JP7663198B2 - Equipment and method for lifting valuable seabed materials - Google Patents

Description

The present invention relates to an ore lifting device that transports valuable seabed mineral resources to the sea with high efficiency, and an ore lifting method using the same.

Various techniques have been disclosed for ore-lifting methods and ore-lifting devices for transporting and conveying valuable materials such as seabed mineral resources to the sea. Japanese Patent Publication No. 6570000 (JP Patent Publication No. 2019-120063) describes a ring-shaped pipeline in which a downcomer pipe that reaches the seabed from the sea surface and an upcomer pipe that reaches the seabed from the sea surface are connected on the seabed side and the sea surface side, a downcomer pipe that reaches the seabed from the sea surface and an upcomer pipe that reaches the seabed from the sea surface and a U-shaped pipeline in which a downcomer pipe that reaches the seabed from the sea surface and an upcomer pipe that reaches the seabed from the sea surface are connected on the seabed side, or a double pipe in which the inner pipe is an upcomer pipe and the outer pipe is a downcomer pipe, or vice versa, the inner pipe is a downcomer pipe and the outer pipe is an upcomer pipe, a carrier material filled in the ring-shaped pipeline, the U-shaped pipeline, or the double pipe pipeline, and a pressure pump that circulates the carrier material, The device has an entrance for carrying in seabed valuable materials, which is provided on the seabed side of the pipeline, and an exit for collecting seabed valuable materials, which is provided on the sea side of the pipeline, and the carrier material is a mixture of granular material having an average particle size of 0.01 mm to 10 mm and a true density of 0.01 to 8 g/ ^cm3 , and a viscous fluid (claim 1). According to this, since a viscous fluid containing granular material is used for lifting the seabed valuable materials, seabed valuable materials in the form of granular material or lumps having a diameter of 30 mm or more can be lifted with high lifting efficiency.

Patent Publication 6,570,000 also states that the annular (loop) pipeline may be a double-pipe in which the inner pipe is an ascending pipe and the outer pipe is a descending pipe, or vice versa, the outer pipe is an ascending pipe and the inner pipe is a descending pipe. It also states that a pipe diameter that is at least twice the maximum diameter of the valuable granular material is preferable, as this prevents clogging inside the pipe and increases the efficiency of transportation and conveyance.

Patent Publication No. 6570000

On the other hand, it is expected that valuable seafloor materials in large chunks, such as those with a maximum particle size of 50 mm, an 80% particle size of 25 mm, and a wet density of 4.1 g/ ^cm3 , will be lifted (Report on the Comprehensive Assessment of the Seafloor Hydrothermal Ore Deposit Development Plan, December 2018, Agency for Natural Resources and Energy, Ministry of Economy, Trade and Industry). Such large-grain, high-density chunks may sink during lifting. Even for chunks with smaller particle sizes, such as those with a maximum particle size of 10 to 30 mm, it cannot be said that they will not sink during lifting. If chunks including these can be lifted with higher lifting efficiency than with conventional technology, productivity will increase, which is desirable.

The object of the present invention is therefore to provide a device for lifting valuable seabed materials that can lift lump-shaped valuable seabed materials with high lifting efficiency, and a method for lifting valuable seabed materials using the same.

In light of this situation, the inventors conducted extensive research and discovered that a spherical ore model passing along the pipe wall inhibits the deformation of the viscous fluid around the ore model, thereby suppressing the settling of the ore model, and that therefore, by narrowing the pipe line by making the riser pipe into two or more pipe lines, the ore-lifting efficiency can be improved, which led to the completion of the present invention.
That is, the present invention (1) provides an ore-lifting device for valuable materials from the seabed, which has a circulation system pipeline equipped with a downcomer pipe that reaches the seabed from the sea surface and an upcomer pipe that reaches from the seabed to the sea surface, the circulation system pipeline being filled with a viscous fluid that is a carrier material, and the upcomer pipe having two or more flow paths.

The present invention (2) also provides an apparatus for lifting valuable seabed materials as described in (1) above, characterized in that the two or more flow paths are two or more compartment paths separated by partitions inside the riser pipe.

The present invention (3) also provides an apparatus for lifting valuable seabed materials as described in (1) above, characterized in that the riser pipe is made up of two or more pipes, each of which is a flow path.

The present invention (4) also provides an apparatus for lifting valuable seabed materials as described in (3) above, characterized in that the two or more pipes are attached around a central downcomer pipe.

The present invention (5) also provides a device for lifting valuable seabed materials as described in (1) above, which further includes an inlet for transporting valuable seabed materials having a maximum dimension X, the inlet being provided on the seabed side of the circulation pipeline, and the minimum inner dimension Y1 of the flow passage being 1.5 to 5.0 times X.

The present invention (6) also provides a device for lifting valuable seabed materials as described in (5) above, characterized in that the entrance is provided with a screen for separating valuable seabed materials of a maximum dimension X from the valuable seabed materials.

The present invention (7) also provides an apparatus for lifting valuable seabed materials as described in any one of (1) to (6) above, characterized in that the riser pipe or pipes are circular or polygonal pipes with a ratio of the minimum dimension to the maximum dimension of the cross section of 0.5 to 1.

The present invention (8) also provides a method for recovering valuable seabed materials above sea level by filling a circulation system pipeline with a carrier material, which includes a downcomer pipe that reaches the seabed from the sea surface and an upcomer pipe that reaches the sea surface from the seabed, circulating the carrier material with a pump, mixing valuable seabed materials with the carrier material, transporting the valuable seabed materials upward together with the carrier material, and recovering the valuable seabed materials above sea level, wherein the carrier material is a viscous fluid, and the upcomer pipe has two or more flow paths.

According to the present invention, the riser pipe has two or more flow paths, and the flow paths can be narrowed, increasing the probability that the lumps (valuable seabed materials) in the riser pipe will pass along the pipe wall. The lumps passing along the pipe wall inhibit the deformation of the viscous fluid around the lumps, suppressing their settling, making it possible to lift the lumps with higher ore lifting efficiency than in the past. In addition, there is no reduction in the overall flow rate.

FIG. 2 is a cross-sectional view of a riser pipe of the ore lifting apparatus in the first embodiment of the present invention. FIG. 4 is another cross-sectional view of the riser pipe of the ore lifting apparatus in the first embodiment of the present invention. FIG. 4 is another cross-sectional view of the riser pipe of the ore lifting apparatus in the first embodiment of the present invention. FIG. 4 is another cross-sectional view of the riser pipe of the ore lifting apparatus in the first embodiment of the present invention. FIG. 4 is another cross-sectional view of the riser pipe of the ore lifting apparatus in the first embodiment of the present invention. FIG. 2 is a cross-sectional view showing an example of an incomplete partition that divides the inside of a circular pipe. FIG. 11 is a cross-sectional view showing an example of an incomplete partition dividing the inside of a triangular tube. FIG. 2 is a cross-sectional view showing an example of an incomplete partition dividing the inside of a rectangular tube. 1A and 1B are model diagrams illustrating the effect of inhibiting the settling of minerals near the pipe wall of a riser pipe of the present invention, where (A) shows the case where the pipe passes along the pipe axis and (B) shows the case where the pipe passes along the pipe wall. FIG. 2 is a model diagram illustrating the effect of suppressing the settling of minerals near the wall of the riser pipe of the present invention, showing the case where the minerals pass through a narrow flow path. 1 is a schematic diagram of an ore lifting device according to a first embodiment of the present invention; 1 is a diagram illustrating an ore collecting method of an ore lifting device in a first embodiment of the present invention. FIG. FIG. 4 is a cross-sectional view of a riser pipe of an ore lifting apparatus according to a second embodiment of the present invention. FIG. 11 is another cross-sectional view of the riser pipe of the ore lifting apparatus in the second embodiment of the present invention. FIG. 11 is another cross-sectional view of the riser pipe of the ore lifting apparatus in the second embodiment of the present invention. FIG. 2 is a cross-sectional view of a cylindrical container used in a test of a reference example, showing the drop start position. 1 is a graph showing the results of measuring sedimentation in Reference Example 1, in which the horizontal axis represents time (seconds) and the vertical axis represents sedimentation distance (m). 1 is a graph showing the results of sedimentation measurements in Reference Example 2. 1 is a graph showing the results of sedimentation measurements in Reference Example 3. 1 is a graph showing the results of sedimentation measurements in Reference Example 4. 13 is a graph showing the results of sedimentation measurements in Reference Example 5. 1 is a graph showing the results of sedimentation measurements in Reference Example 6. 1 is a graph showing the results of sedimentation measurements in Reference Example 7.

The device for lifting valuable seabed materials (hereinafter also referred to as "minerals") of the present invention has a circulation system pipeline with a downcomer pipe that reaches the seabed from the sea surface and an upcomer pipe that reaches from the seabed to the sea surface, the circulation system pipeline is filled with a viscous fluid that is a carrier material, and the upcomer pipe has two or more flow paths. Examples of the circulation system pipeline include a ring-shaped pipeline in which the downcomer pipe and the upcomer pipe are connected on the seabed side and the sea surface side, a U-shaped pipeline in which the downcomer pipe and the upcomer pipe are connected on the seabed side, and a double pipe in which the inner pipe is the upcomer pipe and the outer pipe is the downcomer pipe, or vice versa, in which the inner pipe is the downcomer pipe and the outer pipe is the upcomer pipe.

The two or more flow paths of the riser pipe may be two or more partitions divided by partitions inside the riser pipe, or the riser pipe may be composed of two or more pipes, and the pipes are the flow paths. In the case of two or more partitions, the cross-sectional area of each partition may be the same or different. In the case of two or more pipes, the cross-sectional area of each pipe (pipe line) may be the same or different. When using two or more flow paths with different cross-sectional areas, if seabed minerals of appropriate particle size are transported to each cross section, the ore lifting efficiency is improved compared to the case where seabed minerals of the same particle size are transported to a flow path of the same cross-sectional area. In this case, at the seabed entrance, the ore is separated by particle size using a screen, and the ore is allocated to the riser pipe of the appropriate diameter according to the particle size, such as allocating coarse ore to the large diameter pipe and fine ore to the small diameter pipe. In the case of two or more pipes, it is preferable to have two or more pipes for one downcomer pipe. In addition, it is preferable that the pipe walls forming two of the two or more pipes abut or are close to each other. It is also preferable that two or more pipes are attached around a central downcomer pipe.

Next, a description will be given of a first embodiment of the ore lifting device of the present invention. In the first embodiment of the ore lifting device, the riser pipe has two or more compartments separated by partitions inside the riser pipe. The cross-sectional outline shape of the riser pipe is not particularly limited, and examples include circular pipes, polygonal pipes, and irregularly shaped pipes with a ratio of the minimum dimension to the maximum dimension of the cross section of 0.5 to 1.0. Examples of polygonal pipes include triangles, rectangles, pentagons, hexagons, and octagons. The maximum dimension of the cross section is the diameter of the smallest circle that contains the cross section, and the minimum dimension of the cross section is the diameter of the largest circle that is contained in the cross section.

In the riser pipe, the number of partition passages partitioned by partitions is two or more, preferably three or more. Specific examples include the riser pipe 11 (Figure 1) in which the inside of a triangular pipe is partitioned by three partitions 111 (triangular partitions) to form four triangular cross-sectional flow passages 11a to 11d, the riser pipe 12 (Figure 2) in which the inside of a square pipe is partitioned by a cross-shaped partition 121 to form four square cross-sectional flow passages 12a to 12d, the riser pipe 13 (Figure 3) in which the inside of a circular pipe is partitioned by a cross-shaped partition 131 to form four sector-shaped cross-sectional flow passages 13a to 13d, and the circulation pipe that is a double pipe. Examples of such pipes include the riser pipe 14 (Fig. 4), in which the inner pipe 142 of the circulating pipe is a downcomer pipe, the outer pipe 141 is an upcomer pipe, and the inside of the outer pipe 141 is divided by four partition walls 143 to form four semi-sector-shaped flow paths 14a-14d, and the riser pipe 15 (Fig. 5), in which the outer pipe 151 of the circulating pipe, which is a double pipe, is a downcomer pipe, the inner pipe 152 is an upcomer pipe, and the inside of the inner pipe 152 is divided by a cross-shaped partition wall 153 to form four fan-shaped flow paths 15a-15d. This narrows the flow path in the riser pipe, shortens the distance between the ascending minerals and the pipe wall, and suppresses the descent of the minerals along the pipe wall. Note that in Figs. 1-3, one or two of the four flow paths may be downcomers, and the other two or three flow paths may be upcomers.

In the first embodiment, the partitions that divide the flow path may be incomplete partitions that are missing a part of the partitions (complete partitions that form a closed cross section). Examples of incomplete partitions include those shown in Figures 6 to 8. Figure 6 (A) shows an incomplete partition that is missing an end (on the pipe wall side) of a cross-shaped partition that divides the inside of a circular pipe, Figure 6 (B) shows an incomplete partition that is missing a center (on the pipe axis) of a cross-shaped partition that divides the inside of a circular pipe, and Figure 6 (C) shows an incomplete partition in which a number of holes (punched holes) are formed in a cross-shaped partition that divides the inside of a circular pipe. Also, Figure 7 (A) shows an incomplete partition that is missing the center of a side of a triangular partition that divides the inside of a triangular pipe, Figure 7 (B) shows an incomplete partition that is missing a corner of a triangular partition that divides the inside of a triangular pipe, and Figure 7 (C) shows an incomplete partition in which a number of holes (punched holes) are formed in a triangular partition that divides the inside of a triangular pipe. Also, Figure 8(A) shows an incomplete partition in which the end (on the tube wall side) of the cross-shaped partition that divides the inside of a square tube is missing, Figure 8(B) shows an incomplete partition in which the center (on the tube axis) of the cross-shaped partition that divides the inside of a square tube is missing, and Figure 8(C) shows an incomplete partition in which multiple holes (punched holes) are formed in the cross-shaped partition that divides the inside of a square tube.

The ratio of the missing portion of the incomplete partition is preferably 10% or less of the side length or circumferential length of the complete partition, in order to clearly divide the flow path and improve the ore lifting efficiency. For example, in Fig. 6(A), the missing portion (l ₁ -l ₂ ) of the straight partition 61, which is a part of the cross-shaped partition, is 10% or less of the circular pipe diameter l ₁ , which is a complete partition, in Fig. 7(B), the missing portion (l ₃ -l ₄ ) of the straight partition 71, which is a part of the triangular partition, is 10% or less of the length l ₃ of the complete partition, and in Fig. 8(C), the missing portion (hole portion) of the straight partition 81, which is a part of the cross-shaped partition, is 10% or less of the straight complete partition.

In the first embodiment, the minimum inner dimension Y1 of the partition passage of the riser pipe partitioned by the partition wall is 1.5 to 5.0 times, preferably 2.0 to 4.0 times, the maximum dimension X of the mineral. The maximum dimension X of the mineral means the dimension of the largest mineral among the many minerals of various sizes present in the riser pipe, and does not mean the maximum dimension when a minimum dimension and a maximum dimension exist in one mineral. The mineral of the maximum dimension X in the riser pipe can be determined, for example, by providing an entrance for carrying in the seabed valuable material of the maximum dimension X, which is provided on the seabed side of the circulation system pipe. An example of such an entrance is the installation of a screen for separating the seabed valuable material of the maximum dimension X from the seabed valuable material. In this way, by setting the minimum inner dimension Y1 of the partition passage of the riser pipe to 1.5 to 5.0 times the maximum dimension X of the mineral, the distance between the rising mineral and the pipe wall is shortened, and the descent of the mineral passing along the pipe wall can be suppressed. An example of the screen is a mesh separation net. When using two or more partitions with different cross-sectional areas, a screen corresponding to each cross section can be installed. This improves the ore-lifting efficiency compared to using a single screen to transport seabed minerals of the same grain size through a passage of the same cross-sectional area.

Next, the effect of suppressing the settling of minerals near the walls of the riser pipe in the present invention will be described with reference to Figures 9 and 10. Both Figures 9 and 10 are schematic diagrams showing a state in which a spherical ore model moves relatively downward (settling) in a carrier material. Figure 9 (A) is a schematic diagram of the inside of a single pipe 16 where an ore model Z passes on the pipe axis, and Figure 9 (B) is a schematic diagram of the inside of a single pipe 16 where an ore model Z passes along the pipe wall. Figure 10 is a schematic diagram of the inside of a pipe where an ore model Z passes through an outer pipe of a double pipe (circular pipe) 16A consisting of an inner pipe 162 and an outer pipe 161 divided by a partition wall 163. In both Figures 9 and 10, the upper figure shows a longitudinal section, and the lower figure shows a transverse section. In FIG. 9(A), when the ore model Z sinks downward on the tube axis of the tube, the carrier material in the front direction (downward in the figure) along which the ore model Z moves must be pushed aside from the side to the back direction (upward in the figure). In order to generate such behavior of the carrier material, the carrier material must undergo large shear deformation around the ore model Z, especially in the area from the lower periphery to the side. In the figure, the arc-shaped dashed line below the arrow is the shear fracture surface. On the other hand, in FIG. 9(B), when the ore model Z sinks downward near the tube wall, the shear deformation of the carrier material is constrained on one side of the ore, that is, on the tube wall side. As a result, the relative downward movement (settling) of the ore model Z is suppressed. In FIG. 10, the diameter of the ore model and the inner dimension of the tube are close, and a large ore model passes through a flow path with a small cross section, and the shear deformation of the carrier material is constrained on both sides. In order to suppress the settling of minerals near the pipe wall, it is preferable that the minimum internal dimension Y1 of the riser pipe compartment be as close as possible to the maximum dimension X of the mineral, i.e., 1.5 times, preferably 2.0 times, as long as the pipe is not clogged. If the minimum internal dimension Y1 of the riser pipe compartment exceeds 5.0 times the maximum dimension X of the mineral, the pipe wall will not have an effect, and suppression of mineral settling cannot be expected. In reality, it is necessary to lift many minerals of various dimensions less than the maximum dimension X by entraining them in the carrier material, so the minimum internal dimension Y1 of the riser pipe compartment is set to 1.5 times or more the maximum dimension X of the mineral.

Examples of valuable seabed materials include manganese crusts, manganese nodules, cobalt-rich crusts, sulfide deposits (hydrothermal deposits), rare earth mud, and methane hydrates that exist on the seabed at depths of several hundred to several thousand meters. The ores may be coarse particles of 0.75 mm or more, or may be high-density aggregates with a maximum particle size of 50 mm or more and a particle density of 4.1 g/ ^cm3 or more.

The carrier material of the first embodiment is used for lifting valuable seabed materials, and is a viscous fluid. The viscous fluid described in Patent Publication No. 657000 can be used as the viscous fluid. That is, the viscous fluid has a viscosity at 5°C (JIS Z8803; method for measuring viscosity of liquids) of 1000 mPa·s or more, preferably 1,300 mPa·s or more, particularly preferably 2,000 mPa·s or more, and even more preferably 3000 mPa·s or more. In addition, the plastic viscosity at 5°C is 100 Pa·s or less, and the yield stress at 5°C is 5 Pa or more. The yield stress and plastic viscosity can be measured using a rotational and vibrational viscometer by a method conforming to JIS Z8803. The viscosity of 5°C is chosen because the temperature of seawater is generally stable at 5°C at depths of several tens of meters or more from the ocean surface, and most of the descending and ascending pipes are exposed to an environment of 5°C. The upper limit of the viscosity of a viscous fluid at 5°C is 100,000 mPa·s. If the viscosity is higher than this, it becomes closer to a solid, and pumping it becomes practically difficult.

The viscous fluid may be water-based, oil-based or emulsion-based, but water-based and emulsion-based fluids are preferred, and water-based fluids such as polymer solutions are particularly preferred because they are inexpensive and easy to handle. Polymer solutions include suspensions. Either natural or synthetic polymers can be used in the polymer solution, but synthetic polymers are preferred because a fluidized material can be obtained with a small blend amount. An example of an emulsion system is mayonnaise, which is a mixture of oil or water and an emulsifier.

As the polymer in the polymer solution, those generally called thickeners, thickening materials, or water absorbents can be used, and examples thereof include bentonite, methylcellulose (MC), sodium carboxymethylcellulose (CMC), polyethylene oxide (PEO), sodium hydroxyethylcellulose (HEC), polyvinyl alcohol (PVA), polyacrylamide (PAAM), sodium polyacrylate, starch, gums, pectin, metal alginates, alginate esters, etc. Examples of gums include guar gum, xinthane gum, gellan gum, and diutan gum. Examples of metal alginates include sodium alginate, calcium alginate, and potassium alginate. These compounds can be used alone or in combination of two or more.

In the first embodiment, the viscous fluid may contain granular material. The granular material described in Japanese Patent Publication No. 657000 can be used as the granular material. The granular material is other than the valuable seabed material and is contained in the viscous fluid before use. The granular material has an average particle size of 0.01 mm to 10 mm, preferably 0.1 to 8 mm, and a true density of 0.01 to 8 g/cm ^3. The average particle size is calculated using a known calculation method obtained from particle size distribution. Such granular material may be derived from rocks, plants or organisms, resin materials, or fiber materials, or may be a mixture thereof. Specific examples include foam beads, glass beads, sand such as silica sand, silt/gravel, wood, and metal powder such as iron powder. The amount of the granular material to be mixed is 0.1 to 80 parts by weight, preferably 0.3 to 60 parts by weight, and more preferably 0.5 to 50 parts by weight, relative to 100 parts by weight of the viscous fluid.

According to the first embodiment, the inside of the riser pipe is divided by partitions to form partition passages, or the minimum inner dimension Y1 of the riser pipe partition passage is set to 1.5 to 5.0 times the maximum dimension X of the mineral, so that the minerals are affected by the pipe walls during lifting. This suppresses settling, and valuable granular and agglomerated materials, which are mineral resources, can be transported and conveyed from the seabed several thousand meters deep to the sea surface with high lifting efficiency, specifically 60% or more, and preferably 80% or more. The lifting efficiency is the value obtained by dividing the lifting speed by the carrier material flow rate.

In the first embodiment, the forces that inhibit the settling of minerals include viscous resistance, buoyancy, and effective bearing capacity. Viscous resistance and buoyancy are borne by the viscous fluid, while effective bearing capacity is borne by the granular material. When the location of the seabed minerals is close to the pipe wall, the viscous resistance and effective bearing capacity are influenced by the pipe wall.

Next, the ore lifting device of the first embodiment and the ore lifting method using the same will be described with reference to FIG. 11. The pipeline in the ore lifting device of the first embodiment is a ring (loop). The ore lifting device 10 has a ring-shaped pipeline 7 that connects a descending pipe 1 that reaches the seabed from the sea surface and an ascending pipe 2 that reaches the sea surface from the seabed on the seabed and on the sea surface, a carrier material 3 filled in the ring-shaped pipeline 7, a pressure pump 4 that circulates the carrier material 3, an inlet 5 for carrying seabed valuable materials provided on the seabed side of the pipeline 7, and a recovery port 6 for recovering seabed valuable materials Z provided on the sea surface side of the pipeline 7. The facility on the sea surface is usually installed on a platform such as an ore lifting ship or an ore lifting float. The ascending pipe 2 has four compartments divided by cross-shaped partitions inside the circular pipe shown in FIG. 3.

The annular (loop) pipeline may be a flexible pipe, for example, a general piping. In the annular pipeline, the lower end of the riser pipe and the lower end of the downcomer pipe may be connected to form a continuous pipe. The riser pipe has four compartments, but the downcomer pipe does not need to have a partition. This is because the downcomer pipe is a return pipe for the carrier material, and does not cause the problem of the sedimentation of seabed minerals of the present invention. Therefore, the cross-sectional area of the compartments of the riser pipe and the flow path cross-sectional area of the downcomer pipe may be the same or different.

The annular pipeline 7 has a pump 4 that circulates the carrier material 3. The pump 4 is a pressure pump, and there are no particular restrictions on where it can be installed as long as it is within the pipeline system. In addition, because the pump 4 is installed within the annular pipeline system, even if there is a large difference in elevation between the delivery port 5 on the seabed and the recovery port 6 on the sea surface, the pump 4 is not subjected to any load other than friction loss on the inner wall of the pipeline, making it possible to efficiently pressure-transport the carrier material 3 or the carrier material 3 containing seabed valuables over long distances.

The annular pipeline 7 has an entrance 5 for carrying seabed valuable materials, which is provided on the seabed side of the pipeline 7. The entrance 5 is a place where granular ore collected from a known ore collector is carried in. It is preferable to provide a double door or a revolving door as the entrance 5, since it can prevent leakage of the carrier material 3 filled in the pipeline. Figure 12 shows a revolving door 5a installed at the entrance 5. The revolving door 5a has a door panel 52 that is cross-shaped in side view with a rotation axis 51 at its center, and is installed to be freely rotatable near the entrance 5. Around the entrance 5, there is a partially arc-shaped upper casing 55 and a partially arc-shaped lower casing 53, in which the door panel of the I-shaped part of the cross shape is in close contact. In addition, the symbol 54 is a plate-shaped body that extends diagonally upward from the upper end of the lower casing 53, which widens the entrance and makes it easier to carry in the ore Z. With the revolving door 5a, the pipeline 7 is always isolated from the outside while the door panel 52 is rotating, and ore Z can be transported into the pipeline 7 while maintaining the pressure inside the pipeline 7.

At the entrance 5, there is also installed a screen 57, which is an optional component, for separating seabed minerals of a maximum dimension X from the seabed minerals. That is, the screen 57 can be, for example, a separation net with openings (sieve mesh) of dimension X, and allows the introduction of seabed minerals smaller than the maximum dimension X from seabed minerals of various sizes, and prevents the introduction of minerals larger than the maximum dimension X. As a result, the minimum inner dimension Y2 of the largest partition passage Y1 of the partition passages divided by partitions in the riser pipe 2 can be set to 1.5 to 5.0 times X.

The annular pipeline 7 also has a recovery port 6 provided on the sea side of the pipeline 7 for recovering valuable seabed material X. An offshore device may also be installed at the recovery port 6. That is, for example, the offshore device has a pressure pump, a separation tank, a crushing device, a mineral processing device, and an adjustment tank. The separation tank employs a gravity settling separation method, and recovers carrier material 3 containing seabed minerals from the bottom end of the separation tank, and circulates carrier material 3 not containing seabed minerals from the top end of the separation tank. A known stone crushing device can be used for the crushing device. The mineral processing device separates the crushed seabed minerals into unwanted minerals and useful minerals, and a known mineral processing device can be used.

Next, a method for lifting valuable seabed materials using the ore lifting device 10 in Figure 11 will be described. First, in the ore lifting device 10 in Figure 11, the pressure pump 4 is operated. This causes the carrier material 3 to circulate inside the annular pipeline 7. Next, an ore collector (not shown) is operated to extract ore Z from, for example, an ore deposit Y on the seabed at a depth of 1,000 m, and this is transported into the pipeline 7 through the inlet 5 of the pipeline 7. The ore Z transported through the inlet 5 is transported upwards in the riser pipe 2 together with the circulating carrier material 3. Because the carrier material 3 is a viscous fluid and the inside of the riser pipe 2 is partitioned by a cross-shaped partition wall 131 as shown in Figure 3, forming a narrow flow path (partition passage), the collected ore Z, whether it is coarse particles, lumps, or high-density particles, flows through the pipe 7 while maintaining the relative position of the granular ore Z as much as possible, and is transported and conveyed with high ore lifting efficiency without settling significantly from the carrier material 3. In particular, although large-sized ores close to the maximum dimension X cannot avoid settling while rising, when they settle downward along the pipe wall, the shear deformation of the carrier material is restrained on the pipe wall side. As a result, it is possible to suppress the relative downward movement (settling) of the ore.

The ore Z transported to the sea is introduced into a separation tank together with the carrier material 3 from the discharge port 6, where it is separated into carrier material 3 containing ore Z and carrier material 3 not containing ore Z. The carrier material 3 containing ore Z is introduced into a crushing device and crushed, and the crushed ore Z is further introduced into a mineral processing device and separated into unwanted ore and useful ore.

According to the first embodiment of the ore lifting device and ore lifting method, a viscous fluid carrier material circulates inside the annular pipeline, and the inside of the ascent pipe is narrowed by partitions, so valuable materials such as lumps and high-density granular materials can be lifted with high ore lifting efficiency, long-distance transportation of approximately 1,000 meters is possible, and no waste is produced.

Next, an ore lifting device and an ore lifting method in the second embodiment will be described. In the second embodiment, the description of the same components as in the first embodiment will be omitted, and the differences will be mainly described. The second embodiment differs from the first embodiment in the riser pipe. That is, in the second embodiment, the riser pipe is a plurality of pipes. In the second embodiment, the circulation system pipeline can be a ring-shaped pipeline that connects the downcomer pipe and the riser pipe on the seabed side and the above sea side, a U-shaped pipeline that connects the downcomer pipe and the riser pipe on the seabed side, and an inner pipe that is the riser pipe.

In the first embodiment, the cross-sectional contour shape of each of the multiple tubes constituting the riser pipe is not particularly limited, and examples thereof include circular or polygonal pipes with a ratio of the minimum and maximum dimensions of the cross section of 0.5 to 1.0. Examples of polygonal pipes include triangles, squares, pentagons, hexagons, and octagons. The definitions of the maximum and minimum dimensions of the cross section are the same as in the first embodiment. The multiple tubes may all have the same shape or different shapes. In addition, the multiple tubes may be attached around a central downcomer pipe or multiple tubes adjacent to a downcomer pipe, and among these, those attached around a central downcomer pipe are preferred.

Specific examples of the riser pipe consisting of multiple pipes include the riser pipe 21 (Figure 13), which is made up of three circular pipes 21a-21c and is a multiple circular pipe with lines connecting the axis centers forming an equilateral triangle; the riser pipe 22 (Figure 14), which is made up of eight circular pipes 221 arranged around a central downcomer pipe 222 (circular pipe); and the riser pipe 23 (Figure 15), which is made up of seven hexagonal pipes with six hexagonal pipes 231 arranged around a central hexagonal pipe 232. Note that, in the three circular pipes in Figure 13, one may be a downcomer pipe and the other two may be riser pipes. Also, in the seven hexagonal pipes in Figure 15, one or more pipes other than the central one may be a downcomer pipe and the other two or more may be riser pipes. This narrows the flow path in the riser pipe, shortens the distance between the ascending minerals and the pipe wall, and suppresses the descent of the minerals along the pipe wall.

In the second embodiment, the minimum inner dimension Y2 of the largest pipe among the two or more pipes that are the rising pipes is 1.5 to 5.0 times, preferably 2.0 to 4.0 times, the maximum dimension X of the mineral. The definition of the maximum dimension X of the mineral is the same as the definition of the maximum dimension of the mineral in the first embodiment. In the second embodiment, as in the first embodiment, the minimum inner dimension Y2 of the pipe can be determined, for example, by providing an entrance for carrying in the seabed valuable material of the maximum dimension X, which is provided on the seabed side of the circulation system pipeline. Examples of such an entrance include the installation of a screen for separating the seabed valuable material of the maximum dimension X from the seabed valuable material. In this way, by setting the minimum inner dimension Y2 of the largest pipe among the two or more pipes that are the rising pipes to 1.5 to 5.0 times the maximum dimension X of the mineral, the distance between the rising mineral and the pipe wall is reduced, and the descent of the mineral passing along the pipe wall can be suppressed. In addition, when two or more pipes with different cross-sectional areas are used, appropriate screens corresponding to each cross section may be installed respectively. This improves ore-lifting efficiency compared to transporting seabed minerals of the same particle size sorted by a single screen through two or more channels of the same cross-sectional area.

In the second embodiment, the effect of inhibiting the settling of minerals near the walls of the riser pipe is similar to the effect of inhibiting the settling of minerals passing along the walls of the riser pipe in the first embodiment, and a description thereof will be omitted.

In the second embodiment, the explanation of the seabed valuable material and the carrier material is the same as the explanation of the seabed valuable material and the carrier material in the first embodiment, and the explanation is omitted.

According to the second embodiment, by forming the riser pipe from a plurality of pipes, or by setting the minimum inner dimension Y1 of the pipe with the largest inner dimension among the plurality of pipes of the riser pipe to 1.5 to 5.0 times the maximum dimension X of the mineral, the mineral is affected by the pipe wall during lifting. As a result, settling is suppressed, and valuable materials in the form of granules and lumps, which are mineral resources, can be transported and conveyed from the seabed several thousand meters deep to the sea surface with high lifting efficiency, specifically 60% or more, preferably 80% or more. In the second embodiment, the force suppressing the settling of the mineral is the same as in the first embodiment, and a description thereof will be omitted.

Next, a second embodiment of the ore lifting equipment and an ore lifting method using the same will be described (not shown). The ore lifting equipment of the second embodiment is the same as the ore lifting equipment of the first embodiment shown in Figure 11, except that the riser pipe is the three circular pipes shown in Figure 13. Therefore, only the differences from the ore lifting equipment of the first embodiment and the ore lifting method using the same will be described below.

In the annular (loop) pipeline, the lower end of the riser pipe 2 and the lower end of the downcomer pipe 3 are connected to form a continuous pipe. The downcomer pipe 3 is circular in shape, and its cross-sectional area is approximately the same as the total cross-sectional area of the three riser pipes 2. An inlet 5 for transporting seabed minerals is provided at the connection between the downcomer pipe 3 and the riser pipe 2. The connection between the downcomer pipe 3 and the inlet 5 and between the inlet 5 and the riser pipe 2 may be liquid-tight to prevent the carrier material from leaking into the surrounding sea area or seawater from mixing into the pipe. Note that the cross-sectional area of the downcomer pipe 3 in this example may be larger or smaller than the total cross-sectional area of the three riser pipes 2.

Next, a method for lifting valuable materials from the seabed using the ore lifting device of the second embodiment will be described. First, the pressure pump is operated in the ore lifting device. This causes the carrier material to circulate in the annular pipeline. Next, the ore collector is operated to collect granular ore Z from, for example, an ore deposit Y on the seabed at a depth of 1,000 m, and transport it into the riser pipe from the inlet of the pipeline. The granular ore Z transported from the inlet is transported upward through the three pipes that are the riser pipes, accompanied by the circulating carrier material. Although large ores close to the maximum dimension X cannot avoid settling while rising, the three pipes each have a narrow flow path, so that when they settle downward along the pipe wall, the shear deformation of the carrier material is restrained on the pipe wall side. As a result, it is possible to suppress the relative downward movement (settling) of the ore.

According to the second embodiment of the ore lifting device and ore lifting method, a viscous fluid carrier material circulates inside a circular pipeline, and the ascent pipe is made up of multiple pipes, so valuable materials such as lumps and high-density granular materials can be lifted with high ore lifting efficiency, long-distance transportation of approximately 1,000 meters is possible, and no waste is produced.

In the first and second embodiments, the ore lifting device and ore lifting method are not limited to the above-mentioned embodiment examples, and the pipeline may be U-shaped, with the downcomer pipe and the upcomer pipe connected on the seabed side and not connected on the sea surface side. In this case, a return pipe is installed on the sea surface side between the upcomer pipe and the downcomer pipe to return the carrier material to the downcomer pipe.

The ore lifting device and ore lifting method of the present invention are not limited to the above embodiment, and various modifications can be made. For example, in the riser pipes of Figures 1 to 3, the number of partition passages can be two, three, or five or more by changing the shape and number of partitions. In this case, the cross-sectional areas of the partition passages may be the same or different. In the double pipe of Figure 4, both the inner pipe and the outer pipe may be riser pipes. In this case, the inner pipe may be partitioned by a partition. In the double pipe of Figure 5, both the inner pipe and the outer pipe may be riser pipes. In this case, the outer pipe may be partitioned by a partition. In addition, Figures 4 and 5 are not limited to double pipes, and may be triple pipes or more. When triple pipes or more are used as riser pipes, the inner pipe becomes the partition, so the partitions with a straight cross section can be omitted. In addition, as a method for separating seabed valuable materials of the maximum dimension X from seabed ore, a known separation method other than a screen can be used. For example, a mineral sorting machine separate from the ore lifting device may be operated on the seabed, and the seabed minerals with a maximum dimension X may be selected by the mineral sorting machine, which may then be dumped into the loading port by a shovel. Alternatively, a search machine capable of measuring the size of minerals may be operated on the seabed to determine the maximum dimension X of the seabed minerals in advance. In this case as well, the installation of a screen may be omitted.

(Sedimentation test)
Next, in order to verify the settling behavior of the ore occurring near the wall of the riser pipe in the ore lifting apparatus and ore lifting method of the present invention, the following settling test was carried out as a reference example.

Reference Example 1 (Sedimentation Test No. 1)
A cylindrical acrylic container 31 having a height of 4 m and an inner diameter of 100 mm as shown in Figure 16 was filled with carrier material, and a spherical ore model simulating valuable seabed material was dropped from the top of the cylindrical container, and the relationship between the time required for the ore model to sink and the sinking distance was determined.

<Ore model A (sedimentary material)>
A perfect sphere made of zirconia with a diameter of 50.8 mm and a density of 6.00 g/ ^cm3 was used. This ore model A has a size and specific gravity equal to or greater than that of ore Z, which is a valuable seabed material. A perfect sphere is a sphere whose cross section is nearly a perfect circle.

<Carrier Material A>
77.9% by mass of tap water, 7.1% by mass of bentonite, and 15.0% by mass of silica sand (No. 6) were mixed in a container to prepare carrier substance A. Carrier substance A had a plastic viscosity of 56 Pa·s, a yield stress of 38.9 Pa, and a density of 1.38 g/cm ³ at 25° C. The yield stress and plastic viscosity were measured using a rotational viscometer in accordance with JIS Z 8803: Method for measuring viscosity of liquids.

<Test Method>
The temperature of the carrier material was 5°C, which corresponds to the seabed temperature. However, since the viscosity of carrier material A at 5°C and 25°C is almost the same, it was determined that there was almost no effect of temperature, and the experiment was performed at room temperature (25°C). In addition, silica sand (No. 6) was used in a state where it was uniformly dispersed in the carrier material. First, the ore model was buried under the liquid surface, and the center of the ore model A was held at a depth of 100 mm below the liquid surface. After waiting about 20 seconds until the liquid surface was stationary, the ore model was gently released. Next, the elapsed time and the sinking distance were measured. The falling start position was measured at two points, on the pipe axis (position _Z2 ) and along the pipe wall (position _Z1 ) (see Figure 16). The results are shown in Figure 17. In Figure 17, the symbol △ indicates on the pipe axis, the symbol ▲ indicates along the pipe wall, and the thick straight solid line indicates the predicted value.
(Prediction of settling on the tube axis)

このように、管軸上での沈降予測値は、上記式（１）及び式（２）により、計算により求めることができる。式（１）及び式（２）は、重力場で静止したビンガム流体の中を完全球が一定の速さ（自由落下した時の終端速度）で沈降することを仮定して求められる。よって、管あるいは管壁の存在を考慮していない条件に相当する。

In this way, the predicted sinking value on the tube axis can be calculated using the above formulas (1) and (2). Formulas (1) and (2) are calculated on the assumption that a perfect sphere sinks at a constant speed (terminal velocity in free fall) in a stationary Bingham fluid in a gravitational field. Therefore, these conditions do not take into account the presence of the tube or the tube wall.

In Reference Example 1, the (pipe diameter)/ore model diameter) is 2.0, and the ore model and pipe wall are close to each other even on the pipe axis. From Figure 17 and the results of the settling prediction on the pipe axis, the time it takes for the ore model to sink 3 m is the same on the pipe axis and the pipe wall, or is shorter along the pipe wall. In the measurement results for both drop start positions, the time it takes for the ore model to sink 3 m was several tens of times the predicted value. Thus, in Reference Example 1, the settling speed of the ore model was suppressed regardless of the starting position of the ore model's introduction.

Reference Example 2 (Sedimentation Test No. 2)
<Test Method>
The test was carried out in the same manner as in Example 1, except that an alumina perfect sphere with a diameter of 15.9 mm and a density of 3.82 g/ ^cm3 was used as the ore model B, and a mixture of 93.2 mass% tap water and 6.8 mass% bentonite was used as the carrier material B. The plastic viscosity of the carrier material B at 25°C was 3.6 Pa·s, the yield stress was 12.6 Pa, and the density was 1.12 g/ ^cm3 . The results are shown in Figure 18. In Figure 18, the symbol ◯ indicates the axis of the tube, the symbol ● indicates the tube wall, and the thick straight solid line indicates the predicted value.

In Reference Example 2, the (pipe diameter/ore model diameter) is 6.3, and the ore model on the pipe axis is away from the pipe wall. From the results in Figure 18, the time it takes for the ore model charged along the pipe wall to sink 3 m is one-tenth of that on the pipe axis. In addition, the predicted value when charged on the pipe axis was close to the measured value when charged on the pipe axis. This shows that the ore model passing along the pipe wall is prevented from sinking by the pipe wall. This is thought to be because the pipe wall restricts the shear deformation of the carrier material for the sinking ore model.

Reference Example 3 (Sedimentation Test No. 3)
<Test Method>
A complete zirconia sphere (ore model C) with a diameter of 25.4 mm and a density of 5.97 g/ ^cm3 was used, and the same test method as in Reference Example 1 was used, except that the carrier material A in Reference Example 1 was used. The results are shown in Figure 19. Note that in Reference Example 3, no calculation was performed to predict sedimentation along the tube axis. In Figure 19, the symbol △ indicates the tube axis, and the symbol ▲ indicates along the tube wall.

Reference Example 4 (Sedimentation Test No. 4)
<Test Method>
The test was carried out in the same manner as in Reference Example 3, except that a mixture of 91.6 mass % tap water and 8.4 mass % bentonite (carrier material C) was used instead of carrier material A. The results are shown in Fig. 20. That is, Reference Example 4 is the same as Reference Example 3, except that the blending of silica sand (No. 6) in the carrier material was omitted.

From the results of Reference Examples 3 and 4, where the (pipe diameter/ore model diameter) is 3.9, the time it took for the ore model inserted along the pipe wall to sink 3 m was a fraction of the time it took on the pipe axis. This shows that the pipe wall suppresses the sinking of the ore model passing along the pipe wall. This is thought to be because the pipe wall restricts the shear deformation of the carrier material for the sinking ore model. It is also clear that when silica sand (No. 6) is included in the carrier material, the sinking of the ore model is significantly suppressed both on the pipe axis and along the pipe wall.

Reference Example 5 (Sedimentation Test No. 5)
<Test Method>
The test was carried out in the same manner as in Reference Example 1, except that a perfect zirconia sphere (ore model D) with a diameter of 12.7 mm and a density of 5.70 g/ ^cm3 was used, and a mixture (carrier material D) of 65.2 mass% tap water, 4.8 mass% bentonite, and 30.0 mass% silica sand (No. 6) was used. The results are shown in Figure 21. Note that in Reference Example 5, no calculation was performed to predict settling along the tube axis. In Figure 21, the symbol △ indicates the tube axis, and the symbol ▲ indicates along the tube wall.

Reference Example 6 (Sedimentation Test No. 6)
<Test Method>
The test was carried out in the same manner as in Reference Example 5, except that a mixture of 93.2 mass% tap water and 6.8 mass% bentonite (carrier material B) was used instead of carrier material D. The results are shown in Figure 22. That is, Reference Example 5 is the same as Reference Example 4 except that the blending of silica sand (No. 6) in the carrier material is omitted. In Figure 22, the symbol △ indicates the pipe axis and the symbol ▲ indicates the pipe wall.

From the results of Reference Examples 5 and 6, it was found that the time it took for the ore model introduced along the pipe wall to sink 3 m was one-tenth of that taken on the pipe axis. This shows that the pipe wall inhibits the sinking of the ore model passing along the pipe wall. It was also found that when silica sand (No. 6) was included in the carrier material, it significantly inhibited the sinking of the ore model both on the pipe axis and along the pipe wall.

Reference Example 7 (Sedimentation Test No. 7)
<Test Method>
The test was carried out in the same manner as in Reference Example 1, except that a perfect alumina sphere (ore model E) with a diameter of 19.1 mm and a density of 3.83 g/ ^cm3 was used, and a mixture (carrier material E) of 79.1 mass% tap water, 5.9 mass% bentonite, and 15.0 mass% silica sand (No. 6) was used. The results are shown in FIG. 23. In Reference Example 7, calculations for predicting sedimentation on the pipe axis were not performed. In FIG. 23, the symbol ◯ indicates the pipe axis, and the symbol ● indicates along the pipe wall. From the results of Reference Example 7, the time it took for the ore model introduced along the pipe wall to sink 3 m was several tenths of that on the pipe axis. This shows that the pipe wall suppresses the sedimentation of the ore model passing along the pipe wall.

According to the present invention, granular and lump seabed ore can be lifted with high lifting efficiency.

REFERENCE SIGNS LIST 1 Downcomer pipe 2 Upcomer pipe 3 Carrier material 4 Pressure pump 5 Delivery inlet 6 Recovery port 7 Pipe 10 Ore lifting device 11-15 Upcomer pipe with compartments 21-23 Upcomer pipe consisting of multiple pipes
Z Ore

Claims (9)

An ore lifting device having a circulation system pipeline including a downpipe that reaches the seabed from the sea surface and an uppipe that reaches the sea surface from the seabed,
The circulatory system is filled with a viscous fluid that is a carrier material,
The riser has two or more flow paths;
The minimum inner dimension Y1 of the flow passage is 1.5 to 5.0 times the maximum dimension X of the seabed resource material to be lifted . The device for lifting valuable seabed materials according to claim 1, characterized in that the two or more flow paths are two or more compartment paths separated by partitions inside the riser pipe. 2. The apparatus for lifting valuable materials from the seabed according to claim 1, wherein said riser pipe comprises two or more pipes, said two or more pipes being two or more flow passages. The apparatus for lifting valuable seabed materials according to claim 3, characterized in that the two or more pipes are attached around a central downcomer pipe. 2. The apparatus for lifting valuable materials from the seabed according to claim 1, further comprising an entrance for carrying in valuable materials from the seabed having a maximum dimension X, the entrance being provided on the seabed side of said circulating pipeline. The device for lifting valuable seabed materials according to claim 5, characterized in that the entrance is provided with a screen for separating valuable seabed materials of a maximum dimension X from the valuable seabed materials. 2. The apparatus for lifting valuable materials from the seabed according to claim 1, wherein said riser pipe is a circular pipe or a polygonal pipe with a ratio of the minimum dimension to the maximum dimension of the cross section of 0.5 to 1. 5. The apparatus for lifting valuable materials from the seabed according to claim 3, wherein said two or more pipes are circular or polygonal pipes with a ratio of the minimum dimension to the maximum dimension of the cross section of 0.5 to 1. A method for lifting valuable materials from the seabed, comprising filling a circulation pipeline having a downcomer pipe extending from the sea surface to the seabed and an upcomer pipe extending from the seabed to the sea surface with a carrier material, circulating the carrier material with a pump, mixing the valuable materials from the seabed into the carrier material, transporting them upward together with the carrier material, and recovering the valuable materials from the seabed on the sea surface, wherein the carrier material is a viscous fluid, the upcomer pipe has two or more flow paths, and the minimum inner dimension Y1 of the flow paths is 1.5 to 5.0 times the maximum dimension X of the valuable materials from the seabed to be lifted .

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