Slurry pump and method for manufacturing the same

Abstract

To provide a slurry pump including a casing liner which is excellent in both of wear resistance and shock resistance.SOLUTION: A slurry pump 100 for allowing flowing delivery of slurry including crushed metal compounds includes, at least, a rotary shaft 60 to be rotated by the rotation driving force of driving means, an impeller 10 the center of which is fixed to the axial core at one end 62 of the rotary shaft 60 and to a metal parent material of which rubber lining is applied, a metal casing 11 encircling the impeller 10 to form a pressure-raising chamber, and a rubber casing liner 12 fitted to the inside of the casing 11 in close contact therewith. Into an opposed range where the casing liner 12 is opposed to the front end side of a blade of the impeller 10, ceramic particle filled epoxy resin lining 15 is applied.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a slurry pump and its manufacturing method , and more specifically relates to a structure aimed at improving the service life of a casing liner of a slurry pump that delivers slurry containing high-hardness metal sulfide.

Background Art

[0002] As a hydrometallurgical process for nickel and cobalt, the MCLE (Matte Chlorine Leach Electrowinning) process is known. In this MCLE process, nickel-cobalt mixed sulfide (hereinafter also referred to as "MS") and nickel matte (main components are trinickel disulfide and metallic nickel) are used as raw materials, and electrolytic nickel and electrolytic cobalt are produced by hydrometallurgy.

[0003] In the MCLE process, as a pretreatment for raw material leaching, MS and electrolytic waste liquid are charged into a wet vertical pulverizer to perform wet pulverization. In this wet pulverization, the particle size of MS, which is a powdery raw material, is pulverized from about 70 to 80 µm (D50) to about 15 to 30 µm (D50) to obtain fine MS. As a result, slurry in which fine MS and electrolytic waste liquid (water) are mixed (hereinafter referred to as "MS slurry") is obtained by wet pulverization. Note that D50 means the median diameter in a volume-based particle size distribution measured by laser diffraction scattering method.

[0004] A wet vertical pulverizer (e.g., Tower Mill (registered trademark)) is used for wet pulverization. At that time, coarse-grained MS is classified, and is returned as the underflow of the classification section to the pulverization section of the wet vertical pulverizer via a circulation pump and pulverized again.

[0005] For example, Patent Document 1 describes a coarse particle removal device comprising a storage tank for temporarily storing the slurry after grinding that overflows from a wet grinder, a strainer for removing coarse particles from the slurry stored in the storage tank, and a container for collecting the coarse particles, stating that a circulation pump for returning the slurry to the wet grinder may be connected from an extraction pipe connected to the lower end flange of the strainer.

[0006] Such a circulating pump is a slurry pump according to one embodiment of the present invention. The slurry pump (for example, the Warman® pump), as will be described later, has a double casing structure as an example, with a replaceable casing liner made of molded rubber attached to the inside of a cast iron casing. An impeller, also lined with rubber, is attached to the casing via a shaft (rotating axis). A metal core is embedded in the casing liner. The impeller rotates via the shaft using motor power, drawing slurry from the front of the pump casing, rotating the liquid in the circumferential direction of the impeller, sending it to the delivery piping, and then discharging it outside the pump casing. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2021-16836 [Overview of the project] [Problems that the invention aims to solve]

[0008] Even if the only solid component of the slurry is MS pulverized by a wet vertical pulverizer, wear progresses in areas with narrow clearances between the impeller and casing due to locally increased flow velocity. While conventional casing liners (natural rubber, butyl rubber) are suitable from a wear resistance standpoint, it is thought that wear due to impacts normal to the rotating shaft also progresses in parallel in these areas.

[0009] Furthermore, relatively large foreign matter (ceramic fragments derived from the crushed media, detached MS adhering to the inner walls, etc.) may be mixed into the slurry. Because these are of moderate size, if they get into the pump casing, they can cause significant wear due to impact, especially in the clearance areas of the casing liner.

[0010] This invention was made to solve such problems and aims to provide a slurry pump equipped with a casing liner that is excellent in both wear resistance and impact resistance. [Means for solving the problem]

[0011] To achieve the above objective, the inventors conducted extensive research and came up with the idea of ​​applying a ceramic particle-filled epoxy resin lining to the area of ​​the casing liner of a slurry pump that faces the tip edge of the impeller blades.

[0012] In other words, the slurry pump of the first invention of the present invention is a slurry pump for transporting a slurry containing a pulverized metal compound, comprising at least a rotating shaft that rotates by the rotational driving force of a driving means, an impeller whose center is fixed to the axis of one end of the rotating shaft and which is made of a metal base material with a rubber lining, a metal casing that surrounds the impeller and forms a pressure boosting chamber, and a rubber casing liner that is fitted tightly inside the casing, wherein a part of the casing liner faces the tip edge of the impeller blades only A ceramic particle-filled epoxy resin lining layer is made of a ceramic particle-filled epoxy resin on top of a rubber lining layer made of rubber. Formed The ratio of the thickness of the rubber lining layer to the thickness of the ceramic particle-filled epoxy resin lining layer is in the range of 4:6 to 6:4.

[0013] Furthermore, the slurry pump of the second invention of the present invention is, in the first invention of the present invention, The ceramic particles incorporated into the aforementioned ceramic particle-filled epoxy resin are alumina ceramic beads with a diameter of 0.5 to 1.0 mm. It is characterized by the following:

[0014] Furthermore, the slurry pump of the third invention of the present invention is, in the first or second invention of the present invention, The thickness of the layer of the aforementioned ceramic particle-filled epoxy resin lining is 4 to 6 mm. It is characterized by the following:

[0015] Furthermore, the slurry pump of the fourth invention of the present invention is, in any of the first to third inventions of the present invention, In a wet smelting process for nickel and cobalt, a slurry containing a nickel-cobalt mixed sulfide powder is supplied. It is characterized by the following:

[0016] Furthermore, the method for manufacturing a slurry pump according to the fifth invention of the present invention comprises at least a rotating shaft that rotates by the rotational driving force of a driving means, an impeller whose center is fixed to the axis of one end of the rotating shaft and which is made of a metal base material with a rubber lining, a metal casing that surrounds the impeller and forms a pressure boosting chamber, and a rubber casing liner that is fitted tightly inside the casing, in a slurry pump for transporting a slurry containing a crushed metal compound, wherein a part of the casing liner faces the tip edge of the impeller blades Only, The method is characterized by removing the rubber to a depth where the metal liner base material is not exposed, and then applying a ceramic particle-filled epoxy resin in the same volume and shape as the removed rubber. [Effects of the Invention]

[0017] As described above, according to the present invention, even when a hard metal sulfide slurry is pumped, and even when large, hard solid fragments are mixed into the metal sulfide slurry, wear of the casing liner is less likely to progress, and a slurry pump equipped with a casing liner that is excellent in both wear resistance and impact resistance can be provided. [Brief explanation of the drawing]

[0018] [Figure 1] Figure 1 is a longitudinal cross-sectional view showing the structure of a slurry pump according to one embodiment of the present invention. [Figure 2] Figure 2 is an enlarged cross-sectional view of the area around the impeller blades in a slurry pump according to one embodiment of the present invention. [Figure 3] FIG. 3 is a cross-sectional view showing a casing liner in a range facing the tip edge of impeller blades in a slurry pump according to an embodiment of the present invention. MODE FOR CARRYING OUT THE INVENTION

[0019] Hereinafter, preferred embodiments of the present invention will be described in detail in the following order with reference to the drawings. It should be noted that the present embodiment described below does not unduly limit the content of the present invention described in the claims, and not all of the configurations described in the present embodiment are necessarily essential as solution means of the present invention.

[0020] First, an outline of a slurry pump according to the present invention will be described. FIG. 1 is a longitudinal cross-sectional view showing the structure of a slurry pump according to an embodiment of the present invention. As shown in FIG. 1, a slurry pump 100 (by way of example, a Warman (registered trademark) pump) according to an embodiment of the present invention sucks a fluid to be delivered through a suction port 96 at the center by an impeller 10 rotating within a casing 11, and is a centrifugal pump that generates a liquid feeding force to discharge the fluid from a discharge port 97 at the outer peripheral portion. Such a slurry pump 100 has a wide head range of 5 to 60 m, and is employed in many plants.

[0021] In addition, unlike ordinary pumps, the slurry pump 100 according to an embodiment of the present invention can be used exclusively for high-viscosity fluids. In order to improve corrosion resistance and strength, it is necessary to use a robust and corrosion-resistant material for components including the blades of the centrifugal impeller, sealing materials, and the casing. For the blades of the impeller 10, the casing liner 12 provided on the surrounding casing 11, and the shaft seal portion 90, their strength, corrosion resistance, and wear resistance are adapted to the physical properties of the fluid to be delivered and operating conditions.

[0022] A slurry pump 100 according to one embodiment of the present invention, as shown in Figure 1, is mainly composed of a pump unit 95 and a drive unit 99 fixed to a pump stand 91, and these are coaxially coupled by a rotating shaft 60 that is rotationally driven by an external power source. The pump unit 95 is composed of centrifugal vanes enclosed in a casing 11, including a frame plate 20. The drive unit 99 includes a bearing housing (hereinafter also simply referred to as "bearing") 92 fixed to the pump stand 91, and a rotating shaft 60 supported by the bearing 92.

[0023] A V-pulley 94, which is mounted on one end of the rotating shaft 60 and is driven by it, receives driving force from an electric motor (not shown) via a V-belt. This driving force is coaxially coupled to the rotating shaft 60 and imparts rotational force to two centrifugal blades having different functions. The two centrifugal blades are an impeller 10 and an expeller 30, which are coaxially coupled by the rotating shaft 60, and are separated by a frame plate 20 and a frame plate liner 24, forming an expeller seal.

[0024] An expeller seal is a double shaft seal device (also called a "centrifugal shaft seal device," "centrifugal shaft seal section," or "shaft seal section") 90, which is located on the back side of the impeller 10 that generates lift in the centrifugal pump. The centrifugal force of the expeller 30, which rotates coaxially with the impeller 10, pushes the slurry liquid back into the casing, preventing the slurry liquid from entering the shaft seal section 90 during pump operation. When the pump is stopped, the function of the expeller seal also stops, so the slurry liquid is sealed by gland packing or lip seals (hereinafter simply referred to as "seals 80") which are arranged to compensate for this.

[0025] The shaft seal 90 on the pump section 95 is constructed by loosely or tightly fitting the rotating shaft 60, which is supported by the bearing 92 on the drive section 99, with at least the shaft sleeve 70, seal 80, expeller ring 40, and frame plate 20 in the outer diameter R direction from the outer circumference 61 of the shaft. "Loose fitting" means fitting the parts so that they can move relative to each other. Furthermore, in the "loosely fitted" state described here, there is no rattle or leakage. In other words, the rotating shaft 60, shaft sleeve 70, and seal 80 are loosely fitted, supported in a rotatable and liquid-tight manner relative to each other, and maintaining the shaft seal function.

[0026] Meanwhile, the seal 80, the expeller ring 40, and the frame plate 20 are fixed to each other in a tightly fitted state. The slurry pump 100 with this configuration is equipped with a centrifugal shaft seal 90 formed by an expeller 30 axially coupled to a rotating shaft 60, and is configured to suppress leakage from the shaft seal 90 during operation.

[0027] Furthermore, as shown in Figure 1, the bearing 92 of the drive unit 99 is equipped with two sets of tapered roller bearings 93 arranged at a predetermined interval, and these support the rotating shaft 60 with considerable strength. Therefore, the rotating shaft 60 is basically free from looseness and vibration in both the outer diameter R direction and the thrust direction X, and maintenance equivalent to that required for bearings in typical rotating machinery is sufficient.

[0028] Next, the features of the slurry pump according to the present invention will be described. Figure 2 is an enlarged cross-sectional view of the area around the impeller blades in a slurry pump according to one embodiment of the present invention. One aspect of the present invention is a slurry pump 100 for transporting a slurry containing a crushed metal compound, comprising at least a rotating shaft 60 that rotates by the rotational driving force of a driving means, an impeller 10 whose center is fixed to the axis of one end 62 of the rotating shaft 60 and which is made of a metal base material with a rubber lining, a metal casing 11 that surrounds the impeller 10 and forms a pressure boosting chamber, and a rubber casing liner 12 that is fitted tightly inside the casing 11, wherein the area of ​​the casing liner 12 facing the tip edge of the impeller blades 10 is coated with a ceramic particle-filled epoxy resin lining 15.

[0029] The liner of a slurry pump is generally composed of a rubber (natural rubber, butyl rubber, etc.) casing liner 12 surrounding a metal liner base material 16 as the core, and is attached to the casing 11 in a replaceable manner by, for example, bolts 17 corresponding to bolt holes provided in the casing 11.

[0030] In slurry pumps, the clearance between the casing liner and the impeller is approximately 2-3 mm. In the gap between the impeller and the casing liner, the frictional force of the rotating impeller locally increases the slurry flow velocity, and the centrifugal force of the rotating impeller increases the collision perpendicular to the axis of rotation. Therefore, in pumps that pump slurries containing metal sulfides, the increased flow velocity of the slurry in the gap between the impeller and the casing liner accelerates the wear of the casing liner. As a result, the rubber of the casing liner gradually thins as the slurry passes through, causing holes to form in the rubber. This allows the slurry to come into contact with the cast iron casing, causing corrosion, ultimately leading to casing perforation problems. Generally, lowering the rubber hardness of the casing liner reduces friction between the rubber and the slurry, thus slowing the progression of rubber wear. However, if foreign matter enters the pump, the soft rubber can damage the liner, and in some cases, liner perforation may occur. Conversely, increasing the rubber hardness reduces the likelihood of the liner being damaged and perforated if foreign matter enters the pump, but it also increases friction between the rubber and the slurry, accelerating wear.

[0031] Therefore, in this invention, a hybrid specification is achieved by applying a hard, impact-resistant ceramic particle-filled epoxy resin lining to the liner side of the clearance portion. Specifically, a portion of the rubber liner in the region where the flow velocity increases due to the narrow clearance between the impeller and casing liner of the slurry pump is removed, and a ceramic particle-filled epoxy resin, which is a composite material of highly impact-resistant ceramic particles and epoxy resin, is applied in the same volume and shape as the removed rubber. This configuration suppresses liner wear and also prevents liner damage when foreign matter enters the inside of the slurry pump.

[0032] Figure 3 is a cross-sectional view of the casing liner 25 in a slurry pump according to one embodiment of the present invention, showing the area facing the tip of the impeller blades. Conventional casing liners consist only of a rubber casing liner 12, with a thickness L of about 10 mm. On the other hand, in the present invention, as one embodiment, first, a portion of the rubber of the casing liner is uniformly removed to a depth of about 5 mm. The casing liner has a metal liner base material 16 located at a depth of about 10 mm from the wetted part side, so the rubber is removed to a depth of about 5 mm so as not to expose this base material. This is because if the metal liner base material 16 is exposed, the ceramic particle-filled epoxy resin that is ultimately applied will corrode the metal base material when it peels off from the casing liner 25.

[0033] Then, a ceramic epoxy material containing ceramic particles 18 is uniformly applied to the area where the rubber was removed, in the same volume and shape as the removed rubber material. By leaving it as is for 24 hours or more to harden and dry, a ceramic particle-filled epoxy resin liner 15 is formed, and such a casing liner 25 can be assembled into the casing 11 of the slurry pump in the conventional way. At this time, if the total thickness L of the casing liner 25 is 10 mm, it is preferable to form it so that the thickness L1 of the rubber casing liner 12 is 4 to 6 mm and the thickness L2 of the ceramic particle-filled epoxy resin liner 15 is 4 to 6 mm (L = L1 + L2).

[0034] In one aspect of the present invention, the rubber casing liner 12 is not completely removed, but partially removed by scraping or other means, and replaced with a ceramic particle-filled epoxy resin liner 15. That is, as shown in Figure 3, it is preferable that the casing liner 25 has a ceramic particle-filled epoxy resin lining layer 15 made of ceramic particle-filled epoxy resin formed on a rubber lining layer 12 made of rubber.

[0035] As a result, if a method is used in which a portion of the rubber casing liner 12 is scraped off and replaced with a ceramic particle-filled epoxy resin liner 15, as in one aspect of the present invention, the existing casing liner can be used, and maintenance such as liner replacement can be easily performed. Furthermore, if the metal casing has a two-part structure and the ceramic particle-filled epoxy resin is applied directly to the casing, that is, if the entire rubber casing liner 12 is replaced with a ceramic particle-filled epoxy resin liner 15, the sealing performance of the casing joint will decrease. Therefore, since it is necessary to have a structure in which rubber with good adhesion seals against each other, it is preferable to have a configuration in which a ceramic particle-filled epoxy resin lining layer 15 made of ceramic particle-filled epoxy resin is formed on top of the rubber lining layer 12.

[0036] In one aspect of the present invention, it is sufficient to apply a ceramic particle-filled epoxy resin lining to the area facing the tip edge of the impeller blades, and it is not necessary to apply the ceramic particle-filled epoxy resin lining to the impeller itself. Although the impeller is also subject to wear and damage from foreign matter, it is a rotating part and requires balance adjustment, so a similar ceramic epoxy coating is undesirable. Since centrifugal force acts on the impeller as it rotates, wear progresses more rapidly on the casing liner side than on the impeller side, so it is sufficient to apply the ceramic particle-filled epoxy resin lining to the casing liner side.

[0037] The ceramic particles are not particularly limited as long as they have a certain level of hardness or higher, but for example, alumina ceramic beads are used. The particle size of the ceramic particles is also sufficient as long as they can be uniformly dispersed in the epoxy resin, but as an example, particles with a diameter of 0.5 to 1.0 mm are used.

[0038] A slurry pump according to one aspect of the present invention can be used in a wet smelting process of nickel and cobalt to pump a slurry containing nickel-cobalt mixed sulfide (MS) powder. MS is a mixture of NiS and CoS with a composition of approximately 50-60% by weight of Ni, 5% by weight of Co, and 30-40% by weight of S. Although the particle size of MS is approximately 70 μm, it can be applied to pumping a fine MS slurry, which is obtained by grinding it to approximately 30 μm using a tower mill. The slurry concentration of the fine MS slurry is approximately 350 g / L. Note that the above particle size refers to the median diameter in the volume-based particle size distribution measured by laser diffraction and scattering.

[0039] In particular, this invention is a hybrid design that uses optimal materials in optimal ranges to transport multiple types of solids with different physical properties. Conventional wear protection is provided by a rubber casing liner made of natural rubber or butyl rubber, and impact protection is provided by a ceramic particle-filled epoxy resin liner, thus enabling the creation of a slurry pump with excellent wear resistance and impact resistance. [Examples]

[0040] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way to the following examples.

[0041] In the wet smelting process for nickel and cobalt described above, the present invention is applied to the casing liner of the circulation pump for the fine MS slurry used in the wet grinding process, in which nickel-cobalt mixed sulfide (MS) and electrolytic waste liquid are charged into a Tower Mill (registered trademark), which is a wet vertical grinder, to perform wet grinding, thereby creating a slurry pump according to one embodiment of the present invention (pump model: Warman (registered trademark) pump 3-2SC EO R / L manufactured by Taiheiyo Kiko Co., Ltd., casing liner material: NR45 (natural rubber hardness 45 degrees)).

[0042] Specifically, a grinder was used to remove approximately 5mm of rubber from the narrow clearance area of ​​the casing liner with the impeller (the area facing the tip of the impeller blades). After removing the rubber, debris was removed using a rag, and ceramic epoxy material (ceramic epoxy material model: HL-K1, manufacturer: Kansai Pate Kako, particle size of alumina ceramic beads: 0.5~1.0mm) was applied. The ceramic epoxy material was mixed with the hardener in a 1:2 ratio and applied and shaped using rubber gloves to achieve the same volume and shape as the original casing liner. Since the liner itself does not rotate, high-precision balance adjustment is not necessary, and accuracy sufficient for application by hand is adequate as long as there is no contact with the impeller. The applied ceramic epoxy material was allowed to cure and dry for 24 hours or more. The cured and dried casing liner was assembled into the pump and used in the same way as conventional products.

[0043] In conventional pumps, the casing liners were replaced 1 to 3 times a month due to wear from slurry liquid and damage caused by the inclusion of ceramic fragments of about 10 to 40 mm. In contrast, the casing liner of the above example, coated with ceramic epoxy material according to one embodiment of the present invention, could be used for approximately 4 months.

[0044] Therefore, by applying the slurry pump according to one embodiment of the present invention, it was demonstrated that it is superior to conventional products in both wear resistance and impact resistance.

[0045] Although one embodiment of the present invention and its examples have been described in detail above, it will be readily apparent to those skilled in the art that many modifications are possible without substantially departing from the novel aspects and effects of the present invention. Therefore, all such modifications are included within the scope of the present invention.

[0046] For example, any term that appears at least once in the specification or drawings alongside a broader or synonymous term may be replaced with that different term anywhere in the specification or drawings. Furthermore, the configuration of the slurry pump is not limited to that described in the embodiment and examples, and various modifications are possible. [Explanation of Symbols]

[0047] 10 Impeller, 11 Casing, 12 Casing liner (rubber lining layer), 15 Ceramic particle-filled epoxy resin liner, 16 Metal liner base material (metal base material), 17 Bolt, 18 Ceramic particles, 20 Frame plate, 24 Frame plate liner, 25 Casing liner, 30 Expansion, 40 Expansion ring, 60 Rotating shaft, 61 Outer circumference of shaft (of rotating shaft 60), 62 One end (of rotating shaft 60), 70 Shaft sleeve, 80 Seal, 90 Centrifugal shaft seal, 91 Pump stand, 92 Bearing housing (bearing), 93 Tapered roller bearing, 94 V-pulley, 95 Pump section, 96 Suction port, 97 Discharge port, 99 Drive unit, 100 Slurry pump, L Casing liner thickness, L1 Rubber casing liner thickness, L2 Ceramic particle-filled epoxy resin liner thickness, R Outer diameter, X Axis centerline (thrust direction)

Claims

1. A slurry pump for transporting a slurry containing pulverized metal compounds, at least, A rotating shaft that rotates due to the rotational driving force of the driving means, An impeller, whose center is fixed to the axis of one end of the aforementioned rotating shaft, and which is made of a metal base material with a rubber lining, A metal casing surrounding the impeller and forming a pressure boosting chamber, A rubber casing liner is fitted tightly inside the casing, Equipped with, A ceramic particle-filled epoxy resin lining layer is applied to a portion of the casing liner, specifically to the area facing the tip edge of the impeller blades, on top of a rubber lining layer made of rubber. Formed, The ratio of the thickness of the rubber lining layer to the thickness of the ceramic particle-filled epoxy resin lining layer is in the range of 4:6 to 6:

4. A slurry pump characterized by the following features.

2. The ceramic particles incorporated into the aforementioned ceramic particle-filled epoxy resin are alumina ceramic beads with a diameter of 0.5 to 1.0 mm. The slurry pump according to feature 1.

3. The thickness of the layer of the aforementioned ceramic particle-filled epoxy resin lining is 4 to 6 mm. A slurry pump according to claim 1 or 2, characterized by the features described above.

4. In a wet smelting process for nickel and cobalt, a slurry containing a nickel-cobalt mixed sulfide powder is supplied. A slurry pump according to any one of claims 1 to 3.

5. at least, A rotating shaft that rotates due to the rotational driving force of the driving means, An impeller, whose center is fixed to the axis of one end of the aforementioned rotating shaft, and which is made of a metal base material with a rubber lining, A metal casing surrounding the impeller and forming a pressure boosting chamber, A rubber casing liner is fitted tightly inside the casing, Equipped with, In a slurry pump that transports a slurry containing pulverized metal compounds, In a portion of the casing liner, specifically the area facing the tip of the impeller blades, the rubber is removed to a depth where the metal liner base material is not exposed, and a ceramic particle-filled epoxy resin is applied in the same volume and shape as the removed rubber. A method for manufacturing a slurry pump characterized by the following.

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