Ore transfer method

Abstract

To provide an ore transfer method capable of stably transferring ore as slurry together with seawater from the seabed to the sea through an ore lifting pipe.SOLUTION: In an ore transfer method for suppressing generation of slag flow when ore is transferred from the seabed to the sea together with seawater through an ore lifting pipe 60, when slurry is formed by mixing seawater and ore, the slurry concentration, which is represented by the volume ratio of ore in the slurry, is adjusted as shown in equation (1) below. F(D)≤-0.0511×D+22.556...(1) F(D): Slurry concentration D: Maximum grain size of ore (mm) determined by the 2009 edition of JIS A 1204 Soil Grain Test Method.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an ore transporting method for transporting ore together with seawater from the seabed to the sea through a transport pipe. [Background Art]

[0002] As is well known, various mineral resources including, for example, hydrothermal deposits exist on the seabed. In order to utilize ore mined in such hydrothermal deposits and the like, various methods have been proposed for mixing crushed ore with seawater to form a slurry, and transporting this slurry through a lifting pipe to an offshore base (e.g., a ship) (see, for example, Patent Documents 1 and 2). When a slurry is formed from crushed ore and transported through a transport pipe, stable and efficient transport is desired also from the viewpoint of profitability. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2003-269070 [Patent Document 2] Japanese Unexamined Patent Application Publication No. 2012-193578 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] However, when lifting a slurry formed of crushed ore and seawater through a transport pipe, the slurry needs to flow stably in the transport pipe. For example, when the increase in contact force between ore and the pipe wall surface caused by interlocking between ores, the frictional force between ore and the pipe wall, or the self-weight of the accumulated ore group exceeds the lift force of the water flow that transports ore upward, it becomes difficult to stably transport the ore.

[0005] This invention has been made in consideration of these circumstances, and aims to provide an ore transport method that enables the stable transport of a slurry formed by mixing ore and seawater from the seabed to the surface. [Means for solving the problem]

[0006] Therefore, the inventors of the present invention diligently studied slurry flow in the transfer pipe and found that suppressing the generation of slug flow and reducing the interlocking of ore particles in the transfer pipe is important for the stable transfer of slurry, and that adjusting the slurry concentration (= (volume of ore) / (volume of slurry)) is effective for this purpose. Furthermore, visual confirmation of particle behavior in simulations revealed that adjusting the slurry concentration according to the ore particle size (hereinafter sometimes referred to as ore particle size) when feeding the slurry into the transfer pipe is effective. Additionally, it was found that adjusting the slurry concentration so that the maximum locally formed slurry concentration within the transfer pipe is 55 vol% or less is extremely effective. Here, slug flow refers to a flow state in which particles of slurry (solid-liquid multiphase flow) flowing through a transfer pipe interlock, creating alternating regions of dense and sparse particles along the pipe axis. This increases the likelihood of increased pressure loss and difficulty in particle movement.

[0007] To solve the above problems, this invention proposes the following means. (1) A first aspect of the present invention is an ore transport method for suppressing the generation of slag flow when transporting ore together with seawater from the seabed to the surface of the sea through an ore lifting pipe, characterized in that when mixing seawater and ore to form a slurry, the slurry concentration, which is indicated by the volume ratio of ore in the slurry, is adjusted as shown in the following formula (1). F(D)≦-0.0511×D+22.556 (1) F(D): Slurry concentration D: Maximum particle size (mm) of ore as determined by JIS A 1204 Soil particle testing method, 2009 edition.

[0008] According to the ore transport method of this invention, when transporting ore from the seabed to the surface of the sea along with seawater through a lifting pipe, a slurry with adjusted concentration is formed by mixing seawater and ore, and this slurry with adjusted concentration (slurry concentration) is sent into the lifting pipe, thereby suppressing the generation of slag flow within the lifting pipe. When the slurry concentration is F(D)(vol%), for example, by adjusting the ore particle size D(mm) to F(D) ≤ -0.0511 × D + 22.556, the ore will be transported while the density of the ore is likely to change within the transport pipe, but the generation of slag flow is suppressed. As a result, the slurry formed by mixing ore and seawater can be stably transported through the ore lifting pipe.

[0009] Here, slurry concentration refers to the ratio of the volume of ore to the volume of slurry when ore and seawater are mixed to form a slurry, and can be expressed as: Slurry concentration (volume concentration) = Volume of ore / (Volume of ore + Volume of seawater). Furthermore, slurry flow velocity refers to the value obtained by dividing the flow rate (volume) of slurry transported per unit time by the ore transport pipe by the cross-sectional area of ​​the ore transport pipe. Alternatively, the amount of slurry transported per unit time may be divided by the cross-sectional area and the measurement time. In addition, the slurry flow rate per unit time in measuring slurry concentration refers to the slurry flow rate when the amount of ore contained in the slurry reaches a steady state (stable and constant state), and the method for measuring the slurry flow rate may be set arbitrarily. For example, the slurry discharged from the transport pipe per unit time may be received in a bucket or the like and measured. Furthermore, the maximum particle size of ore specified by the 2009 edition of JIS A 1204 Soil Grain Testing Method can also be described as "the particle size expressed by the smallest mesh opening of a metal sieve through which the entire sample passes."

[0010] (2) The ore transport method described in (1) above may be used to form the slurry after adjusting the major axis of the ore to a set dimension or less.

[0011] According to the ore transport method of this invention, the slurry is formed after adjusting the major axis of the ore to a set dimension or less, so all of the ore can be transported stably. Here, adjusting the major axis of the ore to be less than or equal to the set dimension can be done by any means, such as crushing it with a crusher, or adjusting it when excavating with an excavator (for example, a surface miner such as a drum cutter, a vertical excavator, etc.). Here, particle size refers to the major axis of the ore (the distance (dimension) between the two furthest points in each ore), and may be substituted with the dimensions (particle size) specified by JIS A 1204 "Method for testing the particle size distribution of soil".

[0012] (3) The ore transport method described in (1) above is F(D) ≤ 38 × D -0.333 The ore may be crushed in such a way that the following condition is met.

[0013] (4) The ore transport method described in (1) above may be carried out by setting the particle size of the ore to 25 mm or less and the slurry flow velocity to 4 m / s or more.

[0014] According to the ore transfer method of this invention, the particle size of the ore is set to 25 mm or less, and the slurry flow velocity is set to 4 m / s or more, so a large amount of ore can be transferred efficiently and stably. As a result, for example, by keeping the slurry concentration below 12.7 vol%, the ore extraction rate can be increased to 5,000 tons / day.

[0015] (5) The ore transport method described in (1) above may be carried out by setting the particle size of the ore to 50 mm or less and the slurry flow velocity to 5 m / s or more.

[0016] According to the ore transfer method of this invention, the ore particle size is set to 50 mm or less and the slurry flow velocity is set to 5 m / s or more, so a large amount of ore can be transferred efficiently and stably. As a result, for example, by keeping the slurry concentration below 10.6 vol%, the ore extraction rate can be increased to 5,000 tons / day.

[0017] (6) In the ore conveying method according to any one of the above (1) to (5), the maximum value of the local slurry concentration in the hoisting pipe may be set to be equal to or less than an allowable concentration.

[0018] According to the ore conveying method of the present invention, the maximum value of the local slurry concentration in the hoisting pipe is set to be equal to or less than an allowable concentration (for example, 55%), thereby suppressing the risk of blockage of the conveying pipe caused by ore. Here, the local slurry concentration in the conveying pipe refers to the maximum concentration at a local position (any position) in the axial direction of the conveying pipe.

[0019] (7) In the ore conveying method according to the above (6), the local slurry concentration in the hoisting pipe may be set to 55% or less.

[0020] According to the ore conveying method of the present invention, since the local slurry concentration in the hoisting pipe is set to 55% or less, ore can be conveyed stably. Furthermore, by increasing the local slurry concentration to near 55%, a large amount of ore can be efficiently conveyed while avoiding the risk of blockage. Effects of the Invention

[0021] According to the ore conveying method of the present invention, ore can be stably conveyed as slurry together with seawater from the seabed to the sea through the conveying pipe. Brief Description of the Drawings

[0022] [Figure 1] It is a conceptual diagram illustrating an example of the schematic configuration of an ore hoisting system according to a first embodiment of the present invention. [Figure 2] It is a diagram schematically illustrating conditions in slurry flow analysis according to the first embodiment. [Figure 3] It is a conceptual diagram schematically illustrating flow analysis of slurry according to the first embodiment. [Figure 4]This graph illustrates the general outline of the slurry flow analysis according to the first embodiment, where (A) shows the local concentration in the pipe axis direction across the entire analysis region, and (B) shows the change in local slurry concentration over time. [Figure 5] This is a conceptual diagram illustrating the general flow mode of the solid-liquid multiphase flow in the ore transfer method according to the first embodiment. [Figure 6] This figure shows the slurry flow analysis results for an ore transfer method according to the first embodiment, with an ore lifting rate of 5000 tons / day. [Figure 7] This figure shows the slurry flow analysis results for an ore transfer method according to the first embodiment, with an ore lifting rate of 10,000 tons / day. [Figure 8] This graph illustrates an example of the particle size setting range applicable to the ore transfer method according to the first embodiment. [Modes for carrying out the invention]

[0023] <First Embodiment> The first embodiment of the present invention will be described below with reference to Figure 1. Figure 1 is a conceptual diagram illustrating the schematic configuration of the ore handling system according to the first embodiment. In Figure 1, reference numeral 100 denotes the ore lifting system, reference numeral 10 denotes the drilling means, reference numeral 20 denotes the stockpile, reference numeral 30 denotes the crusher, reference numeral 40 denotes the dredging pump, reference numeral 50 denotes the ore feeder, reference numeral 60 denotes the ore lifting pipe, and reference numeral 70 denotes the ore lifting mother ship (ore lifting base).

[0024] As shown in Figure 1, the ore hoisting system 100 includes, for example, a drilling means 10 for drilling a seabed ore vein, a stockpile 20, a crusher 30, a dredging pump 40, a transfer pipe 45, an ore feeder 50, an ore hoisting pipe 60, and an ore hoisting mother ship (ore hoisting base) 70.

[0025] The ore handling system 100 is configured such that, for example, the ore excavated by the drilling means 10 is crushed to a particle size (set dimension) or smaller by the crusher 30, and the slurry, whose concentration is adjusted in the ore feeder 50, is transferred to the ore handling vessel 70 by the ore handling pipe 60.

[0026] Furthermore, in this embodiment, the ore lifting system 100 is equipped with a bucket lifting device (not shown) as a backup for transferring crushed ore to the ore lifting mother ship 70 in the event of a problem with slurry transfer. Various known bucket conveyors and the like can be used as the bucket lifting device.

[0027] For example, when excavating a hill-shaped mound from the surface, a surface miner can be applied to the excavation means 10. Furthermore, when excavating a chimney (small mound), a vertical excavator can be applied to the excavation means 10, and the configuration of the excavation means 10 can be arbitrarily set according to the type of ore vein being excavated.

[0028] The stockpile 20 temporarily stores the ore excavated by the excavation means 10. Furthermore, the means of transporting the excavated ore to the stockpile 20 can be set arbitrarily. Then, the stockpile 20 transports the stored ore to the crusher 30, for example, using a screw conveyor 21.

[0029] The crusher 30 crushes the ore sent from the stockpile 20 to a set particle size D (mm) suitable for transport in the ore lifting pipe 60. Specifically, the crusher crushes the ore to a particle size D (mm) such that F(D) ≤ -0.0511 × D + 22.556 satisfies the desired slurry concentration (volume concentration) F(D) (vol%) calculated from the amount of ore lifted. Here, F(D) is the volume concentration of the slurry, and the particle size D can be the particle size specified by a sieve through which all (100%) of the particles pass, according to JIS A 1204 Soil Particle Size Test Method. In other words, particle size D can be the maximum particle size of the ore specified by the 2009 version of JIS A 1204 Soil Particle Size Test Method. More specifically, the crushing conditions are set so that the crushed ore passes through the sieve corresponding to the particle size D completely (100%).

[0030] The dredging pump 40 transfers the crushed and size-adjusted ore from the crusher 30 to the ore feeder 50 via the transfer pipe 45. Any known configuration can be applied to the dredging pump 40.

[0031] The ore feeder 50, for example, mixes ore with seawater to form a slurry of a predetermined concentration. Furthermore, when forming the slurry, the ore feeder 50 adjusts the amount of seawater and the amount of ore to adjust the slurry concentration so that the above-mentioned F(D) ≤ -0.0511 × D + 22.556 holds true. Here, the slurry concentration is calculated based on the volume of ore and seawater mixed per unit time using the formula: slurry concentration (vol%) = volume of ore / (volume of ore + volume of seawater). For example, the volume of ore and the volume of seawater, calculated using the slurry flow velocity (or flow rate per unit time), are adjusted according to the slurry concentration. The ore feeder 50 then feeds the formed slurry of a predetermined concentration into the ore lifting pipe 60.

[0032] Furthermore, with a view to more stable transport, the crusher 30 sets the slurry concentration (volume concentration) F(D) (vol%) to F(D) ≤ 38 × D -0.333 The ore is crushed to a particle size D (mm) such that the above condition F(D) ≤ 38 × D, and when forming a slurry using the ore feeder 50, the amount of seawater and the amount of ore are adjusted so that the above condition F(D) ≤ 38 × D -0.333 Adjusting the slurry concentration to one that satisfies the condition is preferable because it reduces the risk of slug flow generation.

[0033] Furthermore, the slurry flow rate per unit time used in measuring slurry concentration is the slurry flow rate when the slurry flow reaches a steady state, and the method for measuring the slurry flow rate can be arbitrarily set. For example, the slurry discharged from the ore lifting pipe 60 per unit time may be collected in a bucket or the like and measured.

[0034] The ore lifting pipe 60 is made of, for example, a steel pipe. The ore lifting pipe 60 connects, for example, the ore feeder 50 and the ore lifting carrier 70. The configuration of the ore lifting pipe 60 can be arbitrarily set, and for example, it may be made of a flexible riser pipe (flexible riser).

[0035] Specifically, the ore lifting pipe 60 has its lower end connected to the ore feeder 50 and its upper end opening at the top of the solid-liquid separation and water treatment device 71 mounted on the ore lifting mother ship 70. Then, the ore lifting pipe 60 transports the slurry from the seabed to the surface along arrow M and discharges the slurry to the solid-liquid separation and water treatment device 71.

[0036] On the other hand, a high-pressure circulation pump 72 is connected to the solid-liquid separation and water treatment device 71, and a discharge pipe 61 is connected to the downstream side of the high-pressure circulation pump 72. The discharge pipe 61 then discharges the seawater, which has been used to extract ore from the slurry in the solid-liquid separation and water treatment device 71, into the sea along the arrow W.

[0037] The ore handling vessel 70 can generally be a ship (ore handling vessel), which is anchored in the ocean in the target area to perform ore handling. However, it is not limited to a ship, and may be any known configuration such as a platform constructed at sea.

[0038] The ore handling vessel 70 is equipped with a solid-liquid separation and water treatment device 71 that separates the ore slurry, which is transported from the seabed via the ore handling pipe 60, from the seawater. The solid-liquid separation and water treatment apparatus 71 can, for example, be composed of a series of overflow tanks, but it is not limited to overflow tanks as long as it can separate ore and seawater. For example, a cyclone, a filtration device, a sieve, etc., may also be used.

[0039] The following describes the conditions for setting slurry suitable for lifting ore using the lifting pipe 60 according to the first embodiment, with reference to Figures 2 to 8. The conditions for a slurry suitable for lifting ore using the lifting pipe 60 according to the first embodiment are set, for example, based on the results of an analysis obtained by simulating the slurry flow as shown below.

[0040] [Parameters in slurry flow analysis] The simulations targeted ores with particle sizes of 5 mm, 10 mm, 25 mm, and 50 mm, and examined the scenarios of each ore being extracted at slurry flow velocities of 4 m / s, 5 m / s, 6 m / s, and 7 m / s, and at extraction rates of 5,000 tons / day and 10,000 tons / day. Here, the ore particle size D refers to the major axis of the ore, and is approximated by the particle size specified by JIS A 1204 Soil particle size distribution test method.

[0041] [Prerequisites for slurry flow analysis] Slurry flow analysis is performed as shown in Figure 2, for example, with a lifting pipe inner diameter d: 0.217 m, periodic boundary of the lifting pipe (=20·d): 4.34 m, inner surface roughness of the lifting pipe: 0.05 mm, and ore density: 3740 kg / m³. 3 ), density in seawater: 1037 (kg / m³) 3 The simulation was conducted using a seawater viscosity coefficient of 0.0018 (Pa·s) (water temperature 0°C).

[0042] [Slurry Flow Analysis Method] The slurry flow analysis was performed using computational fluid dynamics (CFD) and the discrete element method (DEM) to simulate the coupled motion of ore particles and fluid within the lifting pipe, thereby evaluating the behavior of the ore in slurry flow. For the sake of computational convenience, the simulations were performed using computational fluid dynamics (CFD) and discrete element method (DEM), assuming that each ore was a sphere with a diameter equal to its grain size (major axis). Specifically, as shown in Figure 3, the area A (shaded area) to be inspected was set to a height equal to the inner diameter d: 0.217 m of the ore lifting pipe. The slurry concentration within this area A was calculated along the elapsed time since the start of slurry flow, and this was slid along the pipe axis O direction (the direction in which the slurry flows) to graph and confirm the local concentration in the entire analysis area B (periodic boundary of the ore lifting pipe (L=20·d): 4.34 m). Here, the local concentration is the maximum concentration at a local point in the direction of the pipe axis. Here, the area A targeted for inspection is a part of the space where the flow analysis of the slurry is simulated using computational fluid dynamics (CFD) and discrete element method (DEM). The local concentration is obtained by arithmetic calculation of the volume ratio of ore continuously present in space by sliding the area A targeted for inspection in the direction of the pipe axis.

[0043] Below, with reference to Figure 4, we will explain an example of slurry flow analysis in a transfer pipe. Figure 4 is a graph illustrating the overview of slurry flow analysis. Figure 4(A) shows the relationship between the axial position of the entire analysis domain and the maximum local concentration. In the graph shown in Figure 4(A), the vertical axis represents the axial position of the domain, and the horizontal axis represents the maximum local concentration (vol%). The vertical axis corresponds to the axial position of the entire analysis domain B shown on the left. Figure 4(B) is a graph showing the change in local concentration of the slurry over time since the start of slurry flow. The horizontal axis represents the elapsed time (sec) since the start of slurry flow, and the vertical axis, indicated by arrow C in Figure 4(A), shows the maximum local concentration (vol%) at a given time.

[0044] As shown in Figure 4(A), the local slurry concentration in the entire analysis area B within the transfer pipe varies depending on the position along the pipe axis O. As shown in Figure 4(B), these localized slurry concentrations fluctuate depending on the time elapsed since the start of slurry flow. Visual observations have confirmed that the risk of slurry slug flow increases in areas where the slurry concentration is above a certain level, and where the local concentration exceeds approximately 60 vol%. As a result, it becomes more likely that the slurry will have difficulty moving stably.

[0045] Furthermore, as shown in Figure 4(B), it can be seen that such localized slurry concentrations gradually increase over time, for example, until approximately 3.5 seconds have elapsed since the start of slurry flow. Furthermore, it can be seen that the local slurry concentration rises to 60% and converges after approximately 5 seconds.

[0046] Furthermore, the form of slurry (solid-liquid two-phase flow) when ore and seawater are mixed is classified into (A) dispersed flow, (B) massive flow, (C) bundled flow, and (D) slug flow as shown in Figure 5, and each has the following properties. (A) Dispersed flow: A flow in which ore particles are dispersed without aggregating. (B) Bulky flow: A flow in which a large cluster of ore particles, consisting of a small amount of solid particles, is scattered throughout. (C) Bundle flow: A flow in which most solid particles are concentrated in the center of the pipe. (D) Slag flow: A flow consisting of a portion where ore occupies the entire cross-section of the pipe and a portion where there are fewer particles. Furthermore, if the slurry flow is (A) dispersed flow, (B) lumpy flow, or (C) bundled flow, blockage will not occur in the transfer pipe. On the other hand, if a slug flow occurs as shown in Figure 5 (D), the risk of blockage of the ore lifting pipe is very high, and this slug flow occurs when the local concentration of slurry exceeds, for example, 55 vol%.

[0047] Next, referring to Figures 6 and 7, we will explain the verification results of slurry flow in combinations of ore particle size and slurry flow velocity, or in other words, slurry flow in combinations of ore particle size and slurry concentration. Figure 6 shows the slurry flow analysis results for an ore transfer method according to the first embodiment with an ore handling rate of 5,000 tons / day. Figure 7 shows the slurry flow analysis results for an ore handling rate of 10,000 tons / day.

[0048] Next, slurry flow analysis was performed on ores with particle sizes of 5 mm, 10 mm, 25 mm, and 50 mm, at slurry flow velocities of 4 m / s, 5 m / s, 6 m / s, and 7 m / s. Figures 6 and 7 show the results when slurries formed by mixing ore with particle sizes D of 5 mm, 10 mm, 25 mm, and 50 mm with seawater were flowed at slurry flow velocities of 4 m / s, 5 m / s, 6 m / s, and 7 m / s. In Figures 6 and 7, "○" indicates that the flow corresponds to one of the following: (A) dispersed flow, (B) massive flow, or (C) bundled flow, as shown in Figure 5; "△" indicates that alternating levels of ore density are occurring within the slurry flow, but it is not a slug flow; and "×" indicates that it is a slug flow. Furthermore, the "vol%" shown in each column indicates the concentration of the slurry flowing into the transfer pipe (slurry concentration), which is determined by the ore particle size and slurry flow rate.

[0049] As shown in Figure 6, in slurry flow at a retrieval rate of 5000 tons / day, slag flow did not occur for any of the slurry flow velocities of 4 m / s to 7 m / s when the ore particle size D was 5 mm, 10 mm, or 25 mm. However, it was found that a boundary with slag flow occurred when the ore particle size D was 25 mm and the slurry flow velocity was 4 m / s (slurry concentration 13.8 vol%).

[0050] As shown in Figure 7, in slurry flow at a retrieval rate of 10,000 tons / day, slag flow did not occur when the ore particle size D was 5 mm or 10 mm, regardless of whether the slurry flow velocity was 5 m / s or 7 m / s. However, when the ore particle size D was 25 mm or 50 mm, it was found that the boundary with slag flow occurred regardless of whether the slurry flow velocity was 5 m / s or 7 m / s. Furthermore, it was found that slug flow occurs at a slurry flow velocity of 4 m / s (slurry concentration of 22.4 vol% to 25.3 vol%) for all particle sizes.

[0051] Based on the above, as shown in Figure 8, the ore particle size D (mm) and slurry concentration (vol%) shown in Figures 6 and 7 were plotted on a graph with the ore particle size D (mm) on the horizontal axis and the slurry concentration (vol%) on the vertical axis, and the slurry concentration range in which no slug flow occurs for each particle size was identified using the approximate formula F(D). As a result, based on the "△" in Figure 8, it was found that the range in which ore density variations occur within the slurry but slag flow does not occur can be identified at a slurry concentration F(D) ≤ -0.0511 × D + 22.556. Furthermore, based on the "○" in Figure 8, the range in which stably transport occurs without the generation of slug flow is when the slurry concentration F(D)(vol%) ≤ 38 × D -0.333 In this case, it was found that the risk of slug flow generation is further reduced. F(D): Slurry concentration (the ratio of ore to the volume of slurry, assuming the ore is a sphere with particle size D) D: Maximum particle size (mm) of ore as determined by JIS A 1204 Soil particle testing method, 2009 edition.

[0052] According to the ore lifting system 100 and ore transfer method of the first embodiment, when transferring ore from the seabed to the surface of the sea together with seawater through the ore lifting pipe 60, the seawater and ore are mixed to form a slurry with adjusted concentration, and the slurry with adjusted concentration is sent into the ore lifting pipe 60, thereby suppressing the generation of slag flow within the ore lifting pipe 60. As a result, the slurry formed by mixing ore and seawater can be transported stably.

[0053] Furthermore, according to the ore lifting system 100 and ore transfer method, when crushing the ore with the crusher 30, the particle size D of the ore is adjusted to be below a set size, so the ore can be transferred stably.

[0054] Furthermore, according to the ore lifting system 100 and the ore transfer method, the ore particle size D (mm) is adjusted to a range that satisfies the set slurry concentration F (D) (vol%) ≤ -0.0511 × D + 22.556, so even if the density of the ore changes within the lifting pipe 60, the generation of slag flow is suppressed and the ore can be transferred.

[0055] Furthermore, according to the ore lifting system 100 and the ore transfer method, for example, the particle size D (mm) of the ore is set to the slurry concentration F (D) (vol%) ≤ 38 × D -0.333 By adjusting the particle size D (mm) to a range that satisfies the condition, the generation of slag flow within the lifting pipe 60 is completely suppressed, and the ore can be transported stably.

[0056] Furthermore, according to the ore lifting system 100 and the ore transfer method, by setting the ore particle size to 25 mm or less, the slurry flow velocity to 4 m / s or more, and the slurry concentration to 12.7 vol% or less, an ore lifting volume of 5,000 tons / day can be achieved.

[0057] Furthermore, according to the ore lifting system 100 and the ore transfer method, by setting the ore particle size to 50 mm or less, the slurry flow velocity to 5 m / s or more, and the slurry concentration to 10.6 vol% or less, an ore lifting volume of 5,000 tons / day can be achieved.

[0058] Furthermore, according to the ore lifting system 100 and the ore transfer method, by setting the ore particle size to 10 mm or less, the slurry flow velocity to 5 m / s or more, and the slurry concentration to 18.2 vol% or less, an ore lifting volume of 10,000 tons / day can be achieved.

[0059] Furthermore, according to the ore lifting system 100 and the ore transfer method, by setting the local slurry concentration within the ore lifting pipe 60 to, for example, 55 vol% or less, the risk of blockage of the ore lifting pipe 60 can be suppressed and stable ore lifting can be achieved.

[0060] Furthermore, according to the ore lifting system 100 and the ore transfer method, the slurry concentration in local areas within the transfer pipe is set to 55% or less, allowing for stable ore transfer. In addition, by raising the slurry concentration in local areas to around 55%, a large amount of ore can be efficiently transferred while avoiding the risk of blockage.

[0061] It should be noted that the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention. For example, in the above embodiment, the case in which the particle size D of the ore is adjusted to a set size or less when crushing the ore with the crusher 30 was described, but it is possible to arbitrarily set whether or not to adjust the particle size D of the ore to a set size or less, and the ore may contain particles with a particle size larger than the set size.

[0062] Furthermore, although the above embodiment described a case in which the particle size of the ore is adjusted to a set size or less using a sieve, the method for adjusting the size of the ore is not limited to using a sieve and can be set arbitrarily, and adjustment means other than a sieve may be applied.

[0063] Furthermore, in the above embodiment, the case in which the volume concentration F(D) of the slurry is adjusted to slurry concentration F(D) ≤ -0.0511 × D + 22.556 when the crushed ore has a particle size D (the maximum particle size of ore specified by the 2009 edition of JIS A 1204 Soil particle size test method (mm)) was described. However, it is possible to arbitrarily set whether or not to adjust the particle size D of the ore to F(D) ≤ -0.0511 × D + 22.556, and the slurry concentration F(D) may be adjusted within the range of F(D) > -0.0511 × D + 22.556.

[0064] Furthermore, in the above embodiments, examples were given for cases where the ore particle size D is 25 mm or less and the slurry flow velocity is 4 m / s or more, or 50 mm or less and the slurry flow velocity is 5 m / s or more when the ore output is 5,000 tons / day, and for cases where the ore particle size D is 10 mm or less and the slurry flow velocity is 5 m / s or more when the ore output is 10,000 tons / day, but it goes without saying that the invention is not limited to these examples.

[0065] Furthermore, in the above embodiment, for example, the case in which the local slurry concentration within the ore lifting pipe 60 is set to 55% or less was described, but whether or not to set the local slurry concentration within the ore lifting pipe 60 to 55% or less is arbitrary, and for example, a region with a concentration exceeding 55% may be formed in a part of it.

[0066] Furthermore, although the above embodiment described a case in which the ore handling system 100 is equipped with an ore handling mother ship 70 as an ore handling base, the configuration may also include an offshore floating body such as a semi-submersible type instead of, or together with, the ore handling mother ship 70.

[0067] Furthermore, in the above embodiment, the case in which the ore handling system 100 is equipped with a discharge pipe 61 for discharging solid-liquid separated seawater into the sea was described. However, for example, the discharge pipe 61 may be configured to discharge solid-liquid separated seawater into the sea, or the discharge pipe 61 may be replaced with a return pipe (not shown) for returning solid-liquid separated seawater to the ore feeder 50.

[0068] Furthermore, although the above embodiment described a case in which the ore lifting system 100 is equipped with a bucket ore lifting device 70, it is possible to arbitrarily decide whether or not to include the bucket ore lifting device 70, and the system may be configured without a bucket ore lifting device. In addition, other backup ore lifting means may be provided instead of, or together with, the bucket ore lifting device.

[0069] Although embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments, and modifications, combinations, deletions, etc., of the configuration are also included without departing from the spirit of the present invention. [Explanation of Symbols]

[0070] G Undersea 10 Excavation methods 20 Stockpile 30 Crusher 40 Dredging pump 45 Transfer pipe 50 Ore Feeders 60 ore lifting pipes 70. Ore handling ship (ore handling base)

Claims

1. An ore transport method that suppresses the generation of slag flow when transporting ore from the seabed to the surface of the sea along with seawater through an ore lifting pipe, A method for transporting ore, characterized in that when mixing seawater and ore to form a slurry, the slurry concentration, which is expressed by the volume ratio of ore in the slurry, is adjusted as shown in the following formula (1). F(D)≦-0.0511×D+22.556...(1) F(D): Slurry concentration D: Maximum particle size (mm) of ore identified by JIS A 1204 Soil particle testing method, 2009 edition.

2. A method for transporting ore according to claim 1, The slurry is formed after adjusting the major axis of the ore to a size less than or equal to a set dimension. A method for transporting ore characterized by the features described herein.

3. A method for transporting ore according to claim 1, F(D) ≤ 38 × D －０．３３３ The ore is crushed in such a way that this condition is met. A method for transporting ore characterized by the features described herein.

4. A method for transporting ore according to claim 1, The particle size of the ore is set to 25 mm or less. Transfer the slurry at a flow rate of 4 m / s or higher. A method for transporting ore characterized by the features described herein.

5. A method for transporting ore according to claim 1, The particle size of the ore is set to 50 mm or less. Transfer the slurry at a flow rate of 5 m / s or higher. A method for transporting ore characterized by the features described herein.

6. A method for transporting ore according to any one of claims 1 to 5, The maximum value of the local slurry concentration within the aforementioned ore lifting pipe is Set below the permissible concentration. A method for transporting ore characterized by the features described herein.

7. A method for transporting ore according to claim 6, The slurry concentration in the local area within the aforementioned lifting pipe is set to 55% or less. A method for transporting ore characterized by the features described herein.

Images