JP2020179322A - Sedimentation tank and method for collection of solid matter - Google Patents

Abstract

To provide a technique hardly causing occurrence of clogging in an outlet or pipeline, or capable of automatically resolving the clogging problem in a sedimentation tank for collecting fine solid matters included in a liquid to be treated from a process liquid by taking out from bottom and in a method for collection of the solid matters using the sedimentation tank.SOLUTION: A method for collection of solid matters using a sedimentation tank includes: leaving at rest, a liquid 8 to be treated including fine solid matters 4a leaked from a filter in a sedimentation tank 10 for a prescribed time to precipitate the fine solid matters 4a on the bottom part 11 of the sedimentation tank 10 by sedimentation separation; repeatedly sending the precipitated solid matters 4a on the bottom part 11 of the sedimentation tank 10 to a cooling crystallization tank to promote a grain growth; and then filtering to collect the solid matter. In the sedimentation tank 10, an air 18 is blown toward the solid matter 4a precipitated on the bottom part 11 of the sedimentation tank 10 and/or the solid matter 4a transferred in the inside of a transfer pipe 24 by air blowing means 19.SELECTED DRAWING: Figure 2

Description

The present invention relates to a settling tank for recovering fine solids contained in the liquid to be treated from the liquid to be treated, and a method for recovering solids using the settling tank.

In the electrolytic purification of copper, a blister copper plate containing impurities is used as an anode (anode), and a thin plate such as pure copper, stainless steel, or titanium is used as a cathode (cathode), and the anode and the cathode are alternately charged into the electrolytic tank to be constant. An electrolytic solution whose temperature is controlled in a range is supplied to the electrolytic tank and energized, and copper having a predetermined thickness is electrodeposited on the cathode to obtain electrolytic copper.

When energized, the copper contained in the anode elutes into the electrolytic solution as copper ions. At the same time, impurities such as arsenic, bismuth, antimony, and nickel contained in the anode are also eluted into the electrolytic solution. Only copper ions in the electrolytic solution are electrodeposited on the cathode to obtain high-purity electrolytic copper, but impurities remain in the electrolytic solution, and as a result, the impurity concentration of the electrolytic solution increases.

As the concentration of impurities in the electrolytic solution increases as the electrolytic purification progresses, the impurities co-deposit with copper, lowering the copper quality of electrolytic copper, causing scale in the piping of the electrolytic solution, and hindering operations. , Problems such as lowering the electrical conductivity of the electrolytic solution and increasing the power cost occur.

For this reason, a part of the electrolytic solution is sent to the liquid purification process to remove impurities, and then the electrolytic cell is supplied again to the electrolytic cell. In the purification step, the electrolytic solution is vacuum-evaporated to concentrate, and the oversaturated copper is precipitated and removed as crude copper sulfate by quenching. A concentration and cooling step, and then after recovering the crude copper sulfate. A copper de-copper electrolysis step (arsenic electrolysis step) that removes residual copper, arsenic, bismuth, and antimon from the crude mother liquor, which is a filtrate, by precipitating it on the cathode, and a nickel-containing solution after copper removal. A denicking step is performed in which nickel is separated and recovered as crude nickel sulfate from a certain decopper final solution.

In the nickel removal step, first, a pre-heated decopper final solution is supplied to a nickel concentrating tank, and in this nickel concentrating tank, a graphite electrode is immersed in the decopper final solution to energize the copper. The final solution is heated and concentrated by Joule heat. Next, the concentrated solution that has been concentrated by heating is sent to a cooling crystal tank, and crude nickel sulfate is precipitated from this concentrated solution due to the common ion effect that accompanies the increase in sulfuric acid concentration due to concentration and the decrease in solubility due to cooling. Further, the slurry containing the precipitated nickel sulfate is sent to a filter by a cooling crystal tank pump, the crude nickel sulfate is recovered as a solid by filtration, and the filtrate is sucked by a vacuum pump and stored in a receiver tank. , Is paid out as appropriate.

In this way, not only in the step of recovering crude nickel sulfate, but also in the step of recovering the object which has become a solid by solidifying using the difference in solubility, the concentrated solution heated and concentrated is generally used in a cooling crystal tank. The solid matter is precipitated by reducing the solubility due to cooling after concentration, and the slurry in which the solid matter is precipitated is supplied to the filtration step. In the filtration step, the slurry is separated into a solid substance (residue) and a filtrate by a filter medium such as a filter cloth, a filter paper, or a mesh screen. In particular, in suction filtration such as vacuum filtration, separation can be performed quickly by sucking the filtrate by reducing the pressure on the filtrate side of the filter medium. The sucked filtrate is stored in the receiver tank and discharged as appropriate.

The filtrate to be discharged contains an object that is in a dissolved state due to its solubility and a fine solid substance (fine crude nickel sulfate in the denickel step) that has leaked from the filter. It is a cause of recovery loss.

In order to reduce filtration leakage, it is conceivable to make the filter medium finer, but this method reduces the filtration rate, so if the filter capacity is insufficient, the amount of solid matter produced will decrease. The problem arises.

There is also a method of returning a part of the filtrate from the receiver tank to the cooling crystal tank as in the technique described in JP-A-2009-114520. With this method, the more the amount of filtrate returned, the more fine solids that have leaked from the filtrate can be recovered. However, since the returned filtrate must be processed again with a filter, there is a margin in the capacity of the filter. In the absence of the above, there arises a problem that the amount of solid matter produced is reduced. Further, when the entire filtrate is returned, the amount processed by the filter continues to increase with time, so that only a part of the filtrate can be returned from the receiver tank.

JP-A-2009-114520

Applicants, in Japanese Patent Application No. 2018-128404, settle and separate the filtrate containing fine solids in a settling tank, bottom out the solids settled at the bottom of the settling tank, and cool the crystal tank. We are proposing a way to return it to. According to this method, the recovery rate of solid matter can be improved regardless of the capacity of the filter. However, in this method, the slurry containing the solid matter may be clogged in the outlet for removing the bottom of the slurry from the bottom of the settling tank or the pipe for returning the slurry to the cooling crystal tank. Clogged outlets and pipes can be cleared by disassembling and cleaning the equipment, but it takes a lot of time and effort and the operating rate of the equipment is reduced, so it is difficult for clogging of outlets and pipes to occur. Alternatively, a method that can automatically clear the clogging is required.

An object of the present invention is a settling tank for recovering fine solids contained in a liquid to be treated from the liquid to be treated by bottoming out, and a method for recovering solids using the same, outlets and pipes for bottoming out. It is an object of the present invention to provide a means capable of improving the operating rate of equipment by making it difficult for clogging to occur or by automatically clearing the clogging.

As a result of various studies to solve the above problems, the present inventors return the slurry containing a fine solid substance from the settling tank to the cooled crystal tank or the concentrating tank via the bottom punching outlet and the pipe. By blowing air (compressed air) on the part of the flow path where clogging is likely to occur and stirring it, it is possible to make it difficult for clogging of outlets and pipes to occur, or to automatically clear the clogging. I got the finding that it can be done.

The present inventors have completed the present invention based on this finding.

The settling tank of the present invention
With the tank body
At the bottom
Inlet for receiving liquid to be treated and
An outlet for removing the bottom of solids provided on the bottom,
The liquid to be treated means for supplying the liquid to be treated and the liquid to be treated through the inlet for receiving the liquid to be treated.
A transfer pipe having an upstream end connected to the solid material bottoming outlet is provided, and a slurry containing a solid material obtained by sedimentation separation of the liquid to be treated is provided through the solid material bottoming outlet. A solid material bottoming means for bottoming out,
An air blowing means and / or an air blowing means that blows air toward the solid bottom punching outlet inside the transfer pipe and / or inside the bottom.
An air supply means that supplies air to the air blowing means and
To be equipped.

The solid bottom punching means may include a transfer means having a suction port for sucking the slurry and a discharge port for discharging the slurry, in which case the transfer pipe has a downstream end connected to the suction port. Can have. The transfer means may include an air-driven pump. In this case, the air supply means can supply driving air to the pump.

The air blowing means may include a first air blowing means for blowing air inside the transfer pipe. In this case, the air outlet of the first air blowing means is arranged at an arbitrary position in the transfer pipe in the range from the position adjacent to the upstream side of the suction port to the position 50 cm upstream of the suction port. Will be done.

Additional or alternative, the air blowing means may include a second air blowing means that blows air inside the bottom towards the solids bottoming outlet. In this case, the air outlet of the second air blowing means is located at a position 1 cm to 60 cm above the outlet for removing the bottom of the solid material, preferably a position of 3 cm to 30 cm, and most preferably a position of 5 cm in the bottom portion. Be placed.

The solid matter recovery method of the present invention uses the above-mentioned sedimentation tank of the present invention.

In particular, the sedimentation separation and recovery method of the present invention
The step of supplying the liquid to be treated by the liquid to be treated means and
A step of sedimenting the liquid to be treated in the sedimentation tank and sedimenting the solid matter on the bottom portion.
A bottoming step of bottoming out the solid matter settled on the bottom portion by the solid matter bottoming out means through the solid matter bottoming outlet, and
An air blowing step of blowing air onto the solid matter obtained by sedimentation separation of the liquid to be treated by the air blowing means.
To be equipped.

The bottom punching step and the air blowing step can be performed at the same time.

According to the present invention, in a settling tank for recovering fine solids contained in the liquid to be treated from the liquid to be treated by bottom punching and a method for recovering the solids using the same, the slurry containing the solids is settled. By blowing air (compressed air) to the part of the flow path for returning from the tank to the cooling crystal tank or the concentrating tank where clogging is likely to occur, clogging of the outlet or piping is less likely to occur, or , The clogging can be cleared automatically. As a result, the operating rate of the equipment can be improved and the manufacturing cost per unit quantity of solid matter can be reduced.

FIG. 1 is a schematic view showing the overall configuration of an apparatus for recovering solids from a raw material liquid. FIG. 2 is a schematic cross-sectional view showing the settling tank of the present invention.

In the present invention, in the nickel removal step of separating and recovering nickel as crude nickel sulfate from the copper removal final liquid generated in the liquid purification step for electrolytic refining of copper, a filtrate containing residual crude nickel sulfate that has not been filtered is settled in a settling tank. A settling tank for settling and separating the solid matter from the liquid to be treated containing fine solid matter, such as a settling tank for collecting the residual crude nickel sulfate by bottoming out. Regarding.

As shown in FIG. 1, the apparatus used in the step of separating and recovering the solid matter from the raw material liquid (copper decopper final liquid) 1 containing the solid matter (crude nickel sulfate) such as the denickelization step is basically basically. The concentrating tank 3 for heating and concentrating the raw material liquid 1 to obtain the concentrating liquid 2 and the concentrating liquid 2 sent from the concentrating tank 3 are cooled to precipitate the solid matter (crude nickel sulfate) 4, and the solid matter 4 is prepared. It is provided with a cooling crystal tank 6 for obtaining the slurry 5 to be contained, and a filter 7 for filtering the slurry 5 and collecting the solid matter 4.

Any concentrating tank can be applied to the concentrating tank 3 as long as the raw material liquid 1 can be heated at a temperature equal to or higher than the boiling point of the raw material liquid 1. For example, an electric evaporation tank is applicable. In the electric evaporation tank, a graphite electrode rod that can be energized and is immersed in the liquid to be treated is inserted and arranged in the tank, and the raw material liquid 1 is energized through the graphite electrode rod to energize the raw material liquid 1. Is heated by Joule heat to evaporate the water content to obtain a concentrated solution 2. The heating temperature depends on the type of the liquid to be treated, but in the case of the final copper decopper, it is preferably a temperature in the range of about 150 ° C. to 200 ° C. In addition, as the concentrating tank 3, a structure capable of heating the raw material liquid 1 directly or indirectly from the periphery of the tank by using a heavy oil burner can be adopted.

Also in the cooling crystal tank 6, the concentrate 2 is cooled to a temperature at which the solid substance 4 is sufficiently precipitated, for example, about 50 ° C. in the case of recovery of crude nickel sulfate, depending on the type of solute contained in the concentrate 2. Any possible structure can be adopted. For example, a structure in which a jacket or a serpentine tube is installed around or in the tank and a refrigerant is passed through them is applicable to the cooling crystal tank 6.

As for the filter 7, a filter using natural filtration, reduced pressure filtration, pressurized filtration, centrifugal filtration, or the like can be used. Further, as the filter medium used in the filter 7, a filter cloth, a filter paper, a mesh screen or the like can be used. As the filter 7, for example, a vacuum filter, a centrifuge, a centrifugal settler, or the like can be used, but in the case of recovery of crude nickel sulfate, a vacuum filter is usually applied as the filter 7. ing.

In the case of a vacuum filter, the solid substance 4 such as crude nickel sulfate is recovered in the filter tube 7, and the liquid to be treated 8 which is a filtrate after the solid substance 4 is recovered is sucked into the vacuum pump and is usually a receiver. It is stored in the tank 9 and discharged as appropriate.

In this example, the settling tank 10 is provided in place of or in addition to the receiver tank 9 provided in the conventional device. The liquid to be treated 8 containing the fine solid matter 4a that has leaked from the filter 7 is put into the settling tank 10 directly or via the receiver tank 9, and the fine solid matter 4a is placed on the bottom 11 of the settling tank 10. The slurry 5a containing the solid matter 4a that has been precipitated and settled in the bottom 11 of the settling tank 10 is bottomed out and repeated in the cooling crystal tank 6 or the concentration tank 3.

Conventionally, the liquid to be treated 8 sent from the filter 7 is stored in the receiver tank 9, and the entire amount of the liquid to be treated 8 is discharged as appropriate, or a part of the liquid to be treated 8 is returned to the cooling crystal tank 6 as it is. On the other hand, in this example, the liquid to be treated 8 is held in the settling tank 10 for a sufficient time to precipitate the fine solid matter 4a, and the slurry 5a containing the precipitated solid matter 4a is bottomed out to cool the crystals. It can be returned to the tank 6 or the concentration tank 3, and only the supernatant 12 generated by the precipitation of the solid substance 4a is once discharged out of the system and added to the electrolytic solution to be used for adjusting the acid concentration and the like. As a result, mainly fine solid matter 4a can be effectively recovered by circulation in the system without excessive supply to the cooling crystal tank 6 or the concentration tank 3, and the solid matter from the raw material liquid 1 can be recovered. The recovery rate of the product has been dramatically improved.

As shown in FIG. 2, the basic structure of the settling tank 10 according to an example of the embodiment of the present invention is provided in the tank body 13, the bottom 11, the inlet 14 for receiving the liquid to be treated, and the bottom 11. The liquid to be treated 8 is supplied via the outlet 15 for removing the bottom of the solid material, the inlet 14 for receiving the liquid to be treated, the liquid to be treated 16 to supply the liquid to be treated 8, and the outlet 15 for removing the bottom of the solid material. The solid matter bottoming means 17 for bottoming out the solid portion 4a obtained by the sedimentation separation of the above, the air blowing means 19 for blowing air (compressed air) 18 to the solid matter 4a, and the air 18 being supplied to the air blowing means 19. The air supply means 20 is provided.

The overall shape and size of the settling tank 10 may basically be a size according to surrounding equipment and the like, and is arbitrary. The bottom portion 11 of the settling tank 10 is tilted downward toward the outlet 15 for removing the bottom of the solid material, and has a shape that narrows toward the bottom. With such a shape of the bottom portion 11, the ratio of the volume occupied by the portion directly above the solid material bottom punching outlet 15 to the volume of the bottom portion 11 increases, so that the precipitated solid material 4a is extracted from the solid material bottom punching outlet 15. It is advantageous for.

The inclination of the bottom 11 of the settling tank 10 is such that the inclination angle from the horizontal plane is 40 degrees or more, preferably 45 degrees or more, so that the solid matter 4a settled on the bottom 11 can be quickly brought to the bottom of the bottom 11. It is possible to smoothly bottom out the slurry 5a containing the precipitated solid substance 4a. On the other hand, regarding the inclination of the bottom portion 11, when the inclination angle from the horizontal plane is less than 40 degrees, it takes time for the solid matter 4a precipitated on the bottom portion 11 to flow to the bottommost portion of the bottom portion 11, and the precipitated solid matter 4a Depending on the particle shape, it tends to be deposited on the bottom surface of the bottom portion 11, particularly in the corners of the bottom surface. When the solid matter 4a is deposited on the bottom 11 of the settling tank 10, the tank capacity is reduced and the residence time of the liquid to be treated 8 is shortened. The solid matter 4a is fixed to the inner surface of the settling tank 10. It may cause problems such as clogging. There is no particular upper limit to the inclination angle of the bottom 11 from the horizontal plane, but it is preferably 60 degrees or less from the viewpoint of securing the volume of the settling tank 10.

When the shape of the tank body 13 of the settling tank 10 is cylindrical, the shape of the bottom 11 can have a cone shape (conical) or a mortar shape. With such a shape, the bottommost portion is arranged in the central portion of the bottom portion 11, the solid matter 4a settled in the central portion of the bottom portion 11 is uniformly aggregated, and the slurry 5a containing the solid matter 4a is bottomed from the central portion of the bottom portion 11. It can be easily pulled out.

By arranging the inlet 14 for receiving the liquid to be treated in the gas phase portion of the tank body 13, it is possible to suppress clogging by the solid matter 4a. Specifically, the inlet 14 for receiving the liquid to be treated is provided at an arbitrary position on the upper end of the tank body 13 or the ceiling, but when the tank body 13 does not have a ceiling, the tank body 13 The opening corresponds to the inlet 14 for receiving the liquid to be treated. It is appropriate that the upper limit of acceptance of the liquid to be treated 8 is set below the inlet 14 for receiving the liquid to be treated.

The inlet 14 for receiving the liquid to be treated is connected to the liquid to be treated supply means 16 for transferring the liquid to be treated 8 from the upstream side such as the filter 7 or the receiver tank 9. The liquid to be processed 16 is composed of piping and a fluid transfer device including a vacuum pump, a metering pump, a line pump and other known pumps. In this example, in order to perform vacuum filtration, the liquid to be treated 8 is drawn from the filter 7 by a vacuum pump (VP) provided in the receiver tank 9, and the liquid to be treated 8 stored in the receiver tank 9 is appropriately used. It is transferred to the settling tank 10 through a pipe. Therefore, substantially, the vacuum pump (VP) provided in the receiver tank 9 functions as a fluid transfer device. In the present invention, even when one end of the pipe of the liquid to be treated 16 on the downstream side is arranged in the opening of the tank body 13 or vertically above the opening, the liquid to be treated 16 and the liquid to be treated 16 are covered. It is interpreted that the processing liquid receiving inlet 14 is connected.

Since the outlet 15 for bottoming out the solid material is provided at the bottommost portion of the bottom portion 11, it is possible to selectively bottom out the slurry 5a containing the solid material 4a. When the bottom portion 11 has a cone-shaped or mortar-shaped shape, the solid material bottom-extracting outlet 15 is provided at the radial center portion of the bottom portion 11. The solid material bottoming outlet 15 is connected to the solid material bottoming means 17. The slurry 5a containing the solid matter 4a precipitated by the sedimentation separation of the liquid to be treated 8 is bottomed out by the solid matter bottoming out means 17 via the solid matter bottoming out outlet 15, and then the cooling crystal tank 6 or It is repeated in the concentrating tank 3.

The solid bottom punching means 17 is a transfer means 23 having a suction port 21 for sucking the slurry 5a and a discharge port 22 for discharging the slurry 5a, and an upstream end and transfer means 23 connected to the solid bottom punching outlet 15. A transfer pipe 24 having a downstream end connected to the suction port 21 is provided. The discharge port 22 of the transfer means 23 is connected to the upstream end of the return pipe 25. The downstream end of the return pipe 25 is open to the cooling crystal tank 6 or the concentration tank 3. The slurry 5a bottomed out from the solid material bottoming outlet 15 is sucked from the suction port 21 of the transfer means 23 via the transfer pipe 24, and then discharged from the discharge port 22 to the return pipe 25 to cool crystals. It is repeated in the tank 6 or the concentration tank 3.

In this example, as the transfer means 23, the liquid is sucked from the suction port 21 and discharged (pushed out) from the discharge port 22 by reciprocating the diaphragm using the air 18 supplied from the air supply means 20 as a driving force. A driven metering pump is used.

The air blowing means 19 is obtained by settling and separating the liquid to be treated 8, and is transferred to the solid material 4a existing in the bottom 11 of the settling tank 10 and / or the solid material 4a existing inside the transfer pipe 24. Air 18 is blown onto the solid material 4a. Specifically, the air blowing means 19 changes the flow velocity in the flow path for returning the slurry 5a containing the solid matter 4a from the settling tank 10 to the cooling crystal tank 6 or the concentration tank 3, and the solid matter 4a. By blowing air 18 onto the portion where the solid matter is likely to be clogged and stirring the solid matter 4a, the solid matter 4a can be less likely to be clogged or the clogging can be eliminated. The air blowing means 19 of this example includes a first ejection port 26 for blowing air 18 toward the solid material 4a (that is, the inside of the transfer pipe 24) being transferred in the transfer pipe 24, and a settling tank 10. A second outlet 27 for blowing air 18 toward the solid matter 4a (that is, the solid matter bottoming outlet 15 of the bottom portion 11) settled on the bottom portion 11 of the bottom portion 11 is provided. That is, in this example, the air blowing means 19 includes both a first air blowing means including a first ejection port 26 and a second air blowing means including a second ejection port 27.

The first spout 26 is arranged at an arbitrary position in the transfer pipe 24 in a range from a position adjacent to the upstream side of the suction port 21 of the transfer means 23 to a position 50 cm upstream of the suction port 21. Here, the higher the pressure of the air 18, the longer the distance of the first ejection port 26 from the suction port 21, and the more the air 18 can be blown over a wide range. If the position of the first spout 26 is any position in the range from the position adjacent to the upstream side of the suction port 21 to the position 50 cm upstream of the suction port 21, it is easily available as the air supply means 20. And it is possible to use an inexpensive one. However, the longer the distance from the suction port 21 to the first spout 26, the larger the pressure loss at an accelerating rate, and the higher the equipment cost and operating cost. Therefore, the range is limited to 10 cm on the upstream side of the suction port 21. Is preferable. The first spout 26 is connected to the air supply means 20 and is provided at the downstream end of the first air pipe 28, which corresponds to the first air blowing means, and is provided at the predetermined position of the transfer pipe 24. Open to.

The second outlet 27 is arranged at a position 1 cm to 60 cm above the solid material bottom punching outlet 15, preferably at a position of 3 cm to 30 cm, and most preferably at a position of 5 cm. If the position of the second spout 27 is lower than 1 cm above the outlet 15 for removing the bottom of the solid material or higher than 60 cm above the outlet 15 for removing the bottom of the solid material, the solid material settled on the bottom portion 11. It is possible that 4a cannot be sufficiently agitated to prevent the occurrence of clogging or to clear the clogging. The second spout 27 is connected to the air supply means 20 and is provided at the downstream end of the second air pipe 29, which corresponds to the second air blowing means.

The air supply means 20 supplies the air 18 to the first outlet 26 via the first air pipe 28, and the air 18 to the second outlet 27 via the second air pipe 29. To supply. Further, in this example, the air supply means 20 supplies the air 18 as a driving force to the air drive pump constituting the transfer means 23 via the third air pipe 30. The air supply means 20 is between the compressor 31 that compresses air to generate air (compressed air) 18 and the compressor 31, the first air pipe 28, the second air pipe 29, and the third air pipe 30. It is provided with a valve 32 provided in.

As the compressor 31, a reciprocating compressor that compresses air by changing the cylinder volume by the reciprocating movement of the piston, a rotary compressor that compresses air by utilizing the rotation of rollers and impellers, and other known compressors are used. Can be done.

As the valve 32, either a manual valve that opens and closes and adjusts manually or an automatic valve that automatically performs operation may be used, but the valve 32 automatically opens when the transfer means 23 is driven and stops the transfer means 23. It is preferable to use an automatic valve that closes automatically.

The settling tank 10 of this example further includes an outlet 33 for extracting the supernatant, an in-tank pipe 34 connected to the outlet 33 for extracting the supernatant, a non-contact level sensor 35, and a timer 36.

The supernatant extraction outlet 33 is provided at an arbitrary position in the tank body 13 between the upper limit of acceptance of the liquid to be treated 8 and the upper end portion of the bottom portion 11 (the boundary between the tank body 13 and the bottom portion 11). The supernatant extraction outlet 33 is connected to the supernatant extraction means 37.

Inside the tank body 13, the downstream end (upper end) of the in-tank pipe 34 is connected to the supernatant extraction outlet 33. The upstream end (lower end) of the in-tank pipe 34 is arranged at the horizontal intermediate portion and the height intermediate portion of the bottom portion 11. That is, by arranging the lower end opening of the in-tank pipe 34 at the relevant position in the bottom portion 11, the supernatant 12 can be recovered at once from the bottom, and the solid accumulated on the wall surface after the liquid to be treated 8 is settled and separated. The supernatant 12 can be recovered while avoiding the object 4a. Specifically, the arrangement of the in-tank pipe 34 is appropriately set according to the shape of the bottom portion 11 and the amount of solid matter 4a generated by one treatment. The in-tank pipe 34 communicates between the supernatant extraction outlet 33 and the horizontal intermediate portion and the height intermediate portion of the bottom portion 11, and only the supernatant 12 is extracted out of the system by the supernatant extraction means 37. It is possible. In addition, depending on the type of the non-contact type level sensor 35 described later, if necessary, the in-tank pipe 34 may be used between the supernatant extraction outlet 33 and the upper end of the bottom 11 in the cross section of the tank body 13. The contact level sensor 35 is arranged at a position that does not interfere with the sensing range.

The supernatant extraction means 37 includes piping and a fluid transfer device including a vacuum pump, a metering pump, a line pump, and other known pumps.

The non-contact level sensor 35 can be selected from an ultrasonic level sensor, a radio wave level sensor, and a laser level sensor. These non-contact level sensors 35 determine the level of the liquid to be treated 8 in the settling tank 10 by measuring the time during which ultrasonic waves, radio waves, or lasers are reflected from the liquid surface and returned. Since it can be measured in a non-contact manner, it does not depend on the type of liquid and is resistant to corrosion by the liquid to be treated 8.

However, since the ultrasonic level sensor and the radio wave level sensor have a relatively large spot diameter, they are easily affected by the shape of the inner surface of the settling tank 10 and obstacles. Therefore, when an ultrasonic level sensor or a radio wave level sensor is used as the non-contact level sensor 35, the non-contact level sensor 35 avoids the sensingable range in the settling tank 10. It is necessary to arrange the in-tank pipe 34 as described above.

Specifically, of the in-tank pipe 34, the portion arranged above the upper end of the bottom 11 is arranged along the inner peripheral surface of the tank body 13, and the portion arranged on the bottom 11 is arranged. , It is preferable to arrange it near the surface of the precipitated solid material 4a. In this case, the non-contact level sensor 35 is arranged at a position radially off the center of the ceiling or opening of the settling tank 10, and the in-tank pipe 34 has a sensing range of the non-contact level sensor 35. It is preferable not to enter. The portion of the in-tank pipe 34 arranged at the bottom 11 is less likely to enter the sensing range of the non-contact level sensor 35 as it approaches the precipitated solid 4a, but from the precipitated solid 4a. The farther away, the less likely it is to be buried in the precipitated solid 4a. Therefore, the portion of the in-tank pipe 34 arranged at the bottom 11 does not interfere with the range sensed by the non-contact level sensor 35, and is at a position where it can be prevented from being buried in the precipitated solid material 4a without a gap. Placed in.

On the other hand, when the laser level sensor is used as the non-contact level sensor 35, the spot diameter of the laser level sensor is small, so that the restrictions on the arrangement of the in-tank pipe 34 and the non-contact level sensor 35 are relaxed. However, its application may be limited due to its high cost including management cost.

The range in which the level of the liquid to be treated 8 can be sensed by the non-contact level sensor 35 is limited to the range above the upper end of the bottom 11 of the settling tank 10. This is because in the settling tank 10 of this example, the bottom portion 11 is inclined so as to have an inclination angle of 40 degrees or more from the horizontal plane, so that the level of the liquid to be treated 8 is lower than the height position of the upper end portion of the bottom portion 11. This is because proper sensing cannot be performed. In particular, when the shape of the bottom portion 11 has a cone-shaped (conical) or mortar-shaped shape, if the bottom portion 11 is within the detection distance and detection angle of the non-contact type level sensor 35, the non-contact type level sensor 35 erroneously indicates. Is likely to do. Therefore, the non-contact type level sensor 35 is set to end the sensing at the same time when the level of the liquid to be treated 8 reaches the height of the upper end portion of the bottom portion 11, or the timer 36 described below is activated. It is desirable to shift to process control using the timer 36.

In this example, a timer 36 is installed in addition to the non-contact level sensor 35. In this example, instead of measuring the level of the liquid to be treated 8 at the bottom 11, a timer 36 is used to control the extraction time of the supernatant 12 existing at the bottom 11 and the bottom extraction time of the slurry 5a containing the solid 4a. ing.

That is, the timer 36 is located at a position where the level of the liquid to be treated 8 is slightly above the height of the region where the precipitated solid 4a is present in the bottom portion 11, in other words, the upstream end of the in-tank pipe 34. The time until the opening (lower end) reaches the existing height position is controlled by time, and the operation of the pump constituting the supernatant extraction means 37 is stopped before idling. In short, the timer 36 is the time when the level of the liquid to be treated 8 supplied by the liquid to be treated 16 reaches a predetermined position, specifically, the timer 36 is sensed by the non-contact level sensor 35 to obtain the liquid to be treated 8. Time measurement is started from the time when it is determined that the level has reached the upper end of the bottom 11, and when a predetermined time elapses, which is the time (immediately before) when the level of the liquid to be treated 8 reaches the lower end of the in-tank pipe 34. The operation of the supernatant extraction means 37 is stopped.

The timer 36 then opens the valve 32, which is an automatic valve, to supply air 18 to the first air pipe 28, the second air pipe 29, and the third air pipe 30. The transfer means 23 is operated by supplying the air 18 to the transfer means 23, which is an air drive pump, via the third air pipe 30, and the bottoming out of the slurry 5a containing the solid matter 4a is started. At the same time, from the first spout 26 provided at the downstream end of the first air pipe 28, the inside of the transfer pipe 24 is transferred toward the inside of the transfer pipe 24, more specifically, the inside of the transfer pipe 24. The solid at the bottom of the bottom 11 of the settling tank 10 is blown from the second spout 27 provided at the downstream end of the second air pipe 29 while blowing air 18 toward the solid 4a. More specifically, the air 18 is blown toward the bottom-pulling outlet 15 toward the solid matter 4a that has settled in and near the bottom of the bottom 11. In this way, in the flow path for returning the slurry 5a containing the solid matter 4a from the settling tank 10 to the cooling crystal tank 6 or the concentration tank 3, the flow velocity changes and the solid matter 4a is likely to be clogged. By stirring the solid material 4a on the upstream side of the suction port 21 of the solid material bottom punching outlet 15 and the transfer means 23, the solid material 4a is connected to the solid material bottom punching outlet 15 and the suction port 21 of the transfer means 23. Prevents clogging. When the pressure of the air 18 upstream of the valve 32 drops, the compressor 31 constituting the air supply means 20 is operated.

In this example, an air-powered air-driven pump is used as the transfer means 23, and the first air pipe 28, the second air pipe 29, and the second air pipe 29 are located downstream of the valve 32 of the air supply means 20. The air pipe 30 of No. 3 is branched. Therefore, by opening the valve 32, the transfer means 23 can be driven and the air 18 can be blown onto the solid object 4a at the same time. Further, when the compressor 31 is stopped, one valve 32 prevents the liquid to be processed 8 and the slurry 5a from entering the compressor 31 through the first air pipe 28, the second air pipe 29, and the third air pipe 30. Can be prevented with. However, as the transfer means 23, a pump that employs a motor drive type, a solenoid drive type, or other known drive method can also be used. It is also possible to equip each of the first air pipe 28, the second air pipe 29, and the third air pipe 30 with a valve. Further, it is also possible to make the first air pipe 28, the second air pipe 29, and the third air pipe 30 independent of each other, and to equip each of them with a compressor. In these cases, it is also possible to operate the air blowing means 19 intermittently and / or as needed, independently of the transfer means 23.

The timer 36 is the valve 32 after a predetermined time has elapsed from the start of bottoming out of the solid matter 4a, that is, before the solid matter 4a is sufficiently bottomed out but the transfer means 23, which is an air-driven pump, overheats due to idling. By closing, the supply of air 18 to the first air pipe 28, the second air pipe 29, and the third air pipe 30 is stopped. As a result, the transfer means 23 is stopped, air 18 is blown from the first ejection port 26 to the solid matter 4a settled on the bottom 11, and the inside of the transfer pipe 24 is blown from the second ejection port 27. The blowing of the air 18 onto the solid matter 4a being transferred is stopped.

The operating time of the timer 36 is required to extract the supernatant 12 and the precipitated solid 4a according to the performance of the fluid transfer device constituting the supernatant extraction means 37 and the transfer means 23 constituting the solid matter bottom extraction means 17. It is determined as appropriate by examining each time. When a metering pump is used as the fluid transfer device or the transfer means 23, the tank starts from the time when the level of the liquid to be treated 8 is at a predetermined position (the upper end of the bottom 11) as the capacity of the liquid to be treated 8. The capacity from the lower end of the inner pipe 34 to the lower end and the capacity from the lower end of the tank pipe 34 to the bottom of the bottom 11 can be calculated.

The non-contact level sensor 35 and the timer 36 have a switch for controlling the operation of the liquid to be processed supply means 16, the supernatant extracting means 37, and the solid matter bottoming means 17 by the non-contact level sensor 35 and the timer 36. The mechanism can be used. Alternatively, a computer, a control device, or the like is separately provided, and through these, the entire non-contact level sensor 35, timer 36, liquid to be processed supply means 16, supernatant extraction means 37, and solid matter bottom removal means 17 are provided. Operation can also be managed and controlled.

In this example, the fine solid matter 4a contained in the liquid to be treated 8 is recovered by using the settling tank 10 as follows.

First, the liquid to be treated 16 receives the liquid to be treated 8, and when the non-contact level sensor 35 detects that the level of the liquid to be treated 8 has reached the upper limit of the liquid to be treated, the liquid to be treated is supplied. The operation of the means 16 is stopped, and the acceptance of the liquid to be treated 8 is terminated. The non-contact type level sensor 35 is arranged so that at least the level of the liquid to be treated 8 in the tank body 13 can be detected, but at least when there is a dead zone in the sensing range by the non-contact type level sensor 35. , The lowest level of the dead zone existing at the uppermost portion of the tank body 13 and the upper end portion of the bottom portion 11 are arranged so as to be sensingable. In this case, the upper limit of the liquid to be treated is set at a position below the minimum level of the dead zone, preferably at a position slightly below the minimum level of the dead zone.

After that, a predetermined residence time of the liquid to be treated 8 is provided, the liquid to be treated 8 is settled and separated in the settling tank 10, and the solid matter 4a is settled.

After the elapse of a predetermined residence time, the supernatant extraction means 37 starts extracting the supernatant 12 produced by the sedimentation separation. The non-contact level sensor 35 continues to sense the level of the liquid to be treated 8 up to the lower limit of the height range with respect to the sensing, that is, the top of the bottom 11.

The timer 36 is started at the same time as the sensing by the non-contact level sensor 35 is stopped or when the level of the liquid to be processed 8 reaches a predetermined position. Even after the timer 36 is started, the extraction of the supernatant 12 is continued. After a predetermined time has elapsed from the start of the timer 36 to the time when the level of the liquid to be treated 8 reaches the lower end of the in-tank pipe 34 (immediately before), the operation of the supernatant extraction means 37 is stopped, and the extraction of the supernatant 12 is completed. To do.

Substantially at the same time as stopping the extraction of the supernatant, the air supply means 20, that is, the valve 32, which is an automatic valve, is opened to open the first air pipe 28, the second air pipe 29, and the third air pipe 30. Air 18 is supplied to. Air 18 is supplied to the transfer means 23, which is an air drive pump, via the third air pipe 30, and the slurry 5a containing the solid matter 4a settled in the bottom 11 of the settling tank 10 is used for removing the solid matter bottom. The bottom is punched through the outlet 15. At the same time, air 18 is blown from the first spout 26 provided at the downstream end of the first air pipe 28 toward the solid matter 4a being transferred inside the transfer pipe 24, and Air 18 is blown from the second spout 27 provided at the downstream end of the second air pipe 29 toward the solid matter 4a settled in the bottom 11 of the settling tank 10. As a result, the solid material 4a is agitated on the upstream side of the suction port 21 of the solid material bottom punching outlet 15 and the transfer means 23, and the solid material at the solid material bottom punching outlet 15 and the suction port 21 of the transfer means 23. The clogging of 4a is prevented.

The air supply means 20 supplies the air 18 to the first air pipe 28, the second air pipe 29, and the third air pipe 30 via the valve 32 for a predetermined time until the timer 36 stops the air. continue. As a result, the bottom of the solid matter 4a is removed from the bottom 11 of the settling tank 10, and the solid matter 4a settled in the bottom 11 of the settling tank 10 and the solid matter 4a transferred inside the transfer pipe 24 are agitated. Is continued.

In this way, the slurry 5a containing the solid matter 4a precipitated and concentrated in the settling tank 10 is repeated in the predetermined place in the previous step, that is, the cooling crystal tank 6 or the concentration tank 3 by the solid matter bottoming means 17. .. After the total amount of the solid matter 4a has been removed, the timer 36 is stopped and the operation of the air supply means 20 is stopped as described above to separate the liquid to be treated 8 from settling, and the supernatant 12 and the solid matter. Complete one cycle of extraction of 4a.

In this example, a position 1 cm to 60 cm above the solid material bottom punching outlet 15 and a position 50 cm upstream of the suction port 21 from a position adjacent to the upstream side of the suction port 21 of the transfer means 23 in the transfer pipe 24. Air 18 is blown toward the solid material 4a at two locations in the range up to, but when the present invention is carried out, either the first air pipe 28 or the second air pipe 29 It is also possible to install and blow air toward the solid material only at one of the locations. However, in order to surely prevent or eliminate the occurrence of clogging in the flow path for returning the slurry 5a containing the solid matter 4a from the settling tank 10 to the cooling crystal tank 6 or the concentration tank 3, the first air is used. Both the pipe 28 and the second air pipe 29 are installed, and the position is 1 cm to 60 cm above the outlet 15 for removing the bottom of the solid material, and the transfer pipe 24 is adjacent to the upstream side of the suction port 21 of the transfer means 23. It is preferable to blow the air 18 toward the solid object 4a at two positions, one at an arbitrary position in the range from the position where the air is squeezed to the position 50 cm upstream of the suction port 21.

In the method of recovering the solid matter 4a using the settling tank 10, in order to obtain the precipitation of the fine solid matter 4a such as crude nickel sulfate, a predetermined liquid 8 containing the fine solid matter 4a is used. It is important to settle for time. In order to settle the fine solid matter 4a from the liquid to be treated 8 sent to the settling tank 10 and sufficiently obtain the sedimentation of the solid matter 4a, the pouring of the liquid to be treated 8 into the settling tank 10 is stopped. It is preferable that the residence time in the settling tank 10 is 15 minutes or more, and in order to reliably settle 90% or more of the solid matter 4a, it is necessary to secure a residence time of 20 minutes or more in the settling tank 10. preferable.

The upper limit of the residence time is not limited as long as it is 15 minutes or more, preferably 20 minutes or more, but the longer the residence time, the lower the amount of the treatment liquid per hour. Therefore, a large settling tank 10 is required to hold the liquid to be treated 8 sent out from the filter 7. Considering these circumstances, it is desirable that the residence time is 50 minutes or less, preferably 40 minutes or less.

Further, in the method of recovering the solid matter 4a using the settling tank 10 of this example, the acceptance of the liquid to be treated 8 into the settling tank 10 and the settling and bottoming of the solid matter 4a are clearly distinguished. That is, it is important to settle and bottom out the solid material 4a after stopping the charging of the liquid to be treated 8 into the settling tank 10. In order to effectively carry out the method of recovering the solid matter 4a using the settling tank 10, the liquid to be treated 8 filtered by the filter 7 is intermittently transferred to the settling tank 10 via the receiver tank 9. Good to send. As a result, in the settling tank 10, the liquid to be treated 8 is received and the solid matter 4a is settled while the filter 7 continuously performs the filtration, that is, the amount of liquid flowing through the filter 7 is kept large. And bottoming out can be done by distinguishing time.

The settling tank 10 has a function of providing a waiting time for only settling and separating the liquid to be treated 8 after receiving the liquid to be treated 8 or before removing the bottom of the solid substance 4a and the supernatant 12. As long as such a function of the settling tank 10 can be ensured, it is sufficient to install one settling tank 10. However, in order to secure a sufficient residence time, it is effective to install two or more sedimentation tanks 10. For example, as shown in FIG. 1, two settling tanks 10 are provided, and as the first step, one of them accepts the liquid to be treated 8, and the other one setstles and bottoms the solid matter 4a. Extraction and extraction of the supernatant 12 are performed, and as a second step, one unit that has been receiving the liquid to be treated 8 is switched to precipitation and bottom extraction of the solid matter 4a and extraction of the supernatant 12, and these are performed. In the other one unit in which the solid matter 4a was precipitated and bottomed out, and the supernatant 12 was extracted, the liquid to be treated 8 was received instead of these, and the first step and the first step were performed. It is preferable to alternately perform the two steps. This makes it possible to provide a sufficient waiting time for only the sedimentation and separation of the liquid to be treated 8 after receiving the liquid to be treated 8 or before the bottoming out of the solid matter 4a and the extraction of the supernatant 12. A temporal distinction between sedimentation and bottoming of the object 4a is ensured. In order to distribute the liquid to two or more settling tanks 10, a three-way valve may be arranged upstream of the settling tank 10, but the present invention is not limited to this mode.

A sufficient residence time of the liquid to be treated 8 can be secured, and the acceptance of the liquid to be treated 8 and the sedimentation and bottom removal of the solid matter 4a and the extraction of the supernatant 12 are clearly distinguished, and the solid matter 4a It is possible to omit the receiver tank 9 as long as the sedimentation and bottoming out are performed in a time-sensitive manner. For example, if the total of the residence time of the liquid to be treated 8 and the time for bottoming out the solid substance 4a and the time for extracting the supernatant 12 is shorter than the receiving time of the liquid to be treated 8, the receiver tank 9 may be omitted. The liquid to be treated 8 can be continuously delivered from the filter 7 while switching between the two settling tanks 10.

In the step of bottoming out the solid matter 4a and extracting the supernatant 12 from the settling tank 10, the sediment of the solid matter 4a is bottomed out from the lower part of the settling tank 10 by the transfer means 23 of the solid matter bottoming means 17. , Repeating to the cooling crystal tank 6 or the concentration tank 3 (cooling crystal tank 6 in the example of FIG. 1), and discharging the supernatant 12 from the upper part of the settling tank 10. Since the supernatant 12 contains a large amount of sulfuric acid, it can be added to the electrolytic solution and used for adjusting the acid concentration.

When the liquid to be treated 8 from the filter 7 contains particles of a solid substance 4a having a large particle size, the particles may settle in the receiver tank 9 before reaching the settling tank 10. Therefore, it is preferable to send almost all the particles of the solid matter 4a to the settling tank 10 by appropriately adjusting the residence time of the liquid to be treated 8 in the receiver tank 9.

1 Raw material liquid (copper removal final liquid)
2 Concentrate 3 Concentrator 4, 4a Solid (crude nickel sulfate)
5, 5a Slurry 6 Cooled crystal tank 7 Filter 8 Treatment liquid 9 Receiver tank 10 Sedimentation tank 11 Bottom 12 Supernatant 13 Tank body 14 Treatment liquid receiving inlet 15 Solid material Bottom removal outlet 16 Treatment liquid supply means 17 Solid Bottom removal means 18 Air (compressed air)
19 Air blowing means 20 Air supply means 21 Suction port 22 Discharge port 23 Transfer means 24 Transfer pipe 25 Return pipe 26 First spout 27 Second spout 28 First air pipe 29 Second air pipe 30 Third Air piping 31 Compressor 32 Valve 33 Outlet for extracting supernatant 34 In-tank piping 35 Non-contact level sensor 36 Timer 37 Extracting supernatant means

Claims (7)

With the tank body
At the bottom
Inlet for receiving liquid to be treated and
An outlet for removing the bottom of solids provided on the bottom,
The liquid to be treated means for supplying the liquid to be treated and the liquid to be treated through the inlet for receiving the liquid to be treated.
A solid material bottom provided with a transfer pipe connected to the solid material bottoming outlet, and bottoming out a slurry containing a solid material obtained by sedimentation separation of the liquid to be treated via the solid material bottoming outlet. With the means of extraction
An air blowing means that blows air toward the solid bottom punching outlet inside and / or inside the bottom of the transfer pipe, and
An air supply means for supplying air to the air blowing means and
A settling tank. The solid bottom punching means includes a transfer means having a suction port for sucking the slurry and a discharge port for discharging the slurry, and the transfer pipe has a downstream end portion connected to the suction port. The settling tank described. The settling tank according to claim 2, wherein the transfer means is an air-driven pump, and the driving air is supplied to the pump by the air supply means. The air blowing means includes a first air blowing means for blowing air inside the transfer pipe, and an air outlet of the first air blowing means is adjacent to the upstream side of the suction port in the transfer pipe. The settling tank according to claim 2 or 3, which is arranged at an arbitrary position in the range from the position of the suction port to the position 50 cm upstream of the suction port. The air blowing means includes a second air blowing means that blows air toward the solid material bottom punching outlet inside the bottom portion, and the air outlet of the second air blowing means is of the bottom portion. The settling tank according to any one of claims 2 to 4, which is arranged at a position 1 cm to 60 cm above the outlet for bottoming out solids. Using the settling tank according to any one of claims 1 to 5,
The step of supplying the liquid to be treated by the liquid to be treated means and
A step of sedimenting the liquid to be treated in the sedimentation tank and sedimenting the solid matter on the bottom portion.
A bottoming step of bottoming out the solid matter settled on the bottom portion by the solid matter bottoming out means through the solid matter bottoming outlet, and
An air blowing step of blowing air onto the solid matter obtained by sedimentation separation of the liquid to be treated by the air blowing means.
A method for recovering a solid substance. The method for recovering a solid matter according to claim 6, wherein the bottom punching step and the air blowing step are performed at the same time.

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