JP2003269070A - Mineral lifting method of deep sea bottom mineral resources and mineral lifting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To float valuable mineral resources on the sea-level from the deep sea-bottom with a very simple equipment constitution by utilizing a specific characteristic of a U-shaped pipe 10 capable of maintaining the water level in the same height at both end openings. <P>SOLUTION: The U-shaped pipe 10 with one downward pipe 11 and the other upward pipe 12 is vertically held to the sea-level from the deep sea-bottom, and when seawater W is conveyed to the upper end opening of the downward pipe 11 from the upper end opening of the upward pipe 12, the seawater W circularly flows inside of the U-shaped pipe 10. When a mineral mass M mined out from the deep sea-bottom B is conveyed to the bottom of the upward pipe 12, it is mounted on the upward seawater W rizing through the upward pipe 12 to float the mineral mass M on the sea-level L. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

The present invention relates to Ni, Co, Cu, M
TECHNICAL FIELD The present invention relates to a method and an apparatus for lifting mineral resources rich in valuable metals such as n from the deep sea floor.

[0002]

2. Description of the Related Art Resource consumption has increased exponentially with the progress of various industrial fields and the growth of advanced technology industries, and it is said that the current terrestrial resource dependence system will collapse in the early 21st century. There is. Mineral resources on the deep sea floor are attracting attention in order to supplement onshore resources, which may be depleted, and to ensure a stable supply of resources. For example, manganese nodules containing a large amount of heavy metals are present on the deep sea floor at a water depth of 4000 to 6000 m. Cobalt ore deposits called Co-rich crust are distributed in layers on the deep seabed at a depth of 800-2400 m. The submarine hydrothermal deposit ejected as black smoke from the deep seabed with a depth of 2000 to 3000 m has high Cu and Zn grades. As you can see, there are huge amounts of mineral resources on the deep sea floor,
The reserves of mineral resources such as Ni and Co are now expected to be hundreds or thousands of times the world consumption.

In order to extract mineral resources from the deep sea floor and use them for industry, it is necessary to develop a technology for mining the mineral resources buried in the deep sea floor and transporting the mined mineral resources to the sea (lifting). become. Various methods such as a continuous bucket method and a fluid dredge method have been proposed for lifted ore.
The continuous bucket method is economically excellent, but since it is impossible to control the attitude of the bucket at the deep sea bottom, there are many mineral resources left behind and the efficiency of pumping is poor. The fluid dredge method is
It is a method of sucking up mineral blocks together with seawater from the deep sea floor.
Although the cost is high, the efficiency of lifting is higher than that of the continuous bucket method.

The fluid dredge method is roughly classified into a pump method in which a pump is used for sucking up a mineral lump, and an air lift method in which air is blown from the middle of a lift pipe to apply a lift force to the mineral lump. In the pump method, it is difficult to determine the pump specifications and a large number of pumps are required, which is a drawback. For example, if a pump with a pumping capacity of 50 m is used to raise a mineral block from the deep sea bottom at a depth of 5000 m, 100 pumps are required.
In addition, even if one pump fails, it may not be possible to lift ore.

In the air lift system, the flow pattern is apt to change when the gas-liquid mixed phase fluid containing bubbles rises in the lifting pipe.
For example, when air is blown into the bottom of a vertically arranged ore pipe in seawater, many bubbles generated by the air blow
They change in volume and shape along separate streamlines, and coalesce in the process of ascending the lift pipe, and rise as a large gas mass (slag flow). Moreover, when the flow rate increases with the rise of bubbles and the void ratio increases, phase separation occurs in which gas flows in the center of the lift pipe and seawater flows in the vicinity of the pipe wall, making it impossible to lift mineral blocks. Therefore, the utilization of heavy liquid having a density higher than that of the mineral resources buried in the deep sea floor for lift ore has been studied (Japanese Patent Publication No. 8-26740). In this method, the heavy liquid prepared by mixing the heavy liquid material, seawater, and the additive material is sent to the downcomer pipe and flowed in the seabed U-shaped pipe and the lifting pipe, so that the difference in specific gravity between the heavy liquid and the mineral resources It is raising mineral resources.

[0006]

However, there are problems in adjusting the heavy liquid and controlling the flow in the lifting pipe. For example, in order to give the buoyancy required for manganese nodules having a density of about 2500 kg / m ³ , a heavy liquid having a density higher than the density is required, but it is not easy to prepare a heavy liquid having such a large specific gravity.
Storage stability is also not sufficient. Even if heavy liquid of required specific gravity is provided, the heavy liquid sent into the downcomer will settle at the bottom of the U-shaped pipe, and the heavy liquid will accumulate in the lower part of the lifting pipe and seawater will accumulate in the upper part. It becomes a state. A method for efficiently supplying manganese nodules from the deep sea bottom at a water depth of 5000 m by supplying a heavy liquid in the lift ore pipe without leaking is also unsolved. Furthermore,
Assuming that the density of the heavy liquid is 3000 kg / m ³ , the internal pressure of the lower part of the lifting pipe reaches 1500 atm, and a pressure difference of 1000 atm from the external pressure of 500 at the bottom of the lifting pipe occurs. The lifted pipe is required to have the strength to withstand the pressure difference, but there is a problem that it is difficult to overcome in terms of material and structure.

[0007]

The present invention has been devised to solve such a problem, and is a U-shaped member on which a force for maintaining a constant liquid level at both end open portions acts. Utilizing the characteristics of pipes, the object is to enable transportation of mineral blocks from the deep sea floor to the sea surface with an extremely simple equipment configuration without the need for buckets or heavy liquids.

In order to achieve the object, the lifting method of the present invention vertically holds a U-shaped pipe, one of which is a downcomer pipe and the other of which is an uplift pipe, from the deep sea bottom to the sea surface, and the downcomer pipe is opened from the upper end opening of the uplift pipe. The seawater is circulated and fluidized in the U-shaped pipe by transporting it to the upper opening of the pipe, and the mineral mass mined at the deep sea bottom is sent to the bottom of the rising pipe, and the rising pipe is placed on the rising seawater to float. And

The lift ore apparatus used in this method has a bottom portion arranged at or near the deep sea bottom, and is connected to a U-shaped pipe having a downcomer pipe and an upcomer pipe having open upper ends, and a lower portion of the ascend pipe,
A mineral supply hose that feeds mineral resources mined from the deep sea to the rising pipe, a storage tank that separates and stores the mixed fluid sent from the upper opening of the rising pipe into mineral mass and seawater, and a receiving part of the storage tank To a top opening of the downcomer pipe. It is preferable that the riser pipe has a smaller internal cross-sectional area than the downcomer pipe. Further, if a pressure regulating tank is provided between the pump and the upper part of the downcomer pipe, the lifting ore apparatus can cope with periodic pressure fluctuations in the U-shaped pipe.

[0010]

[Operation and Embodiment] When a U-shaped tube with both ends open is held vertically and liquid is injected into the U-shaped tube to make it stand still, the pressure exerted on the liquid surface is equal to the atmospheric pressure in any of the tube ends. Maintained at the same liquid level. When the liquid is conveyed from one end to the other end of the U-shaped pipe by a pump or the like, the liquid circulates in the U-shaped pipe so that the same liquid level height is maintained in both pipe ends.
The inventors of the present invention focused on the flow of the liquid in the U-shaped pipe and investigated the applicability of the U-shaped pipe 10 (FIG. 1), one of which is the downcomer pipe 11 and the other of which is the uplift pipe 12, to lift-up ore. investigated.
Although FIG. 1 shows a U-shaped pipe 10 in which the downcomer pipe 11 and the ascending pipe 12 are separated, it goes without saying that a U-shaped pipe 10 in which the downcomer pipe 11 and the ascending pipe 12 are integrated can also be used. is there.

When the vertically held U-shaped pipe 10 is filled with seawater and is transported from the upper end of the ascending pipe 12 to the upper end of the descending pipe 11, the seawater W circulates inside the U-shaped pipe 10. Therefore, when the mineral mass M mined by the concentrator 20 installed on the deep sea floor B is sent to the bottom of the rising pipe 12, the rising seawater W exerts a drag force on the mineral mass M and the mineral mass M. Buoyancy acts on. When the resultant force of the drag force and the buoyancy acting on the mineral mass M becomes larger than the gravity of the mineral mass M, the mineral mass M flows toward the sea surface L inside the rising pipe 12, and the megalo float holding the U-shaped pipe 10 or the like. It is discharged to the landing base 30 of.

Since the drag force acting on the mineral lump M is proportional to the square of the relative flow velocity of the seawater W and the mineral lump M, increasing the rising speed of the seawater W provides the force necessary for floating the mineral lump M. The rising speed of the seawater W can be easily increased by increasing the internal cross-sectional area of the downcomer pipe 11 and decreasing the internal cross-sectional area of the upcomer pipe 12, and is required according to the internal cross-sectional area ratio of the downcomer pipe 11 and the upcomer pipe 12. And the ascending speed is obtained. For example, riser 12 /
If the inner diameter ratio of the downcomer pipe 11 is halved, the internal cross-sectional area ratio becomes 1
/ 4, which is calculated to be 4 with respect to the flow velocity in the downcomer 11.
The seawater W rises up the ascending pipe 12 at a double flow rate, and gives a large drag force to the mineral mass M.

Assuming a U-shaped pipe 10 having the same diameters as the downcomer 11 and the ascending pipe 12, the seawater W is rising at a predetermined ascending speed in the ascending pipe 12, and the seawater W is ascending while being supplemented with the seawater W in the descending pipe 11. Seawater W is flowing down at the same speed as the speed.
The seawater W flowing in the downcomer 11 and the ascend pipe 12 suffers a loss proportional to the n-th power of the velocity due to fluid friction and a loss due to the pushing up of the mineral mass M. U-shaped tube 1 while compensating for loss
In order to secure a desired flow velocity within zero, it is necessary to apply a driving force to the seawater W by the thrust of the pump 31, the head difference, and the like.

The pump 31 does not have to be a large pump as long as it has the ability to generate the driving force required for compensating for the loss. The head difference of 100 m or less is practically sufficient. In this respect, it requires a large amount of power for bucket control and bucket rotation, and the equipment configuration is extremely simple compared to the bucket system where there is concern about breaking chains that connect the buckets. However, the land mining work is simplified. The mineral mass M rises in the ascending pipe 12 together with the seawater W, and is sent out from the upper end opening of the ascending pipe 12 to the storage tank 40 arranged at the landing base 30. The ore storage tank 40 is divided into a water receiving portion 42 and a ore storing portion 43 by a partition wall 41, and a screen 44 in which the ore storing portion 43 side is inclined low is provided above the water receiving portion 42.

The ore storage tank 40 is preferably provided at a relatively low position of the lifting base 30 to compensate for the head difference. The arrangement at a low position is less affected by gusts on the sea and is advantageous for safe operation. The head difference generated at both ends of the U-shaped pipe 10 at the time of lifting is due to resistance or the like when the seawater W flows through the U-shaped pipe 10. By directly connecting the pump 31 to the upper end opening of the downcomer 11, a constant flow velocity can be obtained by compensating for the loss caused by resistance or the like. However, in reality, there are pulsations associated with the rise of the mineral mass M and an increase in the resistance of the U-tube 10 that occurs when the U-tube 10 is fed, so the upper end of the downcomer pipe 11 is higher than the upper end of the upcomer pipe 12. It is preferable to maintain and open the upper end of the downcomer 11.

If a pressure regulating tank 34 (FIG. 2) that absorbs pressure fluctuations in the U-shaped pipe 10 is provided between the pump 31 and the downcomer pipe 11, the downcomer pipe 11 protrudes upward from the land mining station 30. Can be suppressed, and the wind pressure resistance of the ore lifting equipment can be improved. The pressure adjusting tank 34 is a closed container in which an appropriate amount of air is sealed, and the pump 3 that sends the seawater W from the water receiving section 42 to the downcomer pipe 11.
It is directly connected to 1. The pressure of the seawater W fed into the U-shaped pipe 10 is adjusted by the contraction of the air enclosed in the pressure regulating tank 34. Further, when the air valve 35 provided in the pressure regulating tank 34 is operated to adjust the amount of air in the pressure regulating tank 34, the characteristic of the pressure regulating tank 34 with respect to pressure fluctuation can be changed. As a result, the length of the U-tube 10 and the riser 1
This is a lift ore apparatus that can cope with periodic pressure fluctuations due to a change in the particle size of the mineral mass M rising up to 2.

The mixed fluid of mineral mass M / seawater W is supplied to the rising pipe 1
It is sent out onto the screen 44 from 2 and flows down the inclined surface of the screen 44 toward the ore storage part 43. Most of the seawater W passes through the screen 44 and flows into the water receiving section 42 while flowing down, and is separated from the mineral mass M. Seawater W in the water receiving section 42
Flows through the water distribution pipe 33 by the pump 31, and the downcomer pipe 11
Is sent to the upper opening of the U-tube 10 and circulates in the U-tube 10. The mineral mass M that does not pass through the screen 44 is stored in the storage part 4
It is recovered in 3 and used as a valuable metal resource.

The mineral mass M is fed into the ascending pipe 12 from the bottom, but the inside and outside of the U-shaped pipe 10 is the same seawater W. Therefore, the pressure difference between the inside and the outside of the U-shaped tube 10 is small at any depth, and the required strength of the U-shaped tube 10 is relaxed. Since the mineral mass M is fed into the U-shaped pipe 10 in which the seawater W is flowing, the Venturi effect generated by the flow of the seawater W, that is, the action of sucking the mineral mass M into the U-shaped pipe 10 also works, and the mineral supply hose. The transportation of the mineral mass M from the 21 to the U-shaped pipe 10 also becomes smooth.

The fact that the pressure difference between the inside and outside of the U-shaped tube 10 is small means that
It is also advantageous in that the connection between the mineral supply hose 21 of the concentrator 20 and the rising pipe 12 is somewhat incomplete, and even if the surrounding seawater leaks or enters the rising pipe 12, it does not significantly affect the pumping capacity. . Moreover, the required propulsive force can be applied to the seawater W flowing in the U-shaped pipe 10 only by the pump 31 that transports the seawater W from the water receiving portion 42 to the upper end of the downcomer 11, so that the facility configuration is greatly simplified. It is possible to reduce the cost of land mining, including equipment costs.

[0020]

[Example] In a simulation test using a water tank having a depth of 3.2 m, the lifting capacity of the U-shaped pipe 10 was investigated. U-shaped tube 1
0 is a clear acrylic resin downcomer pipe 11 having a length of 3.5 m and an inner diameter of 5 cm and a transparent acrylic resin riser pipe 12 having a length of 3 m and an inner diameter of 4 cm, and an elbow pipe having a radius of curvature of 0.1 m and an inner diameter of 4.5 cm. Prepared by connecting with. Riser 12
And the elbow pipe is connected with a three-way joint, and the mineral supply hose 2
The hose assuming 1 was connected to the remaining opening of the three-way joint.

The elbow pipe of the U-shaped pipe 10 was arranged at the bottom of the water tank, and the descending pipe 11 and the ascending pipe 12 were held vertically. The water tank was filled with seawater W having a specific gravity of 1.02 g / cm ³ , and the same seawater W was injected into the U-shaped tube 10 to the same level as the sea level L in the water tank. The colored acrylic beads adjusted to have the same specific gravity as the seawater W were suspended in the seawater W so that the fluidized state was observed.
Seawater W is pumped out from the upper end opening of the rising pipe 12, and the flow rate is 38
When it was sent to the upper end opening of the downcomer pipe 11 at a rate of 1 liter / minute, the seawater W flowed down the downcomer pipe 11 at a flow velocity of 0.32 m / sec and rose in the riser pipe 12 at a flow velocity of 0.5 m / sec.

While circulating the seawater W in the U-shaped pipe 10, colored inorganic particles having a particle diameter of 25 mm and a specific gravity of 2.2 g / cm ³ are fed from the hose to the lower part of the rising pipe 12 to cause the inside of the U-shaped pipe 10 to move. The behavior of inorganic particles was investigated. Most of the sent-in inorganic particles were sent to the upper part of the rising pipe 12 along with the seawater W flowing through the rising pipe 12. The floating of the inorganic particles was similarly stable even after the continuous test for 1 hour.

The drag force F ₁ and the buoyancy force F ₂ acting on the inorganic particles under the above-mentioned conditions are calculated as follows. Since the inorganic particles float due to the resultant force of the drag force F ₁ and the buoyancy force F ₂ , even the inorganic particles having a larger specific gravity than the seawater W can be conveyed from the bottom of the water tank to the upper end opening of the rising pipe 12.

[0024]

As described above, in the present invention, by utilizing the characteristic of the U-shaped tube in which the liquid level heights tend to be the same at the both ends of the opening, the characteristics of the U-shaped tube are increased from the upper opening of the ascending tube to the descending tube. The seawater is circulated and fluidized in the U-shaped pipe by transporting the seawater to the upper end opening, and the mineral mass mined at the deep sea bottom is placed on the rising flow of seawater and floated to the sea surface. When this method is used, the driving force required to float the mineral mass is only the thrust of the pump that conveys the seawater sent from the upper opening of the ascending pipe to the upper opening of the descending pipe, so the facility configuration is greatly simplified, The lifting operation itself becomes easy. As a result, mineral resources can be easily collected from the deep sea floor, and stable supply of valuable resources such as Mn, Co, Ni, Cu and Zn becomes possible.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a lift ore apparatus according to the present invention.

[Fig.2] Lifting base of lifting equipment equipped with pressure regulating tank

[Explanation of symbols]

10: U-shaped pipe 11: Down pipe 12: Up pipe 20: Mining machine 21: Mineral supply hose 30: Lifting base 31: Pump 33: Water pipe
34: Pressure control tank 40: Storage tank 41: Partition wall 42: Water receiving part 4
3: Storage part 44: Screen M: Mineral block W: Seawater B: Deep sea floor L: Sea surface

Claims (4)

[Claims] A U-shaped pipe, one of which is a downcomer and the other of which is an upcomer, is held vertically from the deep sea floor to the sea surface, and seawater is transported from the upper opening of the ascending pipe to the upper opening of the downcomer. A method of pumping deep-sea bottom mineral resources, characterized in that the seawater is circulated and flowed at, the mineral mass mined at the deep-sea bottom is sent to the bottom of the rising pipe, and the rising pipe is placed on the rising seawater to float. 2. A U-shaped pipe having a descending pipe and an ascending pipe, the bottom portion of which is arranged at or near the deep sea bottom and the upper end of which is open,
A mineral supply hose that is connected to the bottom of the ascending pipe and sends mineral resources mined at the deep sea floor to the ascending pipe, and a storage tank that separates and stores the mixed fluid sent from the upper opening of the ascending pipe into mineral clumps and seawater. , A deep sea bottom mineral resource pumping apparatus comprising a pump for transporting seawater from a water receiving portion of a storage tank to an upper opening of a downcomer pipe. 3. The lift ore apparatus according to claim 2, wherein the internal cross-sectional area of the rising pipe is smaller than the internal cross-sectional area of the downcomer pipe. 4. The lifting equipment according to claim 2, wherein a pressure regulating tank is provided between the pump and the upper end of the downcomer pipe.