JP6418143B2 - Repulping apparatus and repulping method - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a repulping apparatus and a repulping method for deironed iron. More specifically, matt chlorine leaching electrowinning (original name is Matte Chlorine Leaching Electrowinning, hereinafter abbreviated as MCLE). The present invention relates to a repulping apparatus and a repulping method when recovering nickel.

In the MCLE process, the raw material is leached with chlorine, iron and zinc are removed, and nickel and cobalt are concentrated.
The iron removal process that removes iron is a process that removes most of the iron contained in the raw material. The resulting iron removal product contains a large amount of soluble nickel, and this is repulped. The nickel is recovered from the iron-free material by dissolving the soluble nickel in the solution.

As shown in FIG. 5, the conventional repulping apparatus has a repulping tank 100 installed between a primary filter press 10 and a secondary filter press 20 and is configured as follows.
A chute 104 is provided at the lower part of the primary filter press 10, and a repulp tank 100 is located therebelow.
The porridge obtained from the primary filter press 10 (hereinafter sometimes referred to as the primary porcelain) falls downward by opening the filter press 10 and is collected by the chute 104 and put into the repulp tank 100. Is done. Further, since the repulp tank 100 receives the porcelain from the chute 104, a large opening 105 is formed on the upper surface.

  In the repulp tank 100, a repulp liquid (for example, a liquid capable of recovering nickel from the aforementioned porridge, such as industrial water and electrolytic waste liquid) is prepared in advance, and the temperature is raised to about 60 ° C. suitable for nickel dissolution, The pH is also adjusted to about 2 at which soluble nickel is easily dissolved. The pH adjustment is performed by adding a pH adjusting agent such as hydrochloric acid, and the pH adjusting agent is added to the repulp tank 100 from the input pipe 106 of the pH adjusting agent. The input pipe 106 is inserted into the repulp tank 100 from above, and the open end of the input pipe 106 is located on the surface of the slurry SL.

  The repulping tank 100 and the secondary filter press 20 are connected by a feed pipe 107, and a liquid feed pump 103 is interposed. The slurry level in the repulp tank 100 is controlled by turning on / off the liquid feed pump 103. The upper limit of the slurry level is lower than the upper edge of the repulping tank 100, and the lower limit is higher than the outlet 108 to which the feeding pipe 107 is connected, preventing the slurry from overflowing from the repulping tank 100 and In general, the liquid feed pump 103 is prevented from being damaged by the inflow of air into the feed pipe 107.

The steps of the repulping operation are as follows.
(Step 1)
The primary filter press 10 is opened to discharge the iron removal deposit and put into the repulp tank 100. The repulp tank 100 is stirred for about 1 hour with the pH maintained at around 2.
(Step 2)
Next, the slurry obtained after stirring is fed to the secondary filter press 20 by the liquid feed pump 103 to separate into solid and liquid. By doing so, nickel that has started to dissolve in the liquid by the repulping is recovered, and the residue obtained from the secondary filter press 20 (hereinafter, may be referred to as a secondary accessory) is discharged out of the system.

  According to the conventional repulping method, since the liquid temperature is appropriate from the beginning, the dissolution time is fast, and the pH is adjusted after the deironed iron is added, so that the pH can be adjusted quickly. Further, since the remaining amount of nickel in the secondary porcelain exhibits a sufficient recovery rate of 10 to 20 g / kg, it has been conventionally employed.

  However, when the first filter press 10 is opened in step 1 of the above process, steam rises from the liquid at a high temperature (about 60 ° C.) through the large opening 105 of the repulp tank 100 and drops of the primary object. A phenomenon occurs in which a part of the steel is blown up as nickel mist m and diffused into the building. In addition, the pH adjusting agent dropped from the charging pipe 106 may hit the surface of the slurry SL and be scattered as small droplets s and mixed with the nickel mist m in some cases.

  Nickel mist m as described above is a strong acid with a pH of about 2 and does not have a fatal effect on the steel frame as the main structural material constituting the building. In order to support a steel frame, a steel round bar is assembled in an X shape, and a member corresponding to a brace of a wooden building) is corroded and broken, resulting in a problem that replacement or repair is forced.

  In order to deal with the above-mentioned problems associated with the occurrence of mist, there is a simple method to install a suction duct and capture and remove the mist, but this method is much more expensive than the cost required for replacement and repair. However, it has not been applied since the cost increases, and the problem of nickel mist has been left unsolved.

  There exists patent document 1 as a prior art relevant to mist generation. In Patent Document 1, the paint mist collected in the circulating water in the water tank of the washing booth is dispersed and accumulated as a paint sludge in a place where the circulating water does not flow, causing dirt and bad odor. And even if it is sucked with a pump and processed with a solid-liquid separator, the paint sludge is dispersed in the circulating water or partially accumulated in the water tank, and the paint sludge cannot be sufficiently separated into solid and liquid. On the other hand, the bottom plate of the water tank is extended to form a swirl chamber / drainage basin, and circulating water containing paint mist from the swirl chamber is discharged from the drainage tank to the auxiliary water tank, and the paint mist is used as paint sludge in the auxiliary water tank. After separating by floating or sinking, the circulating water is returned to the main tank. At the same time, a technique is described in which paint sludge that has floated or settled is sucked into a pump and sent to a solid-liquid separator.

  However, this conventional technology is a technology that solves the problems associated with mist generation during operation, and is a technology that effectively captures the generated mist, but requires a special structure (swirl chamber / drainage), It is a technique for removing mist from circulating water in which mist is mixed, and it is a problem that mist accumulates in a specific place in the first place.

JP 2000-325842 A

  In view of the above circumstances, an object of the present invention is to provide a repulping apparatus and a repulping method for deironed iron that can reduce the influence of corrosion without reducing the nickel recovery rate.

  The inventors of the present invention have found that the problem of corrosion due to mist generation is considerably suppressed by additionally changing the repulping process, and have completed the present invention.

A repulping apparatus according to a first aspect of the present invention is a first filter press, a first repulp tank installed below a porcelain outlet of the first filter press, and feeding of primary treatment slurry from the first repulp tank. A second repulping tank that receives the second repulping tank, and a second filter press that receives the secondary processing slurry from the second repulping tank, the first repulping tank having an upper surface opening type, and having a stirring blade The second repulp tank is a closed type, and includes a stirrer having a stirring blade, a pH adjusting agent charging pipe, a temperature adjusting means, and a temperature measuring device. It is characterized by being.
A repulping apparatus according to a second invention is characterized in that, in the first invention, the starting liquid put in the first filter press is a slurry that has been subjected to a deironing step in the mat chlorine leaching electrowinning process.
The repulping apparatus according to a third aspect of the present invention is characterized in that, in the first or second aspect of the present invention , the outlet of the pH adjusting agent charging pipe of the first repulping tank is located below the slurry liquid level.
The repulping method according to the fourth aspect of the present invention includes a first step of obtaining a porcelain by solid-liquid separation with a first filter press, and a porcelain obtained by the first filter press, in which a repulping liquid at room temperature is placed and the top surface A second step of stirring in the first repulp tank opened and the first treatment slurry obtained in the first repulp tank supplied to a sealed second repulp tank containing a high-temperature repulp liquid It is characterized by comprising a third step of feeding and stirring, and a fourth step of solid-liquid separation of the secondary treatment slurry obtained in the second repulp tank with a secondary filter press.

According to the repulping apparatus of the first invention, when the porridge is put into the first repulp tank from the first filter press, the repulping liquid in the tank remains at room temperature, so no steam is generated and mist is generated from the opening on the upper surface of the tank. It will not scatter. Further, when the primary slurry treated in the first repulping tank is stirred in the second repulping tank, the repulping liquid is high in temperature, so that the mist itself does not scatter because the tank itself is hermetically sealed. Therefore, the corrosion damage of the building can be reduced. Moreover, since it can stir in the high temperature repulp liquid suitable for nickel elution after adjusting pH in a 2nd repulp tank, a nickel recovery rate is not reduced.
According to the second invention, since it is applied to the repulping operation in the iron removal step in the matte chlorine leaching electrowinning process which is a large-scale plant, the industrial value of the effect of reducing the influence on corrosion without reducing the nickel recovery rate Will be expensive.
According to the repulping apparatus of the third invention, since the outlet of the pH adjusting agent charging pipe is below the slurry liquid level, the charged pH adjusting agent does not fall and scatter on the liquid level. Even if it occurs, the pH adjusting agent mixed directly in the mist can be reduced.
According to the repulping method of the fourth invention, the first repulping tank used in the first repulping process is free from mist scattering due to the generation of steam because the repulping liquid is low temperature, and the second repulping tank used in the second repulping process. Since the repulping liquid uses a sealed tank even when the temperature of the repulping liquid is high, mist scattering to the outside does not occur. Therefore, the corrosion damage of the building can be reduced. Moreover, since it can stir in the high temperature repulp liquid suitable for nickel elution after adjusting pH in a 2nd repulp tank, a nickel recovery rate is not reduced.

It is explanatory drawing of the repulping apparatus which concerns on one Embodiment of this invention. It is action | operation explanatory drawing of the repulping apparatus of FIG. It is process drawing of a MCLE process. (A), (B) is explanatory drawing of the repulp tank which concerns on other embodiment of this invention. It is explanatory drawing of the conventional repulping apparatus.

Hereinafter, a repulping apparatus and a repulping method according to the present embodiment will be described with reference to the drawings.
(Repulp equipment)
As shown in FIG. 1, the repulping apparatus according to the present embodiment includes a first filter press 10, a first repulping tank 1 installed below the porcelain outlet of the first filter press 10, and the first repulping machine. The second repulping tank 2 receives the feed of the primary treatment slurry from the tank 1 and the second filter press 20 receives the feeding of the secondary treatment slurry from the second repulping tank 2.

The first repulp tank 1 is an upper surface opening type, and a large opening is formed on the upper surface of the tank body. The “upper surface opening type” referred to in the claims means a structure having a large opening on the upper surface of the tank in which mist easily scatters.
Further, a chute 4 is provided between the opening 5 and the first filter press 10, and when the first filter press 10 is opened, the solid-liquid separated residue is placed in the tank of the first repulp tank 1. It is designed to be dropped.

  Further, the first repulp tank 1 is provided with a stirrer equipped with a stirring blade 11 and a charging pipe 12 for feeding a pH adjuster. In addition, it is arbitrary whether a temperature control means and a temperature measuring device are provided. A feeding pipe 6 is connected between the first repulping tank 1 and the second repulping tank 2, and a feeding pump 3 is interposed.

  The second repulp tank 2 is a closed type, and the tank body has only a very small opening. The “sealed type” in the claims means a structure that is almost closed even if there are some openings, and that does not cause mist scattering. Although these openings in the present embodiment are connection ports of the feed pipe 6, they are small and can be closed with an appropriate sealing material, so the second repulp tank 2 may be said to be a substantially sealed type. . The second repulp tank 2 is provided with a temperature adjusting means and a temperature measuring device in addition to a stirrer equipped with a stirring blade 11 and a charging pipe 12 for feeding a pH adjuster. The second repulp tank 2 and the secondary filter press 20 are connected by a feed pipe 8 and a feed pump 9 is interposed.

  A well-known stirrer can be used for the first repulping tank 1 and the second repulping tank 2 without particular limitation. Further, a known temperature measuring device can be used without any particular limitation.

  Although there is no restriction | limiting in particular in the temperature control means which adjusts the temperature in the 2nd repulp tank 2, It becomes a temperature rise with a high slurry density | concentration, and troubles, such as scaling of a slurry and a blockade, may be generated when a complicated shape equipment is introduced. Therefore, a steam direct blowing type with a simple equipment configuration is preferable. Further, such a temperature adjusting means has an advantage that the fine adjustment of the slurry liquid temperature is easy.

  There is no restriction | limiting in particular in the method of adjusting the pH of the 1st repulp tank 1 and the 2nd repulp tank 2, The method of mixing a well-known pH adjuster with the liquid for repulps can be taken arbitrarily. Further, from the viewpoint of pH adjustment, it is preferable that the tank body has a tank capacity that hardly causes a time difference between the acid addition and the pH of the slurry and that can secure a necessary residence time.

The pH adjusting agent charging pipe 12 in the first repulping tank 1 is introduced into the tank from the outside, and its outlet is under the surface of the slurry SL. Since the liquid level of the slurry SL fluctuates up and down each time it is charged and discharged, even when the slurry SL drops to the lower limit, the outlet of the charging pipe 12 is placed below the lower liquid level of the slurry SL. An upper limit position is determined.
Because, depending on the stirring state of the slurry SL, if the position of the outlet of the input pipe 12 is too low, the mixing efficiency of the pH adjusting agent often deteriorates. Is preferred. Considering the stirring effect, it is because the pH adjusting agent is well stirred if it is put from above.
On the other hand, the lower limit position of the outlet of the pH adjusting agent input pipe 12 is near the level of the outlet 6d, but is most preferably higher. This is because if the outlet of the pipe 12 is close to the extraction port 6d, the pH adjusting agent is discharged to the outside from the extraction port 6d before mixing with the slurry SL.

  Also in the second repulp tank 2, as shown in FIG. 1, a stirring blade 11 of a stirrer and a charging pipe 12 for a pH adjusting agent are provided. The lower limit position of the outlet of the input pipe 12 is in the vicinity of the level of the outlet 8 d of the supply pipe 8, but the highest point is the same as in the case of the first repulping tank 1.

Another example of the pH adjusting agent input pipe 12 will be described with reference to FIG.
As shown in FIG. 2A, a bent charging pipe 12 may be inserted through the side walls of the repulp tanks 1 and 2 so that the outlet thereof is below the surface of the slurry SL. Further, as shown in FIG. 5B, the input pipe 12 may be provided upward through the bottoms of the repulp tanks 1 and 2 so that the outlet thereof is below the surface of the slurry SL. In any of the above cases, the outlet is positioned higher than the outlet.
In short, in the present invention, the outlet of the input pipe 12 is only provided between the lowest descending surface of the slurry SL and the outlet, and the intermediate path of the pipe is arbitrary.

(Repulp method)
Next, the repulping method of the present invention will be described in detail with reference to FIG.
(First step)
The starting liquid is solid-liquid separated by the primary filter press 10 to obtain a residue (hereinafter sometimes referred to as a primary residue).

(Second step)
The porcelain obtained by opening the first filter press 10 is dropped downward, collected by the chute 4, and put into the first repulp tank 1.
In the first repulping tank 1, a repulping liquid (for example, a liquid capable of recovering nickel from the above-mentioned porcelain such as industrial water and electrolytic waste liquid) is injected in advance, and the temperature is normal temperature, for example, 30 ° C to 40 ° C, preferably Is maintained at about 35 ° C. The pH is adjusted to 1 to 3, preferably about 2. In this state, the mixture is stirred for about 1 hour.

(3rd process)
Next, the primary treatment slurry obtained by stirring in the first repulping tank 1 is fed to the sealed second repulping tank 2. In the second repulping tank 2, the temperature of the repulping liquid is increased to 55 to 65 ° C, preferably about 60 ° C, and stirred for about 1 hour.
Since nickel elutes from the primary treatment slurry as the temperature rises, the pH also varies, but the pH is further adjusted to maintain the pH at 1-2, preferably about 2. In this second repulping tank 2, it is only necessary to hold the primary treatment slurry, but stirring in the second repulping tank 2 is preferable because pH adjustment is facilitated.

(4th process)
Next, the secondary treatment slurry obtained from the second repulp tank 2 is fed to the secondary filter press 20, separated into solid and liquid, and the nickel dissolved in the liquid by the repulp is recovered, from the secondary filter press 20. The resulting temple (hereinafter sometimes referred to as secondary temple) is discharged out of the system.

As shown in FIG. 2, according to the repulping apparatus and method of the present invention, when the porridge is put into the first repulping tank 1 from the first filter press 10, steam is not generated because the repulping liquid in the tank is at room temperature. No mist is scattered from the opening on the top of the tank. Further, when the primary slurry treated in the first repulp tank 1 is stirred in the second repulp tank 2, even though the repulping liquid is at a high temperature, the tank itself has a sealed structure, so that mist scattering does not occur. Further, since the outlet of the input pipe 12 is below the surface of the slurry SL, the splash of pH adjusting agent such as hydrochloric acid does not diverge.
Therefore, the corrosion damage of the building can be reduced. Moreover, since it can stir in the high temperature repulp liquid suitable for nickel elution, after adjusting pH in the 2nd repulp tank 2, nickel recovery rate is not reduced.

The effect by the repulping method of this invention is further demonstrated.
(1) Effect on leakage mist The amount of nickel in the atmosphere was measured before the repulping method of the present invention, and it was 0.038 mg / m ³ . Moreover, when a commercially available pH test paper was fixed to the tip of the rod and held above the first repulp tank 1 during the opening of the first filter press 10, simple pH measurement was performed. It was about 3.
On the other hand, when the amount of nickel in the atmosphere was measured after carrying out the repulping method of the present invention, it was 0.020 mg / m ³ . Moreover, when the same simple pH measurement as the above was performed, the pH was about 3 to 5. Furthermore, when the third invention (configuration in which the outlet of the input pipe 12 is equal to or lower than the liquid level of the slurry SL) is applied in addition to the apparatuses of the first and second inventions, the same simple pH measurement as described above is performed. Became 6 or more.

As mentioned above, since the nickel concentration in the atmosphere decreased from 0.038 mg / m ³ to 0.020 mg / m ³ , the chlorine concentration, which is the main cause of equipment corrosion, also decreases proportionally. It is thought to be halved. This consideration is supported by the fact that the pH value of the mist increases toward neutrality by simple pH measurement. From this result, if the repulping apparatus and the repulping method of the present invention are applied, it is possible to greatly reduce the amount of nickel mist leaking from the apparatus and extend the life of the building member.

(2) Equipment cost Since the second repulp tank 2 may be configured in a closed type so that even the rise of steam can be suppressed, a stirring blade 11 or a pH adjusting agent input pipe 12 is provided. Since expensive additional equipment is not required, equipment costs can be kept low.

(3) Effect on nickel recovery rate Since the nickel recovery rate has the effect of securing the residence time of the temple at the same time by adding the second repulp tank 2, a nickel recovery rate comparable to the conventional method is obtained. Can do.

The repulping apparatus and the repulping method of the present invention can be suitably applied to a deironing step in the MCLE process. The MCLE process will be described with reference to FIG.
In the MCLE process, two types of nickel sulfide and mixed nickel / cobalt sulfide (MS: mixed sulfide) are used as the raw material nickel sulfide. The nickel matte is obtained by smelting iron ore nickel ore. The nickel-cobalt mixed sulfide can be obtained by leaching low-grade laterite ore with sulfuric acid and recovering nickel and cobalt in the leachate as sulfides.

  First, after the nickel mat is pulverized in the pulverization step, it is mixed with an electrolytic waste liquid described later to form a mat slurry, which is supplied to the cementation step. In the cementation process, the leachate obtained in the chlorine leaching process is supplied, and the copper ions contained in this leachate (copper concentration 30-60 g / L) cause a substitution reaction with the nickel metal in the nickel mat, Precipitate as copper sulfide. Then, the precipitated copper sulfide is separated as a cementation residue together with other residues and supplied to the chlorine leaching process.

  Cobalt and iron are contained in the final liquid of the cementation process. These elements and trace impurities such as copper, lead and arsenic are removed as hydroxides. The liquid from which impurities have been removed is a pure nickel chloride solution, which is sent to the electrolysis process as an electrolytic feed solution. In the electrolysis process, nickel contained in the electrolytic solution is recovered as electric nickel by electrowinning. Chlorine gas generated in the electrolysis process is reused repeatedly in the chlorine leaching process and the liquid purification process. The electrolytic waste liquid discharged from the electrolysis process is sent to the pulverization process and the liquid purification process.

  The chlorine leaching process is supplied with a slurry comprising cementation residue and nickel / cobalt mixed sulfide. In the chlorine leaching step, substantially all of the metal contained in the solid matter in the slurry is leached into the liquid by the oxidizing power of the chlorine gas blown into the leaching tank. The slurry discharged from the chlorine leaching process is solid-liquid separated into a leaching solution and a leaching residue. The leachate from which the metal has been leached is repeatedly supplied to the cementation process. On the other hand, the sulfur contained in the mat is hardly leached, and most of it is separated as a leaching residue.

  When the present invention is applied to the MCLE process, the raw material charged into the first filter press 10 is a slurry that has gone through the iron removal step. If this is passed through the first step to the fourth step, the slurry Thus, nickel can be recovered, and the influence of corrosion can be reduced without reducing the nickel recovery rate. For this reason, the present invention has extremely great industrial value.

(Example)
Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.
The common conditions are as follows.
Initial liquid: Slurry discharged from the iron removal process in MCLE process cell (Nickel chloride solution contains ferric hydroxide as well as precipitates such as arsenic and manganese as impurity residues)
Example of starting liquid composition: solid content 5 to 10 g / L
: Fe amount in solid 0.5g / weight g
: Ni amount in liquid 160-200 g / L
: Co amount 5-10 g / L
: Liquid pH 1-2
First repulp tank 1: Shape, cylindrical
: Size 10m ³
Second repulp tank 2: Shape: Cylindrical type
: Size 15m ³
Nickel recovery rate: 65 to 90% ([Primary article Ni quality-Secondary article Ni grade] ÷ [Primary article Ni grade])
Nickel content in residue: (Measurement method: X-ray fluorescence analyzer)
Simple pH measurement: A commercially available pH test paper was attached to the tip of a stick and held at 20-30 cm above the center of the first filter press 10.
The holding period is from the start of frame opening to the end of the first filter press 10.

When the present invention was applied and the repulping apparatus shown in FIG. 1 was used and the temperature was raised in the second repulping tank 2 and the repulping operation was performed, the nickel concentration in the atmosphere was 0.020 mg / m ³ . Nickel recovery was 73-89%.
As a result of simple pH measurement, the pH was about 4.

Furthermore, the third invention of the present invention (configuration in which the outlet of the input pipe 12 is below the liquid level of the slurry SL) is applied, and the pH adjuster added to the first repulp tank 1 is supplied from below the slurry liquid level to repulp When operated, the nickel concentration in the atmosphere was 0.015 mg / m ³ . Nickel recovery was 73-89%.
As a result of simple pH measurement, the pH was about 7.

[Comparative Example 1]
When the conventional apparatus shown in FIG. 5 was used without applying the present invention and the temperature was raised in the repulp tank 100 and operated, the nickel concentration in the atmosphere was 0.038 mg / m ³ . Nickel recovery was 65-90%.
As a result of simple pH measurement, the pH was about 2.

DESCRIPTION OF SYMBOLS 1 1st repulp tank 2 2nd repulp tank 3 Liquid feed pump 4 Chute 6d Extraction port 8d Extraction port 10 1st filter press 11 Stirring blade 12 Input pipe 20 2nd filter press SL Slurry

Claims (4)

A first filter press, a first repulp tank installed below the porcelain outlet of the first filter press, a second repulp tank receiving feed of the primary treatment slurry from the first repulp tank, A second filter press that receives the secondary treatment slurry from the second repulp tank,
The first repulp tank is an upper surface opening type, and includes a stirrer equipped with a stirring blade and a pH adjusting agent charging pipe,
The second repulp tank is a closed type, comprising a stirrer equipped with a stirring blade, a pH adjusting agent charging pipe, a temperature adjusting means, and a temperature measuring device. The repulping apparatus according to claim 1, wherein the starting liquid put into the first filter press is a slurry that has been subjected to a deironing step in the mat chlorine leaching electrowinning process. 3. The repulping apparatus according to claim 1 , wherein an outlet of the pH adjusting agent feeding pipe of the first repulping tank is located below the surface of the slurry liquid. 4. A first step of obtaining a porcelain by solid-liquid separation with a first filter press;
A second step in which the porcelain obtained by the first filter press is put into a first repulp tank in which room temperature repulping liquid is placed and the upper surface is open, and stirred;
A third step of feeding and stirring the primary treatment slurry obtained in the first repulp tank to a closed second repulp tank containing a high-temperature repulp liquid;
A repulping method comprising: a fourth step of solid-liquid separating the secondary treatment slurry obtained in the second repulp tank with a secondary filter press.

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