JP6862970B2 - Sulfide production equipment - Google Patents

Description

The present invention relates to a sulfide production facility.

Conventionally, in nickel smelting, a method has been adopted in which a mat having a nickel grade of about 30% by weight is obtained by pyrometallurgical smelting of nickel sulfide ore, and then electric nickel is produced by a chlorine leaching-electrowinning method. ing.

In recent years, as a hydrometallurgical method for nickel oxide ore, a high pressure acid leach method using sulfuric acid has attracted attention. Unlike the conventional dry smelting method, which is a general smelting method for nickel oxide ore, the high-pressure acid leaching method does not include a dry process such as a reduction and drying process, and extracts valuable metals by a consistent wet process. .. Therefore, it is advantageous in terms of energy and cost as compared with the pyrometallurgical method. Further, the high-pressure acid leaching method has an advantage that a nickel sulfide having an improved nickel grade of about 50% by weight can be obtained. The nickel sulfide described herein means a sulfide containing nickel. Nickel sulfide is formed by precipitating by purifying the leachate obtained by leaching nickel oxide ore and then blowing hydrogen sulfide gas in the sulfide step to cause a sulfide reaction (see, for example, Patent Document 1).

In the above-mentioned sulfurization step, a sulfuric acid aqueous solution containing nickel is supplied to the reaction vessel, and hydrogen sulfide gas is blown into the sulfuric acid aqueous solution in the reaction vessel to carry out a sulfurization reaction for producing nickel sulfide and a poor liquid. For this reason, sulfide production equipment including a reaction vessel, pipes connected to the reaction vessel, and a valve is used in the sulfurization step.

Japanese Unexamined Patent Publication No. 2014-141949

The above-mentioned sulfide production facility handles fluids such as hydrogen sulfide gas and sulfuric acid aqueous solution, which may adversely affect the environment if discharged to the outside as they are, so that fluid leakage (gas leakage, liquid leakage, etc.) to the outside occurs. Technology that suppresses with higher accuracy is required.

A main object of the present invention is to provide a technique capable of suppressing fluid leakage to the outside with higher accuracy in a sulfide production facility.

Aspects of the present invention are
In a hydrometallurgy method based on the high-pressure acid leaching method that recovers nickel from nickel oxide ore, a sulfurization step in which hydrogen sulfide gas is blown into a sulfuric acid aqueous solution containing nickel to carry out a sulfurization reaction that produces sulfide containing nickel and a poor liquid. It is a sulfide production facility used in
The reaction vessel for the sulfurization reaction and
The piping connected to the outlet of the reaction vessel and
Multiple shut-off valves installed in the middle of the piping,
It is a sulfide production facility equipped with.

According to the present invention, fluid leakage to the outside can be suppressed with higher accuracy in a sulfide production facility.

It is a process drawing explaining the wet smelting method of nickel oxide ore. It is the schematic which shows the structural example of the reaction vessel inlet side provided with the sulfide production facility. It is the schematic which shows the structural example of the reaction vessel outlet side provided in the sulfide production facility. It is a functional block diagram which shows the structural example of the control system applied to the sulfide production facility which concerns on embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In the embodiment of the present invention, the description will be given in the following order.
1. 1. Wet smelting method of nickel oxide ore 2. Inventor's findings 3. Sulfide production equipment 3-1. Configuration on the inlet side of the reaction vessel 3-2. Configuration on the outlet side of the reaction vessel 3-3. Control system configuration 3-4. Control system processing operation 4. Effect of embodiment 5. Deformation example etc.

<1. Wet smelting method of nickel oxide ore ＞
FIG. 1 is a process diagram illustrating a hydrometallurgical method for nickel oxide ore. Here, a hydrometallurgy method using a high-pressure acid leaching method will be described.

As shown in the figure, in the wet smelting method of nickel oxide ore, the leaching step S1 in which nickel or the like is leached from the nickel oxide ore and the leaching slurry obtained in the leaching step S1 are solid-liquid separated into a leachate and a leachate residue. The liquid separation step S2, the neutralization step S3 for neutralizing the leachate and separating it into the mother liquor for recovering nickel and the neutralized starch slurry, and the sulfurization reaction by blowing hydrogen sulfide gas into the sulfuric acid aqueous solution which is the mother liquor. It has a sulfurization step S4 for obtaining nickel sulfide and a poor liquid. Hereinafter, each step will be described in more detail.

(Leaching process)
In the leaching step S1, sulfuric acid is added to the slurry of nickel oxide ore and stirred at a temperature of 220 to 280 ° C. to generate a leaching slurry composed of a leaching solution and a leaching residue. In the leaching step S1, for example, a high-temperature pressurized container (autoclave) is used.

Examples of the nickel oxide ore used in the leaching step S1 mainly include so-called laterite ores such as limonite ore and saprolite ore. The nickel content of laterite ore is usually 0.8-2.5% by weight and is contained as a hydroxide or magnesium silicate mineral. The iron content is 10 to 50% by weight, which is mainly in the form of trivalent hydroxide (gecite), but some divalent iron is contained in the siliceous earth minerals.

In the leaching step S1, the leaching reaction represented by the following formulas (1) to (5) and the high-temperature thermal hydrolysis reaction occur. As a result, leaching of nickel, cobalt and the like as sulfates and immobilization of the leached iron sulfate as hematite are performed. However, the immobilization of iron ions does not proceed completely. Therefore, the liquid portion of the leaching slurry obtained in the leaching step S1 usually contains divalent and trivalent iron ions in addition to nickel, cobalt and the like.

"Leaching reaction"
MO + H ₂ SO ₄ → MSO ₄ + H ₂ O… (1)
(M in the formula represents Ni, Co, Fe, Zn, Cu, Mg, Cr, Mn, etc.)
2Fe (OH) ₃ + 3H ₂ SO ₄ → Fe ₂ (SO ₄ ) ₃ + 6H ₂ O… (2)
FeO + H ₂ SO ₄ → FeSO ₄ + H ₂ O… (3)
"High temperature thermal hydrolysis reaction"
2FeSO ₄ + H ₂ SO ₄ + 1 / 2O ₂ → Fe ₂ (SO ₄ ) ₃ + H ₂ O… (4)
Fe ₂ (SO ₄ ) ₃ + 3H ₂ O → Fe ₂ O ₃ + 3H ₂ SO ₄ … (5)

The slurry concentration in the leaching step S1 is not particularly limited, but it is preferable to adjust the slurry concentration of the leaching slurry to be 15 to 45% by weight. The amount of sulfuric acid added in the leaching step S1 is not particularly limited, and an excess amount such that iron in the ore is leached is used. For example, the amount of sulfuric acid added per ton of ore can be 300 to 400 kg. If the amount of sulfuric acid added per ton of ore exceeds 400 kg, the cost of sulfuric acid increases, which is not preferable.

(Solid-liquid separation process)
In the solid-liquid separation step S2, the leaching slurry formed in the leaching step S1 is washed in multiple stages to obtain a leaching solution containing nickel and cobalt and other leaching residues.

The multi-stage cleaning method in the solid-liquid separation step S2 is not particularly limited, but is a continuous countercurrent cleaning method in which the above-mentioned leachate slurry is brought into contact with a nickel-free cleaning liquid in a countercurrent manner to wash away the residual water. (CCD method: Counter Current Decantation) is preferably used. As a result, the amount of cleaning liquid newly introduced into the system can be reduced, and the recovery rate of nickel and cobalt can be set to 95% or more.

(Neutralization process)
In the neutralization step S3, while suppressing the oxidation of the leachate separated in the solid-liquid separation step S2, calcium carbonate is added so that the pH of the leachate is 4 or less, so that the mother liquor for nickel recovery and trivalent are added. Produces a neutralized starch slurry containing iron. By neutralizing the leachate in this way, the excess acid used in the leaching step S1 by the high-pressure acid leaching method is neutralized, and trivalent iron ions, aluminum ions, etc. remaining in the solution are removed. ..

The pH of the leachate adjusted in the neutralization step S3 is 4 or less, preferably 3.2 to 3.8, as described above. When the pH of the leachate exceeds 4, the generation of nickel hydroxide increases.

Further, in the neutralization step S3, when removing the trivalent iron ions remaining in the solution, it is preferable not to oxidize the iron ions existing as divalent in the solution. Therefore, it is preferable to prevent oxidation of the solution as much as possible due to, for example, blowing air. As a result, it is possible to suppress an increase in the amount of calcium carbonate consumed and the amount of neutralized starch slurry produced due to the removal of divalent iron. That is, it is possible to suppress the nickel recovery loss to the starch due to the increase in the amount of the neutralized starch slurry.

Further, the neutralized starch slurry obtained in the neutralization step S3 can be sent to the solid-liquid separation step S2 as needed. As a result, nickel contained in the neutralized starch slurry can be effectively recovered. Specifically, by returning the neutralized starch slurry produced in the neutralization step S3 to the solid-liquid separation step S2 operated under low pH conditions, the water adhering to the neutralized starch is washed at the same time as the leachate residue is washed. It is possible to promote the dissolution of nickel hydroxide produced by the local reaction on the surface of the neutralized starch, and it is possible to reduce the nickel content that causes recovery loss. At the same time as nickel, a part of iron hydroxide is also redissolved, and a neutralizing agent may be required again to fix the leached trivalent iron ions. Therefore, from this point as well, it is desirable to reduce the amount of neutralized starch without oxidizing divalent iron ions.

The reaction temperature in the neutralization step S3 is preferably about 50 to 80 ° C. If the reaction temperature is less than 50 ° C., the neutralized starch containing trivalent iron ions formed becomes fine, which adversely affects the treatment in the solid-liquid separation step S2 in which the neutralized starch is circulated as needed. .. On the other hand, if the reaction temperature exceeds 80 ° C., the corrosion resistance of the equipment material is lowered and the energy cost for heating is increased.

(Sulfurization process)
In the sulfurization step S4, hydrogen sulfide gas is blown into the sulfuric acid aqueous solution which is the mother liquor for recovering nickel obtained in the neutralization step S3 to cause a sulfurization reaction, and nickel sulfide and a poor liquid are produced. The mother liquor is a sulfuric acid aqueous solution before the sulfurization reaction in the sulfurization step, that is, a reaction starting solution.

<2. Inventor's findings>
The sulfide production facility used in the sulfurization step S4 uses hydrogen sulfide gas in a sealed state, and has a structure in which the reaction gas and the reaction liquid do not leak to the outside during operation. However, the present inventor presents that when the manufacturing equipment is stopped, the conditions inside the equipment change compared to when the equipment is in operation, so that fluids (liquids, gases) that may adversely affect the environment are, for example, equipment attached to the manufacturing equipment. I noticed that it could leak to the outside due to an unexpected malfunction of the valve (for example, valve erosion). Hereinafter, a specific example will be described.

Normally, when the sulfide production facility is stopped, the supply of liquid or gas is stopped (cut off) by closing the valve. However, gas remains inside the tank or reaction vessel, and gas remains inside the piping. This residual gas will not leak to the outside if the valve attached to the manufacturing equipment is completely sealed and the inside of the piping or the like can be kept in a closed state by the valve closing operation. Therefore, there is no particular problem if the residual gas is detoxified by a detoxifying device and then released to the outside.

However, if the soundness of the manufacturing equipment is not maintained, even if the valve is closed to stop the operation of the manufacturing equipment, the inside of the piping or the like cannot be kept in a sealed state. For example, the reaction vessel for the sulfurization reaction and the vessel used in the subsequent process (hereinafter referred to as "post-process vessel") are connected by a pipe, and a valve is inserted in the middle of the pipe (the outlet portion of the reaction vessel). When attached, if the sealing property of the valve is incomplete, the liquid will flow from the reaction vessel side to the post-process vessel side even after the valve is closed. Then, when the reaction vessel runs out of liquid, the gas remaining there also flows to the post-process vessel side.

The reason is that during the operation of the manufacturing equipment, the inside of the reaction vessel has a positive pressure and the post-process vessel has a negative pressure, and the reaction liquid is sent from the reaction vessel to the post-process vessel by using the differential pressure. Because it is. That is, even if the operation of the manufacturing equipment is stopped, the above-mentioned differential pressure remains, so that the liquid or gas in the reaction vessel naturally flows to the post-process vessel side. In particular, the valve that controls the flow rate of the slurry may have a reduced sealing property due to erosion, and the flow of the liquid may not stop there.

As described above, when the manufacturing equipment is stopped, the environment is different from that during normal operation, so that residual gas may flow out through the piping. On the other hand, the exhaust gas treatment using the abatement device is performed on the residual gas in the reaction vessel and the piping kept in a closed state by the closing operation of the valve. Therefore, the residual gas that has flowed out to the container side in the post-process through the piping may become harmful gas and be released to the outside. Therefore, the present inventor does not take individual measures according to various assumed situations, but gives the sulfide manufacturing equipment a systematic multiple protection function to suppress fluid leakage. The present invention was conceived after obtaining the finding that it is very effective.

<3. Sulfide manufacturing equipment>
Subsequently, the sulfide production facility according to the embodiment of the present invention will be described. The sulfide production facility is used in the sulfurization step S4 and includes a reaction vessel for the sulfurization reaction. The configuration of the sulfide production facility will be described below separately for the reaction vessel inlet side and the reaction vessel outlet side.

(3-1. Configuration on the inlet side of the reaction vessel)
FIG. 2 is a schematic view showing a configuration example on the inlet side of the reaction vessel provided in the sulfide production facility.

In FIG. 2, a plurality of (four in the example) reaction vessels 1 to 4 for the sulfurization reaction are connected in series. A hydrogen sulfide gas supply line (not shown) is connected to each of the reaction vessels 1 to 4.

The four reaction vessels 1 to 4 are connected by using a plurality of pipes 5 to 9. Specifically, of the four reaction vessels 1 to 4, the pipe 5 is connected to the inlet of the reaction vessel 1 located at the uppermost stream. The inlet of the reaction vessel 1 serves as an intake port for taking in the reaction starting liquid in the sulfurization step. The discharge port of the reaction vessel 1 and the inlet of the reaction vessel 2 are connected by a pipe 6, and the discharge port of the reaction vessel 2 and the inlet of the reaction vessel 3 are connected by a pipe 7. Further, the discharge port of the reaction vessel 3 and the introduction port of the reaction vessel 4 are connected by a pipe 8, and the pipe 9 is connected to the outlet of the reaction vessel 4 located at the most downstream. The outlet of the reaction vessel 4 serves as a discharge port for discharging the final reaction liquid produced in the sulfurization step.

A joint 10 is connected to the end of the pipe 5 connected to the reaction vessel 1. A pipe 11 for supplying steam and a pipe 12 for supplying mother liquor are connected to the joint 10. A control valve 14 and a shutoff valve 15 are installed in the middle of the pipe 11. The control valve 14 is a valve for controlling the flow rate of steam for heating, and the shutoff valve 15 is a valve for shutting off the steam supply line. Further, a control valve 16 is installed in the middle of the pipe 12. The control valve 16 is a valve for shutting off the supply line of the mother liquor. As an example, the control valve 14 is composed of a globe valve, the shutoff valve 15 is composed of a gate valve, and the control valve 16 is composed of a butterfly valve. Further, before and after the control valve 16, a butterfly type manual shutoff valve and a gate type manual shutoff valve are installed.

In the present specification, the "shutoff valve" means a valve for shutting off the flow of fluid in a pipe in an emergency or the like. The shutoff valve is required to have high sealing performance and reliability. During normal operation, the shutoff valve is kept open.

On the other hand, a shutoff valve 21 is installed in the middle of the pipe 9 connected to the reaction vessel 4. The shutoff valve 21 is installed in the middle of the pipe 9 together with the control valve 22 and the shutoff valve 23 described later.

In the above configuration, the steam supplied through the pipe 11 and the reaction starting liquid supplied through the pipe 12 are supplied to the reaction vessel 4 through the common pipe 5. Further, hydrogen sulfide gas is supplied to the reaction vessel 4 through a supply line (not shown). Inside the reaction vessel 1, a sulfurization reaction is caused by blowing hydrogen sulfide gas into the sulfuric acid aqueous solution supplied as the reaction starting liquid.

Then, the sulfuric acid aqueous solution is sent from the reaction vessel 1 to the reaction vessel 2 through the pipe 6, and then sent from the reaction vessel 2 to the reaction vessel 3 through the pipe 7. Further, the sulfuric acid aqueous solution is sent from the reaction vessel 3 to the reaction vessel 4 through the pipe 8. At that time, the hydrogen sulfide gas is blown into the sulfuric acid aqueous solution in the same manner in the other reaction vessels 2 to 4. Therefore, the nickel grade of the sulfuric acid aqueous solution gradually increases in the process of moving from the most upstream reaction vessel 1 to the most downstream reaction vessel 4. The final reaction liquid after the sulfide reaction using the four reaction vessels 1 to 4 in the sulfide step is sent from the reaction vessel 4 to the post-process vessel 31 (described later) through the pipe 9.

(3-2. Configuration on the outlet side of the reaction vessel)
FIG. 3 is a schematic view showing a configuration example on the outlet side of the reaction vessel provided in the sulfide production facility.

In FIG. 3, the reaction vessel 4 and the post-process vessel 31 are connected via a pipe 9, and a shutoff valve 21, a control valve 22, and a shutoff valve 23 are installed in the middle of the pipe 9. If two shutoff valves 21 and 23 are installed so as to sandwich the control valve 22 in this way, for example, when performing maintenance or the like, the shutoff valves 21 and 23 are closed to shut off the pipeline for control. The valve 22 can be removed. As an example, the shutoff valve 21 is composed of a gate valve, and the control valve 22 is composed of a ball valve. Further, the shutoff valve 23 is preferably composed of a ball valve.

(Structure of ball valve)
The ball valve has a ball-shaped valve body (not shown) and an annular seat valve seat. When the shutoff valve 23 is composed of a ball valve, it is preferable that each of the valve body and the seat valve seat is coated with tungsten carbide. Further, when the actuator for driving the ball valve is provided, this actuator is preferably a hydraulic actuator.

Here, the post-process container 31 is arranged at a position higher than the reaction container 4 in the vertical direction (vertical direction), and a rising portion 9a is formed in the pipe 9 according to the height difference of these containers. The rising portion 9a is formed by raising a part of the pipe 9. The rising angle of the rising portion 9a with respect to the horizontal plane is preferably 70 degrees or more and 110 degrees or less, and more preferably 80 degrees or more and 100 degrees or less.

In the length direction of the pipe 9 from the reaction vessel 4 to the post-process vessel 31, the shutoff valve 21 and the control valve 22 are installed in a section from the outlet portion of the reaction vessel 4 to the lower end portion of the rising portion 9a. The shutoff valve 21 is installed on the side closer to the reaction vessel 4, that is, on the upstream side than the control valve 22.

On the other hand, the shutoff valve 23 is installed on the downstream side of the control valve 22. Specifically, the shutoff valve 23 is installed at the rising portion 9a of the pipe 9. The shutoff valve 23 is preferably installed in a vertical portion (height) where the slurry does not settle in the valve body when stopped.

A gas introduction unit 32 is connected to the post-process container 31 together with the pipe 17. The pipe 17 is connected to the lower part (bottom) of the post-process container 31. The pipe 17 is for sending the final reaction liquid sent from the reaction vessel 4 through the pipe 9 to the next step. The gas introduction unit 32 is configured so that the inert gas can be introduced into the post-process container 31. In FIG. 3, nitrogen gas (N ₂ ) is illustrated as the inert gas.

The gas introduction unit 32 includes a pipe 33 through which an inert gas pumped from a gas supply source (not shown) is passed, a relay pipe 34 to which the pipe 33 is connected, and a circulation pipe 35 to which the pipe 34 is connected. And an on / off valve 36 installed in the middle of the pipe 33, and a water cooler 37 installed in the middle of the pipe 35. One end of the pipe 35 is connected to the upper part (top) of the post-process container 31, and the other end is connected in the middle of the pipe 17. The on / off valve 36 is composed of, for example, a globe valve. The water cooler 37 cools the pipe 35 by circulating a medium (water or the like) for water cooling.

The on / off valve 36 is held in a closed state during the operation of the manufacturing equipment, and is opened when a predetermined condition is satisfied during the stop or after the stop. When the on / off valve 36 is actually opened, the inert gas sent through the pipe 33 is supplied into the post-process container 31 through the pipes 34 and 35.

On the other hand, the reaction vessel 4 is attached with a liquid level gauge 38a and a pressure gauge 38b, and the post-process vessel 31 is attached with a pressure gauge 39. The liquid level gauge 38a measures the liquid level height of the sulfuric acid aqueous solution in the reaction vessel 4. The pressure gauge 38b measures the pressure in the reaction vessel 4 and corresponds to the "first pressure gauge". The pressure gauge 39 measures the pressure in the post-process container 31 and corresponds to a “second pressure gauge”.

During operation of the manufacturing equipment, the liquid level height of the sulfuric acid aqueous solution in the reaction vessel 4 is measured by the liquid level gauge 38a, and the supply amount of the sulfuric acid aqueous solution is controlled based on the measurement result. When the operation of the manufacturing equipment is stopped, the supply of the sulfuric acid aqueous solution is stopped by closing the control valve 16, but the inside of the reaction vessel 4 is not emptied and a predetermined amount of the sulfuric acid aqueous solution remains.

(3-3. Configuration of control system)
FIG. 4 is a functional block diagram showing a configuration example of a control system applied to the sulfide production facility according to the embodiment of the present invention. Here, as an example, it is assumed that the valve opening / closing operation is automatically performed.

In FIG. 4, the control unit 40 controls the operation of each valve provided in the sulfide production facility. The control unit 40 includes a plurality of input terminals and a plurality of output terminals. A liquid level gauge 38a, a pressure gauge 38b, and a pressure gauge 39 are connected to the input terminal side of the control unit 40. A control valve 14, a shutoff valve 15, a control valve 16, a shutoff valve 21, a control valve 22, a shutoff valve 23, and an on / off valve 36 are connected to the output terminal side of the control unit 40.

(3-4. Control system processing operation)
The operating state (opening / closing state, opening degree, etc.) of each valve connected to the output terminal side of the control unit 40 is controlled as follows by the processing operation of the control unit 40.

First, during normal operation, all the other valves except the on / off valve 36 are in the open state. On the other hand, when the operation of the manufacturing equipment is stopped, the valves are closed on the reaction vessel inlet side and the reaction vessel outlet side as follows.

First, on the inlet side of the reaction vessel, the control valve 14 and the shutoff valve 15 are closed at the same time, and the control valve 16 is closed. As a result, the supply of steam and the reaction starting liquid is stopped. At this time, the pipe 11 is closed by a double valve consisting of a control valve 14 and a shutoff valve 15. Therefore, even when the temperature drops in the steam line, the backflow of fluid is suppressed by the double valve. Regarding the reaction starting liquid supply line, since the pipe 12 and the reaction starting liquid tank (not shown) are filled with the liquid, there is no possibility that the fluid will flow back.

On the other hand, on the outlet side of the reaction vessel, the control valve 22 is closed first, then the shutoff valve 23 on the downstream side is closed, and then the shutoff valve 21 on the upstream side is closed. As a result, the pipe 9 is closed by the double shutoff valves 21 and 23, and when the control valve 22 is included, the pipe 9 is closed by the triple valve. Further, the upstream side of the control valve 22 is shut off by the shutoff valve 21, and the downstream side of the control valve 22 is shut off by the shutoff valve 23. That is, the flow of the fluid in the pipe 9 between the reaction vessel 4 and the post-process vessel 31 is blocked by the double shutoff valves 21 and 23.

Further, the control unit 40 controls the gas introduction unit 32 in order to introduce the inert gas into the post-process container 31 after stopping the operation of the manufacturing equipment. The introduction of the inert gas is performed by opening the on / off valve 36 of the gas introduction unit 32. The on / off valve 36 is opened by the control unit 40 when the operation is stopped and a preset condition (hereinafter, referred to as “predetermined condition”) is satisfied.

There are mainly two of the above-mentioned predetermined conditions. The first condition is a case where the pressure P1 in the reaction vessel 4 measured by the pressure gauge 38b and the pressure P2 in the post-process vessel 31 measured by the pressure gauge 39 satisfy the relationship of P1> P2. During operation (during operation) of the manufacturing facility, the pressure in the reaction vessel 4 is maintained at atmospheric pressure, and the pressure in the post-process vessel 31 is maintained at a pressure lower than atmospheric pressure (vacuum pressure). Therefore, immediately after the operation of the manufacturing equipment is stopped, the relationship of P1> P2 is satisfied.

The second condition is a case where the liquid level height in the reaction vessel 4 measured by the liquid level gauge 38a decreases with time. When the liquid level in the reaction vessel 4 changes with time, there is a valve failure or erosion even though all three valves (21, 22, 23) installed in the pipe 9 are closed. This is a case where the fluid continues to flow inside the pipe 9 and the amount of the sulfuric acid aqueous solution remaining in the reaction vessel 4 gradually decreases with the passage of time. If this phenomenon is left unattended, the liquid level in the reaction vessel 4 will continue to decrease under the condition of a preset height (original liquid pressure feeding stop position) or less.

The control unit 40 opens the on / off valve 36 in order to introduce the inert gas into the post-process container 31 when at least one of the above two conditions is satisfied.

As a result, the inert gas supplied through the pipe 33 is introduced into the post-process container 31 through the pipes 34 and 35. Therefore, for example, when the pressure in the reaction vessel 4 is held at atmospheric pressure and the pressure in the post-process vessel 31 is held at a pressure lower than the atmospheric pressure (vacuum pressure) during operation of the manufacturing facility, it is not possible. The pressure inside the post-process container 31 gradually increases due to the introduction of the active gas. As a result, the pressure difference between the reaction vessel 4 and the post-process vessel 31 (difference in internal pressure of each vessel) becomes small.

Further, the control unit 40 adjusts the opening degree of the on / off valve 36 so that the difference (P1-P2) between the pressure P1 in the reaction vessel 4 and the pressure P2 in the post-process vessel 31 becomes 0 kPa or less. , The pressure in the post-process container 31 is restored to about atmospheric pressure. The "difference (P1-P2) of 0 kPa or less" described here includes both "when P1 = P2" and "when P1 <P2 (when the value of P1-P2 becomes negative)". ..

<4. Effect of embodiment>
In the embodiment of the present invention, the shutoff valve 21 and the shutoff valve 23 are installed in the middle of the pipe 9 connected to the outlet of the reaction vessel 4. Therefore, when the operation of the manufacturing equipment is stopped, the flow of the fluid in the pipe 9 can be shut off by the double valve by closing the respective shutoff valves 21 and 23. Therefore, it is possible to suppress fluid leakage to the outside with higher accuracy in the sulfide production facility.

In the embodiment of the present invention, of the two shutoff valves 21 and 23 installed in the pipe 9, at least the shutoff valve 23 installed at the most downstream side is composed of a ball valve having a relatively high shutoff property. .. Therefore, the outflow of the fluid to the downstream side of the shutoff valve 23 can be shut off more reliably. Further, if the actuator that drives the ball valve is a hydraulic actuator, the ball valve can be opened / closed (rotated) with a stronger torque. Therefore, the pipe 9 can be closed with high blocking property and airtightness. Further, when the shutoff valve 23 is composed of a ball valve, if the valve body and the seat valve seat are coated with tungsten carbide, deterioration of the shielding performance due to erosion can be suppressed.

In the embodiment of the present invention, the shutoff valve 23 is installed at the rising portion 9a of the pipe 9. The slurry flowing inside the pipe 9 is in a biased state due to the influence of gravity in the horizontal portion of the pipe 9, but flows without bias in the rising portion 9a of the pipe 9. Therefore, if the shutoff valve 23 is installed at the rising portion 9a of the pipe 9, the pipe 9 can be closed with no deviation of the slurry or a small degree of the slurry. As a result, the slurry does not settle on the shutoff valve 23 installed at the rising portion 9a of the pipe 9, but settles below the shutoff valve 23, so that the slurry is suppressed from being caught by the shutoff valve 23. Therefore, the risk of damage to the shutoff valve 23 is reduced, and the soundness of the equipment can be maintained.

In the embodiment of the present invention, when the operation of the sulfide production facility is stopped, the control unit 40 controls the gas introduction unit 32 so as to introduce the inert gas into the post-process container 31. ing. As a result, when all three valves (21, 22, 23) are closed, even if the flow of fluid in the pipe 9 is not completely blocked for some reason (for example, valve failure or corrosion), the post-process The outflow of fluid to the container 31 side can be suppressed.

In the embodiment of the present invention, when the pressure P1 in the reaction vessel 4 measured by the pressure gauge 38b and the pressure P2 in the post-process vessel 31 measured by the pressure gauge 39 satisfy the relationship of P1> P2, the latter A configuration is adopted in which an inert gas is introduced into the process container 31. As a result, the outflow of fluid due to the pressure difference between the reaction vessel 4 and the post-process vessel 31 can be suppressed.

In the embodiment of the present invention, when the liquid level in the reaction vessel 4 measured by the liquid level gauge 38a changes with time, an inert gas is introduced into the post-process vessel 31. .. As a result, if there is a fluid flow from the reaction vessel 4 side to the post-process vessel 31 side even after the valve is closed due to valve failure, corrosion, or the like, the flow can be suppressed.

<5. Deformation example, etc.>
The technical scope of the present invention is not limited to the above-described embodiment, but also includes a form in which various changes and improvements are made to the extent that a specific effect obtained by the constituent requirements of the invention and the combination thereof can be derived.

For example, in the above embodiment, two shutoff valves 21 and 23 are installed in the middle of the pipe 9, but the present invention is not limited to this, and three or more shutoff valves may be installed. In addition, "multiplex" means more than double, for example, the number of shutoff valves is two when the shutoff valves are installed in duplicate, and three when the shutoff valves are installed in triplet.

In the above embodiment, of the two shutoff valves 21 and 23 installed in the middle of the pipe 9, only the most downstream shutoff valve 23 is composed of a ball valve, but the present invention is not limited to this, and both shutoff valves 21 and Both 23 may be composed of ball valves. Further, the shutoff valve 15 on the pipe 11 may be formed of a ball valve.

In the above embodiment, when the operation of the manufacturing equipment is stopped, the function of controlling the gas introduction unit 32 (on / off valve 36) based on the measurement results of the pressure gauges 38b and 39 and the measurement result of the liquid level gauge 38a are obtained. Based on this, the control unit 40 has both the functions of controlling the gas introduction unit 32, but the control unit 40 may have only one of the control functions.

In the above embodiment, the case where the valve opening / closing operation is automatically performed has been described, but the present invention is not limited to this, and a configuration in which some valves or all valves are manually opened / closed can be adopted.

1 to 4 ... Reaction vessel 5 to 9 ... Piping 14, 22 ... Control valve 15, 16, 21, 23 ... Shutoff valve 32 ... Gas introduction unit 38a ... Liquid level gauge 38b, 39 ... Pressure gauge 40 ... Control unit

Claims (8)

In a hydrometallurgy method based on the high-pressure acid leaching method that recovers nickel from nickel oxide ore, a sulfurization step in which hydrogen sulfide gas is blown into a sulfuric acid aqueous solution containing nickel to carry out a sulfurization reaction that produces sulfide containing nickel and a poor liquid. It is a sulfide production facility used in
The reaction vessel for the sulfurization reaction and
A post-process vessel arranged at a higher position in the vertical direction than the reaction vessel,
A pipe that connects the outlet of the reaction vessel and the post-process vessel, and allows the reaction liquid, slurry, and residual gas to flow from the reaction vessel to the post-process vessel side.
Multiple shut-off valves installed in the middle of the piping,
Equipped with a,
The pipe includes a rising portion formed by raising a part of the pipe according to the height difference between the reaction vessel and the post-process vessel.
At least one of the plurality of shutoff valves is a sulfide production facility installed at a height at which the slurry at the rising portion does not settle in the valve body. The sulfide production facility according to claim 1, wherein the shutoff valve installed at least on the most downstream side of the plurality of shutoff valves is a ball valve. It has an actuator that drives the ball valve and has an actuator.
The sulfide manufacturing equipment according to claim 2, wherein the actuator is a hydraulic actuator. The sulfurization according to claim 2 or 3, wherein the ball valve has a ball-shaped valve body and an annular seat valve seat, and each of the valve body and the seat valve seat is coated with tungsten carbide. Manufacturing equipment for goods. A gas introduction section for introducing the inert gas into the reaction vessel and the post-process vessel connected via the pipe,
After stopping the operation of the sulfide production facility, a control unit that controls the gas introduction unit to introduce the inert gas into the post-process container, and a control unit.
The sulfide production facility according to any one of claims 1 to 4. A first pressure gauge that measures the pressure inside the reaction vessel, and
A second pressure gauge for measuring the pressure in the post-process container is provided.
In the control unit, when the pressure P1 in the reaction vessel measured by the first pressure gauge and the pressure P2 in the post-process vessel measured by the second pressure gauge satisfy the relationship of P1> P2. The sulfide production facility according to claim 5 , wherein the gas introduction unit is controlled to introduce the inert gas into the post-process container. A liquid level meter for measuring the liquid level in the reaction vessel is provided.
The control unit controls the gas introduction unit to introduce the inert gas into the post-process container when the liquid level height in the reaction vessel measured by the liquid level gauge decreases with time. The sulfide production facility according to claim 5. In the control unit, the difference (P1-P2) between the pressure P1 in the reaction vessel measured by the first pressure gauge and the pressure P2 in the post-process vessel measured by the second pressure gauge is 0 kPa. The sulfide production facility according to claim 6 , wherein the gas introduction unit is controlled so as to be as follows.

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