Mixing device

Abstract

To provide a stirring device that is excellent in corrosion resistance and abrasion resistance and is improved in useful life.SOLUTION: A stirring device 1, which stirs slurry in a tank, comprises at least a rotating shaft 10 provided vertically in the tank, a bracket 20 provided in the rotating shaft 10, and a paddle-type stirring blade 30 attached to the rotating shaft 10 through the bracket 20. A rubber lining 15 is applied to the rotating shaft 10 and a surface of the stirring blade 30 is covered with a member 35 with abrasion resistance. An epoxy resin layer 40 is formed at a portion attached to the stirring blade 30 of the bracket 20 so as to cover the whole of a surface including an end part of the rubber lining 15 and an end part of the member 35 with abrasion resistance, and an epoxy resin bump 50 filled with ceramic particles is formed so as to cover a boundary part between the epoxy resin layer 40 and the member 35 with abrasion resistance.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an agitation device, and more particularly to an agitation device for agitating a slurry in a tank. [Background technology]

[0002] The Matte Chlorine Leach Electrowinning (MCLE) process is known as a hydrometallurgical process for nickel and cobalt. In this MCLE process, electrolytic nickel and electrolytic cobalt are produced by hydrometallurgy using nickel-cobalt mixed sulfide (hereinafter also referred to as "MS") and nickel matte (mainly composed of trinickel disulfide and nickel metal) as raw materials.

[0003] The raw material slurry of nickel-cobalt mixed sulfide (MS) is stirred in a storage tank by a mixer. Nickel and cobalt hydrometallurgical processes often involve handling an acidic aqueous solution of hydrochloric acid. Furthermore, the particle size of nickel-cobalt mixed sulfide (MS) is approximately 70-80 μm (D50), and the raw material slurry is highly concentrated at 300-400 g / L. Therefore, the mixing blades of the mixer frequently come into contact with and collide with the slurry during mixing. For this reason, the mixer must be highly corrosion-resistant and wear-resistant. D50 refers to the median diameter of the volume-based particle size distribution measured by laser diffraction / scattering.

[0004] For example, Patent Document 1 describes a paddle-type impeller for stirring a corrosive and abrasive slurry liquid in a stirring reaction vessel, in which the impeller is made of a titanium blade, and a wear-resistant member selected from an L-shaped cross-section ceramic member, a U-shaped cross-section ceramic member, or a flat-plate-shaped ceramic member is fixed to substantially the entire surface of the impeller that is more corrosive and abrasive.

[0005] According to the invention of Patent Document 1, paddle-type blades are used under stirring conditions that place severe strain on blade wear, and ceramic members of a specific shape are attached to the entire surface of the blades, which require corrosion resistance and wear resistance, to improve wear resistance. This makes it possible to extend the life of the stirring blades, reduce running costs, and reduce downtime losses. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-94646 Summary of the Invention [Problem to be solved by the invention]

[0007] However, even when the stirring device described in Patent Document 1 is used, exposed metal parts such as the attachment part of the stirring blade to the rotating shaft are prone to corrosion, and even if a corrosion-resistant lining or the like is applied to the exposed metal parts, the boundary part between the corrosion-resistant lining and the wear-resistant member is prone to wear, and a corrosive aqueous solution penetrates through these worn parts, causing corrosion.

[0008] The present invention has been made to solve such a situation, and an object of the present invention is to provide a stirring device that has excellent corrosion resistance and wear resistance and an improved service life. [Means for solving the problem]

[0009] In order to achieve the above object, the present inventors have conducted extensive research and have come up with the idea of ​​applying a ceramic particle-filled epoxy resin to areas of the mixing device that are prone to wear.

[0010] That is, one aspect of the present invention is an agitation device for agitating slurry in a tank, comprising at least a rotating shaft arranged vertically in the tank, a bracket attached to the rotating shaft, and a paddle-shaped agitation blade attached to the rotating shaft via the bracket, wherein the rotating shaft is rubber lined, the surface of the agitation blade is covered with a wear-resistant material, and an epoxy resin layer is formed at the attachment portion of the bracket to the agitation blade so as to cover the entire surface including the end of the rubber lining and the end of the wear-resistant material, and ceramic particle-filled epoxy resin nodules are formed so as to cover the boundary portion between the epoxy resin layer and the wear-resistant material.

[0011] According to one aspect of the present invention, the agitator blades are covered with wear-resistant materials, the rotating shaft is lined with rubber, and the connection between the agitator blades and the rotating shaft is covered with epoxy resin and ceramic particle-filled epoxy resin, thereby realizing an agitator with excellent corrosion resistance and wear resistance and an improved service life.

[0012] In this case, in one embodiment of the present invention, the stirring blades may be made of titanium or a titanium alloy, and the wear-resistant member covering the surface may be made of ceramic.

[0013] By covering the surface of a titanium or titanium alloy agitating blade with a ceramic member, the agitating blade can be made to have improved corrosion resistance and wear resistance.

[0014] In one embodiment of the present invention, the ceramic particles mixed in the ceramic particle-filled epoxy resin may be alumina ceramic beads having a diameter of 0.5 to 2.5 mm.

[0015] By blending such alumina ceramic beads with epoxy resin, it is possible to apply a resin with excellent abrasion resistance.

[0016] Furthermore, one aspect of the present invention may be an agitation device that agitates a slurry containing nickel-cobalt mixed sulfide powder in a hydrometallurgical process for nickel and cobalt.

[0017] As in this nickel and cobalt hydrometallurgical refining process, the present invention can be suitably applied to a stirring device that stirs aqueous solutions that are prone to corrosion and wear, such as a hydrochloric acid aqueous solution and a slurry of MS. [Effects of the Invention]

[0018] As described above, according to the present invention, it is possible to provide a stirring device that has excellent corrosion resistance and wear resistance and an improved service life. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 shows an example of an agitation device to which the present invention is applied, where (A) is a front view and (B) is a cross-sectional view of the agitation blade portion. [Figure 2] FIG. 2 is a schematic diagram showing the structure of a stirring device according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. Note that the embodiments described below do not unduly limit the content of the present invention as defined in the claims, and not all of the configurations described in the embodiments are necessarily essential as means for solving the problems of the present invention.

[0021] First, an outline of the mixing device applicable to the present invention will be described. FIG. 1 shows an example of a mixing device applicable to the present invention, with (A) being a front view and (B) being a cross-sectional view of the mixing blade. The mixing device is used with a wear-resistant paddle-type mixing blade 30 fixed to a rotating shaft 10. The mixing blade 30 is constructed using a plate-shaped blade made of, for example, titanium or a titanium alloy as a base. The blade is fixed to a bracket 20 provided on the rotating shaft 10 by a mounting hole 5a in the blade and a bolt 5 at a predetermined angle with respect to the vertical direction, and is connected to the rotating shaft 10 and rotated by a motor (not shown). Note that while FIG. 1(A) shows a single-stage mixing blade, a multi-stage paddle-type mixing blade with one or more additional blades attached thereon may also be used. The inclination angle can be adjusted as appropriate between 45 and 90 degrees.

[0022] In one aspect of the present invention, a plate-shaped blade made of titanium or a titanium alloy is used as a base, and a wear-resistant member selected from an L-shaped ceramic member, a U-shaped ceramic member, or a flat ceramic member is fixed to substantially the entire surface of the blade that is highly corrosive and abrasive.

[0023] As an example, as shown in Figure 1(A), the central portion 2a of the impeller has the plate-shaped blades sandwiched between ceramic members 6a with an L-shaped cross section, and the end portion 2b of the impeller has the tips of the plate-shaped blades sandwiched between ceramic members 6b with an L-shaped cross section and ceramic members 7 with L-shaped cross sections and longitudinal sections. As shown in Figure 1(A), the ceramic member 6a of the central portion 2a has four tapered holes 8 on its side, into which fixing metal fittings made of the same material as the blades are inserted and fixed, and the ceramic members 6b, 7 of the end portion 2b have two tapered holes 8 on their side, into which fixing metal fittings made of the same material as the blades are inserted and fixed.

[0024] This configuration is because the end portion 2b away from the rotating shaft is more susceptible to corrosion and abrasion by the slurry than the central portion 2a close to the rotating shaft. Therefore, it is preferable to fix the ceramic member to the blade in a divided state, so that even if some ceramic members are partially worn, they can be replaced and the impeller can be reused. The entire blade may be covered with the same ceramic or with different ceramics. That is, the end surface of the impeller can be covered with a ceramic member with an L-shaped or U-shaped cross section, which has particularly excellent abrasion resistance, and the remaining portion can be covered with a relatively inexpensive ceramic.

[0025] The ceramic material refers to a wear-resistant material such as silicon nitride, silicon carbide, sialon, zirconium oxide, partially stabilized zirconia, alumina, etc. These ceramics may consist of a single component, or may contain other components as needed, such as oxides of elements in Group 3a of the periodic table, silicate compounds such as disilicate and monosilicate, alumina, silica, magnesia, etc.

[0026] As shown in FIG. 1(B), the ceramic member having an L-shaped cross section has a length in which the short side of the L shape is approximately the same as the thickness of the blade, and the long side of the L shape is slightly longer than the width of the blade. "Slightly longer" means that the ceramic member is longer than the width of the blade by at least one thickness of the ceramic member. The thickness of the ceramic member is not particularly limited, but is, for example, 3 to 10 mm, preferably 3 to 5 mm. A thickness thinner than 3 mm results in insufficient wear resistance, while a thickness exceeding 10 mm results in increased weight and is undesirable from a cost perspective. L-shaped ceramic members include those with one L-shaped side, those with two L-shaped sides (one cross section and one longitudinal section are L-shaped), and those with three L-shaped sides (one cross section and two longitudinal sections are L-shaped). All of these can be used, but those with two or three L-shaped sides are used exclusively at the end of the blade.

[0027] The U-shaped ceramic member has a U-shaped corner of the L-shaped ceramic member, and the portion connected to the short side of the L is relatively short, for example, about 1 to 5 cm. This is because it is somewhat difficult to form and is prone to breakage when attached to the blade. U-shaped ceramic members come in two types: one with a U-shaped end and both with a U-shaped end. Using this U-shaped ceramic member makes it possible to cover the entire end of the blade.

[0028] Next, the characteristics of the agitation device according to the present invention will be described. Figure 2 is a schematic diagram showing the structure of an agitation device according to one embodiment of the present invention. One aspect of the present invention is an agitation device 1 for agitating slurry in a tank, comprising at least a rotating shaft 10 vertically disposed in the tank, a bracket 20 attached to the rotating shaft 10, and a paddle-shaped agitation blade 30 attached to the rotating shaft 10 via the bracket 20. The rotating shaft 10 is provided with a rubber lining 15, and the surface of the agitation blade 30 is covered with a wear-resistant member 35. An epoxy resin layer 40 is formed at the attachment portion of the bracket 20 to the agitation blade 30, covering the entire surface including the end of the rubber lining 15 and the end of the wear-resistant member 35. Ceramic particle-filled epoxy resin nodules 50 are formed to cover the boundary between the epoxy resin layer 40 and the wear-resistant member 35.

[0029] The rotating shaft 10 is made of a material such as SS400 (general structural rolled steel), and has a rubber lining made of natural rubber, butyl rubber, or the like applied to its surface. As mentioned above, hydrochloric acid aqueous solutions are often used in the hydrometallurgical refining process of nickel and cobalt, and stirring of strongly acidic chemicals and the like would cause corrosion of a steel rotating shaft. Therefore, by applying a rubber lining, corrosion resistance to strongly acidic aqueous solutions can be improved.

[0030] As for the stirring blade 30, as described above, the surface is covered with the wear-resistant member 35 such as a ceramic member, and therefore the structure is resistant to wear.

[0031] On the other hand, if a rubber lining is applied to the bracket 20 portion, which is the connection point between the rotating shaft 10 and the agitator blade 30, as with the rotating shaft 10, on the contact surface between the bracket 20 and the agitator blade 30, the agitator blade 30 will not be secured properly and may become loose during subsequent operation. Therefore, since a rubber lining cannot be applied to the bracket 20 portion, there has been a problem in that the connection point between the rotating shaft 10 and the agitator blade 30 is most susceptible to corrosion.

[0032] Therefore, in the present invention, as shown in Figure 2, after the mixing blade 30 is attached to the bracket 20, an epoxy resin layer 40 is formed at the attachment point between the bracket 20 and the mixing blade 30 to cover the entire surface, including the end of the rubber lining 15, the end of the wear-resistant member 35 covering the mixing blade 30, and protrusions caused by bolts 5, etc., and ceramic particle-filled epoxy resin nodules 50 are formed to cover the boundary between the epoxy resin layer 40 and the wear-resistant member 35. In this way, the bracket 20 of the rotating shaft 10, which was previously prone to corrosion, can be protected from corrosion, and the boundary between the epoxy resin layer 40 and the wear-resistant member 35, which was previously prone to wear, can be protected from wear, thereby improving the service life.

[0033] The ceramic particles are not particularly limited as long as they have a certain level of hardness, but for example, alumina ceramic beads are used. The particle size of the ceramic particles may be large enough to be uniformly dispersed in the epoxy resin, and for example, particles with a diameter of 0.5 to 1.0 mm or 2.0 to 2.5 mm are used. From the standpoint of ease of handling, it is preferable to use particles with a diameter of 0.5 to 1.0 mm. By dispersing the ceramic particles in the epoxy resin, the ceramic particles can prevent wear even during stirring of the slurry, thereby protecting the surface on which the ceramic particle-filled epoxy resin is applied and improving wear resistance.

[0034] Such a cured ceramic particle-filled epoxy resin has the following characteristics: Wear resistance: Shore hardness is approximately 90HS, which is 2.5 to 4 times harder than the SS400 material used for the rotating shaft 10 and the titanium material used for the mixing blades 30. Chemical resistance: Resistant to corrosive aqueous solutions such as sulfuric acid, caustic soda, and nickel chloride. -Can be used in high temperature environments of around 150°C. -Good adhesion to metals and resins, no welding required, and easy to handle.

[0035] Furthermore, because the ceramic particle-filled epoxy resin nodules 50 are susceptible to aqueous solutions, there is a risk of hydrochloric acid solution penetrating and corroding the internal material. Therefore, in the present invention, rather than directly applying the ceramic particle-filled epoxy resin to the bracket 20, the epoxy resin is first applied to the bracket 20's attachment point to the agitator blade 30, covering the entire surface, including the ends of the rubber lining 15 and the wear-resistant member 35. Then, the ceramic particle-filled epoxy resin is applied to cover the interface between the epoxy resin layer 40 and the wear-resistant member 35. This configuration improves corrosion resistance because the epoxy resin layer 40 is impermeable to aqueous solutions, while the ceramic particle-filled epoxy resin applied to its exterior provides a hybrid design with improved wear resistance. While the cured epoxy resin itself is generally impermeable to liquids, the ceramic particles, when filled with the epoxy resin, tend to create tiny gaps that may allow aqueous solutions to pass through.

[0036] An agitation device according to one embodiment of the present invention can be used to agitate raw material slurry of nickel-cobalt mixed sulfide (MS) in a storage tank in a nickel and cobalt hydrometallurgical process. MS is a mixture of NiS and CoS, with Ni: 50-60 wt%, Co: approximately 5 wt%, and S: 30-40 wt%. Of course, the agitation device according to one embodiment of the present invention is not limited to this example, and can be used to agitate any slurry consisting of a corrosive, strongly acidic aqueous solution containing abrasive solids. [Example]

[0037] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples in any way.

[0038] In the above-mentioned nickel and cobalt hydrometallurgy process, the present invention was applied to an agitator for a raw material slurry storage tank for nickel-cobalt mixed sulfide (MS), creating an agitation device according to one embodiment of the present invention. Ceramic particle-filled epoxy resin was applied using a ceramic epoxy material (Model HL-K1, manufactured by Kansai Putty Chemical Co., Ltd.) with alumina ceramic beads having a particle diameter of 0.5 to 1.0 mm. The ceramic particle-filled epoxy resin was prepared by mixing the base resin and curing agent in a 1:2 ratio and applying it. The applied ceramic particle-filled epoxy resin was left to stand for at least 24 hours to harden and dry the epoxy material.

[0039] The operating environment in this example is pH 1.5 to 3.0, temperature 55 to 65°C, and rotation speed 80 to 90 rpm. In a conventional example (comparative example) before the application of the present invention, the agitator required replacement after approximately 1.5 years due to wear and corrosion. In contrast, the agitator (example) to which the present invention was applied was still usable without any problems even after 8.5 years. The agitator of the comparative example is the same as the agitator described above as one embodiment of the present invention, except that it does not include the ceramic particle-filled epoxy resin nodules 50.

[0040] Therefore, by applying the present invention, the service life of the stirring device can be significantly improved.

[0041] Although one embodiment and example of the present invention 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 features and effects of the present invention. Therefore, all such modifications are intended to be included within the scope of the present invention.

[0042] For example, a term that is described at least once in the specification or drawings together with a different term having a broader or equivalent meaning can be replaced with that different term anywhere in the specification or drawings. Furthermore, the configuration of the stirring device is not limited to that described in the embodiment and examples of the present invention, and various modifications are possible. [Explanation of symbols]

[0043] 1 Stirring device, 2a central part of stirring blade, 2b end of stirring blade, 5 bolt, 5a mounting hole, 6a, 6b ceramic member (cross section is L-shaped), 7 ceramic member (cross section and longitudinal section are L-shaped), 8 tapered hole, 10 rotating shaft, 15 rubber lining, 20 bracket, 30 stirring blade, 35 wear-resistant member, 40 epoxy resin layer, 50 ceramic particle-filled epoxy resin lump

Claims

1. An agitation device for agitating a slurry in a tank, at least, a rotating shaft vertically disposed within the tank; a bracket provided on the rotating shaft; a paddle-type stirring blade attached to the rotating shaft via the bracket; Equipped with The rotating shaft is provided with a rubber lining, and the surface of the stirring blade is covered with a wear-resistant material, An agitation device characterized in that an epoxy resin layer is formed at the attachment portion of the bracket to the agitation blade so as to cover the entire surface, including the ends of the rubber lining and the ends of the wear-resistant member, and a ceramic particle-filled epoxy resin nodule is formed so as to cover the boundary portion between the epoxy resin layer and the wear-resistant member.

2. 2. The stirring device according to claim 1, wherein the stirring blades are made of titanium or a titanium alloy, and the wear-resistant member covering the surface is made of ceramic.

3. 3. The stirring device according to claim 1, wherein the ceramic particles mixed in the ceramic particle-filled epoxy resin are alumina ceramic beads having a diameter of 0.5 to 2.5 mm.

4. 3. The stirring device according to claim 1, wherein the stirring device is used to stir a slurry containing powder of nickel-cobalt mixed sulfide in a hydrometallurgical process for nickel and cobalt.

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