50 ℃ and add polyethylene glycol. Stir for 10~20 min. After it is dissolved, add polyacrylamide and stir at a speed of 200~500 r / min for 60~120 min. S3. Pass the slurry obtained in step S2 through an 800-mesh sieve and collect the slurry that passes through the sieve, which is the binder.

8. The modifier I according to claim 1, characterized in that, Modifier I is used to remove impurities, adjust surface roughness and chemical activity, thereby improving subsequent adhesion performance, and is prepared by the following steps: S1. Weigh out 50-150 parts of oxalic acid dihydrate and 950-1350 parts of desalinated water by mass. S2. Mix oxalic acid dihydrate and desalinated water, stir at a rate of 300~600 r / min for 2~5 min, remove undissolved or coarse solids from the mixture through an 800 mesh sieve, and collect the permeate through the sieve as modifier I.

9. The modifier II according to claim 1, characterized in that, Modifier II is based on silicon and may incorporate elements such as iron, magnesium, calcium, and phosphorus, or add organic components such as polyethylene glycol, polyvinyl alcohol, and citric acid to form a composite sol system. This system is used to construct a stable nanoscale porous layer on the surface of the substrate pore wall to improve the specific surface area and surface activity.

10. The microbial culture medium according to claim 2, characterized in that, The microorganisms in the microbial culture medium are derived from the local microbial community attached to the surface of polymetallic nodules in the mining area.

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