JP2009000661A - Agitation apparatus and reaction tank using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an agitation apparatus having a shaft sealing mechanism capable of preventing a liquid or a gas from leaking from a shaft seal part of a gland packing type to be arranged instead of a mechanical seal type having little resistance to a shaft runout phenomenon and to provide a reaction tank using the agitation apparatus. <P>SOLUTION: Compressed air is blown into the gland packing type shaft seal part of the agitation apparatus to prevent the liquid or the gas from leaking from the shaft seal part and restrain the abrasion of a shaft sleeve. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a stirring device and a reaction tank using the same, and in particular, is a stirring device for various reaction tanks used in electrolytic nickel and electrolytic cobalt refining, wherein the pressure in the reaction tank is atmospheric pressure, and the reaction tank The present invention relates to a stirrer equipped with a gland packing type shaft seal mechanism that is often employed when the temperature is about 150 ° C. or less, and a reaction tank using the same.

  As a method of wet refining of nickel, there is a chlorine leaching electrowinning method as a conventional method (see Patent Document 1). In this method, a nickel mat containing nickel sulfide as a main component is pulverized, then repulped into a chloride solution, and chlorine gas is blown into the nickel matte to leach out a metal containing nickel. Then, from the obtained nickel leaching solution, impurities such as copper, cobalt and iron are removed by chemical treatment to obtain a clear nickel chloride solution. And nickel is electrolyzed from this nickel chloride solution, and nickel ingot is produced.

  In this nickel refining method, there is an oxidation neutralization method using chlorine gas as an oxidizing agent and carbonate as an alkaline agent as a method for removing impurities from the nickel leachate (cleaning step). This oxidative neutralization method utilizes the property that, when heavy metals such as cobalt and iron become higher-order oxide ions, they tend to be hydroxides in a low pH region. This method is widely used for wastewater treatment including heavy metals.

  In general, chlorine gas, hypochlorous acid, oxygen, air, etc. are used as the oxidizing agent used in the oxidation neutralization method, and hydroxides such as caustic soda, ammonia, carbonates, etc. are used as the alkaline agent. Is used. These chemicals are used in combination suitable for the process conditions, but in the nickel refining process, it is common to use chlorine gas as the oxidizing agent and nickel carbonate as the alkaline agent.

  By the way, in the reaction tank used for the oxidation neutralization method, a stirrer is installed in order to promote the reaction and prevent the solid matter from settling. As shown in FIG. 1, the agitation device of various reaction tanks is exemplified by a general mechanism. 1 is an electric motor, 2 is a V belt, 3 is a speed reducer, 4 is a bearing portion, 5 is a shaft seal portion, and 6 is The stirring shaft 7 is composed of stirring blades. The rotational power obtained from the electric motor 1 is transmitted by the V-belt 2, decelerated to a desired rotational speed by the speed reducer 3, and the reaction shaft (by rotating the stirring shaft 6 and the stirring blade 7 through the bearing portion 4) The liquid inside (not shown) is stirred.

  The shaft seal portion 5 of the stirrer has a role of preventing or reducing leakage of liquid or gas in the reaction tank to some extent, and its structure is determined by the pressure and temperature in the reaction tank. When the pressure in the reaction tank is atmospheric pressure, the reaction tank temperature is about 150 ° C or less, and no toxic gas that cannot be leaked is used, most shaft seals have excellent durability and maintainability. 2 is used. In general, in this system, a cylindrical shaft sleeve 9 is attached and fixed to the agitation shaft 8 (6 in FIG. 1) to prevent wear due to contact of the agitation shaft with the gland packing 10.

In terms of maintenance, when the packing retainer nut 11 is tightened, the packing retainer 12 is pushed in and compresses the gland packing. The compressed gland packing expands in the vertical direction of the compressed force, and ensures sealing performance by contacting and sliding with the outer surface of the shaft sleeve fixed to the rotating stirring shaft. When the shaft sleeve 9 and the gland packing 10 are worn out, the amount of liquid or gas leaking to the outside increases, so it is important to maintain the sealing performance by appropriately tightening the packing holding nut 11. Since the outer surface of the shaft sleeve 9 and the gland packing 10 are worn and gradually worn, periodic inspection to stop the stirring device requires inspection or replacement of the gland packing 10 and the shaft sleeve 9.
JP 2005-248245 A

  As described above, when the operation is carried out using the stirring device having the shaft seal part of the gland packing system, a disadvantage of the gland packing system is that some leakage is allowed due to its characteristics. Therefore, depending on the reaction tank, leakage of highly corrosive liquid or gas may occur from the shaft seal of the stirrer, leading to corrosion of each component of the stirrer, or the leaked liquid may be crystallized at the shaft seal and the shaft sleeve and ground There is early wear on both sides of the packing. If the wear of the shaft sleeve is neglected, in the worst case, the shaft sleeve may be worn out, and the stirring shaft and the gland packing may come into contact with each other, resulting in wear or breakage of the stirring shaft.

  In general, when the leakage from the shaft seal portion is disliked, the mechanical seal method is often adopted. The mechanical seal method is characterized by high sealing performance even under conditions of high temperature, low temperature, high pressure, vacuum, etc., but it is very expensive when used with a corrosion-resistant material in a large stirrer, and once damaged Then there are problems such as difficult maintenance.

  In various reaction tanks for electric nickel and electrocobalt refining, a stirrer employing a mechanical seal system is also installed, and some of them have high reliability. However, depending on the reaction vessel, solid matter produced by the reaction may adhere to the surface of the stirring blade, and when this grows into a large mass, the rotation balance of the stirring device may be out of order, causing the shaft to shake. The mechanical seal method has a much narrower allowable range for shaft runout than the gland packing method, and if the allowable range is exceeded, the sliding part of the mechanical seal (mainly carbon materials or ceramic materials are used) will be damaged, resulting in an early stage. The sealing performance cannot be maintained.

  In such a stirrer in which shaft shake may occur, the gland packing method has been adopted even if some leakage occurs when the reaction tank pressure is atmospheric pressure.

  Accordingly, an object of the present invention is to provide a stirrer equipped with a shaft seal mechanism capable of preventing leakage of liquid and gas from a shaft seal portion of a gland packing method instead of a mechanical seal method weak against a shaft runout phenomenon, and a reaction using the same. To provide a bath.

  In order to solve the above-described problems, the stirring device of the present invention includes a stirring shaft attached to a lower portion of a stirring blade for stirring the inside of the reaction vessel, and a periphery of the stirring shaft adjacent to the upper portion of the reaction vessel. A gland packing arranged in a compressed state in the axial direction, and a lantern ring arranged between the gland packings and having a hole for blowing compressed air.

  According to the present invention, in a stirrer for various reaction tanks used in electrolytic nickel and electrolytic cobalt refining, etc., by blowing compressed air into the shaft seal portion of the gland packing system, liquid or gas leakage from the shaft seal portion is prevented. It became. The absence of leakage of liquid or gas leads to improved safety during inspection of the shaft seal, and also extends the life of the shaft sleeve, leading to reduction of pause loss. Ultimately, stable operation of various reaction vessels is achieved. It was.

  The stirrer of the present invention is arranged with a stirring shaft attached to the lower part of a stirring blade for stirring the inside of the reaction tank and an axially compressed state around the stirring shaft adjacent to the upper part of the reaction tank. And a lantern ring disposed between the gland packings and having a hole for blowing compressed air.

  More specifically, in the present invention, the compressed air is blown into the gland packing type shaft seal portion of the stirrer to prevent leakage of liquid from the shaft seal portion. FIG. 3 shows the structure of the main part of the stirring device of the present invention. In the shaft seal part of the gland packing system, a cylindrical lantern ring 14 (also called a water injection ring in the pump) is arranged in the middle part of several gland packings 13 (10 in FIG. 2) and compressed by an external compression device. Air is blown from the conduit 15. The lantern ring has a concave outer peripheral portion, and the compressed air guided by the conduit is uniformly accumulated in a ring-shaped space formed by the packing box 16 and the concave portion on the outer periphery of the lantern ring. From there, the compressed air passes through several holes machined from the outer peripheral part of the lantern ring, and is fixed to the rotating stirring shaft 17 (6 in FIG. 1, 8 in FIG. 2) and the shaft sleeve 18 (9 in FIG. 2). And the gap between the gland packing 13. Thereafter, most of the compressed air is blown into the reaction tank through the route indicated by the arrow A, and the rest leaks outside through the route indicated by the arrow B.

As shown in FIG. 4, the inner peripheral surface of the lantern ring 14 has a clearance δ1 with the shaft sleeve 18 on the reaction tank side set to about 6 to 8 mm, and a clearance δ2 with the outer side shaft sleeve about 2 to 3 mm. By setting to, the shape of the leakage of compressed air to the outside is reduced.
In other words, the lantern ring 14 has a tapered shape whose inner side surface extends downward.

  As described above, the lantern ring 14 is an important component that efficiently and uniformly guides the compressed air to the gap between the shaft sleeve 18 and the gland packing 13. If there is no lantern ring, the compressed air is uniformly distributed between the shaft sleeve and the gland. Since it is not blown into the gap with the packing, liquid or gas may leak from the shaft seal.

  The required pressure of the compressed air may be at least atmospheric pressure, but if it is too low, liquid leakage is allowed, so 0.1 to 0.5 MPa is desirable. In general, in the case of a pump, liquid is injected from the outside into the gland packing part. However, when this mechanism is applied to the shaft seal part of the stirrer, the liquid injected from the outside into the shaft seal part enters the reaction tank, reducing the reaction efficiency. Problems are expected. Depending on the pump capacity, the amount of water injected in the pump is generally several liters to tens of liters per minute. Compressed air is the most suitable fluid to be injected into the gland packing.

  In terms of maintenance, maintenance similar to the conventional gland packing method is required. When the packing retainer nut 19 (11 in FIG. 2) is tightened, the packing retainer 20 (12 in FIG. 2) is pushed in and compresses the gland packing. The compressed gland packing 13 expands in the vertical direction of the compressed force, contacts and slides with the outer surface of the shaft sleeve fixed to the rotating stirring shaft, and ensures sealing performance. As the shaft sleeve and gland packing wear, the amount of compressed air leakage to the outside increases, so it is important to tighten the packing holding nut appropriately to maintain the sealing performance. Since the outer surface of the shaft sleeve 18 and the gland packing 13 are worn and gradually worn, periodic inspection to stop the stirring device requires inspection or replacement of the gland packing and the shaft sleeve.

  The shaft sealing mechanism equipped with the compressed air blowing system of the present invention was attached to the stirring device, and the operation was carried out. The compressed air pressure was reduced to 0.2 MPa, and the tightening amount of the gland packing was adjusted so that the compressed air leaked from the shaft seal part. As a result, there was no leakage of liquid or gas from the shaft seal.

  In the inspection after 6 months of operation, the wear amount of the shaft sleeve was within the allowable range. After one year of inspection, there was no shaft sleeve wear exceeding the allowable range, and most of them could be used continuously.

Comparative example

  As described above, in a stirrer having a shaft sealing mechanism of only a conventional gland packing system in which compressed air is not blown into the shaft sealing portion, leakage of liquid or gas and early wear of the shaft sleeve are generated.

It is the schematic which shows the general example of a mechanism of the whole stirring apparatus. It is the schematic which shows the shaft seal part of the gland packing system of the conventional stirring apparatus. It is the schematic which shows the mechanism which blows the compressed air of this invention in the shaft seal part of a gland packing system. It is an enlarged view explaining the shape of the internal peripheral surface of the lantern ring of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric motor 2 V belt 3 Reduction gear 4 Bearing part 5 Shaft sealing part 6 Stirring shaft 7 Stirring blade 8 Stirring shaft 9 Shaft sleeve 10 Gland packing 11 Packing presser nut 12 Packing presser 13 Gland packing 14 Lantern ring 15 Conduit 16 Packing box 17 Stirring Shaft 18 Shaft sleeve 19 Packing presser nut 20 Packing presser 21 Lantern ring 22 Shaft sleeve δ1 Clearance between reaction tank side of lantern ring inner surface and shaft sleeve δ2 Clearance between outer side of lantern ring inner surface and shaft sleeve

Claims (4)

A stirring shaft attached to the lower part of a stirring blade for stirring the inside of the reaction vessel;
A gland packing disposed adjacent to the top of the reaction vessel and overlaid on the stirring shaft in a compressed state in the axial direction;
A lantern ring disposed between the gland packings and having a hole for blowing compressed air;
A stirring apparatus comprising:   The stirring device according to claim 1, wherein the lantern ring has a tapered shape in which an inner surface extends downward.   The stirring device according to claim 1, wherein compressed air of 0.1 to 0.5 MPa is blown through the lantern ring.   A reaction vessel using the stirring device according to any one of claims 1 to 3.