JP6762150B2 - Underwater resource collection method and system - Google Patents

Description

The present invention relates to a method and system for collecting bottom resources, and more particularly to a method and system for collecting bottom resources capable of efficiently collecting specific resources contained in water bottom sediments.

In the development of marine resources, sediments containing marine resources such as rare earths are collected by pump lifts, air lifts, etc. on unloading vessels. Then, the collected sediment is transported to the beneficiation facility by using a shuttle ship or the like, and the beneficiation is performed at the beneficiation facility. The proportion of marine resources contained in sediments is very small. Therefore, a huge amount of sediment is collected from the seabed in order to collect a small amount of marine resources. Along with this, a large amount of cost is required for the collection and transportation of sediment. Further, after the sediment is beneficiated and left behind, a large amount of unnecessary substances such as tail ore and residue remains, and therefore, a large amount of cost is required for disposal of these unnecessary substances.

Therefore, there has been proposed a sediment transport method capable of reducing the energy required to transport the sediment deposited on the water bottom onto the water surface (see Patent Document 1). In this sediment transport method, the cost required for the collection of sediment is reduced by transporting the sediment onto the water using hydrogen gas and oxygen gas generated by electrolyzing water near the bottom of the water. Can be done. However, with this method, since the yield of sediment is the same as before, it is not possible to reduce the cost required for transporting sediment and disposing of unnecessary matter.

Japanese Unexamined Patent Publication No. 2015-74925

An object of the present invention is to provide a method and a system for collecting a bottom resource that can efficiently collect a specific resource contained in the sediment on the bottom of the water.

In order to achieve the above object, the method for collecting bottom resources of the present invention is arranged in water in the method for collecting bottom resources by lifting a specific resource contained in the sediment on the bottom of the water onto the water. Using a cyclone-type centrifuge, coarse-grained deposits containing more coarse-grained sediments with relatively large particle sizes and fine-grained sediments containing more fine-grained particles with relatively small particle sizes. By continuously classifying into minutes, the resources are unevenly distributed in either the coarse-grained deposits or the fine-grained sediments, and the one-sided deposits in which the resources are unevenly distributed are placed on the water. It is characterized in that it is transported and one of the other said deposits remains on the bottom of the water.

The underwater resource extraction system of the present invention is a cyclone type centrifugal separation arranged in water in a submarine resource extraction system provided with a lifting means for transporting a specific resource contained in the sediment on the bottom of the water onto the water. It has an apparatus, an inflow means for inflowing the sediment into the centrifuge, and a connecting portion for connecting the centrifuge and the lifting means, and the centrifuge relatively causes the deposit. The resources are continuously classified into coarse-grained deposits containing more coarse-grained particles having a large particle size and fine-grained sediments containing more fine-grained particles having a relatively small particle size. One of the deposits, which is unevenly distributed in one of the deposit and the fine-grained deposit, and the resource is unevenly distributed, is sent to the lifting means through the connecting portion, and the other deposit is It is characterized in that it is configured to be discharged into water from the centrifuge.

According to the method and system for collecting bottom resources of the present invention, coarse-grained sediments and fine-grained sediments are deposited on the bottom of the water containing a specific resource by using a cyclone-type centrifuge placed in water. By classifying into minutes, resources are unevenly distributed in one of the sediments. Then, only one of the sediments in which a specific resource is unevenly distributed is extracted and transported onto the water, and the other sediment remains on the bottom of the water. As a result, the resources existing on the bottom of the water can be efficiently collected because the resources can be transported to the water in a concentrated state while reducing the total amount of sediments to be transported to the water. Along with this, it is advantageous to reduce the work and cost of disposing of unnecessary materials. Further, by classifying using a cyclone type centrifuge, it is possible to set the classification boundary particle size to a very small particle size.

When the classification boundary particle size by the centrifuge is in the range of 10 μm or more and 30 μm or less and the resources are unevenly distributed in the coarse grain deposits, the resources having the characteristic of being unevenly distributed in the coarse grain deposits in water are efficiently distributed. Can be collected in. The resource is, for example, a rare earth concentrated in a phosphate of biological origin.

The inflow rate of the sediment into the centrifuge device by the inflow means is variable, and by changing the inflow rate, the classification boundary particle size by the centrifuge device can be changed. With this configuration, the classification boundary particle size can be appropriately changed according to the resource to be collected, which is more advantageous for efficiently collecting the resource. In addition, it can be used for collecting various bottom resources, which makes it extremely versatile.

It is explanatory drawing which illustrates the embodiment of the underwater resource extraction system of this invention. It is an enlarged explanatory view of the centrifuge device of FIG. 1 and its vicinity. It is explanatory drawing which illustrates the internal situation of the centrifuge of FIG. 2 in the vertical cross-sectional view. It is explanatory drawing which illustrates the centrifuge device of FIG. 3 in the cross-sectional view of AA. It is explanatory drawing which illustrates another embodiment of the underwater resource extraction system of this invention. It is an enlarged explanatory view of the centrifuge device of FIG. 5 and its vicinity. It is a graph which shows the particle size distribution of the sediment (raw mud) before classification by the centrifuge, and the sediment after classification.

Hereinafter, the method and system for collecting the bottom resource of the present invention will be described based on the embodiment shown in the figure.

The present invention is a method and system for collecting a specific resource 20c contained in the sediment 20 on the bottom B by lifting it onto the water. In the embodiment illustrated in FIGS. 1 to 4, the case where the rare earth contained in the muddy sediment 20 is collected as the resource 20c is shown.

As shown in FIG. 1, the bottom resource sampling system 1 (hereinafter referred to as the sampling system 1) of the present invention includes a lifting means 2 for lifting the sediment 20 on the bottom B onto the water and a cyclone arranged in the water. It has a type centrifuge 3, an inflow means 4 for flowing sediment 20 into the centrifuge 3, and a connecting portion 5 for connecting the centrifuge 3 and the lifting means 2.

Further, in this embodiment, the mining means 6 for mining the sediment 20 on the bottom B, the storage tank 7a for storing the mined sediment 20, and the discharge pipe 8 connected to the centrifuge 3 are provided. There is. A unloading vessel 9 is connected to the unloading means 2, and a support vessel 10 is connected to the mining means 6 via a cable 10c.

The unloading means 2 has a unloading device 2a and a unloading pipe 2b that connects the unloading device 2a and the unloading vessel 9. The lift device 2a is composed of, for example, an air lift pump, a slurry pump, a sand pump, or the like.

The centrifuge 3 uses centrifugal force to separate the coarse-grained sediment 20a containing a larger amount of coarse-grained sediment 20 having a relatively large particle size and the fine-grained sediment 20a having a relatively small particle size. It is classified into a fine grain deposit 20b containing a large amount. As shown in FIGS. 2 to 4, the inside of the centrifuge 3 has a truncated cone shape in which the inner diameter of the lower portion is smaller than the inner diameter of the upper portion. An inflow port 3a is provided in the upper part of the centrifuge device 3, and a descending vortex that flows downward along the inner wall of the centrifuge device 3 by allowing the sediment 20 to flow in from the inflow port 3a at high speed. The structure is such that an ascending vortex that flows upward is generated in the center of the centrifuge device 3.

When the sediment 20 flows in from the inflow port 3a, the coarse-grained sediment 20a, which has a relatively large specific gravity, is greatly affected by the centrifugal force due to the descending vortex, and therefore descends while swirling along the inner wall along the descending vortex. Then, it is discharged from the underflow outlet 3b provided below the centrifuge device 3. On the other hand, the fine-grained deposit 20b, which has a relatively small specific gravity, rises along the central rising vortex because the influence of the centrifugal force due to the falling vortex becomes smaller, and overflow provided above the centrifuge 3. It is discharged from the outlet 3c.

The size of the particle size at the boundary of classification by the centrifuge 3 (hereinafter referred to as the classification boundary particle size) can be appropriately determined according to the type of the resource 20c to be collected and the like. The classification boundary particle size can be changed by changing the size of the centrifuge device 3 itself or the inflow rate of the deposit 20 flowing into the centrifuge device 3. It is also possible to connect a plurality of centrifuges 3 to classify the deposit 20 in several stages.

The inflow means 4 has an inflow device 4a and an inflow pipe 4b. The inflow device 4a is composed of, for example, a slurry pump, a sand pump, or the like. The inflow device 4a of this embodiment is arranged inside the storage tank 7a. The inflow device 4a is connected to the inflow port 3a via the inflow pipe 4b. The inflow device 4a has a variable specification that allows the inflow rate of the sediment 20 to the centrifuge 3 to be arbitrarily changed or in several steps. In this way, it can be used for collecting various resources 20c without replacing the centrifuge device 3, so that the versatility is very high.

The connecting portion 5 is a pipe body that connects any one of the underflow outlet 3b and the overflow outlet 3c of the centrifuge 3 and the lifting means 2. In this embodiment, the underflow outlet 3b and the lifting means 2 are connected. Is connected to. The discharge pipe 8 is connected to either the underflow outlet 3b or the overflow outlet 3c to which the connecting portion 5 is not connected.

Rare earths have the property of concentrating on phosphates of biological origin. Phosphates in which rare earths are concentrated are mostly distributed in coarse particles having a relatively large particle size of about 20 μm to 125 μm, and the content ratio of rare earths distributed in fine particles of 20 μm or less is small. Therefore, in this embodiment, the underflow outlet 3b and the collection device 2a are connected by the connecting portion 5, and the discharge pipe 8 is connected to the overflow outlet 3c.

The mining means 6 has a mining device 6a for mining the sediment 20 and a connecting pipe 6b. The mining device 6a and the storage tank 7a are connected via a connecting pipe 6b, and the sediment 20 mined by the mining device 6a is sequentially sent to the storage tank 7a through the connecting pipe 6b. As the mining device 6a, various types of construction machines and underwater robots can be adopted depending on the state of the sediment 20 to be mined and the working environment. The mining device 6a may be configured to be operated by a worker on board, or may be configured to be remotely controlled from the water.

The mining device 6a of this embodiment includes a rotary blade for excavating the deposit 20 and a suction facility for sucking the excavated sediment 20 and sending it to the connecting pipe 6b. The support ship 10 supplies power to the mining device 6a through the cable 11a.

Next, a method of collecting a specific resource 20c using this collection system 1 will be described below.

First, the mining device 6a is operated to mine the muddy sediment 20 on the bottom B containing the resource 20c (for example, rare earth). In this embodiment, while excavating the deposit 20 with the rotary blade of the mining device 6a, the sediment 20 excavated by the suction facility is sucked together with the surrounding water. The sediment 20 mined by the mining device 6a is sequentially sent to the storage tank 7 through the connecting pipe 6b.

The deposit 20 stored in the storage tank 7 is made to flow into the inflow port 3a of the centrifuge device 3 through the inflow pipe 4b by the inflow device 4a. The inflow rate of the deposit 20 into the centrifuge device 3 by the inflow device 4a is appropriately set according to the classification boundary particle size.

The classification boundary particle size suitable for unevenly distributing the resource 20c to either the coarse-grained deposit 20a or the fine-grained sediment 20b differs depending on the type of the resource 20c and the state of the deposit 20 containing the resource 20c. .. Therefore, it is advisable to carry out an experiment or the like in advance to grasp the classification boundary particle size capable of efficiently unevenly distributing the resource 20c to be collected.

As described above, rare earths have a characteristic of being unevenly distributed in coarse-grained deposits 20a having a particle size of 20 μm or more. Therefore, when the resource 20c is a rare earth, the classification boundary particle size may be set in the range of 10 μm or more and 30 μm or less.

Rare earths are contained in the sediments having a particle size of 20 μm or less, although the content ratio is small. Therefore, when the amount of the sediment 20 that can be mined is small, it may be preferable to set the classification boundary particle size to 20 μm or less. However, if the classification boundary particle size is smaller than 10 μm, the content ratio of rare earth contained in the coarse-grained sediment to be collected decreases, so that the efficiency is reduced.

When the classification boundary particle size is set to be larger than 20 μm, it is possible to increase the content ratio of rare earth in the coarse-grained sediment 20a to be collected. Therefore, when the amount of the deposit 20 that can be mined is large and efficiency is important, the classification boundary particle size should be set to 20 μm or more. However, if the classification boundary particle size is made larger than 30 μm, the amount of rare earth discharged from the overflow outlet 3c increases. Therefore, the classification boundary particle size is set to, for example, 20 μm.

In the centrifuge 3, the sediment 20 flowing in from the inflow port 3a contains more coarse-grained deposits 20a having a relatively large particle size and more fine-grained particles having a relatively small particle size. It is continuously classified into the fine-grained deposit 20b containing it. The coarse-grained deposit 20a classified by the centrifuge 3 is discharged to the underflow outlet 3b, and the fine-grained deposit 20b is discharged to the overflow outlet 3c. The resource 20c is unevenly distributed in either the coarse-grained deposit 20a or the fine-grained sediment 20b.

Then, one of the deposits in which the resource 20c is unevenly distributed is sent to the lifting device 2a through the connecting portion 5, and is transported to the lifting ship 9 on the water through the lifting pipe 2b. The other sediment, which has a relatively low content of the resource 20c, is discharged to the water or the bottom B through the discharge pipe 8 and remains on the bottom B.

In this embodiment, the resource 20c to be collected is used as a rare earth, and the classification boundary particle size by the centrifuge 3 is set to 20 μm. Therefore, the sediment 20 contains coarse particles having a particle size of 20 μm or more. It is classified into a deposit 20a and a fine grain deposit 20b containing more fine particles having a particle size smaller than 20 μm. Most of the rare earths contained in the deposit 20 are unevenly distributed in the coarse-grained deposit 20a together with the phosphate of biological origin.

Then, the rare earth is discharged to the underflow outlet 3b together with the coarse-grained sediment 20a, passes through the connecting portion 5, and is lifted onto the water by the lifting means 2. The fine-grained sediment 20b containing almost no rare earth is discharged to the underflow outlet 3b, passes through the discharge pipe 8, is discharged into water from the discharge port of the discharge pipe 8, and remains on the bottom B.

As described above, in the present invention, by using the centrifuge 3 placed in water to classify the coarse-grained sediment 20a and the fine-grained sediment 20b, one of the sediments can be collected at the underwater stage. The specific resource 20c is unevenly distributed. Then, only the sediment in which the resource 20c is unevenly distributed is extracted and transported onto the water, and one of the other is left on the bottom B of the water. Therefore, the resource 20c existing on the bottom B can be efficiently collected because the resource 20c can be transported to the water in a concentrated state while reducing the total amount of sediment to be transported onto the water. Along with this, it is possible to significantly reduce the cost required for transporting the collected sediment and disposing of unnecessary materials.

Further, in the conventional method, when the resource 20c contained in the sediment 20 has a low content rate, it is difficult to collect and use it because the cost effectiveness in the collection business is low. However, by adopting the present invention, even if the resource 20c has a low content, efficient collection becomes possible, so that it becomes easy to promote the collection business.

In the present invention, since the centrifuge device 3 is used as a means for classifying the deposit 20, the classification boundary particle size can be set to a very small particle size. Therefore, even when the classification boundary particle size suitable for unevenly distributing the resource 20c is small, as in the case of collecting rare earths, it is possible to perform classification with high accuracy. Moreover, the centrifuge 3 can continuously and quickly classify a large amount of deposits 20. The sediments that are continuously classified and the resources 20c are unevenly distributed are continuously lifted onto the water by the lifting means 2, which is extremely advantageous for improving the collection efficiency.

5 and 6 show another embodiment of the sampling system 1 of the present invention. In the previous embodiment, the case of collecting the resource 20c having the property of concentrating on the coarse grain deposit 20a has been described, but in this embodiment, the property of concentrating on the fine grain deposit 20b having a certain particle size or less has been described. An example will be given in the case of collecting the resource 20c having the above.

In the sampling system 1 of this embodiment, the mining device 6a includes a storage tank 7a, an inflow means 4, a centrifuge 3 and a discharge pipe 8, and is configured to be integrally movable. The deposit 20 mined by the mining device 6a has a structure of being stored in a storage tank 7a arranged inside the mining device 6a via a connecting pipe 6b. An inflow device 4a is installed inside the storage tank 7a, and the inflow device 4a is connected to the inflow port 3a of the centrifuge device 3 via an inflow pipe 4b.

A discharge pipe 8 is connected to the underflow outlet 3b of the centrifuge 3. The overflow outlet 3c of the centrifuge 3 is connected to a storage tank 7b installed outside the mining device 6a via a connecting portion 5. A lifting device 2a is installed inside the storage tank 7b, and the lifting device 2a is connected to the lifting ship 9 via a lifting pipe 2b.

Next, a method of collecting the resource 20c using this collection system 1 will be described below.

First, the mining device 6a is operated to mine the sediment 20 on the bottom B containing the resource 20c. The sediment 20 mined by the mining device 6a is sequentially sent to the storage tank 7a through the connecting pipe 6b. The deposit 20 stored in the storage tank 7a is sequentially flowed into the inflow port 3a of the centrifuge device 3 through the inflow pipe 4b by the inflow device 4a. In the centrifuge 3, the deposit 20 flowing in from the inflow port 3a is continuously classified into a coarse-grained deposit 20a and a fine-grained sediment 20b. Most of the resource 20c contained in the sediment 20 is unevenly distributed in the fine-grained sediment 20b.

The fine-grained deposit 20b in a state where the resource 20c is unevenly distributed is discharged from the overflow outlet 3c and sent to the storage tank 7b through the connecting portion 5. The fine-grained sediment 20b and the resource 20c stored in the storage tank 7b are sent to the unloading vessel 9 through the unloading pipe 2b by the unloading device 2a. The coarse-grained sediment 20a is discharged to the underflow outlet 3b, passes through the discharge pipe 8, is discharged into the water from the discharge port of the discharge pipe 8, and remains on the bottom B.

For example, polymetals such as copper, lead, zinc, average, and silver and methane hydrate existing in submarine hydrothermal deposits have the property of concentrating in fine-grained sediments 20b with a certain particle size or less in water. ing. Therefore, in order to efficiently collect these resources 20c, as in this embodiment, the resources 20c are unevenly distributed on the fine-grained deposits 20b by the centrifuge 3, and the fine-grained deposits 20b are collected on the water. Then, the coarse grain deposit 20a may remain on the bottom B of the water.

Rare earth mud (raw mud MW) was prepared with a density set to the expected density when the mud-like bottom deposits containing rare earths were introduced into a cyclone-type centrifuge placed in water. Then, the raw mud MW was classified by a centrifuge placed in water. The underflow deposit UF discharged from the underflow outlet of the centrifuge and the overflow deposit OF discharged from the overflow outlet were collected. The particle size distribution and rare earth concentration of each of the UF, OF, and unclassified raw mud MW were analyzed. The classification boundary particle size by the centrifuge was set to 20 μm. The result of the particle size distribution is as shown in the graph shown in FIG.

As shown in FIG. 7, in the crude mud MW, about 20% of the coarse grain deposits of 20 μm or more are classified by a centrifuge, but the coarse grain deposits of 20 μm or more are 50% or more. It means that more than 80% of the coarse grain deposits of 20 μm or more contained in the raw mud MW are classified into the underflow deposits UF. The volume ratio of the underflow deposit UF discharged from the underflow outlet after classification was 16.9% and the weight ratio was 39.3% with respect to the raw mud MW. Therefore, it can be seen that the rare earth mud can be classified by the centrifuge even in water, and the volume of the sediment to be lifted onto the water can be significantly reduced by the classification. Along with this, it becomes possible to reduce the work and cost of disposing of unnecessary materials.

The rare earth concentration of the raw mud MW was 3733 ppm, and the rare earth concentration of the underflow sediment UF was 8070 ppm. Therefore, it can be seen that the rare earths contained in the sediment can be unevenly distributed and concentrated in the underflow sediment UF by performing the classification by the centrifuge.

1 Underwater resource collection system 2 Lifting means 2a Lifting device 2b Lifting pipe 3 Cyclone type centrifuge 3a Inflow port 3b Underflow outlet 3c Overflow outlet 4 Inflow means 4a Inflow device 4b Inflow pipe 5 Connecting part 6 Mining means 6a Mining equipment 6b Connection pipe 7a, 7b Storage tank 8 Release pipe 9 Lifting ship 10 Support ship 10a Cable 20 Sediment 20a Coarse grain deposit 20b Fine grain deposit 20c Specific resource B Water bottom

Claims (5)

In the method of collecting seabed resources, which is collected by transporting specific resources contained in the sediments on the seabed to the water.
Using a cyclone-type centrifuge device placed in water, the sediment is divided into coarse-grained sediments containing more coarse-grained sediments with a relatively large particle size and fine-grained sediments with a relatively small particle size. By continuously classifying into fine-grained deposits containing a large amount, the resources are unevenly distributed in either the coarse-grained deposits or the fine-grained deposits, and the resources are unevenly distributed. A method for collecting bottom resource, which comprises transporting the sediment onto the water and leaving one of the other sediments on the bottom of the water. The water bottom resource according to claim 1, wherein the resource is a rare earth, the rare earth is unevenly distributed on the coarse-grained sediment, the coarse-grained sediment is lifted onto the water, and the fine-grained sediment remains on the water bottom. How to collect. The method for collecting bottom resources according to claim 2 , wherein the classification boundary particle size by the centrifuge is in the range of 10 μm or more and 30 μm or less. In a bottom resource extraction system equipped with a means of lifting certain resources contained in bottom sediments onto the water.
It has a cyclone type centrifuge arranged in water, an inflow means for inflowing the sediment into the centrifuge, and a connecting portion for connecting the centrifuge and the lifting means.
By the centrifuge, the sediment is continuous with coarse-grained deposits containing more coarse-grained particles with relatively large particle size and fine-grained sediments containing more fine-grained particles with relatively small particle size. The resources are unevenly distributed in either the coarse-grained deposits or the fine-grained deposits, and the one-sided deposits in which the resources are unevenly distributed are transferred to the lifting means through the connecting portion. A bottom resource extraction system characterized in that the sediment is sent and one of the other sediments is discharged into water from the centrifuge. The specific resource is a rare earth, the rare earth is unevenly distributed in the coarse-grained deposit, the coarse-grained deposit is sent to the lifting means through the communication portion, and the fine-grained deposit is sent to the centrifuge. The underwater resource sampling system according to claim 4, which is configured to be discharged into water from the water .

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