JP6720946B2 - Angle valve - Google Patents

Description

The present invention relates to an angle valve, and more particularly, to an angle valve used as a slurry control valve for adjusting the transfer of high temperature and high pressure acidic slurry, for example.

In refining low-grade nickel ore using a high pressure acid leaching (hereinafter referred to as "HPAL") method, nickel and cobalt are selectively extracted from a slurried ore (hereinafter referred to as "ore slurry"). In order to leach, the temperature of the ore slurry is raised stepwise and transferred to an autoclave.

In the autoclave, sulfuric acid or the like is added for leaching treatment, and then the ore slurry is stepwise lowered in temperature and reduced in pressure and transferred to the next step. The ore slurry after the leaching treatment contains many particles of high hardness that do not contain nickel.

For example, as in the temperature-reducing/pressure-reducing processing system 50 shown in FIG. 1, the temperature-reducing/pressure-reducing treatment step in the HPAL method includes three pressure vessels (hereinafter referred to as “pressure vessels”) in which ore slurry pushed up by the internal pressure from the autoclave discharge pipe 51 is installed in series. , "Flash tank") 52 (52a, 52b, 52c). In the temperature lowering process, the ore slurry that has passed through the flash tank 52 is finally cooled to a temperature of 100° C. or lower, and the pressure is reduced to atmospheric pressure.

When stepping down the pressure of the ore slurry in the flash tank 52 stepwise, the liquid level of the autoclave installed in the preceding stage and the flash tank 52a are controlled by the control valves 53 (53a, 53b, 53c) installed in the upper part of each flash tank 52. The liquid level of the ore is controlled to be constant, and the ore slurry is continuously extracted. Since the ore slurry is transferred at high temperature and high speed due to the pressure difference between the flash tanks 52, it has high wear resistance. Further, the ore slurry is also highly corrosive because it becomes acidic by the sulfuric acid added in the autoclave.

An angle valve suitable for use with a slurry, a corrosive fluid, a high-temperature high-pressure fluid, or the like is used as the control valve 53 above the flash tank 52. Due to the structure of the control valve 53, a ceramic material having excellent wear resistance is generally used as the material of the plug main body and the seat component, which are rapidly worn. On the other hand, it has excellent corrosion resistance for wetted parts where it is difficult to use ceramic materials, such as the valve body, the plug stem that constitutes the plug shaft, and the bonnet that guides and holds the vertical sliding of the plug stem. Titanium material is used.

However, inside the angle valve, the slurry flowing at high temperature and at high speed inevitably causes wear to proceed with continued use, which causes the slurry to squirt through the valve body. Things can happen. Since the progress of wear greatly changes depending on the operating condition, it is necessary to periodically remove the angle valve, inspect the internal condition of the valve, repair it according to the worn condition, and replace parts.

Specifically, wear inside the valve locally progresses around the plug body and the plug stem where the flow of the slurry is disturbed, and conventionally, wear of the plug insertion portion of the bonnet and wear of the root portion of the plug stem cause Frequent replacement of plugs and bonnets. Further, depending on the progress of wear of these portions, there is a possibility that slurry leakage to the outside may occur due to a defective shaft seal portion. When replacing parts of such a valve, it is necessary to stop the equipment for a long time in order to decrease the temperature when the equipment is shut down and raise the temperature when the equipment is started up. Therefore, it is desired to reduce the inspection cycle and the frequency of parts replacement.

Here, in order to enhance wear resistance inside the angle valve, a technique of forming a protective coating by glass lining or ceramic spraying is generally proposed. For example, Patent Document 1 discloses an angle valve for slurry in which glass lining is applied to the inside of the valve to improve corrosion resistance and wear resistance. However, the glass lining inside the valve may be damaged due to temperature change, and scales adhering to the inside of the pipe and fragments of bricks lined on the inner wall of the tank will flow into the valve together with the slurry, and the inner wall The glass lining easily breaks due to the collision and cannot exhibit sufficient abrasion resistance.

Further, Patent Literature 2 discloses a slurry control valve in which a protective coating is deposited on a slurry control valve in which ceramic is sprayed and a protective coating is deposited, and the peeling is prevented by forming a structure in which a coated coating end portion is not exposed. There is. However, even when this method is enabled, the ceramic protective coating is easily damaged by the collision of scale objects or bricks, as in the glass lining.

As described above, the conventional techniques cannot sufficiently suppress the wear inside the valve.

JP-A-5-118448 JP-A-6-159528

The present invention has been proposed in view of such circumstances, and an object thereof is to provide an angle valve that can effectively suppress wear inside the angle valve through which the slurry flows.

The present inventor has conducted extensive studies in order to solve the above problems. As a result, in an angle valve that includes a valve body and a plug that is slidably arranged vertically inside the valve body and that controls the outflow of slurry, a liquid contact part with the slurry inside the valve body In addition, it was found that the local wear inside the valve can be effectively suppressed by applying the overlay welding with tungsten carbide, and the present invention has been completed.

(1) A first aspect of the present invention is directed to a valve main body that discharges a slurry received from a slurry inflow port while changing its direction to a slurry outflow port, and to be slidable in the flow direction inside the valve main body. An angle valve provided with a plug for controlling opening/closing of the slurry outlet, wherein the plug is composed of a plug body and a plug stem having the plug body connected to a tip thereof. Inside, at least an upper surface portion of the plug body and a slurry contact portion of the bonnet that slidably guides and holds the plug stem have a tungsten carbide overlay welded thereto, and the plug stem and the bonnet. A sealing material is provided between and, and in the plug stem, tungsten carbide is welded by overlay welding only to a root portion to which the plug main body is connected.

(2) The second invention of the present invention is the angle valve according to the first invention, wherein the slurry is a high temperature and high pressure acidic slurry obtained by high pressure acid leaching.

(3) A third aspect of the present invention is the angle control method according to the first or second aspect, wherein the liquid contact portion inside the valve body is made of a metal material having corrosion resistance and heat resistance. It is a valve.

According to the angle valve of the present invention, it is possible to effectively suppress local wear inside the angle valve through which the slurry flows. As a result, it is possible to prevent the trouble of the angle valve due to wear, reduce the cost for repairs, etc., and improve the efficiency of operation.

It is a figure which shows an example of a structure of the processing system of temperature fall and pressure fall provided with the flash tank and the control valve (angle valve) installed in the upper part of the flash tank. It is sectional drawing which shows the structure of an angle valve. It is an expanded sectional view in the specific part of the angle valve shown in Drawing 2, and is a figure for explaining the mode of the surface treatment processing in the liquid contact part inside the valve body.

Hereinafter, specific embodiments of the present invention (hereinafter, referred to as “this embodiment”) will be described in detail with reference to the drawings. The present invention is not limited to the following embodiments, and various modifications can be made without changing the gist of the present invention.

<<1. Angle valve configuration ≫
The angle valve according to the present embodiment is a control valve that is installed in the upper portion of a flash tank and controls the transfer of slurry between the flash tanks, as shown in FIG. 1, for example.

The slurry is not particularly limited, and examples thereof include nickel oxide ore slurries used in the HPAL process, which are high temperature and acidic slurries obtained by leaching treatment with sulfuric acid under high temperature and high pressure. it can. As described above, in the HPAL process, the temperature and pressure of the slurry in a high temperature and high pressure state are gradually lowered by using a plurality of flash tanks. The slurry flows at high speed.

The slurry is not limited to the above-mentioned ore slurry, and any kind of slurry can be applied. Further, the angle valve according to the present embodiment can be effectively applied as a control valve for controlling the transfer of corrosive fluid, high-temperature and high-pressure fluid other than the above-mentioned slurry, and the like. These fluids are also included within the meaning of the term "slurry".

FIG. 2 is a cross-sectional view showing the structure of the angle valve. As shown in FIG. 2, the angle valve 1 includes a valve body 11 and a plug 12 that is slidable up and down inside the valve body 11. The valve main body 11 has a slurry inflow port 11A that opens in the horizontal direction and a slurry outflow port 11B that opens in the vertical direction, and the slurry flowing from the slurry inflow port 11A flows inside the valve main body 11 and It flows out through the slurry outlet 11B.

Further, the plug 12 controls the opening and closing of the slurry outlet 11B of the valve body 11 by moving up and down (arrow X in FIG. 2) inside the valve body 11. It should be noted that FIG. 2 shows a state where the slurry outlet 11B is closed by the plug 12.

The angle valve 1 is characterized in that the surface of the valve body 1 that comes into contact with the slurry is surface-treated with titanium nitride. Here, the “wetted portion” inside the valve body 1 refers to a portion where the slurry flowing at a high speed in the valve body 1 is brought into contact with the valve body 1 based on the pressure difference, and is particularly made of a material such as ceramic having abrasion resistance. Not referred to.

[Valve body]
The valve body 11 constitutes the body of the angle valve 1, and the slurry flows inside the valve body 11. As described above, the valve main body 11 is provided with the slurry inflow port 11A that is opened in the horizontal direction and the slurry outflow port 11B that is opened in the vertical direction. It flows at high speed inside and flows out from the slurry outlet 11B.

In the valve main body 11, at least the liquid-contacting portion with the slurry inside the valve main body 11 is made of a metal material capable of being welded with a predetermined metal. Further, the metal material is preferably one having corrosion resistance and heat resistance. For example, when transferring a high temperature and acidic slurry obtained by performing a leaching treatment with sulfuric acid by the HPAL process, the liquid contact part inside the valve body 11 is a metal material having corrosion resistance and heat resistance. By being configured with such as, it is possible to prevent deterioration and wear due to corrosion and heat. Further, by using such a metal material, it becomes possible to efficiently perform surface treatment by overlay welding of titanium nitride, as will be described later.

In the valve body 11, at the slurry outlet 11B, opening/closing control by a plug 12 described later is performed. Specifically, when the plug 12 moves up and down, the plug body 21 comes into contact with the opening of the slurry outlet 11B to be in a closed state, and when the plug body 21 separates from the opening of the slurry outlet 11B, the plug 12 opens. It becomes a state.

In the slurry outlet 11B of the valve body 11, since the opening/closing control is performed by the contact or non-contact of the plug 12 (plug body 21) in this manner, the inner wall of the opening of the slurry outlet 11B is For example, a sheet member 11s made of a ceramic material or the like is provided so as to improve wear resistance. Further, by providing the sheet member 11s on the inner wall of the opening in this way, it is possible to suppress the abrasion due to the slurry flowing out at high speed.

A connection pipe 40 for transferring the slurry to a subsequent flash tank or the like is connected to the slurry outlet 11B. A sheet member 40s made of a ceramic material or the like can also be provided on the inner wall of the connection pipe 40.

[plug]
The plug 12 moves up and down inside the valve body 11 (arrow X in FIG. 2) to control the outflow (transfer) of the slurry through the slurry outflow port 11B. The plug 12 includes a plug body 21 and a plug stem 22 having the plug body 21 connected to its tip.

(Plug body)
The plug body 21 has, for example, an inverted mountain shape having a taper or an inverted conical shape. The plug body 21 closes the opening of the slurry outlet 11B of the valve body 11 by contacting the opening, thereby stopping the outflow of the slurry. The plug body 21 is made of, for example, a material such as ceramic, or a surface of a metal material is coated with ceramic or the like to improve its wear resistance.

(Plug stem)
The plug stem 22 has a rod-like shape and constitutes the shaft of the plug 12. The plug body 21 is connected to the tip of the plug stem 22, and the plug body 21 is moved up and down by sliding upward or downward. The plug stem 22 is surrounded by the bonnet 13 inside the valve body 11, and can be slid up and down by being guided and held by the bonnet 13.

Here, between the plug stem 22 and the bonnet 13 that slidably guides and holds the plug stem 22, a seal member (shaft seal member) 13s for preventing the ejection of the slurry from the gap is provided on the circumference. It is provided in. The shaft seal member 13s can be formed of, for example, packing, and if the material that enhances the sealing property between the plug stem 22 and the bonnet 13 but does not hinder the sliding of the plug stem 22, the material thereof is used. Is not particularly limited. For example, it can be made of an organic material such as rubber or an inorganic material such as ceramic, and is particularly preferable as long as it has heat resistance.

<<2. Surface treatment of wetted parts >>
As described above, the angle valve 1 according to the present embodiment is characterized in that the surface of the valve body 11 in contact with the slurry is surface-treated with titanium nitride. Specifically, titanium nitride is overlay welded to a predetermined liquid contact portion inside the valve body 11.

FIG. 3 is an enlarged cross-sectional view of a specific portion of the angle valve 1 shown in FIG. 2, and is a view for explaining a state of surface treatment processing in the liquid contact portion inside the valve body 11. As shown in FIG. 3, in the angle valve 1, titanium nitride 30 is welded to the inside of the valve main body 11 at the liquid contact portion with the slurry by overlay welding. Titanium nitride is a material having excellent wear resistance as well as corrosion resistance and heat resistance. By subjecting the titanium nitride to a surface treatment for overlay welding at the portion in contact with the slurry, it flows at high speed inside the valve body 11 and effectively suppresses wear due to the slurry having high temperature and strong acidity. You can

For example, as shown in FIG. 3, as the liquid contacting part for the surface treatment, at least the upper surface part 21t of the plug body 21 and the slurry in the bonnet 13 that slidably guides and holds the plug stem 22 are wetted. It is preferably part 13t. The upper surface of the plug body 21 is the surface to which the plug stem 22 is connected. The upper surface portion 21t of the plug main body 21 and the liquid contact portion 13t with the slurry in the bonnet 13 are locations where the slurry flowing at high speed is frequently contacted and the flow of the slurry is disturbed, and the slurry is likely to be worn. .. Further, these portions are portions which come into collision contact with each other as the plug 12 moves up and down, and not only abrasion due to the slurry but also deterioration abrasion due to mutual contact easily occurs. Therefore, by forming the titanium nitride 30 in such a position by overlay welding, wear inside the valve body 11 can be suppressed more effectively.

In addition to the upper surface of the plug body 21, as shown in FIG. 3, not only the root portion 22r of the plug stem 22, that is, the root portion of the plug stem 22 to which the plug body 21 is connected is surface-treated by overlay welding. The titanium nitride 30 can be formed by processing.

Here, the plug stem 22 is guided and held by the bonnet 13 and slides up and down, and since it comes into contact with the slurry flowing inside the valve body 11, the plug stem 22 covers almost the entire surface of the plug stem 22. It may be desirable to apply surface treatment. However, between the plug stem 22 and the bonnet 13, it is necessary to secure the sealing property from the viewpoint of preventing the ejection of the slurry, and the shaft seal member 13s is provided in the gap. Therefore, when titanium nitride is welded over substantially the entire surface of the plug stem 22, the overlay welded titanium nitride may damage the shaft seal member 13s as it slides up and down. Therefore, in the plug stem 22, the wear of the plug stem 22 can be effectively suppressed and the shaft seal can be effectively prevented by making the titanium nitride build-up weld only on the root portion 22r to which the plug body 21 is connected. It is possible to prevent the member 13s from being damaged and to effectively prevent the slurry from being spouted.

When titanium nitride is formed on the root portion 22r of the plug stem 22 by overlay welding, the formation height of the titanium nitride (the formation height of titanium nitride in the axial direction of the plug stem 22) is not particularly limited. The height of the plug body 21 is about 15% to 25% of the diameter of the plug body 21. The specific length numerical value cannot be unconditionally defined because it depends on the size of the angle valve 1, but it can be set to a height of about 0.5 mm to 50 mm.

The thickness (formed thickness) of the titanium nitride 30 formed by the surface treatment of overlay welding is not particularly limited and is preferably adjusted appropriately according to the size of the angle valve 1. For example, 0.5 mm to It is preferably about 2.5 mm, and more preferably about 1.0 mm to 2.0 mm. If the thickness of the titanium nitride 30 is less than 0.5 mm, sufficient wear resistance may not be exhibited, and the frequency of component replacement cannot be effectively reduced. On the other hand, if the thickness exceeds 2.5 mm, the cost increases and the slurry flow path inside the valve body 11 may be narrowed.

As described above in detail, in the present embodiment, the valve body 11 and the plug 12 that is slidably arranged inside the valve body 11 and that controls the opening and closing of the slurry outlet 11B are provided. In the angle valve 1 provided, titanium nitride 30 is welded to the inside of the valve body 11 at the liquid contact portion with the slurry by overlay welding. According to such an angle valve 1, it is possible to effectively suppress the wear due to the high temperature slurry flowing at a high speed. As a result, troubles of the angle valve 1 due to wear can be prevented, costs for repairs and the like can be reduced, and efficiency of operation can be improved.

In addition, in this Embodiment, although the aspect in which the titanium nitride 30 was welded to the liquid contact portion with the slurry inside the valve body 11 was described, instead of titanium nitride, for example, tungsten carbide (WC) was used. Even in a mode in which an alloy material such as (4) is welded by overlay welding, the wear due to the slurry can be effectively suppressed in the same manner.

1 Angle Valve 11 Valve Body 12 Plug 13 Bonnet 21 Plug Body 22 Plug Stem 30 Titanium Nitride

Claims (3)

A valve body which discharges the slurry received from the slurry inflow port while turning it to the slurry outflow port, and is disposed inside the valve body so as to be slidable in the flow direction and controls the opening and closing of the slurry outflow port. An angle valve with a plug,
The plug is composed of a plug main body and a plug stem having the plug main body connected to a tip thereof,
Inside the valve body, at least the upper surface of the plug body, the liquid contact portion of the slurry in the bonnet that slidably guides and holds the plug stem, tungsten carbide is overlay welded,
A sealing material is provided between the plug stem and the bonnet,
In the plug stem, tungsten carbide is welded by overlay welding only to the root portion to which the plug body is connected. The angle valve according to claim 1, wherein the slurry is a high temperature and high pressure acidic slurry obtained by high pressure acid leaching. The angle valve according to claim 1 or 2, wherein the liquid contact portion in the valve body is made of a metal material having corrosion resistance and heat resistance.

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