JP2014201784A - Metal recovery method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal recovery method in which appearance quality of the metal is high.SOLUTION: A metal recovery method in which a manganese clinker (a first mixture) including manganese as a main component is recovered from a waste dry cell including a manganese cell and/or an alkali manganese cell, includes: a screening step in which the manganese cell and/or the alkali manganese cell is performed by screening from the waste dry cell; a crush step in which the screened manganese cell and/or manganese cell is crushed to obtain a crushed object; a sieve separation step in which the crushed object is performed by sieve separation to obtain a particulate matter; and a calcination step in which zinc included in the particulate matter is reduced to be thereby vaporized, the particulate matter is performed by calcination, and the manganese clinker (the first mixture) including manganese as a main component is obtained.

Description

  The present invention relates to a metal recovery method for recovering manganese from a discarded dry battery (waste dry battery).

  As a method for recovering a metal such as manganese from a waste dry battery, for example, the technique of Patent Document 1 has been proposed. Specifically, it is a technique of separating, recovering and recovering manganese dioxide and zinc chloride by sorting, crushing, and sieving the parts mainly composed of manganese batteries and alkaline batteries from waste dry batteries.

JP 2004-871 A

  In recovering metals such as manganese from such waste batteries, it is important to increase the quality of the metal that is the object of recovery (the proportion of metal).

  Then, this invention makes it a subject to provide the metal recovery method with the high quality of a metal.

  As a means for solving the above-mentioned problems, the present invention provides a metal recovery method for recovering a first mixture containing manganese as a main component from a waste battery including a manganese battery and / or an alkaline manganese battery. A sorting process for sorting manganese batteries and / or alkaline manganese batteries, a crushing process for crushing the sorted manganese batteries and / or alkaline manganese batteries to obtain a crushed material, and sieving the crushed material to obtain a granular material Characterized by comprising a sieving step, and volatilizing by reducing zinc contained in the granular material, calcining the granular material, and obtaining a first mixture mainly comprising manganese. This is a metal recovery method.

  According to such a structure, in a calcination process, zinc can be removed from a granular material by volatilizing by reducing the zinc contained in a granular material. Thereby, in the 1st mixture, manganese (manganese dioxide) becomes high quality in the 1st mixture.

  In the metal recovery method, it is preferable that in the calcination step, the granular material is heated from room temperature to 1200 ° C. or higher.

  According to such a structure, in a calcination process, by heating a granular material from normal temperature to 1200 degreeC or more, zinc can be reduce | restored and it can volatilize favorably.

  In the metal recovery method, it is preferable that the gas generated by calcination in the calcination step is heated to 800 ° C. or higher and then cooled to 200 ° C. or lower to obtain a second mixture mainly composed of zinc.

  According to such a structure, the gas which generate | occur | produced by the calcination in the calcination process can be obtained by heating to 800 ° C. or higher and then cooling to 200 ° C. or lower to obtain a second mixture containing zinc as a main component.

  In the metal recovery method, it is preferable to recover the residue in the calcination step to obtain the first mixture.

  According to such a structure, a 1st mixture can be obtained by collect | recovering residues in a calcination process.

  In the metal recovery method, after mixing the first mixture and 2 to 50% by mass of the binder with respect to the first mixture, press forming and solidifying step to obtain a solidified first mixed object It is preferable to contain.

  According to such a configuration, in the solidification step, after mixing the first mixture and 2 to 50% by mass of the binder with respect to the first mixture, the first mixture is solidified by pressure molding. You can get a body.

  According to the present invention, it is possible to provide a metal recovery method with high metal quality.

It is process drawing of the selection grinding | pulverization sieving process S100 (selection process, crushing process, sieving process) which concerns on this embodiment. It is process drawing of the water washing process S200 which concerns on this embodiment. It is process drawing of the reduction | restoration volatilization process S300 (calcination process, solidification process) which concerns on this embodiment.

  An embodiment of the present invention will be described with reference to FIGS.

  The metal recovery method according to the present embodiment recovers manganese briquette (first mixed object) mainly composed of manganese and zinc dust (ZnO, second mixture) mainly composed of zinc from a waste dry battery. It is. The metal recovery method includes a selection pulverization sieving step S100 (selection step, crushing step, sieving step, see FIG. 1), a water washing treatment step S200 (FIG. 2), and a reduction volatile treatment step S300 (calcination step, solidification). Process, FIG. 3). In addition, manganese briquette (1st mixed object) is solidified by pressure-molding manganese clinker (1st mixture) so that it may mention later.

<Waste battery>
The waste dry battery is a used dry battery, and includes a manganese battery and an alkaline manganese battery. The size of the manganese battery or the like may be any of single to single. However, a manganese battery or an alkaline manganese battery may be included.

The manganese battery is composed of manganese dioxide (MnO ₂ ) as a positive electrode, zinc (Zn) as a negative electrode, and zinc chloride (ZnCl ₂ ) as an electrolytic solution. And the battery reaction formula of a manganese battery is given by Formula (1).
8MnO ₂ + 8H ₂ O + ZnCl ₂ + 4Zn → 8MnO (OH) + ZnCl ₂ .4Zn (OH) ₂ (1)

The alkaline manganese battery is composed of manganese dioxide (MnO ₂ ) as a positive electrode, zinc (Zn) as a negative electrode, and an aqueous potassium hydroxide solution (KOH) and zinc oxide (ZnCl ₂ ) as an electrolytic solution. And the battery reaction formula of an alkaline manganese battery is given by Formula (2).
MnO ₂ + H ₂ O + Zn → Mn (OH) ₂ + ZnO (2)

<Selective grinding and sieving step S100>
With reference to FIG. 1, the selective pulverization sieving step S100 will be described.

In step S101, hand sorting (sorting process) is performed.
Specifically, a manganese battery and an alkaline manganese battery are selected from waste dry batteries by visual inspection and manual work. In other words, foreign substances (such as dust), foreign batteries (such as button batteries), and corrosion batteries are removed from the waste dry battery.

In step S102, size selection is performed.
Specifically, waste dry batteries (manganese batteries, alkaline manganese batteries) from which foreign substances and the like have been removed are sorted into single 1, single 2, single 3 size, and other batteries (square type, etc.).

In step S103, type (product type) selection is performed.
Specifically, for each battery size, selection is made into a manganese battery, an alkaline manganese battery, and other batteries. Other batteries are a nickel cadmium battery (Ni-Cd battery) and a nickel hydride battery (Ni-H battery), for example.

In step S104, pulverization (crushing step) is performed.
Specifically, using an appropriate crusher, the crushed material is obtained by crushing at each battery size.

In step S105, magnetic sorting is performed.
For example, a magnetic separator described in Japanese Patent Application Laid-Open No. 2000-229269 is used, and an iron skin (iron scrap) made of a magnetic material such as iron is selected and removed by the magnetic force of the magnetic separator. The iron skin constitutes the outer shell of the dry battery.

In step S106, sieving (sieving step) is performed.
Specifically, using a sieve having an appropriate mesh (for example, 3 mm), the pulverized product from which the iron skin has been removed is divided into a sieved product and a sieved product (powdered product).

In step S107, wind power selection is performed.
Specifically, using a suitable wind sorter, wind-selected products such as metal particles are selected from the sieved product. Resin or the like will remain.

<Washing treatment step S200>
With reference to FIG. 2, the washing process S200 will be described.

In step S201, the raw materials are mixed.
Specifically, in the raw material mixing tank, the granular product obtained in step S106 of FIG. 1 and caustic soda (sodium hydroxide aqueous solution) are mixed to obtain a mixed solution (slurry).

In step S202, sieving is performed.
Specifically, a mixture of the raw material, which is the granular product obtained in step S201, and caustic soda (sodium hydroxide) is sieved with a trommel (cylindrical sieve screen) to remove large-diameter foreign matter from the mixture. To do. Thus, the chloride adhering to a granular product can be removed by carrying out alkali washing of the granular product with caustic soda (sodium hydroxide). Therefore, it is possible to reduce the amount of chlorine brought into the reduction volatile treatment step S300 described later.

In step S203, the first cleaning is performed.
Specifically, the liquid mixture that has passed through the trommel in step S202 is charged into the first cleaning tank. Next, the stirring blade is rotated, and the mixed solution is stirred and mixed in the first cleaning tank.
Then, zinc chloride (ZnCl ₂ , see formula (1)) contained in the granular product is eluted in water as a solvent. Thereby, dechlorination of a granular product advances and washing | cleaning advances.
Note that the first cleaning and the second cleaning described later are performed at a predetermined time obtained by a preliminary test or the like, for example. In addition, since zinc chloride is deliquescent and easily soluble in water, zinc chloride can be recovered as zinc hydroxide by alkaline washing with caustic soda (sodium hydroxide aqueous solution).

In step S204, first sedimentation is performed.
Specifically, after the mixed liquid after the stirring in step S203 is put into a first settling tank (thickener), a settling agent is added, and the scraping blade (rake) of the first settling tank is rotated at a low speed. Then, manganese dioxide (MnO ₂ , see formula (1)) settles.
Note that the first sedimentation and the second sedimentation described below are performed, for example, at a predetermined time obtained by a preliminary test or the like.

In step S205, the second cleaning is performed.
Specifically, the sediment (slurry, underflow liquid) that settles in the first sedimentation tank in step S203 and contains manganese dioxide (MnO ₂ ) is charged into the second cleaning tank. In addition, the overflow liquid (supernatant liquid) of a 1st sedimentation tank and the 2nd sedimentation tank mentioned later is conveyed to the neutralization tank, and is neutralized with acids, such as dilute sulfuric acid.

Next, the stirring blade is rotated, and the precipitate is stirred and mixed in the second cleaning tank. In this case, caustic soda may be added to promote dechlorination.
Then, zinc chloride (ZnCl ₂ , see formula (1)) contained in the granular product (under sieve product) is eluted in water as a solvent. As a result, dechlorination of the granular product (under sieve product) proceeds and cleaning proceeds.
Thus, chlorine can be removed satisfactorily by washing the granular product (under sieve product) in two stages of the first washing and the second washing. Therefore, the cleaning process may be three or more stages.

In step S206, second sedimentation is performed.
Specifically, the mixed liquid after stirring in step S205 is put into a second settling tank (thickener). Next, the scraping blade (rake) of the second settling tank is rotated at a low speed. Then, manganese dioxide (MnO ₂ , see formula (1)) in the granular product (under sieve product) settles. Similarly to step S203, zinc chloride having deliquescence that is an electrolytic solution of a manganese battery is also recovered as zinc hydroxide.

In step S207, dehydration is performed using a dehydrator equipped with a filter cloth belt.
Specifically, the sediment (slurry, underflow liquid) that has settled in the second sedimentation tank in step S206 is conveyed onto the upper surface of an endless filter cloth belt formed of nonwoven fabric or the like. Then, moisture in the sediment is removed from the sediment, that is, dehydrated, to obtain a cleaned product whose main component is manganese dioxide (MnO ₂₎ on filter cloth belt.

Note that the endless filter cloth belt runs while being guided by a plurality of rolls in a dehydrator as described in, for example, Japanese Patent No. 3711222. A suction box connected to a suction pump is disposed on the lower surface of the filter cloth belt so that moisture in the sediment is sucked into the suction box.
Such dehydration treatment is preferably repeated twice or more using two or more dehydrators.

<Reduction Volatilization Process S300>
With reference to FIG. 3, the reduction volatilization process (calcination process, solidification process) will be described.

The calcination process for calcining the pulverized, granular and washed products of manganese and alkaline batteries will be described.
In step S301, the pulverized product obtained in step S105, the wind-selected product obtained in step S107, and the washed product obtained in step S207 are charged into the raw material receiving hopper.

  In step S302, coke (carbon) as a reducing agent is charged into a coke receiving hopper.

In step S303, a mixture (pulverized material) formed by mixing a mixture of the pulverized product of the raw material receiving hopper, the air-selected product and the washed product and the coke of the coke receiving hopper into the kiln charging hopper. Prepare.
In addition, in the said mixture, it is preferable that coke is 5-30 mass% with respect to the said compound, and it is especially preferable that it is 10-20 mass%.

  In step S304, the composition of the kiln charging hopper in step S303 is charged into the rotary kiln and the compound is heated. Here, the heating source of the rotary kiln is a heavy oil burner using A heavy oil as fuel.

Here, in the rotary kiln, the blend is heated from room temperature to 1200 ° C. or higher.
Then, zinc (Zn (OH) ₂ , ZnO, see formulas (1) and (2)) contained in the formulation is reduced by coke (carbon) and volatilizes, and the formulation is calcined. That is, zinc is removed from the formulation and the zinc grade is 0-0.6% (see Table 1). In Table 1, the coke addition rate (%) is given by coke (g) / battery (g) × 100.
In addition, this compound (residue) has manganese dioxide (MnO ₂ , see formulas (1) and (2)) as a main component. On the other hand, the volatilized (gasified) zinc is supplied to the secondary combustion furnace in step S311 described later together with the exhaust gas.

Specifically, for example, zinc oxide (ZnO) contained in the blend is reduced with coke (carbon) to generate zinc gas and carbon dioxide (see formula (3)), zinc is removed, and manganese dioxide ( A residue containing MnO ₂ ) as a main component remains. Then, the zinc gas reacts with oxygen in the rotary kiln and is oxidized again to become zinc oxide (ZnO, zinc dust) (see formula (4)), and goes to the secondary combustion furnace (S311).

ZnO (solid) + C (solid) → Zn (gas) + CO ₂ (gas) (3)
Zn (gas) + 1 / 2O ₂ (gas) → ZnO (solid) (4)

  On the other hand, when the heating temperature (baking temperature) is, for example, 1000 ° C. or less, zinc contained in the blend does not volatilize, and zinc remains in the residue that is the blend after firing. For example, when the addition amount of coke is changed to 0% by mass, 10% by mass, and 20% by mass with respect to a battery in which the grade (content%) of zinc before firing is 28%, the heating temperature is set to 800%. Test results have been obtained in which the quality (content%) of zinc in the residue is 30%, 27%, and 25% when the temperature is set to 0 ° C. (see Table 1). Moreover, when heating temperature was 1000 degreeC, the test result that the quality (content%) of zinc in the said residue was set to 7%, 8%, and 10% was obtained (refer Table 1).

In step S305, after collecting the residue which is the compound after calcination, the residue is cooled with a rotary cooler to obtain manganese clinker (first mixture). Manganese clinker contains manganese dioxide (MnO ₂ ) as a main component (for example, 63% by mass or more). On the other hand, as described above, since zinc is volatilized and removed, the content of zinc in the manganese clinker is, for example, 0.4 to 2.1% by mass or less.

A solidification process for solidifying manganese clinker will be described.
In step S306, the manganese clinker obtained in step S306 is put into a manganese hopper.

  In step S307, the binder is charged into the binder hopper. As the binder, for example, at least one selected from polystyrene (melting point: 70 ° C.), polyethylene, polypropylene, polyester and the like can be used.

  In step S308, manganese clinker of the manganese hopper and binder of the binder hopper are charged into the solidifying machine. In this case, the binder is 2 to 50% by mass (preferably 10% by mass) with respect to the manganese clinker. In addition, a solidification machine is an apparatus which mixes and press-molds a to-be-charged object, for example, as described in patent 3490904 gazette.

  Specifically, in a solidifying machine, after mixing manganese clinker and a binder, the mixture is pressure-molded, whereby the binder made of polystyrene or the like is melted by pressure frictional heat, and the manganese clinker is melted. To obtain a manganese briquette (first mixed body). In this case, manganese in the manganese briquette is 35 mass% or more, which is high quality.

  Next, processing of gas containing zinc generated and volatilized in the rotary kiln in step S304 will be described.

  In step S311, the gas from the rotary kiln in step S304 is heated to 800 ° C. or higher using a secondary combustion furnace. Note that a small amount of zinc dust generated due to insufficient heating is mixed with zinc dust collected by a bag filter in step S313 described later.

In step S312, the gas from the secondary combustion furnace in step S311 is cooled to 200 ° C. or lower using a gas cooling tower.
As described above, the gas from the rotary kiln is heated to 800 ° C. or higher to decompose the dioxin particles (S311), and then rapidly cooled to 200 ° C. or lower (S312), so that the regeneration of dioxins can be suppressed.

  In step S313, the gas from step S312 is passed through the bag filter. Then, zinc dust contained in the gas is collected by the filter cloth of the bag filter, and zinc dust is obtained. In addition, zinc in this zinc dust (ZnO) becomes 75 mass% or more, and is high quality.

  In step S314, the gas that has passed through the bag filter in step S313 is brought into gas-liquid contact with an aqueous sodium hydroxide solution for completeness in NaOH-TCA (Turbulent Contact Absorber) to absorb dioxins. To do.

  In step S315, the gas that has passed through the NaOH-TCA in step S314 is further brought into gas-liquid contact with water in water-TCA to absorb dioxins.

  In step S316, the gas processed in step S315 is diluted in a dilution tower and then exhausted to the outside.

S100 Screening and pulverizing process S200 Washing process S300 Reduction volatilization process

Claims (5)

A metal recovery method for recovering a first mixture containing manganese as a main component from a waste battery including a manganese battery and / or an alkaline manganese battery,
A sorting step for sorting manganese batteries and / or alkaline manganese batteries from waste dry batteries;
Crushing step of crushing the selected manganese battery and / or alkaline manganese battery to obtain a crushed material;
Sieving the crushed material and obtaining a granular material; and
Reducing the zinc contained in the powder and volatilizing it, calcining the powder and obtaining a first mixture containing manganese as a main component,
A metal recovery method characterized by comprising: In the said calcination process, the said granular material is heated from normal temperature to 1200 degreeC or more. The metal recovery method of Claim 1 characterized by the above-mentioned. The gas generated by calcination in the calcination step is heated to 800 ° C or higher and then cooled to 200 ° C or lower to obtain a second mixture containing zinc as a main component. The metal recovery method described. The metal recovery method according to any one of claims 1 to 3, wherein the first mixture is obtained by recovering a residue in the calcination step. A solidification step of mixing the first mixture and 2 to 50% by mass of a binder with respect to the first mixture and then pressing to obtain a solidified first mixed object. The metal recovery method according to any one of claims 1 to 4.

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