JP2018127676A - Slurry transfer method, and slurry transfer apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide slurry transfer means capable of suppressing scale deposition more effectively than conventional means in a narrow pipe through which slurry is transferred from a large-sized storage tank.SOLUTION: In a slurry transfer method, slurry stored in a storage tank of an inner diameter of 1,000 mm or more is transferred through a discharge pipe of an inner diameter of 200 mm or less connected to the side wall of the storage tank. A scale inhibitor is directly supplied into the discharge pipe from a scale inhibitor supply port installed at a position 0 mm-100 mm distant from a connection end of the discharge pipe with the storage tank.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a slurry flow method and a slurry flow apparatus. Specifically, the present invention relates to a slurry feeding method and a slurry feeding apparatus that can be particularly preferably applied to the feeding of a crude zinc oxide slurry generated in a production plant that obtains zinc oxide ore from a zinc-containing ore.

  In general, in industrial fields that handle raw water or treated water, such as water treatment using ion exchange membranes, boiler water and cooling water treatment, exhaust gas cleaning water treatment, etc., this is caused by silica or calcium dissolved in raw water or treated water. As a result, scale may be generated on the surface of the ion exchange membrane, the heat transfer surface of the boiler, the piping, and the heat exchanger. When this scale occurs, various problems such as significantly reducing the efficiency of ion exchange and heat exchange, or clogging the piping and making the flow extremely difficult are caused.

  This problem of scale generation occurs without exception even during the processing of the crude zinc oxide slurry obtained by wet dust removal of the crude zinc oxide dust generated by melting, roasting, heating, or drying in an industrial furnace. . For example, the said process in the manufacturing plant which obtains a zinc oxide ore from a zinc containing ore corresponds to it. The generation of such scale has been a factor that reduces the operating rate of the manufacturing plant and the like, for example, by blocking the piping for feeding the slurry and forcing the operation to be interrupted.

  As a measure for scaling in a general water treatment device, a water treatment device (see Patent Document 1) provided with an addition device for adding a scale dispersant to raw water to be treated, or divalent ions such as Ca ions. The water treatment system (refer patent document 2) etc. which have the scale inhibitor supply part which supplies a scale inhibitor with respect to the mixed water containing are disclosed. Also in the zinc oxide ore manufacturing plant, as a measure against scale, a measure for supplying various scale inhibitors corresponding to scale components to be treated to a slurry storage tank has been taken.

  However, the effect of the above-described measures against scale is not always sufficient particularly in a pipe having a narrow inner diameter for feeding slurry from a large storage tank. In addition, such a pipe having a narrow inner diameter is difficult to clean and remove after the scale is generated, and therefore, a means that can more effectively prevent the adhesion of the scale has been demanded.

JP 2012-183472 A JP2015-128754A

  The present invention has been devised in view of the above problems, and in a narrow pipe for feeding slurry from a large reservoir, scale adhesion can be more effectively suppressed than conventional means. It is an object to provide a slurry flow means.

  In the extraction pipe connected to the side surface of the storage tank, the present inventors directly supply the scale inhibitor into the extraction pipe at a position within a specific distance range from the connection end to the storage tank. The inventors have found that the amount of scale attached to the inside can be extremely effectively suppressed, and have completed the present invention. Specifically, the present invention provides the following.

  (1) A slurry feeding method for feeding slurry stored in a storage tank having an inner diameter of 1000 mm or more through an extraction pipe having an inner diameter of 200 mm or less connected to a side surface of the storage tank, wherein the scale inhibitor is A slurry flow method in which the pipe is directly supplied into the extraction pipe from a scale inhibitor addition port installed at a position of 0 mm or more and 100 mm or less from the connection end of the extraction pipe on the storage tank side.

  In the invention of (1), as a measure against the scale of the extraction pipe, the scale inhibitor is directly supplied to a predetermined position of the extraction pipe for feeding the slurry without going through the storage tank. According to this, compared with the case of the conventional method in which the same amount of scale inhibitor is supplied to the storage tank, the effect of suppressing the adhesion of scale in the piping is remarkably improved. This is because, in the case of the conventional method, many parts of the scale inhibitor act in the storage tank having a long residence time, whereas according to the invention of (1), the adhesion of the scale is fatal. This is because almost all of the scale inhibitors can be effectively operated in a narrow pipe that is likely to cause a general problem.

  (2) The slurry is a crude zinc oxide slurry in which a crude zinc oxide dust having a zinc content of 30 wt% or more and 70 wt% or less is suspended at a slurry concentration of 1 g / L or more and 50 g / L or less, The scale inhibitor is a scale inhibitor comprising at least one of a chelating agent, a phosphonic acid, and a maleic acid polymer, and is 1 μL / L or more and 30 μL / L or less with respect to the crude zinc oxide slurry. The slurry feeding method according to (1), wherein the supply amount of the scale inhibitor is adjusted so as to have a concentration.

  According to the invention of (2), for example, the invention of (1) is particularly preferable for measures against the scale of piping generated due to a general zinc oxide slurry generated in a zinc oxide ore production plant. Can be applied.

  (3) The slurry feeding method according to (1) or (2), wherein the scale inhibitor is supplied only to the extraction pipe without being supplied to the storage tank.

  According to the invention of (3), the scale inhibitor is extracted and supplied only into the piping. According to this, in the implementation of the slurry flow method described in (1) or (2), it is possible to obtain a sufficient scale adhesion suppressing effect with the minimum amount of scale inhibitor supplied, (1 ) Or production cost in zinc oxide ore production or the like performed using the slurry flow method described in (2) can be suppressed.

  (4) The slurry tank according to any one of (1) to (3), wherein the storage tank is a tank for storing a crude zinc oxide slurry generated in a manufacturing plant for obtaining zinc oxide ore from zinc-containing ore. Method.

  According to the invention of (4), the above-mentioned effect of the slurry flow method of any one of (1) to (3) is enjoyed and contributes to the improvement of the operating rate and the economic efficiency of the zinc oxide ore production plant. can do.

  (5) A slurry feeding device for feeding slurry, comprising: a storage tank having an inner diameter of 1000 mm or more; and an extraction pipe having an inner diameter of 200 mm or less connected to a side surface of the storage tank, wherein the storage of the extraction pipe A slurry feeding apparatus in which a scale inhibitor addition port is installed at a position of 0 mm or more and 100 mm or less from a connecting end on the tank side.

  According to invention of (5), it was set as the structure which can supply the scale inhibitor supplied as a scale countermeasure of piping directly to the predetermined position of the extraction piping which flows slurry in without passing through a storage tank. According to this, compared with the case of the conventional method in which the same amount of scale inhibitor is supplied to the storage tank, the effect of suppressing the adhesion of scale in the piping is remarkably improved. This is because, in the case of the conventional apparatus, many parts of the scale inhibitor acted in the storage tank having a long residence time, whereas according to the invention of (5), the adhesion of the scale. This is because almost all of the scale inhibitors can be effectively operated only in a narrow pipe that tends to be a fatal problem.

  (6) The slurry feed apparatus according to (5), further comprising a feed pump having a suction side connected to the extraction pipe and a feed pipe having an inner diameter of 200 mm or less connected to the discharge side of the feed pump. .

  According to the invention of (6), since the scale inhibitor is supplied to the suction side of the inflow pump, the scale inhibitor is uniformly dispersed in the pipe due to the ejector effect. The effect of the present invention can be enjoyed at a preferable level without additional processing such as insertion of a thin tube.

  (7) The slurry is a crude zinc oxide slurry in which a crude zinc oxide dust having a zinc content of 30 wt% or more and 70 wt% or less is suspended at a slurry concentration of 1 g / L or more and 50 g / L or less. The slurry feeding apparatus according to 5) or (6).

  According to the invention of (7), for example, the invention of (5) or (6) is used as a measure against the scale of piping generated due to a general zinc oxide slurry generated in a zinc oxide ore production plant. Can be applied in a particularly preferred manner.

  ADVANTAGE OF THE INVENTION According to this invention, in the narrow piping which flows a slurry from a large sized storage tank, the slurry feeding means which can suppress adhesion of a scale more effectively than a conventional means can be provided.

It is the schematic diagram which showed the structure of the slurry flow apparatus of this invention.

  Hereinafter, a preferred embodiment of a slurry flow method and a slurry flow device of the present invention will be described. The present invention is widely applicable to various industrial processes including a step of feeding a slurry from a tank for storing the slurry, and in particular, in an industrial process including a step of feeding a crude zinc oxide slurry by piping. It can be implemented preferably. As a typical example of an industrial process including a step of feeding a crude zinc oxide slurry by piping, a “zinc oxide ore manufacturing process” shown in detail below, that is, a reduction roasting step, a wet step, and a drying heating step are included. The production process of zinc oxide ore can be exemplified. In the following, application of the method or apparatus of the present invention to a zinc oxide ore production process will be described in detail as an example of a preferred embodiment of the present invention. However, the present invention is not limited to the embodiments described below, and modifications can be made without changing the gist of the present invention.

<Manufacturing process of zinc oxide ore>
The manufacturing process of zinc oxide ore by the Wertz method is a reduction roasting process in which zinc-containing ore such as steel dust is reduced and roasted to obtain crude zinc oxide dust, fluorine and cadmium from the crude zinc oxide dust obtained in the reduction roasting process. This is a process of sequentially performing a wet process for separating and removing a zinc oxide cake to obtain a crude zinc oxide cake, and a dry heating process for drying and heating the crude zinc oxide cake obtained by the wet process to obtain a zinc oxide ore (calcined ore). The present invention can be carried out very preferably as a means for feeding a crude zinc oxide slurry containing DRK exhaust gas dust discharged from a drying and heating step from a storage tank in such a zinc oxide ore production process. . The present invention can be preferably implemented in a general zinc oxide ore production process in which the amount of zinc oxide ore is about 6 t / h or more and 10 t / h or less, and is not limited to this. It can be similarly implemented in a scale manufacturing plant.

[Reduction roasting process]
In the reduction roasting process, the raw material etc. which pelletized steel dust beforehand with the reducing material are reduced and roasted by the rotary kiln (RRK) for reduction roasting. In this step, the raw material pellets are continuously charged into the RRK together with limestone and the like. The raw material derived from steel dust is reduced and roasted in the RRK furnace, and the volatilized metallic zinc is re-oxidized in the furnace to powdery zinc oxide. Powdered zinc oxide is introduced into the dust collector together with the exhaust gas from the RRK, captured, and recovered as crude zinc oxide dust.

[Wet process]
In the wet process following the reduction roasting process, water-soluble impurities such as chlorine and fluorine contained in the crude zinc oxide dust obtained in the reduction roasting process are separated and extracted into the processing liquid, and further by solid-liquid separation processing, A wet process is performed in which impurities are removed from the crude zinc oxide dust by a water washing method to obtain a crude zinc oxide cake. More specifically, in a state where halogen-based impurities such as chlorine and fluorine are removed in the treatment liquid, the treatment liquid in which the impurities are distributed is removed from the slurry by solid-liquid separation. Thereby, the crude zinc oxide dust becomes a crude zinc oxide cake from which the halogen impurities are removed.

[Dry heating process]
In the drying and heating process, the crude zinc oxide cake obtained in the wet process is put into a rotary kiln (DRK) for drying and heating and baked to further reduce the halogen concentration and produce high-grade zinc oxide ore. Process. The moisture content of the crude zinc oxide cake to be treated in this step is generally 20% by mass or more and 30% by mass or less. Further, the general composition of the crude zinc oxide cake is as follows: zinc is 61 mass% or more and 68 mass% or less, lead is 7 mass% or more and 10 mass% or less, chlorine is 0.3 mass% or more and 0.9 mass% or less, Fluorine is 0.2% by mass or more and 1.5% by mass or less (both are based on dry amount). Such a crude zinc oxide cake is put into the DRK by a quantitative charging device such as a screw feeder in the form of a water-containing cake. The crude zinc oxide cake charged into the DRK is granulated into pellets at the charging end inside a rotary kiln having a length of about 30 m, then dried, heated, and baked at the discharge end.

  The DRK is provided with an oil burner on the discharge end side for discharging zinc oxide ore, and is heated by direct fire from the discharge end side. The temperature of the zinc oxide ore burned from the rotary kiln is continuously measured and monitored with a radiation thermometer. In addition, about a calcination temperature, it maintains and manages so that it may become the range of 900 degreeC or more and 1200 degrees C or less with the temperature of the zinc oxide ore. The firing temperature can be adjusted by, for example, the amount of oil supplied to the oil burner. In the drying and heating step, the size of the zinc oxide ore discharged from the DRK is generally 1 mm or more and 6 mm or less, and the general composition thereof is 60% by mass to 70% by mass of zinc and 3% by mass or more of lead. 5% by mass or less, chlorine is 0.5% by mass or more and 1.5% by mass or less, and fluorine is about 0.6% by mass or less (both are based on dry amount).

Charges such as a crude zinc oxide cake charged in the DRK are granulated, dried, heated and fired in order in a rotary kiln of about 30 m. And dust of the charged material scattered in the process of granulation and drying, and oxides and halides volatilized in the process of heating and baking become dust. The dust concentration of the DRK exhaust gas is about 30 g / Nm ³ or more and 40 g / Nm ³ or less. Further, the exhaust gas flow discharged from the DRK is much higher 15000 m ³ / h or less 14000m ³ / h.

[Exhaust gas treatment]
The exhaust gas discharged from the DRK is sucked from the charging end side, and finally is removed by a wet gas cleaning tower and a wet electrostatic precipitator, and is discharged from the chimney via a fan or other exhaust fan. In the slurry flow method and the slurry flow apparatus of the present invention, in a series of processes for cleaning the DRK exhaust gas discharged from the drying and heating step, the crude zinc oxide slurry containing the exhaust gas dust in the exhaust gas, It can be preferably used as a means for feeding from the storage tank.

  Here, in the above-described series of processes related to the cleaning process of the DRK exhaust gas, the preliminary cleaning with the cleaning water is usually performed in the flue immediately after the discharge from the rotary kiln immediately before the final cleaning process by the wet processing apparatus. Cleaning is performed. More specifically, the present invention can be very preferably used as a means for extracting the crude zinc oxide slurry from the storage tank (circulation tank) and feeding it through the extraction pipe in the preliminary cleaning.

  The above pre-cleaning is installed near the exhaust gas outlet of the rotary kiln, and the cleaning water is poured into the flue where the exhaust gas is sent to the next process, and the treated water containing the exhaust gas dust is taken out from the flue and collected in the circulation tank. The crude zinc oxide slurry stored in the tank is carried out by flowing through the extraction pipe.

  In addition, the slurry in said circulation tank in the manufacturing process of a zinc oxide ore is a slurry of crude zinc oxide dust, The slurry density | concentration is 5 g / L or more and 10 g / L or less, The zinc content rate of crude zinc oxide dust is 30. % By weight to 40% by weight (dry basis). The crude zinc oxide slurry is repeatedly circulated and used for the cleaning treatment.

[Slurry flow device]
FIG. 1 is a diagram schematically showing a configuration of a slurry feeding apparatus of the present invention. The slurry feeding apparatus 10 of the present invention can be preferably used as an apparatus for treating the crude zinc oxide slurry 6 generated in a production plant for obtaining zinc oxide ore from zinc-containing ore. More specifically, a storage tank (circulation tank) is used as a circulation tank and a drain pipe for slurry connected thereto in the above-described preliminary cleaning performed during a series of exhaust gas treatment in a zinc oxide ore production process. In the piping that feeds the slurry from, the adhesion of scale can be effectively suppressed.

  The slurry feeding device 10 is a device for feeding the crude zinc oxide slurry 6, and is formed at a position within a predetermined distance range from the storage tank 1, the extraction pipe 2, and the connection end of the extraction pipe 2 on the storage tank side. The scale additive addition port 3 is used as an essential component. Moreover, it is preferable that this slurry flow apparatus 10 is provided with a flow pump 4 whose suction side is connected to the extraction pipe 2 side. An inflow pipe 5 is further connected to the discharge side of the inflow pump 4.

  When the storage tank 1 is a large storage tank and the inner diameter of the extraction pipe 2 connected to the storage tank 1 is relatively narrow, the above-described problem of scale generation occurs. Specifically, when an extraction pipe having an inner diameter of 200 mm or less is connected to a storage tank having an inner diameter of 1000 mm or more, this problem is likely to occur, and the present invention is configured as such a storage tank and an extraction pipe. In particular, a particularly advantageous effect can be exhibited.

  In addition, when the inner diameter of the flow pipe 5 is 200 mm or less, in order to clean the inside of the pipe, a part of the flange is removed and jet cleaning is performed by injecting high-pressure water from the tip of a special nozzle. A special method, such as pig cleaning, was required to remove the flange, apply high pressure, remove the flange, and push a ball into the piping. In some cases, the outer surface of the pipe is hit manually with a hammer and peeled off by the vibration. Also, in these pipe cleaning operations, the piping is long and often in high places, so the removal of the flange, jet cleaning, and manual pipe tapping work may be high places work, which is dangerous. Met. In order to prevent clogging of piping, that is, generation of scale, a method of diluting with a large amount of water and a method of adjusting the pH of the target treated water can be considered, but an increase in the amount of water, use of chemicals, or This is not realistic because it involves an undesirable reaction. The present invention also solves the above-described problems that occur when a pipe having an inner diameter of 200 mm or less is connected to a large storage tank.

  In the slurry feeding device 10, the scale inhibitor addition port 3 is formed at a position where the distance d (see FIG. 1) from the connection end of the extraction pipe 2 on the storage tank side is 0 mm or more and 100 mm or less. It is characterized by that. Thereby, the scale inhibitor conventionally supplied to the storage tank can be directly supplied from the appropriate position into the extraction pipe 2 without going through the storage tank 1.

[Slurry flow method]
The slurry flow method of the present invention is a method in which the slurry is extracted from a large storage tank in which the crude zinc oxide slurry is stored, and is flowed through the extraction pipe, which is particularly advantageous in preventing the generation of scale in the pipe. It is.

  This slurry flow method can exhibit the above-mentioned advantageous effect when the slurry stored in a storage tank having an inner diameter of 1000 mm or more is flowed through an extraction pipe having an inner diameter of 200 mm or less connected to the side surface of the storage tank. It is a method and can be implemented by using the above-mentioned slurry flow apparatus 10 as a concrete implementation means. Conventionally, the slurry flow method is a storage tank for the extraction pipe 2 in which a scale inhibitor that has been directly supplied to a storage tank for collecting treated water or a corresponding circulation tank or the like in the same processing step is used. It is characterized in that it is supplied directly from the scale inhibitor addition port 3 installed at a position of 0 mm or more and 100 mm or less from the connection end on the side into the extraction pipe.

  The scale inhibitor can be supplied into the extraction pipe 2 by press-fitting with a metering pump from the tank storing the scale inhibitor into the scale inhibitor addition port 3.

  Here, when the scale inhibitor is supplied to the storage tank 1 as in the prior art, the residence time in the storage tank 1 is longer than the residence time in the extraction pipe 2 and the flow-in pipe 5, and the storage tank 1. The scale preventive agent will act inside. If the inner diameter of the extraction pipe 2 and the flow pipe 5 is 50 mm and the inner diameter of the storage tank 1 is 1000 mm, the residence time in the storage tank 1 is 400 times longer from a simple calculation. Therefore, in the present invention, in the extraction pipe 2 connected to the side surface portion of the storage tank 1, the scale inhibitor is extracted at a position where the distance from the connection end of the side surface portion of the storage tank 1 is 0 mm or more and 100 mm or less. It was decided to supply directly inside. By making this supply position a position where the distance from the connection end is within 100 mm, the scale inhibitor is sufficiently dispersed throughout the pipe, including the vicinity of the connection end inside the pipe, so that the scale is reduced throughout the pipe. Can be sufficiently prevented. Further, the supplied scale inhibitor effectively acts only in the extraction pipe 2 and the flow pipe 5.

  In the practice of the present invention, when the scale inhibitor is not supplied to the storage tank 1 at all and is supplied only to the inside of the extraction pipe 2, the scale prevention effect on the inner wall of the storage tank 1 is not obtained. When the thickness of the scale to be performed is 5 mm, if the inner diameter of the storage tank 1 is 1000 mm, the range is negligible. On the other hand, if the inner diameter of the extraction pipe and the flow pipe is 50 mm, the actual inner diameter becomes 40 mm due to the 5 mm scale adhesion, and even if the slurry flow rate is assumed to be the same, the flow rate is 0.6. It will be reduced to about twice and will hinder transport. Moreover, since the pressure loss increases, the flow rate further decreases. In addition, the amount of the scale inhibitor used can be suppressed to the necessary minimum amount by supplying the scale inhibitor only to the inside of the extraction pipe 2 without supplying it to the storage tank 1 in this way.

  Conventionally, as a scale inhibitor, a substance having a high effect of being dissolved and dispersed in accordance with a scale component has been appropriately selected. For example, phosphate or phosphonic acid compounds are used for calcium-based scales. Yes. Also in the present invention, a conventionally known scale inhibitor can be selected as appropriate. For example, a scale inhibitor comprising at least one of a chelating agent, a phosphonic acid, and a maleic acid-based polymer can be preferably used in the treatment for feeding the crude zinc oxide slurry. Specific examples of such scale inhibitors include “Polyclin T-231 (trade name) (manufactured by Kurita Kogyo Co., Ltd.)” composed of two types of chelating agents, phosphonic acid and maleic acid polymers.

  The crude zinc oxide slurry to be treated is a crude zinc oxide slurry in which crude zinc oxide dust having a zinc content of 30 wt% or more and 70 wt% or less is suspended at a slurry concentration of 1 g / L or more and 50 g / L or less. In some cases, it is preferable to adjust the supply amount of the scale inhibitor containing various chelating agents and the like so as to have a concentration of 1 μL / L to 30 μL / L with respect to the crude zinc oxide slurry.

(Example)
Circulation tank, extraction pipe, flow pump, flow of dry heat rotary kiln (DRK) exhaust gas pre-cleaning device in zinc oxide ore production plant where zinc oxide ore production is 6t / h or more and 10t / h or less The slurry feeding apparatus of the present invention was applied to an apparatus composed of piping, and the slurry feeding method of the present invention was carried out. The slurry in the circulation tank (storage tank) is a slurry of crude zinc oxide dust, the slurry concentration is 8 g / L or more and 10 g / L or less, and the zinc content of the crude zinc oxide dust is 30 wt% or more and 40 wt% or less. (Dry basis). As a scale inhibitor, Polyclin T-231 (trade name) (manufactured by Kurita Kogyo Co., Ltd.) was used, and was supplied so as to have a concentration of 10 μL / L with respect to the crude zinc oxide slurry. The inner diameter of the circulation tank was 2500 mm, the inner diameter of the extraction pipe was 80 mm, and the inner diameter of the feed pipe was 80 mm. Under the above conditions, the test operation to which the present invention was applied was continued for about one month. About one month later, when the thickness of the scale generated in the pipe was measured at three locations of the inflow pipe, the average was 4 mm.

(Comparative example)
The test operation under the same conditions as in the Examples was continued for about 1 month except that the scale inhibitor was directly supplied to the circulation tank. After about 10 days, the slurry flow rate in the inflow pipe decreased, and the amount of water in each place was adjusted. About one month later, the thickness of the scale generated in the pipe was measured at the same three locations as in the example of the flow pipe, and the average was 15 mm.

  From the above results, it can be seen that the present invention is a slurry feeding means that can more effectively suppress the adhesion of the scale than the conventional means in a narrow pipe for feeding the slurry from a large storage tank.

DESCRIPTION OF SYMBOLS 1 Reservoir 2 Extraction piping 3 Scale inhibitor addition port 4 Flow pump 5 Flow piping 6 Coarse zinc oxide slurry 10 Slurry flow apparatus

Claims (7)

A slurry feeding method for feeding a slurry stored in a storage tank having an inner diameter of 1000 mm or more through an extraction pipe having an inner diameter of 200 mm or less connected to a side surface of the storage tank,
A slurry feeding method in which the scale inhibitor is directly supplied into the extraction pipe from a scale inhibitor addition port installed at a position of 0 mm or more and 100 mm or less from the connection end of the extraction pipe on the storage tank side. The slurry is a crude zinc oxide slurry in which a crude zinc oxide dust having a zinc content of 30 wt% or more and 70 wt% or less is suspended at a slurry concentration of 1 g / L or more and 50 g / L or less,
The scale inhibitor is a scale inhibitor comprising at least one of a chelating agent, a phosphonic acid, and a maleic acid polymer, and is 1 μL / L or more and 30 μL / L or less with respect to the crude zinc oxide slurry. The slurry feeding method according to claim 1, wherein a supply amount of the scale inhibitor is adjusted so as to have a concentration.   The slurry feeding method according to claim 1 or 2, wherein the scale inhibitor is supplied only to the extraction pipe without being supplied to the storage tank. The reservoir is
The method for feeding a slurry according to any one of claims 1 to 3, wherein the slurry is a tank for storing a crude zinc oxide slurry generated in a production plant for obtaining zinc oxide ore from zinc-containing ore. A slurry feeding device for feeding a slurry,
A storage tank having an inner diameter of 1000 mm or more;
An extraction pipe having an inner diameter of 200 mm or less connected to the side surface of the storage tank,
A slurry feeding apparatus in which a scale inhibitor addition port is installed at a position of 0 mm or more and 100 mm or less from a connection end of the extraction pipe on the storage tank side.   The slurry feed apparatus according to claim 5, further comprising a feed pump having a suction side connected to the extraction pipe and a feed pipe having an inner diameter of 200 mm or less connected to the discharge side of the feed pump.   The slurry is a crude zinc oxide slurry in which a crude zinc oxide dust having a zinc content of 30 wt% or more and 70 wt% or less is suspended at a slurry concentration of 1 g / L or more and 50 g / L or less. 6. The slurry feeding apparatus according to 6.

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