A method for transporting slurry between deep-sea mining vessels

Abstract

This invention discloses a method for transporting ore slurry between deep-sea mining vessels, relating to the field of marine engineering technology. The method employs a continuous process of slurry preparation, pipe laying, pumping, dewatering, and rinsing. On the mining mother ship, ore is crushed and mixed with seawater and dispersant to create a high-solids-content slurry, which is then stabilized by stirring in a storage tank. A transport channel is established between the mother ship and the transport ship via floating hoses, and the slurry is pumped using a slurry pump. After receiving the slurry, the transport ship performs solid-liquid separation using screening, centrifugation, or filter press devices. Sludge is stored in a hold, and tailwater is treated to meet standards before being discharged into the sea. After the operation is completed, the entire transport path is rinsed online with clean water, the hoses are recovered, and the equipment is reset. This invention achieves continuous and stable marine transport of ore slurry, improves operational efficiency, reduces marine ecological risks, has strong engineering adaptability, and is suitable for ore transport operations between deep-sea mining vessels.

Description

Technical Field

[0001] This invention relates to the field of marine engineering technology, and in particular to a method for transporting deep-sea mining slurry between vessels. Background Technology

[0002] With the increasing depletion of onshore mineral resources, the development value and demand for seabed mineral resources such as deep-sea polymetallic nodules continue to rise, becoming a research and application hotspot in the field of marine engineering. Currently, the mainstream deep-sea mining system mainly uses mining risers to lift ore collected from the seabed to a mining mother ship, which then completes the sea transfer operation of the ore. As an important part of the deep-sea mining industry chain, the efficiency and technological adaptability of the ore transfer link directly affect the overall development benefits.

[0003] In existing technologies, the marine transshipment of ore for deep-sea mining mostly adopts dry bulk transportation. This mode requires complex loading and unloading machines and hatch sealing devices, and has revealed many technical defects in actual operations: the loading and unloading process is difficult to achieve continuous operation, and the overall transshipment efficiency is low; a large amount of dust is easily generated during the operation, causing serious dust pollution, which not only affects the ship's operating environment but also does not meet marine environmental protection requirements; various loading and unloading equipment occupy a large amount of deck space on the mother ship and transport ship, restricting the realization of other ship operation functions; at the same time, the operation process has strict requirements on sea conditions, and loading and unloading operations are difficult to carry out in bad sea conditions, resulting in poor continuity and stability of operations.

[0004] To address the aforementioned issues in dry bulk cargo transportation, the industry has proposed using a ship-to-ship slurry transfer method. This involves processing ore into a pumpable slurry on the mining mother ship and transferring it between the mother ship and the transport ship via flexible hoses. This reduces dust pollution and improves operational continuity. However, existing ship-to-ship hose transfer technologies are primarily suited for oil loading scenarios and do not fully consider the material characteristics of deep-sea slurry, such as large particle size, high solids content, and strong abrasiveness. They also fail to take into account the environmental characteristics of large relative ship movements during offshore operations. There is a lack of a complete and systematic operational method for deep-sea mining slurry transfer, which cannot meet the actual needs for continuous, efficient, and stable ship-to-ship slurry transfer in deep-sea mining. Therefore, there is an urgent need to develop a ship-to-ship slurry transfer method adapted to deep-sea mining scenarios, achieving a balance between operational efficiency, environmental friendliness, and engineering adaptability. Summary of the Invention

[0005] The purpose of this invention is to propose a method for transporting deep-sea mining slurry between mining mother ships and transport ships, so as to realize the continuous, efficient and automated transportation of seabed ore in the form of slurry between mining mother ships and transport ships, while taking into account marine environmental protection, solving many problems existing in the current deep-sea mining ore maritime transportation, and adapting to the characteristics of deep-sea slurry and the marine operating environment.

[0006] To achieve the above objectives, this invention proposes a method for transporting ore slurry between deep-sea mining vessels. This method employs a continuous process of slurry preparation, pipe laying, pumping, dewatering, and washing between surface vessels to achieve continuous and stable transport of ore in slurry form at sea. Specifically, it includes the following steps: Step S1: The ore is crushed on the mining mother ship to form sub-millimeter-sized mineral powder. It is then mixed with seawater using a dispersant to form a high-solids slurry, which is then sent to the mother ship's slurry storage tank for continuous stirring to maintain the uniformity and stability of the slurry. Step S2: Deploy floating hoses, connecting the two ends to the slurry outlet of the mining mother ship and the slurry injection port of the transport ship, respectively, to form a slurry transport channel between the two ships; Step S3: Open the outlet valve of the slurry tank and start the slurry pump to pump the high solids slurry to the transport ship through the floating hose; Step S4: The transport ship receives the slurry and uses one or more of the following dewatering units—screening machine, centrifuge, and filter press—to complete the solid-liquid separation of the slurry, forming sludge with low water content. The sludge is directly stored in the hold via a conveying device, and the tailwater is collected and collected in a collection tank, then treated in accordance with environmental protection requirements and discharged into the sea. Step S5: Stop the slurry supply and switch to clean water for online flushing of the mother ship, hoses, and transport ship throughout the entire process; after the flushing meets the standards, close the valves in sequence, disconnect the joints, retrieve the hoses, check the equipment reset, and then the transport ship departs.

[0007] Preferably, in step S1, the specific steps are as follows: Step S11: The seabed-collected minerals are fed into a crusher for crushing, and then mixed with supplementary seawater, dispersants, and regulators in a slurry tank to adjust the particle size distribution, solid volume fraction, and rheological properties of the slurry. Step S12: The high-solids slurry is transported to the slurry storage tank below the mother ship. The slurry storage tank is equipped with a liquid level monitoring, venting and stirring device to prevent air blockage and to achieve continuous and stable feeding to the subsequent slurry pump, while maintaining the uniformity and stability of the slurry.

[0008] Preferably, in step S11, the particle size of the crushed mineral nodules is no greater than 1 mm, the volume fraction of the slurry solids is adjusted to 25% to 35%, the particle size of the slurry is refined to sub-millimeter level, and the rheological properties meet the conveying requirements of the hose at a flow rate of 2 to 20 m / s.

[0009] Preferably, in step S2, the specific steps are as follows: Step S21: Pre-install floating hoses at the bow of the mining mother ship. The length of the floating hoses is determined according to the relative position of the two ships and the conditions of the operating water area. Connection interfaces matching the slurry discharge pipeline of the mining mother ship and the slurry injection pipeline of the transport ship are reserved at both ends of the hoses. Step S22: During the operation, the floating hose is slowly deployed from the mother ship. With the assistance of the deck operation equipment, the free end of the hose is guided to the predetermined docking position on the side of the transport ship. Step S23: Connect both ends of the floating hose to the slurry outlet of the mining mother ship and the slurry injection port of the transport ship respectively, and perform a sealing check to ensure that the connection is firm and form a continuous slurry transportation path of mother ship-hose-transport ship.

[0010] Preferably, in step S3, the specific steps are as follows: Step S31: After confirming that the slurry transport path has been completed and all connections are securely sealed, open the outlet valve of the mother ship's slurry storage tank and start the slurry pumps installed on the mother ship. Step S32: The slurry in the storage tank is pumped through the mother ship's deck pipeline to the floating hose by the slurry pump, so that the slurry flows along the conveying channel to the transport ship and further enters the transport ship's feed pipeline. Step S33: By adjusting the speed of the slurry pump and the valve opening, the system flow and pressure are controlled so that the flow rate and pressure drop of the slurry in the conveying channel meet the requirements of continuous conveying and anti-clogging.

[0011] Preferably, in step S4, the specific steps are as follows: Step S41: The slurry is transported to the transport vessel through a floating hose, so that the slurry is evenly distributed to multiple dewatering units according to the set flow rate; Step S42: In the dewatering unit, the slurry is subjected to solid-liquid separation to obtain solid sludge and tailings water; Step S43: The solid sludge is transported to the cargo hold of the transport ship for storage via the unloading device and belt conveyor. The sludge hold is equipped with ventilation, drainage and monitoring devices to ensure the safety and stability of the sludge during the voyage. Step S44: Collect the wastewater into the collection tank, and discharge it after sedimentation and filtration treatment according to the operation requirements.

[0012] Preferably, in step S42, the moisture content of the slurry is controlled within 30%.

[0013] Preferably, in step S5, the specific steps are as follows: Step S51: After completing the predetermined delivery volume, stop supplying slurry to the storage tank, and only retain clean water as the medium to flush the entire delivery path from the mother ship to the hose to the transport ship online until the liquid at the outlet of the transport ship reaches the preset cleanliness level. Step S52: After rinsing to the required standard, close the valves at both ends of the mother ship and the transport ship in sequence, and disconnect the floating hose from the pipeline interfaces of the two ships. Step S53: Retrieve the floating hose from the water surface to the designated storage location on the mother ship, and rinse or inspect the outer surface of the hose with clean water as needed; Step S54: After the hose is fully recovered and the relevant equipment is reset, the two vessels are released from mooring, completing the deep-sea mining slurry transfer operation between vessels.

[0014] Therefore, this invention proposes a method for transporting deep-sea mining slurry between vessels, which has the following advantages: (1) The present invention divides the mineral pretreatment of the mother ship, the construction of the inter-ship transport path, the slurry pressurization pumping, the dewatering and storage of the transport ship and the hose flushing and recycling into five stages, and refines each stage to form a closed-loop process from seabed collection to the transport ship sludge entering the hold. This overcomes the problems of fragmented design and discontinuous process in the existing technology, and facilitates engineering implementation and automated control.

[0015] (2) The present invention sets up a multi-stage dewatering unit and a sludge loading system on the transport ship, so that the high solids content slurry can be directly converted into a sludge form suitable for long-distance shipping at sea. This not only reduces the transport volume and energy consumption, but also reduces the pressure of shore-based dewatering and storage, which is conducive to forming a coordinated overall development model of "mining mother ship - marine transportation - shore-based treatment".

[0016] (3) The present invention collects and treats the wastewater generated during dehydration before discharging it, which helps to reduce the risk of seawater pollution and takes into account both environmental protection and resource utilization efficiency.

[0017] (4) The present invention focuses on process methods and operation steps, without making too many restrictions on specific equipment models or ship structures. It can be parametrically adjusted according to different deep-sea mining conditions, different mining systems and different transport ship layouts, and has good engineering adaptability and promotion value.

[0018] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0019] Figure 1 This is a flowchart of a deep-sea mining slurry inter-ship transportation method according to the present invention; Figure 2 This is an equipment layout diagram of a deep-sea mining slurry inter-ship transportation method according to the present invention.

[0020] Figure Labels 1. Ore crusher; 2. Pulping machine; 3. Pulp outlet; 4. Grouting port; 5. Screening machine; 6. Centrifuge; 7. Filter press; 8. Heavy-duty gravel pump; 9. Ore slurry; 10. Ore slime. Detailed Implementation

[0021] To make the technical solutions, advantages, and objectives of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below. The described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0022] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0023] Example 1 like Figures 1-2 As shown, the present invention provides a method for transporting deep-sea mining slurry between vessels, the specific steps of which are as follows: Step S1: The ore is crushed on the mother ship to form sub-millimeter-sized mineral powder, which is then mixed with seawater using a dispersant to form a high-solids slurry. This slurry is then temporarily stored in the mother ship's slurry tank and continuously stirred. The specific steps are as follows: Step S11: After screening, the wet ore collected from the seabed is sent to the ore crusher 1 on the deck of the mother ship for crushing, and the particle size of the nodules is controlled to be no greater than 1 mm. The crushed ore powder enters the pulping machine 2, and is mixed with supplementary seawater and dispersant. The solid volume fraction is adjusted to 25% to 35%, so that the particle size of the resulting slurry 9 is refined to the sub-millimeter level and the rheological properties meet the conveying requirements of the hose at a flow rate of 2 to 20 m / s. Step S12: The prepared high-solids slurry 9 is pumped into a container with a volume of approximately 10,000 m³. 3 The mother ship has a slurry storage tank equipped with a level gauge, an exhaust system, and a stirring device. The level is controlled within the range of 40% to 80%. Stirring keeps the slurry uniform and stable, and provides a continuous and stable source of slurry for subsequent pumping.

[0024] Step S2: Deploy floating hoses, connecting both ends to the slurry outlet 3 of the mining mother ship and the slurry injection outlet 4 of the transport ship, forming a slurry transport channel between the two ships. The specific steps are as follows: Step S21: Pre-install a floating hose with a length of about 150m at the bow of the mining mother ship. One end of the hose is connected to the grout outlet pipeline on the mother ship's deck, and the other end is reserved to connect to the grouting pipeline of the transport ship. Step S22: When the ship-to-ship transport operation begins, the mother ship slowly releases the floating hose. With the help of the guide cable device, the free end of the hose is guided to the operation area about 80 to 100 meters away from the mother ship. Step S23: Using the deck operating equipment of the transport ship, lift the free end of the hose to the predetermined position, connect the hose to the grouting pipeline interface of the transport ship and check the sealing performance. At the same time, confirm that the mother ship end of the hose is firmly connected to the grout outlet 3 of the mother ship, thereby forming a continuous transport path of mother ship-hose-transport ship.

[0025] Step S3: Open the outlet valve of the slurry storage tank and start the heavy-duty gravel pump 8 to pump the high-solids slurry to the transport ship through the floating hose. The specific steps are as follows: Step S31: After confirming that the conveying path is completed and all connections are securely sealed, open the outlet valve of the mother ship's slurry storage tank and start the rated flow rate of 4000 m³ / h. 38. Heavy-duty gravel pump with a head of approximately 80m and a flow rate of approximately 8h; Step S32: The slurry in the storage tank is pumped into the deck pipeline of the mother ship via the heavy-duty gravel pump 8, then into the floating hose, flowing towards the transport ship and further into the side feed pipeline of the transport ship. In actual operation, the slurry flow rate is controlled at 2500-3000 m³ / h. 3 Within the range of / h, continuous operation for 4 to 5 hours can complete the inter-ship transfer of one tank of slurry; Step S33: During the transportation process, the system pressure and flow rate are kept within the preset range by adjusting the speed of the slurry pump and the opening of the relevant valves, so as to ensure that the flow velocity in the floating hose is stable and that no sedimentation or blockage occurs.

[0026] Step S4: The transport ship receives the slurry 9 and uses devices such as a screening machine 5, centrifuge 6, and filter press 7 to complete the solid-liquid separation of the slurry 9, forming a low-moisture-content sludge 10, which is then stored in the hold. The tailwater is collected and discharged into the collection tank, treated according to environmental protection requirements, and then discharged into the sea. The specific steps are as follows: Step S41: Distribute the slurry 9 from the floating hose evenly to two dewatering units consisting of a screening machine 5, a centrifuge 6, and a filter press 7 at a set flow rate; wherein the filter press 7 is a belt filter press, and each belt filter press has a processing capacity of approximately 1500 m³. 3 / h; In step S42, the slurry 9 undergoes solid-liquid separation in the dewatering unit, and the filtrate (tailwater) is collected in the collection tank. The moisture content of the filter cake sludge 10 after pressure filtration is controlled within 30%. In step S43, the ore slime 10 is unloaded onto a belt conveyor and transported to the cargo hold of the transport ship. When a total of 15,000–20,000 tons of ore slime has been loaded, the transport ship departs. The ore slime hold is equipped with ventilation and drainage facilities to ensure the stability and safety of the ore slime during navigation. Step S44: Collect the wastewater into the collection tank, and discharge it after sedimentation and filtration treatment according to the operation requirements.

[0027] Step S5: Stop the slurry supply and switch to clean water for online flushing of the entire path from the mother ship to the hose to the transport ship; after flushing to the required standard, close the valves in sequence, disconnect the joints, retrieve the hose, check the equipment reset, and then the transport ship departs. The specific steps are as follows: Step S51: When the predetermined transport volume for this voyage is reached or when operations need to be interrupted, stop supplying slurry 9 to the slurry storage tank, and only retain clean water as the pumping medium, at a rate of 1500-2000 m³ / h. 3 The flow rate is / h to perform online flushing of the entire delivery path from mother ship to hose to transport ship until the liquid at the outlet of transport ship meets the cleaning standard. Step S52: After rinsing is completed, close the valves at both ends of the mother ship and the transport ship in sequence, and disconnect the floating hose from the feed pipe of the transport ship and the discharge pipe of the mother ship. Step S53: Smoothly retrieve the floating hose from the water surface to the designated position on the mother ship, and rinse the outer surface of the hose with clean water and visually inspect it as needed until the hose is completely retracted. After step S54, when the hoses and related equipment are reset, the two vessels are released from mooring, and the transport vessel departs from the work area, thus concluding this slurry transfer operation between vessels.

[0028] It is worth noting that all contents not described in detail in this invention are existing technologies and are well known to those skilled in the art.

[0029] Therefore, this invention provides a method for transporting ore slurry between deep-sea mining vessels. By constructing a closed-loop continuous ore slurry transport operation process, the ore slurry is dehydrated and shaped at sea at the transport vessel end, solving the problems of dust and tailwater pollution from the source of the process. Furthermore, it can be flexibly adjusted according to different deep-sea mining scenarios, ultimately achieving a synergistic improvement in the efficiency, environmental protection, and engineering adaptability of deep-sea mining ore transport between vessels.

[0030] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for transporting deep-sea mining slurry between vessels, characterized in that, A continuous process of slurry preparation, pipe laying, pumping, dewatering, and washing is adopted between surface vessels to achieve continuous and stable transportation of ore at sea in slurry form. The specific steps include: Step S1: The ore is crushed on the mining mother ship to form sub-millimeter-sized mineral powder. It is then mixed with seawater using a dispersant to form a high-solids slurry, which is then sent to the mother ship's slurry storage tank for continuous stirring to maintain the uniformity and stability of the slurry. Step S2: Deploy floating hoses, connecting the two ends to the slurry outlet of the mining mother ship and the slurry injection port of the transport ship, respectively, to form a slurry transport channel between the two ships; Step S3: Open the outlet valve of the slurry tank and start the slurry pump to pump the high solids slurry to the transport ship through the floating hose; Step S4: The transport ship receives the slurry and uses one or more of the following dewatering units—screening machine, centrifuge, and filter press—to complete the solid-liquid separation of the slurry, forming sludge with low water content. The sludge is directly stored in the hold via a conveying device, and the tailwater is collected and collected in a collection tank, then treated as required and discharged into the sea. Step S5: Stop the slurry supply and switch to clean water for online flushing of the mother ship, hoses, and transport ship throughout the entire process; after the flushing meets the standards, close the valves in sequence, disconnect the joints, retrieve the hoses, check the equipment reset, and then the transport ship departs.

2. The method for transporting deep-sea mining slurry between vessels according to claim 1, characterized in that, In step S1, the specific steps are as follows: Step S11: The seabed-collected minerals are fed into a crusher for crushing, and then mixed with supplementary seawater, dispersants, and regulators in a slurry tank to adjust the particle size distribution, solid volume fraction, and rheological properties of the slurry. Step S12: The high-solids slurry is transported to the slurry storage tank below the mother ship. The slurry storage tank is equipped with a liquid level monitoring, venting and stirring device to prevent air blockage and to achieve continuous and stable feeding to the subsequent slurry pump, while maintaining the uniformity and stability of the slurry.

3. The method for transporting deep-sea mining slurry between vessels according to claim 2, characterized in that, In step S11, the particle size of the crushed mineral nodules is no greater than 1 mm, the volume fraction of solids in the slurry is adjusted to 25% to 35%, the particle size of the slurry is refined to sub-millimeter level, and the rheological properties meet the conveying requirements of the hose at a flow rate of 2 to 20 m / s.

4. The method for transporting deep-sea mining slurry between vessels according to claim 1, characterized in that, In step S2, the specific steps are as follows: Step S21: Pre-install floating hoses at the bow of the mining mother ship. The length of the floating hoses is determined according to the relative position of the two ships and the conditions of the operating water area. Connection interfaces matching the slurry discharge pipeline of the mining mother ship and the slurry injection pipeline of the transport ship are reserved at both ends of the hoses. Step S22: During the operation, the floating hose is slowly deployed from the mother ship. With the assistance of the deck operation equipment, the free end of the hose is guided to the predetermined docking position on the side of the transport ship. Step S23: Connect both ends of the floating hose to the slurry outlet of the mining mother ship and the slurry injection port of the transport ship respectively, and perform a sealing check to ensure that the connection is firm and form a continuous slurry transportation path of mother ship-hose-transport ship.

5. A method for transporting deep-sea mining slurry between vessels according to claim 1, characterized in that, In step S3, the specific steps are as follows: Step S31: After confirming that the slurry transport path has been completed and all connections are securely sealed, open the outlet valve of the mother ship's slurry storage tank and start the slurry pumps installed on the mother ship. Step S32: The slurry in the storage tank is pumped through the mother ship's deck pipeline to the floating hose by the slurry pump, so that the slurry flows along the conveying channel to the transport ship and further enters the transport ship's feed pipeline. Step S33: By adjusting the speed of the slurry pump and the valve opening, the system flow and pressure are controlled so that the flow rate and pressure drop of the slurry in the conveying channel meet the requirements of continuous conveying and anti-clogging.

6. A method for transporting deep-sea mining slurry between vessels according to claim 1, characterized in that, In step S4, the specific steps are as follows: Step S41: The slurry is transported to the transport vessel through a floating hose, so that the slurry is evenly distributed to multiple dewatering units according to the set flow rate; Step S42: In the dewatering unit, the slurry is subjected to solid-liquid separation to obtain solid sludge and tailings water; Step S43: The solid sludge is transported to the cargo hold of the transport ship for storage via the unloading device and belt conveyor. The sludge hold is equipped with ventilation, drainage and monitoring devices to ensure the safety and stability of the sludge during the voyage. Step S44: Collect the wastewater into the collection tank, and discharge it after sedimentation and filtration treatment according to the operation requirements.

7. A method for transporting deep-sea mining slurry between vessels according to claim 6, characterized in that, In step S42, the moisture content of the slurry is controlled within 30%.

8. A method for transporting deep-sea mining slurry between vessels according to claim 1, characterized in that, In step S5, the specific steps are as follows: Step S51: After completing the predetermined delivery volume, stop supplying slurry to the storage tank, and only retain clean water as the medium to flush the entire delivery path from the mother ship to the hose to the transport ship online until the liquid at the outlet of the transport ship reaches the preset cleanliness level. Step S52: After rinsing to the required standard, close the valves at both ends of the mother ship and the transport ship in sequence, and disconnect the floating hose from the pipeline interfaces of the two ships. Step S53: Retrieve the floating hose from the water surface to the designated storage location on the mother ship, and rinse or inspect the outer surface of the hose with clean water as needed; Step S54: After the hose is fully recovered and the relevant equipment is reset, the two vessels are released from mooring, completing the deep-sea mining slurry transfer operation between vessels.

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