JP7298754B1 - Method and equipment for recovering manganese contained in waste dry batteries - Google Patents

Abstract

A high-purity manganese-containing solution is recovered from a waste dry battery with a high yield. A method for recovering manganese contained in waste dry batteries includes a sorting step of sorting out one or both of manganese dry batteries and alkaline manganese dry batteries from waste dry batteries, and crushing and sieving to obtain powdery particles. a separation step, a heat treatment step in which heat treatment is performed in a non-oxidizing atmosphere, an acid leaching step for obtaining a leachate containing manganese ions, zinc ions and iron ions, and a solidification step for separating the leachate from other leach residues. A liquid separation step and a manganese extraction step for obtaining a solution containing manganese ions are performed in this order, and the manganese extraction step includes a zinc removal step including a sulfide precipitation treatment step and a zinc separation step, an oxidation treatment step and an iron and an iron removal step including a separation step in random order, and the sulfiding agent is allowed to act only while the pH change after addition of the sulfiding agent in the zinc separation step is +1 or less. [Selection drawing] Fig. 2

Description

TECHNICAL FIELD The present invention relates to a method and equipment for recovering valuable metals from waste dry batteries. In the present invention, after treating discarded manganese dry batteries and/or alkaline manganese dry batteries with an acid and an oxidizing agent, manganese, which is a main valuable component of waste dry batteries, is separated as a valuable metal, and can be used for various batteries. The present invention relates to a method and equipment for recovering manganese contained in waste dry batteries, which can be recovered as high-purity manganese.

In recent years, due to the depletion of metal resources and rising transaction prices, etc., it has become necessary to actively recover valuable metals from low-grade raw ores, concentrates, by-products from ironworks, industrial wastes, and the like. For example, manganese, which is one of the valuable metals, is regarded as an essential metal in a wide variety of industrial fields, and there is concern that the demand for manganese will exceed the reserves in the future. Steelworks consume a large amount of manganese as a raw material for steelmaking, and securing manganese sources is an extremely important issue in the ironmaking field. Moreover, in recent years, the consumption of manganese for secondary batteries such as lithium ion batteries has increased, and securing a source of manganese has become a very serious problem in this secondary battery field as well.

On the other hand, in Japan, a huge amount of dry batteries are produced, consumed, disposed of and discarded as industrial waste. Some dry batteries discarded as industrial waste (waste dry batteries) have a high manganese content. For example, manganese dry batteries and alkaline manganese dry batteries, which are typical primary batteries, use manganese dioxide as a positive electrode material.

Therefore, if a manganese component can be recovered with high purity from these waste dry batteries, it is promising in terms of securing a stable source of manganese.

However, waste dry batteries contain metal components such as zinc and iron in addition to manganese. Zinc is mainly contained in the negative electrode material and the electrolyte. Iron is mainly contained in the dry battery outer casing. Therefore, when recovering manganese from waste dry batteries, it is important to separate metal components such as zinc and iron from manganese as much as possible.

The inventors studied a technique for separating zinc and iron from waste dry batteries and recovering manganese with high purity, and proposed Patent Document 1 "Method and equipment for recovering manganese from waste dry batteries". As shown in FIG. 1, the proposal in Patent Document 1 is to mix an acid solution and a reducing agent after heat-treating granules obtained by crushing and sieving waste dry batteries in a non-oxidizing atmosphere. In this method, high-purity manganese is obtained by acid leaching, followed by precipitation and removal of zinc and iron.

However, in order to remove zinc in the method disclosed in Patent Document 1, it is necessary to add a sulfiding agent in excess of the amount of zinc ions in the liquid. Therefore, it became clear that the amount of zinc in the solution had to be measured in advance, and the operation was complicated. In addition, surplus sulfurizing agent (sulfurizing agent that has not reacted with zinc) may react with protons (H ⁺ ) in water to generate undesirable hydrogen sulfide gas.

By the way, as a method of suppressing the generation of hydrogen sulfide gas by allowing a sulfiding agent to react with heavy metal ions in a solution in just the right amount, for example, Patent Document 2 discloses a method in which a hydrogen sulfide gas monitor is installed in a heavy metal wastewater treatment apparatus, and sulfide is removed from the wastewater. There is a description that a sulfiding agent is added so as to maintain a state in which hydrogen gas begins to be generated.

WO2021/075136 WO2003/020647

The method of Patent Literature 1 requires a detoxification facility (such as a scrubber) for hydrogen sulfide gas, which poses a problem of increased capital investment.

In the method of Patent Document 2, a time lag occurs between the generation of hydrogen sulfide gas and the detection by the gas monitor. Therefore, the problem is that it is difficult to precisely control the amount of the sulfiding agent to be added. In addition, depending on the shape of the reaction vessel or exhaust system piping, there is a possibility that a "gas pool" with a high concentration of hydrogen sulfide may be locally formed. If the amount of the sulfiding agent to be added is determined based on the concentration of hydrogen sulfide, there is a risk of underestimating the amount to be added if gas pools are formed, and there is a risk that the metal cannot be sufficiently removed.

The present invention has been made in view of the above problems, and the manganese contained in waste dry batteries can be recovered with a high yield as a highly pure manganese-containing solution containing extremely little zinc and iron, and a sulfiding agent can be used. It is an object of the present invention to provide a method and equipment for recovering manganese from waste dry batteries, in which manganese is reacted with zinc ions in a solution just enough to suppress the generation of hydrogen sulfide gas.

Here, the "high-purity manganese-containing solution" means that zinc (Zn) and iron (Fe) as impurities in the solution are analyzed using the analysis method specified in the commonly used JIS standards. shall refer to a manganese-containing solution that is less than, for example, less than 0.1 mg/L.

Manganese dry batteries and/or alkaline manganese dry batteries are sorted out from the waste dry batteries, crushed and sieved, and the materials constituting the dry battery are separated into solid matter on the sieve and powder particles under the sieve. Among the materials that make up the dry battery, mainly steel packaging materials, zinc cans, brass rods, paper materials, plastics, etc. are crushed into foil-like or flake-like solids and separated on a sieve. On the other hand, manganese dioxide, carbon, zinc chloride, ammonium chloride, potassium hydroxide, or MnO(OH), Zn(OH) ₂ , Mn(OH) ₂ , ZnO, etc. generated by discharge become powders and sieves. separated into Here, usually, a very small amount of iron is unavoidably mixed in the granules.

In order to achieve the above-described object, the present inventors diligently studied means for separating impurities that are effective for recovering manganese contained in waste dry batteries as a highly pure manganese-containing solution with few impurities. In particular, the present inventors sorted out one or both of manganese dry batteries and alkaline manganese dry batteries from waste dry batteries, and further crushed and sieved them to obtain unintended components (impurities) from the granules obtained. and to add the sulfiding agent just enough to remove zinc, which is contained in the second largest amount after manganese.

As a result, the present inventors obtained a leachate in which iron and remaining manganese and zinc were leached by reacting an acid and a reducing agent on the powder, and then added sulfides such as sodium hydrosulfide NaHS to the leachate. By adding the agent only while the pH change of the leachate is +1 or less, the zinc ions remaining in the leachate are selectively precipitated as sulfides (zinc-containing sulfides), and the sulfiding agent can be added just enough. I thought that I could do it (sulfide precipitation treatment process). The present inventors have also found that the zinc component can be further removed from the leachate by subjecting the resulting zinc-containing precipitate to a zinc separation step. The inventors have found that the zinc ion concentration in the solution left after the zinc removal step can be easily reduced to below the analytical limit of 0.1 mg/L.

The following reactions occur in the sulfide precipitation treatment process. A case where the sulfiding agent is NaHS will be described as an example.

Case 1: Zinc ion molar equivalent ≥ sulfurizing agent molar equivalent (insufficient to equivalent amount of sulfurizing agent)
NaHS→Na ^{+ +} HS (1)
HS ⁻ →H ⁺ + S ^2- (2)
Zn ²⁺ + S ²⁻ → ZnS↓ (3)
In formula (2), since protons (H ⁺ ) are generated, the pH of the leachate is lowered by adding the sulfiding agent.

Case 2: Zinc ion molar equivalent < sulfurizing agent molar equivalent (excess sulfurizing agent)
NaHS→Na ⁺ + HS ⁽ 4)
HS ⁻ +H ₂ O→H ₂ S↑+OH ⁻ (5)
In the formula (5), since hydroxide ions (OH ⁻ ) are generated, the pH of the leachate is increased by adding the sulfiding agent, and hydrogen sulfide is generated.

Furthermore, the inventors carefully observed how the pH changed, and found that there was a difference between the pH increase rate when an alkaline chemical was added to match the control pH and the pH increase rate in the reaction of formula (5). I found out. FIG. 5 shows the difference in pH increase rate. Since the alkaline chemicals added to adjust the pH to the control are often strongly basic, they are added in a state in which ionization and OH ⁻ are almost completely generated. As a result, the addition of an alkaline agent to match the control pH instantly raises the pH.

On the other hand, the increase in pH when the sulfurizing agent is excessively added needs to go through the two-step reaction of formulas (4) and (5). As a result, the rate of increase in pH becomes slower than that of an alkaline chemical added to match the controlled pH.

Since the rate of increase in pH when adding an alkaline agent to adjust to the control pH is different from the rate of increase in pH in the reaction of formula (5), the inventors added a sulfiding agent while observing the pH change, thereby increasing the rate of sulfidation. It was conceived that the addition amount of the agent can be controlled.

As procedure A2, which is a more specific embodiment, the present inventors made the leaching solution react with a sulfiding agent such as sodium hydrosulfide NaHS only while the pH change of the leaching solution was +1 or less. A sulfide precipitation treatment step for selectively precipitating residual zinc ions as sulfides (zinc-containing sulfides) and a zinc separation step for separating the resulting zinc-containing precipitates are performed to remove zinc components from the leachate. further removed (the zinc removal step in Procedure A2), and that the zinc ion concentration in the solution left after the zinc removal step can be easily reduced to below the analytical limit of 0.1 mg/L, after which this solution is subjected to further oxidation treatment. It was confirmed that a high-purity manganese solution can be easily obtained at a high yield as the solution remaining after the separation of the iron component by further separating the iron ions as an iron-containing precipitate (iron separation step). (iron removal step in procedure A2).

Further, as a procedure B which is another specific embodiment, the present inventors selectively precipitate iron ions contained in the leachate, for example, as hydroxides, by oxidizing the leachate, for example, with air. The concentration of iron ions in the solution remaining after the separation of the iron component can be significantly reduced (iron removal step in procedure B) while preferentially separating only the iron component from the leachate. If a sulfide precipitation treatment is performed in which a sulfiding agent such as sodium hydrosulfide NaHS is applied only while the pH change of the leachate is +1 or less, and the zinc ions remaining here are further separated as zinc-containing precipitates, they will remain after separation. It was also confirmed that a high-purity manganese solution can be obtained simply and with a high yield as a solution (zinc removal step in Procedure B).

The results of Experiment (A1), Experiment (A2), and Experiment (B) performed by the present inventors according to the above procedures will be described.

(Experiment (A1))
Manganese dry batteries and alkaline manganese dry batteries were sorted out from the waste dry batteries (sorting step), and further subjected to crushing and sieving steps to obtain granules.

Graphite as a reducing agent was further blended into the obtained granules so that the blending ratio of graphite (:graphite/granules) was in the range of 0 to 1 in terms of mass ratio. Next, the granules mixed with graphite at various ratios were subjected to a heat treatment step in a heating furnace in a non-oxidizing nitrogen gas atmosphere at a heating temperature of 1000° C. for a heating time of 30 minutes. The weight and zinc content of the granules before and after heat treatment are measured, and the zinc removal rate by heat treatment is determined according to the following formula from the difference in zinc content in the granules before and after heat treatment. Calculated.
Zinc removal rate [%] = (Zn content [kg] in granular material before heat treatment - Zn content [kg] in granular material after heat treatment) x 100 / granular material before heat treatment Zn content [kg]

FIG. 6 is a graph showing the relationship between the compounding ratio of the reducing agent (graphite) and the zinc removal rate in the heat treatment process.

From FIG. 6, it can be seen that even when the blending ratio of graphite is 0 (that is, when graphite as a reducing agent is not blended in the heat treatment step), the zinc removal rate is 84%. This is presumed to be due to the following mechanism. That is, in the reaction between the graphite contained in the powder particles derived from the dry battery and ZnO, ZnO is first reduced to Zn (zinc). The boiling point of zinc is around 900°C. Therefore, when the heating temperature is 1000° C., the generated zinc is volatilized and removed from the granules as zinc vapor.

Furthermore, it can be seen from FIG. 6 that the zinc removal rate increases as the blending ratio of graphite is increased, and a maximum zinc removal rate of 96% is obtained. However, as can be seen from FIG. 6, even if the graphite blending ratio exceeds 0.5, a significant improvement in the zinc removal rate cannot be expected.

Here, the heat treatment of the granules is performed in a non-oxidizing atmosphere such as an inert atmosphere or a reducing atmosphere. In an oxidizing atmosphere such as an air atmosphere, part of the graphite contained in the powder or added to the powder reacts not with ZnO but with oxygen in the air and burns. Therefore, the reduction of ZnO to zinc is inhibited. In addition, most of the zinc contained in the granules is volatilized and removed by the heat treatment, but as can be seen from FIG. do.

Next, an acid solution and a reducing agent are allowed to act on the heat-treated granules, and the manganese component, the iron component, and the remaining zinc component contained in the granules are leached into the leaching solution. Acid leaching processed (acid leaching step). In addition, the effect of the amount of reducing agent added on the leaching rate of the manganese component in this acid leaching process was investigated.

Manganese dry batteries and alkaline manganese dry batteries are sorted from waste dry batteries, and the powder obtained by further crushing and sieving is processed in a nitrogen atmosphere (inert atmosphere) without adding a reducing agent such as graphite. Heating temperature: Heat treatment was performed at 1000° C. for 30 minutes. An acid leaching step of mixing an acid solution and a reducing agent was performed on the obtained heat-treated granular material. The acid leaching treatment conditions were as follows. This acid leaching step resulted in a mixture of leaching solution containing at least manganese ions, residual zinc ions and iron ions, and other leaching residues.
Acid solution: 50 mL of sulfuric acid
Sulfuric acid concentration: 1.5 mol / L (mass% concentration about 13.2%)
_Reducing agent: 35% hydrogen peroxide solution _H2O2
Amount of reducing agent added: 0 g (0 g/L), 0.56 g (11 g/L), 1.1 g (22 g/L), 1.7 g (33 g/L), 2.2 g (45 g/L)
Acid leaching treatment time: 1 hour (stirring treatment)
Solid-liquid ratio between powder and acid solution: 100 g/L

After the acid leaching treatment, the resulting mixture was filtered through a filter paper with a pore size of 1 μm, and the leaching solution and the leaching residue were solid-liquid separated (solid-liquid separation step). Manganese concentration in the separated leachate was quantified by ICP emission spectroscopy. Next, based on the measured values obtained, the mass of manganese in the leachate is obtained, and the ratio of the mass of manganese in the leachate to the mass of manganese contained in the powder after heat treatment (in terms of manganese element) is Manganese leaching rate was calculated. FIG. 7 shows the results obtained.

From FIG. 7, the manganese leaching rate was approximately 100% regardless of the amount of the reducing agent (hydrogen peroxide solution) added, and the manganese component contained in the powder after heat treatment was removed by the acid leaching process. It can be seen that the entire amount is leached into the As is clear from FIG. 8, the form of manganese contained in the powder after the heat treatment step is mainly MnO. MnO dissolves only with acid. Therefore, the present inventors have found that by subjecting the granular material to a heat treatment process, almost all of the manganese component contained in the granular material can be leached out without adding a reducing agent in the acid leaching process.

Here, depending on the heating conditions such as the amount of graphite contained in or added to the powder before heat treatment, the heating temperature and the heating time, MnO ₂ , Mn ₂ O ₃ , Mn ₃ O ₄ even after heat treatment In some cases, the Mn form remains, and the manganese is not completely leached out with acid alone. In such a case, if a reducing agent (hydrogen peroxide solution) is added, manganese existing as MnO ₂ , Mn ₂ O ₃ and Mn ₃ O ₄ can also be leached out as Mn ²⁺ .

Most of the zinc contained in the granules is volatilized and removed by the heat treatment, but as described above, some zinc remains in the heat-treated granules. Therefore, the powder after heat treatment is subjected to an acid leaching treatment in which an acid and, if necessary, a reducing agent are further applied to leaching out the remaining zinc component, and the obtained leaching solution is further added with sulfide precipitation. The treatment can selectively and sufficiently precipitate the remaining zinc component as described in detail below. As a result, the inventors have come to realize that the zinc component can be removed reliably, easily, and inexpensively.

The heat-treated granules, which had been subjected to the heat treatment step without graphite, were subjected to acid leaching treatment in which only an acid solution was applied (acid leaching step). A solid-liquid separation step of filtration was performed to obtain a leachate. Here, the acid concentration of the acid solution was set to sulfuric acid concentration: 1.5 mol/L (mass % concentration: about 13.2%), and the stirring treatment was performed with the acid leaching treatment time of 1 hour. A leachate containing at least manganese ions, zinc ions and iron ions was obtained by this acid leaching step and solid-liquid separation step.

Quantitative analysis of the manganese, zinc and iron concentrations in the resulting leachate by ICP emission spectrometry revealed a manganese concentration of 66198 mg/L, a zinc concentration of 5031 mg/L and an iron concentration of 1131 mg/L.

Then, the resulting leachate was subjected to a sulfide precipitation treatment step in which sodium hydrosulfide NaHS was added as a sulfiding agent under various conditions. Here, sodium hydrosulfide (NaHS) was dissolved in distilled water and added in the form of a solution.

The conditions for the sulfide precipitation treatment were as follows.
Exudate: 100 mL
Type of sulfiding agent: sodium hydrosulfide (NaHS)
Addition amount of sulfurizing agent: 1 to 3 equivalents as sulfur to dissolved zinc pH of leachate during reaction: 0.5 to 5
pH adjuster: 3M sulfuric acid or 100 g/L sodium hydroxide Treatment time: Stirring for 0.5 hours after adding sodium hydrosulfide

After the sulfide precipitation treatment, solid-liquid separation is performed by suction filtration with a filter paper having a pore size of 1 μm (zinc separation step), and the components (zinc, iron, manganese) of the separated second solution are quantified by ICP emission spectrometry. analyzed. Here, the analytical values obtained were corrected for the diluted effects of sodium hydrosulfide solution and the addition of pH adjusters. Figures 9A-9C show the results obtained.

From FIG. 9A, when the added amount of the sulfiding agent is 1 equivalent (NaHS: 1 equivalent), precipitation of zinc is removed, but it exceeds the analytical limit (0.1 mg/L) and is incomplete. Moreover, it can be seen that the final Zn removal rate is not stable when the pH of the leachate is increased.

On the other hand, as shown in FIG. 9B, when the added amount of the sulfiding agent is 2 equivalents (NaHS: 2 equivalents), precipitation and removal of zinc become remarkable. In particular, under the condition that the pH of the leachate is 3 or higher, the zinc concentration in the second solution after the zinc removal step (sulfide precipitation treatment step and zinc separation step) becomes less than the analytical limit (0.1 mg/L). found to have been removed. In addition, even when the amount of the sulfurizing agent added is 3 equivalents (NaHS: 3 equivalents) shown in FIG. It is below the analytical limit (0.1 mg/L), and precipitation removal of zinc is remarkable.

Here, from FIGS. 9A to 9C, it can be seen that iron precipitation is also removed by the zinc removal step. As shown in FIG. 9B, when the added amount of the sulfiding agent is 2 equivalents (NaHS: 2 equivalents), iron is precipitated and removed under the condition that the pH of the leachate is 3 or more, and when the pH is about 5, Fe It can be seen that the concentration is reduced to about 1 mg/L. Under the conditions shown in FIG. 9B, although not shown, the manganese concentration also began to decrease to approximately 24000 mg/L. In other words, it can be seen that manganese is partially precipitated and removed together with zinc and iron under the condition that the added amount of the sulfiding agent is 2 equivalents and the pH is 3 or more.

Moreover, even when the addition amount of the sulfiding agent shown in FIG. 9C is 3 equivalents (NaHS: 3 equivalents), iron is precipitated and removed with the same tendency as in the case of 2 equivalents. As shown in FIG. 9C, when the pH of the leachate is 5, the removal of iron precipitates is particularly remarkable, and it can be seen that iron is removed to less than 0.1 mg/L. However, although not shown, when the pH was 5 in FIG. 9C, the manganese concentration decreased significantly, and 30% or more of manganese was precipitated and removed. In other words, when the added amount of the sulfiding agent is 3 equivalents and the pH exceeds 3, in addition to the removal of zinc, iron and manganese are also precipitated in larger amounts than when the added amount of the sulfiding agent is 2 equivalents. .

As described above for experiment (A1), the sulfide precipitation treatment step for the leachate containing manganese ions, iron ions and zinc ions can precipitate, separate and remove the zinc component to below the analytical limit. However, a rotten egg odor was observed during this experiment, suggesting the generation of hydrogen sulfide gas. When the hydrogen sulfide gas concentration was measured, it was 1.5 ppm at maximum. This concentration exceeds the control concentration (1 ppm) of hydrogen sulfide, and improvement is required. Therefore, in experiment (A2), the relationship between the added amount of the sulfiding agent and the concentration of hydrogen sulfide was investigated, and a method of controlling the added amount of the sulfiding agent while minimizing the amount of hydrogen sulfide gas generated was studied.

(Experiment (A2))
The manganese concentration, zinc concentration, and iron concentration in the leachate separated by the solid-liquid separation process were measured by ICP emission spectrometry according to the same method as in experiment (A1), and the manganese concentration was 66198 mg / L and the zinc concentration was 5031 mg. /L, and the iron concentration was 1131 mg/L.

Then, sodium hydroxide was added to the resulting leachate to adjust the pH to 4, and then a sulfiding agent was added in an amount of 0.1 equivalent to zinc, and the pH and hydrogen sulfide concentration were measured. The control pH was set to 4, and when the pH was lower than the control pH, 100 g / L sodium hydroxide aqueous solution was added, and when the pH was higher than the control pH, 3M sulfuric acid was added. After confirmation, the sulfiding agent was added.

FIG. 10 shows the correlation between the amount of sulfiding agent added, pH, and hydrogen sulfide concentration. When the amount of the sulfurizing agent added was 1 equivalent or less, the pH decreased after the sulfurizing agent was added, and the hydrogen sulfide gas concentration was zero. On the other hand, when the added amount of the sulfurizing agent exceeded 1 equivalent, the pH increased after the addition of the sulfurizing agent, and the hydrogen sulfide gas concentration increased as the amount added increased. That is, it was considered possible to grasp the end point of the sulfide precipitation reaction by observing the pH change after the addition of the sulfiding agent.

As a result of measuring the zinc concentration in the second solution when the sulfurizing agent was added in an amount of 1.1 equivalents, it was found that zinc was reduced to below the analysis limit (0.1 mg/L). At this time, the hydrogen sulfide gas concentration was less than 0.05 ppm, which was found to be below the control concentration (1 ppm) of hydrogen sulfide. Therefore, it was found that the amount of hydrogen sulfide gas generated can be suppressed and zinc can be removed under safer treatment conditions than in experiment (A1).

As described above for Experiment (A2), the sulfide precipitation treatment step for the leachate containing manganese ions, iron ions and zinc ions can precipitate, separate and remove zinc components to below the analytical limit. . Also, iron (Fe) may partially precipitate together with zinc (Zn). If the iron (Fe) concentration has been precipitated and removed to some extent, the treatment may be terminated at this stage. However, in order to remove iron to a higher degree, the iron removal step (oxidation treatment step and iron separation step) of precipitating the iron ions contained in the second solution separated after the zinc removal step as iron-containing precipitates such as hydroxides. process) was further applied.

(Experiment (B))
According to the same method as experiment (A2), the manganese concentration, zinc concentration, and iron concentration in the leachate obtained by acid treatment after heat treatment were measured by ICP emission spectrometry. was 5031 mg/L and the iron concentration was 1131 mg/L.

Then, the resulting leachate was subjected to air aeration as oxidation treatment (oxidation treatment step). The air aeration conditions were as follows.
Blowing amount: (same volume as leachate amount)/minute Aeration time: 30 minutes pH of leachate during reaction: 4-6
pH adjuster: 3M sulfuric acid or 100g/L sodium hydroxide

Here, the blowing amount and aeration time are within the range of normal practical conditions (blowing amount: 0.1 to 1 times the amount of solution/minute, aeration time: 15 to 60 minutes). .

Then, the total amount of the leachate after air aeration is suction filtered with a filter paper having a pore size of 1 μm to separate solid and liquid (iron separation step), and the component concentrations (zinc, iron, manganese) of the separated third solution are determined by ICP emission spectrometry. Measured in Here, the measured values obtained were corrected for the influence of dilution with the pH adjuster. FIG. 11 shows the results obtained. Since precipitation of manganese and zinc due to the oxidation treatment process was hardly confirmed, FIG. 11 shows only the iron concentration in the solution after the iron removal process (oxidation treatment process and iron separation process).

From FIG. 11, it can be seen that Fe (iron) is selectively precipitated and removed when the pH of the leachate is 4 to 6. Here, although not shown, manganese and zinc hardly precipitated in this pH range, and although zinc was slightly precipitated and removed at pH: 6, the amount was as small as about 10 to 20 mg / L. . When the leachate had a pH of 5 or 6, the removal of iron precipitates remarkably progressed, and the iron concentration was reduced to less than 0.5 mg/L. In this way, the iron concentration could be greatly reduced simply by subjecting the leachate to air aeration, which is an inexpensive oxidation treatment.

In FIG. 11, the leachate adjusted to pH: 5 is subjected to air aeration (oxidation treatment) to reduce the iron concentration to less than 0.1 mg / L, and the solution obtained by performing the iron separation process by solid-liquid separation In addition, a sulfide precipitation treatment process was further performed under various conditions.

The conditions for the sulfide precipitation treatment were as follows.
Third solution: 100 mL
Type of sulfiding agent: sodium hydrosulfide (NaHS)
Amount of sulfurizing agent added: 1.1 equivalents as sulfur to dissolved zinc (same as experiment (A2))
pH of third solution during reaction: 4
pH adjuster: 3M sulfuric acid or 100 g/L sodium hydroxide Treatment time: Stirring for 0.5 hours after adding sodium hydrosulfide

After the above-described sulfide precipitation treatment step, suction filtration was performed with a filter paper having a pore size of 1 μm to perform solid-liquid separation (zinc separation step), and the components of the separated fourth solution were analyzed by ICP emission spectrometry.

As a result of measuring the zinc concentration in the fourth solution, it was found that zinc was reduced to below the analytical limit (0.1 mg/L). At this time, the hydrogen sulfide gas concentration was 0.2 ppm, which was found to be below the control concentration (1 ppm) of hydrogen sulfide. Therefore, it was found that zinc can be removed below the analysis limit while suppressing the amount of hydrogen sulfide gas generated.

As described above for experiment (B), the leachate containing manganese, zinc, and iron, which was obtained by mixing the waste dry battery granules with an acid solution and a reducing agent, was subjected to a simple oxidation treatment called air aeration. By doing so, it is possible to obtain a solution in which most of the iron component is precipitated, separated and removed (iron removal step). Then, if the separated fourth solution is subjected to a sulfide precipitation treatment step in which a sulfiding agent is applied, the amount of zinc-containing precipitates is reduced, so the zinc component can be precipitated and removed to less than the analytical limit ( zinc removal step).

In this way, according to experiments (A2) and (B), both zinc and iron were reliably and easily precipitated, separated and removed by going through the zinc removal process and the iron removal process, regardless of the process order. A high-purity manganese-containing solution can be produced, and zinc can be removed while suppressing the amount of hydrogen sulfide gas generated by adding the sulfiding agent only while the pH change is +1 or less when adding the sulfiding agent in the zinc removal step. I have found that it is possible.

The present invention has been completed by further studies based on such findings. That is, the gist of the present invention is as follows.

(1) a sorting step of sorting out one or both of manganese dry batteries and alkaline manganese dry batteries from waste dry batteries;
A crushing and sieving step of crushing and sieving one or both of the manganese dry battery and the alkaline manganese dry battery selected in the sorting step to obtain powders;
a heat treatment step of subjecting the granular material obtained in the crushing and sieving step to a heat treatment in a non-oxidizing atmosphere;
The heat-treated powder is mixed with an acid solution or a reducing agent to leach manganese, zinc, and iron contained in the powder from the powder, thereby producing manganese ions and zinc. an acid leaching step to obtain a leachate containing ions and iron ions;
a solid-liquid separation step of separating the leaching solution obtained in the acid leaching step from other leaching residues;
a manganese extraction step of removing the zinc ions and iron ions from the leachate separated in the solid-liquid separation step to obtain a solution containing the manganese ions;
in this order,
The manganese extraction step is
a zinc removal step including a sulfide precipitation treatment step of reacting the zinc ions with a sulfiding agent to precipitate the zinc ions, and a zinc separation step of separating the obtained zinc-containing precipitates;
An iron removal step including an oxidation treatment step of oxidizing the iron ions to precipitate the iron ions, and an iron separation step of separating the obtained iron-containing precipitates;
in any order,
A method for recovering manganese contained in waste dry batteries, wherein the sulfiding agent is allowed to act only while the pH change after addition of the sulfiding agent is +1 or less in the zinc separation step.

(2) In (1), the manganese extraction step is performed in the order of the zinc removal step and the iron removal step,
In the zinc removal step, the leachate is subjected to a sulfide precipitation treatment for precipitating zinc ions in the leachate by acting a sulfiding agent, and then zinc-containing precipitates obtained in the sulfide precipitation treatment step and manganese ions are removed. and solid-liquid separation from the first solution containing iron ions,
In the iron-removing step, the first solution obtained in the zinc-removing step is oxidized to precipitate iron ions in the first solution. 1. A method for recovering manganese contained in waste dry batteries, characterized by solid-liquid separation of the substance and a second solution containing manganese ions.

(3) The method for recovering manganese contained in waste dry batteries according to (2), wherein in the sulfide precipitation treatment step, the pH of the leachate is adjusted to 2 or more and 6 or less.

(4) In (2) or (3), in the oxidation treatment step, the first solution containing manganese ions and iron ions is aerated with air, or an oxidizing agent is added to the first solution. and adjusting the pH of the first solution to be 3 or more and 7 or less.

(5) In (1), the manganese extraction step is performed in the order of the iron removal step and then the zinc removal step,
In the iron removal step, after performing an oxidation treatment step of oxidizing the leachate to precipitate iron ions in the leachate, the obtained iron-containing precipitate and a third solution containing manganese ions and zinc ions are separated. Applying the iron separation process to separate solid and liquid,
In the zinc removal step, the third solution obtained in the iron removal step is subjected to a sulfide precipitation treatment step of causing a sulfiding agent to act on the third solution to precipitate zinc ions in the third solution. A method for recovering manganese contained in waste dry batteries, comprising performing a zinc separation step of solid-liquid separation of contained precipitates and a fourth solution containing manganese ions.

(6) In (5), in the sulfide precipitation treatment step, the pH of the third solution containing manganese ions and zinc ions is adjusted to 2 or more and 6 or less, and the manganese contained in the waste dry battery is removed. collection method.

(7) In (5) or (6), in the sulfide precipitation treatment step, the leachate is aerated with air and the pH of the leachate is adjusted to 3 or more and 7 or less. A method for recovering contained manganese.

(8) In any one of (1) to (7), the heat treatment is a treatment of heating to a temperature in the range of 800° C. or higher and 1200° C. or lower, and removes manganese contained in waste dry batteries. collection method.

(9) In any one of (1) to (8), in the heat treatment step, a carbon material is added to the granules in a mass ratio of 0.5 or less with respect to the total amount of the granules. A method for recovering manganese contained in waste dry batteries, characterized in that

(10) In any one of (1) to (9), the acid solution in the acid leaching step is dilute sulfuric acid with a mass% concentration of 1.4% or more and 45% or less or a mass% concentration of 1% or more and 14% or less. A method for recovering manganese contained in a waste dry battery, characterized in that the dilute hydrochloric acid is used.

(11) A waste dry battery according to any one of (1) to (10), characterized in that the solid-liquid ratio of the granules in the acid leaching process and the acid leaching process is 50 g/L or more. A method for recovering contained manganese.

(12) In any one of (1) to (11), the reducing agent in the acid leaching step is hydrogen peroxide, sodium sulfide, sodium bisulfite, sodium thiosulfate, or iron sulfate. A method for recovering manganese contained in waste dry batteries.

(13) In any one of (1) to (12), the sulfiding agent used in the sulfide precipitation treatment step is any one of sodium hydrosulfide, sodium sulfide, and hydrogen sulfide. and a method for recovering manganese contained in waste dry batteries.

(14) a sorting device for sorting out one or both of manganese dry batteries and alkaline manganese dry batteries from waste dry batteries;
A crushing device for obtaining a crushed product by inserting one or both of the manganese dry batteries and alkaline manganese dry batteries sorted by the sorting device and subjecting them to crushing treatment;
a sieving device for obtaining powder by sieving the crushed material obtained by the crushing device;
a heating device for heat-treating the granular material obtained by the sieving device in a non-oxidizing atmosphere;
The powder heat-treated by the heating device is mixed with an acid solution or a reducing agent to leach manganese, zinc, and iron contained in the powder from the powder, thereby manganese ions, an acid treatment tank for obtaining a leachate containing zinc ions and iron ions;
a solid-liquid separator for separating the leachate obtained in the acid treatment tank from the leach residue;
a group of manganese extraction devices for removing the zinc ions and iron ions from the leachate separated by the solid-liquid separation device to obtain a solution containing the manganese ions;
in this order,
The manganese extraction device group
A sulfide precipitation treatment tank for causing a sulfide agent to act on the zinc ions to precipitate the zinc ions; a zinc removal device group including a zinc separation device for solid-liquid separation of the zinc-containing precipitate;
an iron removal device group including an oxidation treatment tank for oxidizing the iron ions to precipitate the iron ions, and an iron separation device for solid-liquid separation of the obtained iron-containing precipitates;
Equipment for recovering manganese contained in waste dry batteries, including in random order.

According to the present invention, the manganese component, which is a valuable component contained in waste dry batteries, can be separated from the zinc component and the iron component with high accuracy and ease, and manganese with a high purity that can be used as a raw material for secondary battery electrode materials. can be recovered at a high yield and at a low cost, and has a remarkable industrial effect.

FIG. 1 is a flow for explaining the manganese recovery process shown in Patent Document 1. As shown in FIG. FIG. 2 is a flow for explaining the steps of the manganese recovery method of the present invention. FIG. 3 is a flow explaining one embodiment (procedure A2) of the manganese recovery method of the present invention. FIG. 4 is a flow for explaining another embodiment (procedure B) of the manganese recovery method of the present invention. FIG. 5 is a diagram showing the difference in pH increase rate between an alkaline agent for pH control and a sulfiding agent. FIG. 6 is a graph showing the effect of the blending ratio of graphite as a reducing agent on the rate of zinc removal from the powder in the heat treatment step. FIG. 7 is a graph showing the effect of the amount of H ₂ O ₂ added as a reducing agent on the rate of manganese leaching from the heat-treated granules into the leaching solution in the acid leaching step. FIG. 8 is an X-ray diffraction pattern of the granular material after the heat treatment process. FIG. 9A is a graph showing the effect of the amount of sulfide added (NaHS: 1 equivalent) and the pH condition on the precipitation removal of zinc, iron and manganese in the sulfide precipitation treatment process according to the flow of FIG. FIG. 9B is a graph showing the effects of the amount of sulfide added (NaHS: 2 equivalents) and the pH condition on the precipitation removal of zinc, iron and manganese in the sulfide precipitation treatment process according to the flow of FIG. FIG. 9C is a graph showing the effects of the amount of sulfide added (NaHS: 3 equivalents) and the pH condition on the precipitation removal of zinc, iron and manganese in the sulfide precipitation treatment process according to the flow of FIG. FIG. 10 is a graph showing the correlation between the added amount of sulfiding agent, pH, and hydrogen sulfide gas concentration. FIG. 11 is a graph showing the effect of pH on iron precipitation removal in the oxidation treatment process according to the flow of FIG. FIG. 12 is a schematic diagram illustrating an embodiment (configuration A2) of the manganese recovery facility of the present invention. FIG. 13 is a schematic diagram illustrating another embodiment (configuration B) of the manganese recovery facility of the present invention.

The present invention is intended for waste dry batteries, and the manganese component, which is a valuable component contained in waste dry batteries, is separated from the zinc and iron components contained together in the waste dry batteries, and is recovered as a high-purity manganese-containing solution at a high yield. Manganese recovery method and recovery equipment. Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. The following embodiments show preferred examples of the present invention, and the present invention is not limited by these examples.

(Method for recovering manganese)
As shown in FIG. 2, the manganese recovery method of the present invention has, in order, a selection step, a crushing/sieving step, a heat treatment step, an acid leaching step, a solid-liquid separation step, and a manganese extraction step. Also, the manganese extraction process includes a predetermined zinc removal process and an iron removal process in random order. The manganese recovery method of the present invention may follow the flow shown in FIG. 3 or the flow shown in FIG. 4 depending on the order of the zinc removal step and the iron removal step.

By following the predetermined steps in the recovery method of the present invention, components other than manganese contained in the waste dry battery can be removed in order reliably and easily. As a result, according to the recovery method of the present invention, the manganese component can be easily recovered from waste dry batteries with high purity and high yield so that it can be used as a raw material for secondary battery electrode materials. . The recovery method of the present invention can be suitably carried out using a manganese recovery facility to be described later.

(Sorting process)
Waste dry batteries are generally collected in a form in which various kinds of dry batteries are mixed. Therefore, in the present invention, one or both of manganese dry batteries and alkaline manganese dry batteries (manganese dry batteries and/or alkaline manganese dry batteries) are sorted out of collected waste dry batteries. In order to efficiently extract the manganese component in a later step, only manganese dry batteries may be screened, only alkaline manganese dry batteries may be screened, or both manganese dry batteries and alkaline manganese dry batteries may be screened. As a sorting method, any method such as manual sorting or mechanical sorting using a sorting device may be used.

(Crushing/sieving process)
Next, the manganese dry batteries and/or alkaline manganese dry batteries sorted in the sorting step are crushed. The purpose of crushing is to remove as much as possible materials containing components other than manganese, zinc and carbon from the constituent materials of the manganese dry battery and/or alkaline manganese dry battery selected in the screening process. A crushed product is obtained by the crushing treatment.

When these waste dry batteries are crushed, packaging materials (iron, plastic, paper, etc.), zinc cans, which are the negative electrode material of manganese dry batteries, and brass rods, which are current collectors of alkaline manganese dry batteries, are turned into foil-like or flake-like solids. becomes. On the other hand, manganese dioxide as a positive electrode material, carbon rods as current collectors for manganese dry batteries, zinc powder as negative electrode materials for alkaline manganese dry batteries, and MnO(OH), Zn(OH) ₂ and Mn(OH) generated by discharge. _2. Compounds such as ZnO and various electrolytic solutions become finer particles than foil-like or flake-like solids.

A crushing device is usually used to crush waste dry batteries. The type of the crushing device is not particularly limited, and for example, it is preferable to use a type that can separate solids such as packaging materials constituting the dry battery from granules after crushing. As such a crushing device, for example, a twin-shaft rotary crushing device is exemplified.

The mesh size of the sieve used for sieving the crushed material (sieving between foil-like or flake-like solids and powder) is preferably about 1 mm or more, preferably 20 mm or less, and 10 mm or less. More preferably, 3 mm or less is even more preferable. The mesh size of the sieve is preferably about 1 to 20 mm, more preferably about 1 to 10 mm, even more preferably about 1 to 3 mm. If the mesh opening of the sieve is at least the above lower limit, a larger amount of powder containing a manganese component can be secured. In addition, if the sieve opening is equal to or less than the above upper limit, solid matter containing unintended components other than manganese can be further removed, and subsequent steps can be performed more efficiently.

Therefore, if waste dry batteries are crushed and then sieved using the above-mentioned sieve with mesh openings, large solids such as packaging materials are removed from the waste dry batteries, and powder particles containing carbon as well as manganese and zinc are mainly removed. body can be obtained efficiently.

Thus, the granules obtained through the crushing and sieving process are the main constituent materials of manganese dry batteries and / or alkaline manganese dry batteries, manganese dioxide, carbon, zinc chloride or ammonium chloride, caustic potash, and It is a granular material in which MnO(OH), Zn(OH) ₂ , Mn(OH) ₂ , ZnO, and the like generated by discharge are mixed. Here, usually, an iron component is inevitably mixed in the powder.

(Heat treatment step)
As a heat treatment step, the granules obtained through the crushing and sieving steps are subjected to heat treatment in a non-oxidizing atmosphere such as an inert atmosphere or a reducing atmosphere. Zinc (Zn) in the granules mainly exists as ZnO, and by heat treatment, graphite in the granules reacts with ZnO, and ZnO is reduced to zinc (Zn). When the heat treatment is performed in an oxidizing atmosphere, part of the graphite in the powder or the graphite mixed as a reducing agent reacts with oxygen in the atmosphere instead of ZnO and burns. The reduction reaction is inhibited, and the removal rate of zinc from the powder particles is lowered. Therefore, the heat treatment is performed in a non-oxidizing atmosphere, for example, in an inert atmosphere, for example, in a reducing atmosphere.

In the heat treatment, the powder is preferably heated to 800°C or higher, more preferably 850°C or higher, even more preferably 900°C or higher, and preferably 1200°C or lower. Heating to a temperature in the range of 800° C. or higher and 1200° C. or lower is preferable. If the temperature of the heat treatment is 800° C. or higher, the volatilization of zinc is substantially started, and the zinc vapor is removed from the granules. On the other hand, if the heat treatment temperature exceeds 1200° C., the usable heating furnace is limited. From such a point of view, the heat treatment is preferably performed at a temperature within the above preferred range.

In addition, in the heat treatment, only the graphite in the powder can cause a reduction reaction from ZnO to zinc. However, in order to increase the efficiency of the zinc reduction reaction, it is preferable to add a non-metallic carbon material such as graphite as a reducing agent to the granules. When a carbon material is blended, the mass ratio of the carbon material to the total amount of powder (carbon material blending ratio = carbon material/granule) is 0.5 or less, more preferably 0.01 to 0.5. is preferably adjusted within the range of , more preferably about 0.1. Since the bulk density of the carbon material is smaller than that of the powder, if a large amount of the carbon material is blended at a carbon material blending ratio exceeding 0.5, large-sized heating equipment is required, which is economically disadvantageous. be.

Here, if a metal-based reducing agent is used, the unreacted reducing agent may be dissolved by the acid used in the subsequent steps, deteriorating the quality of the manganese-containing solution. Therefore, the reducing agent to be used is preferably a non-metallic carbon material.

(Acid leaching process)
In the acid leaching step, the granules obtained in the crushing and sieving step are mixed with an acid solution and a reducing agent, and the granules are subjected to the acid leaching step. Through this acid leaching step, a leaching solution is obtained in which mainly the manganese component, the zinc component, and the iron component are leached from the granules into the acid solution. Here, the carbon component remains as a solid-state leaching residue.

The acid used for the acid solution may be a common acid, and sulfuric acid, nitric acid, hydrochloric acid or other acids can be used. Although it can be appropriately selected depending on the price and purpose, it is preferable to use sulfuric acid or hydrochloric acid as the acid solution in consideration of cost, ease of procurement, and the like.

When sulfuric acid is used, it is preferable to use dilute sulfuric acid having a sulfuric acid concentration of 1.4% or more and 45% or less by mass. More specifically, the sulfuric acid concentration is preferably 1.4% or more, more preferably 2% or more, still more preferably 5% or more, preferably 45% or less, more preferably 30% or less, and further preferably 25% or less. preferable. The sulfuric acid is more preferably dilute sulfuric acid with a concentration of 2% or more and 30% or less, and more preferably dilute sulfuric acid with a concentration of 5% or more and 25% or less.

When hydrochloric acid is used, it is preferable to use dilute hydrochloric acid having a hydrochloric acid concentration of 1% or more and 14% or less by mass %. More specifically, the hydrochloric acid concentration is preferably 1% or more, more preferably 2% or more, preferably 14% or less, and more preferably 8% or less. Hydrochloric acid is more preferably dilute hydrochloric acid with a concentration of 2% or more and 8% or less.

Any commercially available sulfuric acid or hydrochloric acid can be used, but the cost of the acid solution can be reduced by using diluted waste acid for industrial use or containing less harmful metal components. Also, the "mass % concentration" herein is a value obtained by multiplying the mass of the acid in the acid solution by the mass of the entire acid solution and multiplying the result by 100.

Here, regardless of which acid solution is used, the acid concentration required for leaching the zinc component depends on the solid-liquid ratio of the powder and the acid solution, the amount of the powder and the content of zinc in the powder. , varies depending on the form of zinc in the granules. Therefore, it is preferable to determine the optimum acid concentration by performing a preliminary experiment assuming an actual machine in advance.

In the acid leaching step of the present invention, the powder that has undergone the heat treatment step is mixed with an acid solution or a reducing agent. If the acid alone is not enough to leach out, a reducing agent may be further added as necessary to almost completely leach out the manganese component contained in the granules. The form of manganese contained in the powder that has undergone the heat treatment process is mostly MnO, but may contain a small amount of MnO ₂ , Mn ₂ O ₃ , Mn ₃ O ₄ and the like. Of these, only MnO and a part of Mn ₃ O ₄ are dissolved by acid alone. Manganese dissolves in acid when it has a valence of two. need to be redeemed. Therefore, a reducing agent is required as a substance that supplies electrons for reduction. Here, the amount of the reducing agent to be added is not particularly limited, but it depends on the form of manganese contained in the granules, so about 1 to 500 g/L of the acid solution is sufficient.

Any of various commonly used reducing agents can be used as the reducing agent. Examples of reducing agents include hydrogen peroxide _H2O2 , sodium sulfide _{Na2S.9H2O ,} sodium hydrogen sulfite _{NaHSO3 ,} sodium _{thiosulfate Na2S2O3 ,} and iron sulfate _{FeSO4.7H2O .} . Here, the sulfur-based reducing agent may generate corrosive gases such as sulfurous acid gas and hydrogen sulfide gas, and caution is required from the viewpoint of safety. From this point of view, the reducing agent is preferably hydrogen peroxide H ₂ O ₂ .

Here, almost all of the zinc component contained in the granules is dissolved (leached out) by increasing the concentration of the acid regardless of the presence or absence of the reducing agent.

In addition, from the viewpoint of improving the efficiency of the acid leaching treatment, the solid-liquid ratio (granules (g)/acid solution (L)) between the powder and the acid solution in the acid leaching step is set to 50 g/L or more. is preferred. On the other hand, if the solid-liquid ratio exceeds 800 g/L, there is a possibility that the viscosity will rise and handling problems will occur, or that the yield during the solid-liquid separation step will deteriorate. Therefore, the solid-liquid ratio is preferably 800 g/L or less. In addition, a sufficient effect can be obtained even at room temperature (about 15 to 25° C.) as the processing temperature (ambient temperature, acid solution temperature, etc.) of the acid leaching treatment, but heating may be performed. If heating is performed, the reaction efficiency can be expected to improve as the temperature is raised within a range in which the treatment solution does not boil. The treatment time of the acid leaching treatment is preferably 5 minutes or longer, and preferably 6 hours or shorter.

(Solid-liquid separation step)
In the solid-liquid separation step, the leaching solution obtained in the acid leaching step and the leaching residue are subjected to solid-liquid separation. The separated leachate contains manganese ions, zinc ions and iron ions. On the other hand, the separated solid leach residue is primarily the result of residual carbon. Thereby, the manganese component, the zinc component and the iron component contained in the powder can be separated from the carbon.

The solid-liquid separation means is not particularly limited. For the solid-liquid separation step, it is preferable to use a commonly used means such as gravity sedimentation, filtration, centrifugation, filter press, membrane separation, and the like.

(Manganese extraction process)
In the present invention, it is necessary to perform a manganese extraction step in which zinc ions and iron ions are removed from the leachate separated in the solid-liquid separation step to obtain a highly pure solution containing manganese ions (manganese-containing solution). . Specifically, the manganese extraction step includes a predetermined zinc removal step and an iron removal step in random order. More specifically, the zinc removal step included in the manganese extraction step includes a sulfide precipitation treatment step in which zinc ions are reacted with a sulfiding agent to precipitate zinc ions, and a zinc separation step in which the resulting zinc-containing precipitate is separated. including. Further, the iron removal step included in the manganese extraction step includes an oxidation treatment step of oxidizing iron ions to precipitate iron ions, and an iron separation step of separating the obtained iron-containing precipitate.

Thus, in the manganese extraction step, zinc ions and iron ions are selectively precipitated, respectively, and the zinc ions and iron ions are reliably removed from the leachate. Moreover, it can be easily recovered with a high yield.

In the manganese extraction step, a zinc removal step for preferentially precipitating and removing zinc ions may be performed first (procedure A2), or an iron removal step for preferentially precipitating and removing iron ions may be performed first (procedure B ). From the viewpoint of facilitating simplification of the process, it is preferable to perform the iron removal process first (procedure B).

In procedure A2, first, a mixture of zinc-containing precipitate and a first solution containing manganese ions and iron ions is obtained from the leachate and then separated. Also, in procedure B, first, a mixture of the iron-containing precipitate and the third solution containing manganese ions and zinc ions is obtained from the leachate, and then these are separated. The details of procedure A2 and procedure B will be described below.

(Zinc removal step (procedure A2))
In the zinc removal step in procedure (A2), the leachate that has undergone solid-liquid separation is first subjected to a sulfide precipitation treatment step. In this sulfide precipitation treatment step, a sulfiding agent is allowed to act on the leachate to precipitate zinc ions, which mainly remain among the ions contained in the leachate, as zinc sulfide, making it removable from the leachate. This treatment yields a mixture of a first solution containing manganese ions and iron ions and a zinc-containing precipitate from the leachate.

The leachate separated in the solid-liquid separation step contains manganese ions, iron ions, and residual zinc ions. It reacts with ^2- to form sulfide and precipitate. The susceptibility to precipitation of this sulfide depends on the solubility product _KSP . The solubility products for manganese, zinc and iron sulfides are shown below.
MnS:K _SP =2.5×10 ⁻¹⁰
ZnS:K _SP =1.6×10 ⁻²⁴
FeS:K _SP =6.3×10 ⁻¹⁸
(Lange, N.A.: Lange's Handbook of Chemistry. Third edition 1985)

Since the smaller the value of the solubility product _KSP , the easier it is to form sulfides, zinc (Zn) is the easiest to form sulfides among manganese, zinc, and iron. Therefore, when a leachate containing ions of manganese, zinc and iron is treated with a sulfiding agent, zinc (Zn) can be selectively precipitated as sulfide. By adjusting the concentration of sulfide ions and the pH of the leachate, the zinc ion concentration in the leachate can be easily reduced below the analytical limit (0.1 mg/L).

Here, as described above, if the leachate contains a large amount of zinc ions, a large amount of fine zinc-containing precipitates are generated by the sulfide precipitation treatment process, so coprecipitation of manganese is promoted and the final Manganese yield tends to be low. In addition, the filter cloth and the like are likely to clog during the subsequent solid-liquid separation, making the zinc separation step difficult. However, in the present invention, in the acid/oxidizing agent treatment step prior to the sulfide precipitation treatment step, most of the zinc component in the powder is removed in advance while the manganese component is retained. can be avoided to increase the final manganese yield. In addition, the amount and quality of the zinc-containing precipitate can be controlled, and the zinc separation step described below can be performed simply and efficiently.

Suitable sulfiding agents include sodium hydrosulfide NaHS, sodium sulfide NaS, and hydrogen sulfide _H2S . Here, since hydrogen sulfide is a gas, it needs to be aerated. Therefore, sodium hydrosulfide and sodium sulfide are more preferable as the sulfiding agent to act.

The sulfurizing agent to act is added only while the pH change after addition of the sulfurizing agent is +1 or less, more preferably +0.5 or less. Here, pH variation is defined as (pH variation)=(pH after addition of sulfurizing agent)−(pH before addition of sulfurizing agent). By adding the sulfiding agent only while the pH change is +1 or less, it is easier to suppress unintended precipitation of manganese ions while precipitating zinc ions better, and the amount of the sulfiding agent acting is excessive, resulting in sulfidation. It is possible to prevent generation of a large amount of hydrogen gas.

In addition, if the pH of the leachate when the sulfiding agent is applied is too low, such as less than 2, the precipitation of zinc tends to be insufficient. The reduction is remarkable, the manganese loss progresses, and the manganese yield tends to decrease. From this point of view, the pH of the leachate in the sulfide precipitation treatment step is preferably 2 or more, more preferably 3 or more, preferably 6 or less, more preferably 5 or less, and even more preferably less than 5. The pH of the leachate is preferably pH 2 or more and 6 or less, more preferably pH 2 or more and 5 or less, still more preferably pH 3 or more and 5 or less, and still more preferably pH 3 or more and less than 5.

Subsequently, in the zinc removal step in procedure (A2), the mixture obtained in the sulfide precipitation treatment step is separated into the first solution and the zinc-containing precipitate to remove the zinc component.

More specifically, the first solution containing manganese ions and iron ions, which is obtained in the sulfide precipitation treatment step, is separated from the zinc-containing precipitate, which mainly consists of the remaining zinc sulfide. Thereby, the zinc component can be easily separated from the mixture after the sulfide precipitation treatment step, and the first solution containing manganese ions and iron ions can be obtained. Separation means is not particularly limited, and may follow the solid-liquid separation process described above. If the zinc-containing precipitate produced is large or fine, coprecipitation of manganese is likely to occur, and troubles such as clogging of the filter cloth during zinc separation are likely to occur. In , since most of the zinc component in the granules is removed in advance while the manganese component is retained, coprecipitation of manganese can be satisfactorily avoided and the final yield of manganese can be increased. In addition, the amount and refinement of zinc-containing precipitates can be suppressed, and the zinc separation step can be performed simply and efficiently.

Here, in the sulfide precipitation treatment described above, part of the iron (Fe) component may be precipitated and removed from the solution. In this case, if the iron content is removed below the preset iron component concentration, the treatment may be finished at this stage. However, in procedure (A2), an iron removal step, which will be described later, is further performed in order to further separate and remove the iron component to obtain a high-purity manganese component.

(Iron removal step (procedure A2))
In procedure (A2), following the zinc removal step described above, an iron removal step is performed. In the iron removal step in procedure (A2), first, the first solution containing manganese ions and iron ions obtained in the previous zinc removal step is subjected to an oxidation treatment step to convert iron ions in the first solution into iron-containing precipitates. As a substance, the iron component can be separated and removed. By this treatment, a mixture of a second solution (manganese-containing solution) containing highly pure manganese ions and an iron-containing precipitate is obtained from the first solution.

As the oxidation treatment method, it is sufficient to follow the oxidation treatment method in the procedure (B), which will be described later, including the suitable pH of the first solution. Here, if the first solution obtained through the sulfide precipitation treatment step is subjected to air aeration under practical conditions, the iron component in the first solution may not be completely separated and removed. This is because the sulfiding agent added in the sulfide precipitation process acts as a reducing agent in this step. It is believed that this reducing agent consumes the oxygen supplied by air aeration, and depending on the amount of air aeration, the amount of oxygen becomes insufficient, and iron that cannot be separated and removed remains in the solution after treatment. Here, if air aeration is continued, the sulfiding agent will become sulfate ions, and finally the solution will become an oxidizing atmosphere, and the iron component will also precipitate. However, this method requires a long aeration time and is not practical.

Therefore, in the oxidation treatment step of procedure (A), it is preferable to add an oxidizing agent as a finishing oxidation treatment after air aeration. The amount of the oxidizing agent to be added is preferably adjusted so that the oxidation-reduction potential (vs. SHE) is measured and the oxidation-reduction potential is 550 mV or higher. Suitable oxidizing agents include hydrogen peroxide and potassium permanganate.

Here, after performing the zinc removal step, if the oxidation treatment step is performed after leaving it for an appropriate period of time, the iron component can be sufficiently precipitated only by air aeration without performing the final oxidation treatment. This is because hydrogen sulfide, which is a reducing substance in the first solution generated in the sulfide precipitation treatment step in the previous stage, is diffused into the air, and the first solution is easily oxidized, that is, the redox potential is easily increased. It is thought that this is due to the fact that The proper period here is different depending on the storage conditions such as whether it is a closed system or an open system.

Then, in the iron removal step in procedure (A2), the mixture obtained in the oxidation treatment step described above is separated into the second solution and the iron-containing precipitate to remove the iron component. Thus, a highly pure manganese-containing solution (second solution) can be recovered.

Separation means is not particularly limited, and may follow the solid-liquid separation process described above.

(Iron removal step (procedure B))
Next, in the iron removal step in procedure (B), the leachate obtained in the solid-liquid separation step is first subjected to an oxidation treatment. In this oxidation treatment, the leachate is oxidized to precipitate iron ions among the ions contained in the leachate as iron-containing precipitates, so that the iron component can be removed from the leachate first. This treatment yields a mixture of a third solution containing manganese and zinc ions and an iron-containing precipitate from the leachate.

As the oxidation treatment method, a commonly used oxidation treatment method can be applied, but in the present embodiment, only air aeration, which is an inexpensive oxidation treatment method, is sufficient. The conditions for air aeration are normal practical conditions (blowing amount: (0.1 to 1 times the amount of leachate)/minute, aeration time: 15 to 60 minutes). It is preferable from an economic point of view. Here, a process of adding an oxidizing agent may be added as the finishing oxidation.

Here, the oxidation treatment is preferably carried out by adjusting the pH of the leachate using a pH adjuster. If the pH of the leachate is too low, such as less than 3, it is difficult for the iron component to precipitate. On the other hand, if the pH of the leachate exceeds 7 and is too high, the manganese component tends to precipitate at the same time. Therefore, it is preferable to adjust the pH of the leachate to a range of 3-7. The leaching solution preferably has a pH of 5 or higher, more preferably a pH of 6 or lower, and still more preferably a pH of around 5 to 6. As a result, the precipitation of manganese can be suppressed, and the iron component can be precipitated, separated and removed from the leachate, and a high-purity manganese-containing solution containing few impurities can be obtained at a high yield.

Subsequently, in the iron removal step in procedure (B), the mixture obtained in the oxidation treatment step described above is combined with a third solution containing manganese ions and zinc ions and an iron-containing precipitate that may mainly contain iron hydroxide. separate into Thereby, the iron component can be easily separated and removed from the mixture after the oxidation treatment step, and the third solution containing the manganese component and the zinc component can be obtained.

Separation means is not particularly limited, and may follow the solid-liquid separation process described above.

(Zinc removal step (procedure B))
In procedure (B), following the iron removal step described above, a zinc removal step is performed. In the step of removing zinc in procedure (B), the third solution obtained in the previous step of removing iron is reacted with a sulfiding agent to precipitate mainly zinc ions among the ions in the third solution as zinc sulfide. Allowing the zinc component to be removed from the third solution. By this treatment, a mixture of the fourth solution (manganese-containing solution) containing manganese ions with high purity and the zinc-containing precipitate is obtained from the third solution.

The third solution separated in the previous iron removal step contains manganese ions and residual zinc ions, and when a sulfiding agent is applied to the third solution, the sulfide precipitation treatment step of the procedure (A2) described above Zinc components are selectively precipitated as sulfides following a similar mechanism. Then, by adjusting the amount of sulfiding agent to be added, the concentration of sulfide ions, and the pH of the third solution, the zinc ion concentration in the third solution can be easily reduced below the analytical limit (0.1 mg/L). be able to.

The type of sulfiding agent and the suitable pH of the third solution may follow the suitable type of sulfiding agent and the pH of the leachate in the sulfide precipitation treatment of procedure (A2) described above. The pH of the third solution is particularly preferably pH:4.

The sulfurizing agent to act is added only while the pH change after addition of the sulfurizing agent is +1 or less, more preferably +0.5 or less. Here, pH variation is defined as (pH variation)=(pH after addition of sulfurizing agent)−(pH before addition of sulfurizing agent). By adding the sulfiding agent only while the pH change is +1 or less, it is easier to suppress unintended precipitation of manganese ions while precipitating zinc ions better, and the amount of the sulfiding agent acting is excessive, resulting in sulfidation. It is possible to prevent generation of a large amount of hydrogen gas.

Then, in the zinc removing step in the procedure (B), the mixture obtained in the above-described sulfide precipitation treatment step is separated into the fourth solution and the zinc-containing precipitate, which is mainly zinc sulfide precipitated, and the zinc component to remove In this way, the remaining zinc component is also removed, and a highly pure solution containing only the manganese component can be easily recovered with a high yield.

As described above, when the third solution contains a large amount of zinc ions, the sulfide precipitation treatment step produces a large amount of fine zinc-containing precipitates, which promotes co-precipitation of manganese, resulting in the final manganese It is easy to lower the yield of In addition, the filter cloth and the like are likely to clog during the subsequent solid-liquid separation, making the zinc separation step difficult. However, in the present invention, in the acid/oxidizing agent treatment step prior to the sulfide precipitation treatment step, most of the zinc component in the powder is removed in advance while the manganese component is retained. can be avoided to increase the final manganese yield. In addition, the amount and quality of the zinc-containing precipitate can be controlled, and the zinc separation step can be performed simply and efficiently.

Separation means is not particularly limited, and may follow the solid-liquid separation process described above.

By sequentially going through each of the above steps, the carbon, zinc, and iron components other than the manganese component contained in the waste dry battery can be almost completely separated and removed, and the zinc and iron components are reduced to below the analysis limit. It can be recovered as a pure manganese-containing solution with a high yield.

Here, the obtained manganese-containing solution may be used for various purposes as high-purity manganese hydroxide by, for example, alkali precipitation. Also, the obtained manganese-containing solution may be mixed with another metal such as Ni, and then subjected to an alkali precipitation treatment or the like, and used as a material for a secondary battery electrode material.

(manganese recovery facility)
Next, the manganese recovery equipment of the present invention will be explained. The recovery equipment of the present invention includes a sorting device, a crushing device, a sieving device, a heat treatment device, an acid treatment tank, a solid-liquid separation device and a group of manganese extraction devices in this order, and has the same features and characteristics as the manganese recovery method of the present invention. have an effect. Also, the group of manganese extraction devices includes a group of predetermined zinc removal devices and a group of iron removal devices in random order.

And the manganese recovery equipment of this invention can be suitably utilized, for example, when implementing the manganese recovery method of this invention.

(Configuration A2)
As one aspect of the recovery facility of the present invention, FIG. 12 shows a configuration (A2) that can preferably implement the above-described procedure (A2). As schematically shown in FIG. 12, the recovery equipment includes a sorting device 10, a crushing device 20a, a sieving device 20b, a heat treatment device 100, an acid treatment tank 30, a solid-liquid separation device 40, and a sulfurizing device. A precipitation treatment tank 50, a pH meter 60, a zinc separation device 70, an oxidation treatment tank 80, an iron separation device 90, and a manganese-containing solution recovery tank 140 are provided in this order from upstream to downstream. can be done. Here, the sulfide precipitation treatment tank 50, the pH meter 60, and the zinc separator 70 constitute a zinc removal apparatus group, and the oxidation treatment tank 80 and the iron separation apparatus 90 constitute an iron removal apparatus group. Also, the group of zinc removal devices and the group of iron removal devices constitute the group of manganese extraction devices.

The sorting device 10 sorts out one or both of manganese dry batteries and alkaline manganese dry batteries from waste dry batteries. The type of sorting device is not particularly limited, and a device that sorts by using shape, radiation, or the like can be preferably exemplified. Here, sorting of waste dry batteries may be done manually.

As the crushing device 20a, any ordinary crusher can be applied, but a twin-shaft rotary crusher is preferable.

The sieving device 20b is preferably provided with a sieve with an opening of 1 mm or more and 20 mm or less. The mesh size of the sieving device 20b is preferably 1 mm or more, preferably 20 mm or less, more preferably 10 mm or less, and still more preferably 3 mm or less, for the same reason as described above for the manganese recovery method.

The heat treatment device 100 is a device that heats the granular material obtained through the crushing device 20a and the sieving device 20b to a set temperature in a non-oxidizing atmosphere such as an inert atmosphere or a reducing atmosphere. If it is The structure of the heat treatment apparatus 100 is not particularly limited. Here, if the heating apparatus is of a batch type, a heating furnace capable of normal atmosphere adjustment is suitable. If the heating device is a continuous type, a rotary kiln or the like that can heat to a set temperature and can adjust the atmosphere is suitable. Here, the atmosphere adjustment referred to here also includes provision of means for collecting exhaust gas containing zinc vapor.

The acid treatment tank 30 mixes the granules, the acid solution and the oxidizing agent together with the leaching residue, the acid solution and the reducing agent to proceed with the leaching reaction. A tank is preferred. If a reducing agent is used, it is preferable to further provide equipment for adding the reducing agent into the tank.

The sulfide sedimentation treatment tank 50 is preferably a general agitation tank equipped with a stirrer in order to subject the leachate to a sulfiding treatment in which a sulfiding agent acts on the leachate. A pH meter 60 is also provided for controlling the addition amount of the sulfiding agent while observing the pH change. Furthermore, it is preferable to further include a pH adjuster capable of adjusting the pH of the leachate by adding a pH adjuster.

Further, the oxidation treatment tank 80 is preferably a general stirring tank equipped with a stirrer in order to oxidize the first solution. Moreover, it is preferable to further include a pH adjuster capable of adjusting the pH of the first solution by adding a pH adjuster.

The solid-liquid separator 40, the zinc separator 70, and the iron separator 90 can all be devices selected from, for example, gravity sedimentation devices, filtration devices, centrifugal separation devices, filter press devices, membrane separation devices, and the like. . Here, it is preferable that each separation device is provided with recovery tanks 110, 120, and 130 capable of recovering sediments and the like that have undergone solid-liquid separation.

The manganese-containing solution recovery tank 140 is preferably a tank that can recover, store, and discharge the manganese-containing solution separated into solid and liquid by the iron separator 90 .

(Configuration B)
Also, as another aspect of the recovery equipment of the present invention, FIG. 13 shows a configuration (B) that can preferably implement the above-described procedure (B). As schematically shown in FIG. 13, the recovery equipment includes a sorting device 10, a crushing device 20a, a sieving device 20b, a heat treatment device 100, an acid treatment tank 30, a solid-liquid separation device 40, an oxidation A treatment tank 51, an iron separation device 61, a sulfide precipitation treatment tank 71, a pH meter 81, a zinc separation device 91, and a manganese-containing solution recovery tank 140 are provided in this order from upstream to downstream. can be done. Here, the oxidation treatment tank 51 and the iron separation device 61 constitute an iron removal device group, and the sulfide precipitation treatment tank 71, the pH meter 81 and the zinc separation device 91 constitute a zinc removal device group. In addition, the group of iron removal devices and the group of zinc removal devices constitute the group of manganese extraction devices.

Here, the sorting device 10, the crushing device 20a, the sieving device 20b, the acid treatment tank 30, the solid-liquid separation device 40, the iron separation device 61, the zinc separation device 91, the recovery tanks 110, 121, 131, the manganese-containing solution recovery tank 140 are all as described above for configuration A2. Here, the iron separator 61, zinc separator 91, and recovery tanks 121, 131 correspond to the iron separator 90, zinc separator 70, and recovery tanks 130, 120 of configuration A2, respectively.

The oxidation treatment tank 51 is preferably a general agitation tank equipped with a stirrer in order to oxidize the leachate. In addition, it is preferable to further include a pH adjuster capable of adjusting the pH of the leachate by adding a pH adjuster.

In addition, the sulfide precipitation treatment tank 71 is preferably a general stirring tank equipped with a stirrer in order to subject the third solution to a sulfide precipitation treatment in which a sulfiding agent is applied. Also, a pH meter 81 is provided for controlling the addition amount of the sulfiding agent while observing the pH change. Furthermore, it is preferable to further include a pH adjuster capable of adjusting the pH of the third solution by adding a pH adjuster.

Here, in the present embodiment, various devices, reaction tanks, and recovery tanks that constitute the recovery facility may have any structure as long as they have the respective functions described above.

Examples are described below. Here, the following examples show a preferred example of the present invention and are not intended to limit it in any way. In addition, the following examples can be modified within the scope of the present invention, and such aspects are also included in the technical scope of the present invention.

(Example 1)
(Preparation of Granules)
Waste dry battery granules were obtained by a sorting step of sorting out manganese dry batteries and alkaline manganese dry batteries from waste dry batteries, crushing the sorted waste dry batteries and sieving them with a sieve with an opening of 2.8 mm. Table 1 shows the composition of the obtained granules. Here, in addition to the elements shown in Table 1, the obtained powder contains oxygen derived from oxides or hydroxides and a small amount of hydrogen.

(Preparation of leachate)
A heat treatment step was performed in which the obtained powder or granular material was charged into the heat treatment apparatus 100 and subjected to heat treatment without blending graphite. The heat treatment was carried out in an inert _N2 atmosphere at a heating temperature of 1000° C. for 1 hour.

The granules obtained through the heat treatment process were put into the acid treatment tank 30 and subjected to the acid treatment process. In the acid leaching step, 10 g of the powder was mixed with 100 mL of an acid solution, and acid leaching was performed to leach manganese, zinc and iron from the powder. The acid concentration of the acid solution was sulfuric acid concentration: 3N (concentration in mass %: about 13.2%). Here, the acid leaching treatment time was 1 hour, and the acid leaching treatment was a stirring treatment. In this case, the solid-liquid ratio, which is the ratio of the powder to the acid solution, is 100 g/L, and the amount of the reducing agent added to the acid solution is 100 g/L.

(Solid-liquid separation step)
After the acid treatment step, the resulting leachate and leach residue were put into a solid-liquid separator 40 and filtered through a filter paper with a pore size of 1 μm to perform a solid-liquid separation step. Manganese concentration, zinc concentration and iron concentration (mg/L) in the resulting leachate were quantified by ICP emission spectrometry. Table 2 shows the quantitative results. Here, based on the obtained manganese concentration in the leachate, the mass of manganese in the leachate is calculated. Manganese element conversion) was calculated and taken as the manganese leaching rate. The manganese leaching rate was 100%.

(Preparation of first solution (zinc removal step))
Next, the leachate obtained from the solid-liquid separation process was added to sodium hydrosulfide NaHS as a sulfiding agent. The sulfurizing agent was added so that the pH change after addition of the sulfurizing agent was within +1. Also, the pH of the leachate during the sulfide precipitation treatment was adjusted to 4 with a pH adjusting liquid (3M sulfuric acid or 100 g/L sodium hydroxide). Moreover, the treatment time of the sulfide precipitation treatment was 30 minutes, and the stirring treatment was performed.

The mixture after the sulfide precipitation treatment step was subjected to suction filtration through a filter paper having a pore size of 1 μm to separate the mixture into the first solution and the zinc-containing precipitate (zinc separation step). Then, the components of the obtained first solution were quantitatively analyzed by ICP emission spectrometry. Here, the amounts of sodium hydrosulfide solution and pH adjuster added were recorded and the analytical values were corrected for the effects of dilution with these solutions. In Table 2, the obtained results are also written as "first solution after zinc removal step".

(Preparation of second solution (iron removal step))
Then, the first solution obtained through the zinc removal step was subjected to air aeration as oxidation treatment. The air aeration conditions were as follows: blowing amount (the same volume as the amount of the first solution)/minute, and aeration time of 30 minutes. After air aeration, the components contained in the intermediate solution were subjected to suction filtration through a filter paper with a pore size of 1 μm and quantitatively analyzed by the above method. In Table 2, the obtained results are also written as "intermediate solution after oxidation treatment".

Then, as a further oxidation treatment, an oxidizing agent was immediately added to the first solution after the air aeration. In the addition of the oxidizing agent, the pH of the first solution is adjusted to 5 by adding a pH adjusting solution (3M sulfuric acid or 100 g/L sodium hydroxide), and then hydrogen peroxide solution is used as an oxidizing agent. It was added so that the reduction potential was 550 mV or higher. In this way, the iron component in the first solution precipitated as iron hydroxide and became removable. Here, the treatment time with the oxidizing agent was 30 minutes.

The mixture after the oxidation treatment step by air aeration and the addition of an oxidizing agent was subjected to suction filtration with a filter paper having a pore size of 1 μm, and an iron separation step was performed in which solid-liquid separation was performed into a manganese-containing solution (second solution) and an iron-containing precipitate. .

The components contained in the obtained second solution were quantitatively analyzed by the above method. Here, the amounts of hydrogen peroxide solution and pH adjuster added were recorded, and the analytical values were corrected for the effects of dilution with these solutions. In Table 2, the obtained results are also listed as "second solution after iron removal step".

From Table 2, according to procedure A2, which is one embodiment of the manganese recovery method of the present invention, the zinc component and iron component other than the manganese component contained in the waste dry battery are reduced to less than the analysis limit (0.1 mg / L). It can be seen that they can be easily separated and removed. As described above, according to the present invention, the manganese component contained in waste dry batteries can be easily and efficiently recovered as a highly pure manganese ion-containing solution at a high yield.

(Example 2)
A granular material was prepared in the same manner as in Example 1, and a granular material having the composition shown in Table 1 was obtained. A leachate was prepared in the same manner as in Example 1. Table 3 shows the contents (mg/L) of manganese, zinc, and iron in the leachate after the solid-liquid separation step. Here, the manganese leaching rate determined in the same manner as in Example 1 was 100%.

Next, when the first solution was prepared (zinc removal step) in the same manner as in Example 1, the components in the first solution after the zinc removal step were as shown in Table 3.

Then, the first solution obtained through the zinc separation step was allowed to stand at room temperature for one week, and then subjected to an oxidation treatment step. In the oxidation treatment process, only air aeration was performed. The air aeration conditions were blowing amount: (the same volume as the amount of the third solution)/minute, and aeration time: 30 minutes. After air aeration, the contained components of the manganese-containing solution (second solution) filtered by suction through a filter paper with a pore size of 1 μm were quantitatively analyzed by the above method. In Table 3, the obtained results are also listed as "second solution after iron removal step".

From Table 3, in procedure A2, which is one embodiment of the manganese recovery method of the present invention, if the first solution separated by the sulfide precipitation treatment is allowed to stand for an appropriate period of time and then subjected to the oxidation treatment step, , it can be seen that the iron component can be sufficiently separated and removed as a precipitate even by oxidation treatment only by air aeration. As a result, the manganese component could be recovered with a high yield.

(Example 3)
A granular material was prepared in the same manner as in Example 1, and a granular material having the composition shown in Table 1 was obtained. Further, when the acid treatment process was performed in the same manner as in Example 1, the content (mg/L) of each component of manganese, zinc and iron in the leachate after the solid-liquid separation process was as shown in Table 4.

(Preparation of third solution (iron removal step))
Next, the leachate separated in the solid-liquid separation step was subjected to an oxidation treatment step. In the oxidation treatment step, the obtained leachate is subjected to air aeration to generate iron hydroxide from the iron component contained in the leachate, and the iron component can be separated and removed from the leachate as an iron-containing precipitate. The conditions for air aeration were blowing amount: (same volume as the amount of leachate) mL/min, and aeration time: 30 minutes. Here, in performing the oxidation treatment, the leachate was adjusted to pH: 5 using a pH adjuster (3M sulfuric acid or 100 g/L sodium hydroxide).

After the oxidation treatment, the third solution and the iron-containing precipitate were subjected to suction filtration with a filter paper having a pore size of 1 μm to separate the third solution and the iron-containing precipitate (iron separation step). Then, the components (Mn, Zn, Fe) contained in the third solution obtained in the iron removal step were quantitatively analyzed by ICP emission spectrometry. Here, the amount of pH adjuster added was recorded and the measured values were corrected for the effects of dilution by the pH adjuster. In Table 4, the concentration (mg/L) of each component of manganese, zinc and iron in the obtained first solution is also written as "third solution after iron removal step".

(Preparation of fourth solution (zinc removal step))
Next, a sulfiding agent is caused to act on the third solution separated in the iron separation step, mainly zinc ions remaining in the third solution are precipitated as zinc sulfide (zinc-containing precipitate), and are removed from the third solution. A sulfide precipitation treatment step was performed to make it separable and removable. The sulfurizing agent used was sodium hydrosulfide NaHS, and was added so that the pH change after addition of the sulfurizing agent was within +1. Here, sodium hydrosulfide was added in the form of a solution dissolved in distilled water. Further, the pH of the third solution during the sulfide precipitation treatment was adjusted to 4 with a pH adjusting liquid (3M sulfuric acid or 100 g/L sodium hydroxide). Moreover, the treatment time of the sulfide precipitation treatment was 30 minutes, and the stirring treatment was performed.

After the sulfide precipitation treatment, the mixture was subjected to suction filtration through a filter paper having a pore size of 1 μm to separate a manganese-containing solution (second solution) and a zinc-containing precipitate (zinc separation step). Then, the components of the fourth solution obtained after the separation were quantitatively analyzed by ICP emission spectrometry. Here, the amounts of sodium hydrosulfide solution and pH adjuster added were recorded and the measured values were corrected for the effects of dilution with these solutions. In Table 4, the obtained results are also listed as "fourth solution after zinc removal step". The Mn leaching rate in the obtained fourth solution (manganese ion-containing solution) was 100%.

From Table 4, according to Procedure B, which is one embodiment of the manganese recovery method of the present invention, zinc and iron components other than manganese components contained in waste dry batteries can be easily reduced to less than the analysis limit (0.1 mg / L). can be separated and removed. As described above, according to the present invention, the manganese component contained in waste dry batteries can be easily and efficiently recovered as a highly pure manganese ion-containing solution with a high yield.

10 Sorting Device 20a Crushing Device 20b Screening Device 30 Acid Treatment Tank 40 Solid-Liquid Separation Device 50 Sulfide Precipitation Treatment Tank 51 Oxidation Treatment Tank 60 pH Meter 61 Iron Separator 70 Zinc Separator 71 Sulfide Precipitation Treatment Tank 80 Oxidation Treatment Tank 81 pH meter 90 iron separator 91 zinc separator 100 heat treatment device 110 recovery tank 120 recovery tank 121 recovery tank 130 recovery tank 131 recovery tank 140 manganese-containing solution recovery tank

Claims (14)

A sorting step of sorting out one or both of manganese dry batteries and alkaline manganese dry batteries from waste dry batteries;
A crushing and sieving step of crushing and sieving one or both of the manganese dry battery and the alkaline manganese dry battery selected in the sorting step to obtain powders;
a heat treatment step of subjecting the granular material obtained in the crushing and sieving step to a heat treatment in a non-oxidizing atmosphere;
The heat-treated powder is mixed with an acid solution or a reducing agent to leach manganese, zinc, and iron contained in the powder from the powder, thereby producing manganese ions and zinc. an acid leaching step to obtain a leachate containing ions and iron ions;
a solid-liquid separation step of separating the leaching solution obtained in the acid leaching step from other leaching residues;
a manganese extraction step of removing the zinc ions and iron ions from the leachate separated in the solid-liquid separation step to obtain a solution containing the manganese ions;
in this order,
The manganese extraction step is
a zinc removal step including a sulfide precipitation treatment step of reacting the zinc ions with a sulfiding agent to precipitate the zinc ions, and a zinc separation step of separating the obtained zinc-containing precipitates;
An iron removal step including an oxidation treatment step of oxidizing the iron ions to precipitate the iron ions, and an iron separation step of separating the obtained iron-containing precipitates;
in any order,
A method for recovering manganese contained in waste dry batteries, wherein the sulfiding agent is allowed to act only while the pH change after addition of the sulfiding agent is +1 or less in the zinc separation step. The manganese extraction step is performed in the order of the zinc removal step and the iron removal step,
In the zinc removal step, the leachate is subjected to a sulfide precipitation treatment for precipitating zinc ions in the leachate by acting a sulfiding agent, and then zinc-containing precipitates obtained in the sulfide precipitation treatment step and manganese ions are removed. and solid-liquid separation from the first solution containing iron ions,
In the iron-removing step, the first solution obtained in the zinc-removing step is oxidized to precipitate iron ions in the first solution. 2. A method for recovering manganese contained in a waste dry battery according to claim 1, wherein the manganese ion and the second solution containing manganese ions are subjected to solid-liquid separation. 3. The method for recovering manganese contained in waste dry batteries according to claim 2, wherein in said sulfide precipitation treatment step, said leachate is adjusted to have a pH of 2 or more and 6 or less. In the oxidation treatment step, the first solution containing manganese ions and iron ions is aerated with air, or an oxidizing agent is added to the first solution, and the first solution has a pH of 3 or more. 4. The method for recovering manganese contained in waste dry batteries according to claim 2 or 3, wherein the manganese content is adjusted to be 7 or less. The manganese extraction step is performed in the order of the iron removal step and then the zinc removal step,
In the iron removal step, after performing an oxidation treatment step of oxidizing the leachate to precipitate iron ions in the leachate, the obtained iron-containing precipitate and a third solution containing manganese ions and zinc ions are separated. Applying the iron separation process to separate solid and liquid,
In the zinc removal step, the third solution obtained in the iron removal step is subjected to a sulfide precipitation treatment step of causing a sulfiding agent to act on the third solution to precipitate zinc ions in the third solution. 2. The method for recovering manganese contained in a waste dry battery according to claim 1, wherein a zinc separation step is performed for solid-liquid separation of the contained precipitate and the fourth solution containing manganese ions. 6. The method for recovering manganese contained in waste dry batteries according to claim 5, wherein in the sulfide precipitation treatment step, the third solution containing manganese ions and zinc ions is adjusted to have a pH of 2 or more and 6 or less. . 7. The manganese contained in the waste dry battery according to claim 5, wherein in said sulfide precipitation treatment step, said leachate is aerated with air and said leachate is adjusted to have a pH of 3 or more and 7 or less. collection method. The method for recovering manganese contained in waste dry batteries according to any one of claims 1 to 3, wherein the heat treatment is a treatment of heating to a temperature in the range of 800°C or higher and 1200°C or lower. . 4. The method according to any one of claims 1 to 3, characterized in that in said heat treatment step, a carbon material is further added to said granular material in a mass ratio of 0.5 or less with respect to the total amount of said granular material. 2. A method for recovering manganese contained in waste dry batteries according to claim 1. 4. The method according to any one of claims 1 to 3, wherein the acid solution in the acid leaching step is dilute sulfuric acid with a mass% concentration of 1.4% or more and 45% or less or dilute hydrochloric acid with a mass% concentration of 1% or more and 14% or less. A method for recovering manganese contained in a waste dry battery according to any one of the above items. 4. The waste dry battery according to claim 1, characterized in that the solid-liquid ratio of the powder in the acid leaching process and the solid-liquid material in the acid leaching process is 50 g/L or more. Manganese recovery method. 4. The method according to any one of claims 1 to 3, characterized in that the reducing agent in the acid leaching step is one of hydrogen peroxide, sodium sulfide, sodium hydrogen sulfite, sodium thiosulfate and iron sulfate. A method for recovering manganese contained in waste dry batteries. The waste according to any one of claims 1 to 3, wherein the sulfiding agent used in the sulfide precipitation treatment step is any one of sodium hydrosulfide, sodium sulfide, and hydrogen sulfide. A method for recovering manganese contained in a dry battery. a sorting device for sorting out one or both of manganese dry batteries and alkaline manganese dry batteries from waste dry batteries;
A crushing device for obtaining a crushed product by inserting one or both of the manganese dry batteries and alkaline manganese dry batteries sorted by the sorting device and subjecting them to crushing treatment;
a sieving device for obtaining powder by sieving the crushed material obtained by the crushing device;
a heating device for heat-treating the granular material obtained by the sieving device in a non-oxidizing atmosphere;
The powder heat-treated by the heating device is mixed with an acid solution or a reducing agent to leach manganese, zinc, and iron contained in the powder from the powder, thereby manganese ions, an acid treatment tank for obtaining a leachate containing zinc ions and iron ions;
a solid-liquid separator for separating the leachate obtained in the acid treatment tank from the leach residue;
a group of manganese extraction devices for removing the zinc ions and iron ions from the leachate separated by the solid-liquid separation device to obtain a solution containing the manganese ions;
in this order,
The manganese extraction device group
A sulfide precipitation treatment tank for causing a sulfide agent to act on the zinc ions to precipitate the zinc ions; a zinc removal device group including a zinc separation device for solid-liquid separation of the zinc-containing precipitate;
an iron removal device group including an oxidation treatment tank for oxidizing the iron ions to precipitate the iron ions, and an iron separation device for solid-liquid separation of the obtained iron-containing precipitates;
Equipment for recovering manganese contained in waste dry batteries, including in random order.

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