JPH0774404B2 - Method for recovering metallic nickel from ferric chloride waste liquid - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an etching waste liquid,
In the process of regenerating ferric chloride waste liquid containing nickel and other heavy metals, when precipitating nickel dissolved in the waste liquid as sludge, the ratio of the nickel component contained in the sludge is increased and To efficiently recover the

[0002]

2. Description of the Related Art Generally, ferric chloride solution is widely used as an etching solution for precision processing of a metal plate made of a material such as stainless steel or nickel alloy. As the number of times this etching solution is used for corrosion treatment increases, heavy metal ions such as nickel ions are accumulated in the solution, and trivalent iron ions are reduced to divalent, resulting in a decrease in corrosive power and finally It becomes a waste liquid. Since this waste liquid causes a lot of pollution problems if it is discarded by only performing neutralization treatment with an alkali, it is desired to recycle and recycle it.

As a method for treating the above waste liquid, it is considered that chlorine gas is directly blown into the waste liquid to oxidize divalent iron ions to trivalent iron. However, as a practical matter, this treatment method does not sufficiently restore the corrosive power of the regenerating treatment liquid.
It is presumed that this is because heavy metal ions such as nickel eluted from the metal plate into the waste liquid by the etching treatment interfere with the oxidation reaction.

Therefore, as a regeneration treatment method for sufficiently recovering the corrosive force, Japanese Patent Publication No. Sho 61-44814 discloses a method in which massive metallic iron is added to a waste liquid and heated and stirred to deposit a heavy metal. It has been proposed to remove chlorine as sludge and then blow chlorine gas into the waste liquid to regenerate it into ferric chloride liquid.

[0005]

However, in the above-mentioned regeneration treatment method, an excessive amount of metallic iron must be added in order to precipitate heavy metals, and the unreacted content of the added metallic iron is contained in the sludge produced. , And most of the metal components are iron components, and the content ratio of valuable metals such as nickel is not so high. For example, when metallic iron is added to a waste liquid of ferric chloride obtained by etching a stainless steel plate and a regeneration treatment is performed, 9 out of the metallic components contained in the sludge are
The iron component occupies 0% or more, and the nickel component is less than 10%. As a result, valuable metals such as nickel cannot be efficiently recovered from the obtained sludge, and there is a problem that the economical value of the sludge is low.

In order to increase the precipitation concentration, the present inventor previously proposed a method of adding metallic copper together with metallic iron to increase the treatment reaction rate (JP-A-2-229724). However, in this method, although the treatment reaction rate is increased, the metal copper to be added is expensive, and like the above-mentioned conventional technique, the sludge contains a large amount of unreacted unreacted metallic iron and the valuable metal in the sludge is contained. The content ratio of is low. Moreover, since a large amount of added metallic copper is contained in this sludge, the precipitated metallic nickel has a low purity, and there is still a problem that the economical value of the sludge is still low.

The present invention has been made paying attention to such a point, and nickel ions in the ferric chloride waste liquid can be efficiently recovered as metallic nickel, and nickel among the metallic components contained in the sludge can be effectively recovered. The technical issue is to increase the content ratio of sludge and improve the economic value of sludge.

[0008]

In order to achieve the above object, the present invention has the following method for recovering metallic nickel from a ferric chloride waste liquid containing nickel ions.
(Invention of Claim 1) Metallic iron is added to a liquid to be treated consisting of a ferric chloride waste liquid, and the mixture is heated and stirred to reduce the contained nickel ions to metallic nickel and to produce a ferrous chloride liquid. Precipitation treatment for separating a suspension containing ferrous iron liquid and sludge containing the above-mentioned metallic nickel precipitate (2)
And, newly add metallic iron to the separated sludge.
Without adding new ferric chloride waste liquid and stirring with heating,
After dissolving the iron component in the sludge is reacted with ferric waste chloride increased the concentration of the nickel component in the sludge, this
Concentration Treatment for Separating High Concentration Sludge and Suspension (3)
And a recovery process (4) for taking out the separated high-concentration sludge after the concentration process (3).

(Invention of Claim 2) In the constitution of Claim 1, the ferric chloride waste liquid is injected and hydrochloric acid is added in the concentration treatment (3).

(Invention of Claim 3) In the structure of Claim 1 or Claim 2, after the precipitation treatment (2), a liquid to be treated consisting of a new ferric chloride waste liquid is injected into the separated sludge, Nickel in sludge by adding metallic iron to the treatment liquid and stirring with heating, and subjecting the suspension containing the generated ferrous chloride liquid and the sludge precipitated to separate precipitation retreatment (2a) one or more times. The concentration of the components is increased, and then the concentration treatment (3) and the recovery treatment (4) are performed.

(Invention of Claim 4) In the structure of any one of claims 1 to 3,
The high concentration sludge separated after the concentration treatment (3) is again subjected to the concentration treatment (3) one or more times.

(Invention of Claim 5) In the structure of any one of claims 1 to 4,
The suspension separated in the concentration treatment (3) is used for at least one of the liquid to be treated of the precipitation treatment (2) and the reprecipitation treatment (2a).

Here, the above-mentioned reduction means that the dissolved metal ion is converted to a metal as a result of substitution, adsorption, coprecipitation, or another reaction. Further, the sludge means a precipitate in a broad sense including a precipitate of heavy metal which is reduced and precipitated.

[0014]

[Function] The ferric chloride waste liquid becomes ferrous chloride by the reaction with the metallic iron added in the precipitation treatment, but nickel ions in the waste liquid are reduced by the metallic iron added excessively, and metallic nickel is deposited. . The sludge containing the metallic nickel and a large amount of unreacted iron is separated from the suspension and then concentrated.
Since a new ferric chloride waste liquid is added without adding new metallic iron, the metal components in the sludge are dissolved .
It At this time, iron has a greater ionization tendency than nickel.
Therefore, the iron content is higher than the nickel content in the sludge.
It dissolves in a large amount. Moreover, the dissolved iron component and the ferric waste chloride ferrous liquid salts by being reacted generated, to
Is it due to nickel ions or sludge contained in the waste liquid?
Part of the dissolved nickel ions is converted to metallic nickel
To deposit.

When hydrochloric acid is added in the above concentration treatment ,
Metallic iron hydroxide and sludge in the suspension was dissolved, this
Dissolved iron component and the ferric waste or hydrochloric chloride to produce a ferrous chloride solution reacts.

Further, since a large amount of unreacted iron remains in the sludge precipitated by the precipitation treatment, when the precipitation retreatment is performed on this sludge, the amount of newly added metallic iron is smaller than that during the precipitation treatment. As a result, the metallic nickel component in the sludge increases.

On the other hand, when the unreacted metallic iron in the sludge is not sufficiently consumed by the reaction with the ferric chloride waste liquid in the concentration treatment, the unreacted metallic iron is sufficiently consumed in the sludge by repeating the concentration treatment. The concentration of metallic nickel in is increased.

Further, since no metallic iron is newly added in the concentration treatment, the suspension separated after the concentration treatment contains a relatively large amount of nickel ions, and this suspension is subjected to precipitation treatment or reprecipitation. When used as a liquid to be treated, nickel ions in this suspension are reduced and deposited as metallic nickel.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show a first embodiment of the present invention, FIG. 1 is a flow chart of a regeneration treatment process of ferric chloride waste liquid incorporating the recovery method of the present invention, and FIG. 2 shows a flow of this regeneration treatment. It is a device conceptual diagram shown.

In the nickel recovery method of this embodiment, as shown in FIG. 1, the precipitation treatment (2) incorporated in the regeneration treatment (1) of the ferric chloride waste liquid and the precipitation treatment (2) are performed. was repeated twice precipitated reprocessing to be performed on sludge and (2a), concentration treatment to elute unreacted excess metal iron contained in the sludge in di after the second deposition reprocessing (2a) (3 ) And the concentration process
According to (3), a recovery treatment (4) for recovering high-concentration sludge having a high content ratio of metallic nickel components is performed.

In the precipitation treatment (1), as shown in FIG. 2, first, a waste liquid of ferric chloride obtained by etching stainless steel is pumped from the waste liquid storage tank (11) into a reaction tank (1) by a pump (12).
3) Inject into Then, while adding metallic iron prepared in the form of granules having a size of about 5 mm to the waste liquid, the waste liquid is heated and heated to boil by vigorous stirring.

By this operation, the heavy metal ions in the waste liquid replace the added metallic iron to produce ferrous chloride liquid, and the nickel ions in the waste liquid precipitate as metallic nickel, and the unreacted excess of the metallic iron remains. It precipitates as sludge along with the generated ferrous hydroxide, etc. And
At the end of the above reaction, a suspension composed of ferrous chloride solution containing ferrous hydroxide having a relatively small specific gravity while leaving the sludge precipitated in the reaction tank (13) is treated liquid tank ( 14)
And the precipitation treatment (2) is completed.

The metallic iron added in the precipitation treatment (2) is 5
Although it may be in the form of lumps having a size larger than mm, or conversely, fine powders, the reaction proceeds faster as the surface area is increased by finely adjusting the size. Further, the temperature of the waste liquid may be heated to about 40 ° C. for the reaction, but the reaction can be remarkably accelerated by boiling or raising the temperature to near the boiling point as described above.

Next, a waste liquid storage tank is placed in the reaction tank (13).
A ferric chloride waste liquid is newly injected from the inside of (11), new metallic iron is added, and the mixture is heated and boiled, and precipitation reprocessing (2a) of vigorous stirring is repeatedly performed. This precipitation retreatment (2a) is
The sludge can be repeatedly applied until the remaining amount of sludge becomes large and stirring or the like becomes impossible, and in this embodiment, the precipitation retreatment (2a) is performed twice. In the precipitation retreatment (2a), an appropriate amount of hydrochloric acid may be added to dissolve ferrous hydroxide that could not be separated from the sludge in the previous precipitation treatment (2).

In the above precipitation reprocessing (2a), the previous precipitation processing is performed.
The excess amount of metallic iron remains in the sludge due to (2) or precipitation retreatment (2a), so that the amount of newly added metallic iron can be small. Then, although a certain amount of excess unreacted remaining in sludge in accordance with the amount of waste to be treated of the added metal iron remains, and contrast, each iteration of the metal nickel deposition reprocessing (2a) Since a predetermined amount corresponding to the treatment liquid amount is newly deposited, the metal nickel content ratio in the sludge can be increased as the precipitation retreatment (2a) is repeated.

The sludge produced by the precipitation treatment (2) and the precipitation retreatment (2a) increases the nickel content ratio and the residual amount by repeating the precipitation retreatment (2a), and finally the agitation is performed. Becomes impossible. Therefore, the concentration treatment (3) is performed immediately before the stirring becomes impossible. In other words, metallic iron is newly added to the sludge in the reaction tank (13) left after separation.
Without pressure, strongly stirred by injecting a new chloride ferric waste allowed to warm boiling, dissolving the iron component in sludge
After increasing the concentration of nickel component in the sludge,
The concentrated sludge and the suspension are separated.

By performing this concentration treatment (3), the iron component in the sludge, that is, the above-mentioned precipitation treatment (2) and precipitation retreatment
The metallic iron remaining in the unreacted portion added in (2a) is dissolved and reacts with the ferric chloride solution. At this time, the deposited nickel metal is also partially dissolved by the ferric chloride waste liquid,
Since iron has a greater ionization tendency than nickel,
The component dissolves more than the nickel component in the sludge
It Moreover, this dissolved iron component is the same as the ferric chloride waste liquid.
The reaction produces ferrous chloride solution, but with this reaction,
It dissolves from the nickel ions and sludge contained in the waste liquid.
A part of the solved nickel ions is reduced to give metallic nickel.
Is deposited as. As a result, a large amount of metallic iron component in sludge is consumed, while the dissolved amount of metallic nickel is
It is less than the amount of metal nickel , and therefore the content ratio of metallic nickel contained in the sludge increases.

Although only the ferric chloride waste liquid was injected in this embodiment, an appropriate amount of hydrochloric acid may be added at this time. In addition, in the present embodiment, the precipitation treatment (2a) is performed after the precipitation treatment (2).
However, the precipitation retreatment (2a) was omitted and the precipitation treatment was performed.
The sludge after (2) may be directly subjected to the concentration treatment (3), and also in this case, the concentration ratio of metallic nickel can be increased by the concentration treatment (3).

[0029] Then, after performing the concentration treatment (3), and facilities the collecting process (4) water washing removed the high concentration sludge is precipitated in the reaction <br/>応槽(13), nickel Obtain a recovered product with a high content. On the other hand, the suspension separated in the concentration treatment (3)
In a waste liquid storage tank (11) along with iron hydroxide with a lighter specific gravity
Will be returned.

Incidentally, in the sludge just subjected to the above precipitation treatment (2), as described in the prior art, the iron component occupies 90% or more of the metal component contained in the sludge,
Nickel content is less than 10%, but after precipitation treatment (2),
Precipitation reprocessing (2a) is performed twice, concentration processing (3) and recovery processing
In the recovered product of this example obtained by performing (4), as shown in Table 1 below, a recovered product containing more nickel component than iron component could be obtained.

[0031]

[Table 1]

The recovery process (4) completes all the process steps of the present invention, but the waste liquid regeneration process (1) is discharged to the process liquid tank (14) as shown in FIGS. 1 and 2. Separation treatment (5) and oxidation treatment (6) for ferrous chloride liquid
Is applied.

That is, the ferrous chloride solution stored in the treatment liquid tank (14) is sent to a filter press (15) and subjected to a separation treatment (5) for removing solid components such as ferrous hydroxide. To be done. Then, the solid component was separated in the separation treatment (5) .
The ferrous chloride solution is sent to the chlorine reaction tank (16), subjected to oxidation treatment (6) with chlorine gas, regenerated into ferric chloride solution, and stored in the ferric chloride solution tank (17). It is reused for etching.

At this time, the metal component of the solid component removed by the filter press (15) is dissolved with hydrochloric acid immediately after recovery, and if the nickel component is small, metallic iron is added to react with the remaining hydrochloric acid. After the above processing liquid tank (14)
When the nickel component is large, it is returned to the waste liquid storage tank (11), subjected to the above-mentioned regeneration treatment (1), and recycled without waste.

FIG. 3 is a flow chart showing the second embodiment of the present invention. The process of this embodiment is performed by the precipitation treatment (2) and 2
It consists of two precipitation retreatments (2a), three concentration treatments (3), and a recovery treatment (4).

First, in the precipitation treatment (2), the suspension separated in the previous concentration treatment (3) in the metallic nickel recovery step is used as a treatment liquid. In other respects, the same operation as the precipitation treatment (2) in the first embodiment is performed. Here, since the metallic iron is not added in the concentration treatment (3), the suspension separated in the concentration treatment (3) used as the treatment liquid contains a relatively large amount of nickel ions. Therefore, by subjecting this suspension to the precipitation treatment (2), the nickel ions contained therein can be reduced to metallic nickel,
The nickel component can be efficiently recovered.

Next, the precipitation retreatment (2a) is successively performed twice. In this case as well, similar to the above precipitation process, the previous concentration process
The suspension separated in (3) is used. Other points are
The same operation as the precipitation retreatment (2a) in the first embodiment is performed.

After performing the second precipitation retreatment (2a), the concentration treatment (3) is performed. In this case, the sludge separated by the precipitation reprocessing (2a) was newly added without adding metallic iron.
A stock solution of ferric chloride waste liquor is added and the same operation as in the first embodiment is performed. The sludge after the concentration treatment (3) still contains a large amount of unreacted iron, so the concentration treatment (3) is further performed twice. Although the amount of metallic nickel contained in the sludge is slightly reduced by the three times of concentration treatment (3), unreacted iron in the sludge is considerably consumed.
The content ratio of metallic nickel in sludge is significantly increased.

Thereafter, the recovery process (4) is carried out in the same manner as in the above embodiment.
Is applied.

[0040]

The present invention has the following effects because it is constructed and operates as described above. (Invention of Claim 1) In the process of regenerating the ferric chloride waste liquid, the liquid to be treated can be treated without adding new metallic iron to the sludge produced.
The content ratio of metallic nickel in the sludge can be increased by a simple treatment operation of adding a certain waste liquid, and the economic value of the sludge recovered product can be improved.

Moreover, the method for recovering nickel of the present invention can be incorporated in the reprocessing step of the ferric chloride waste liquid and can be carried out by using the reaction tank of the reprocessing as it is, so that no special equipment is newly required. Moreover, since it is only necessary to add metallic iron, it can be carried out at an extremely low cost.

Further, the added metallic iron is consumed for producing the ferric chloride solution, and the resources can be recycled without waste.

(Invention of Claim 2) When hydrochloric acid is added in the concentration treatment, unreacted metallic iron can be consumed by that much, and the metallic nickel content ratio in the sludge can be increased.

(Invention of Claim 3) Furthermore, when the precipitation retreatment is performed, the amount of metallic iron added is smaller than that in the case of the precipitation treatment because unreacted metallic iron is contained in the sludge. On the other hand, since a predetermined amount of metallic nickel corresponding to the amount of the treating liquid is deposited from the treatment liquid, a larger amount of metallic nickel can be deposited by repeatedly performing this precipitation retreatment. As a result, the content ratio of metallic nickel in the sludge can be dramatically increased, and the economic value of the sludge recovered product can be further improved.

(Invention of Claim 4) By repeating the concentration treatment, the iron component in the sludge can be reduced according to the number of repetitions, and as a result, the metallic nickel content ratio in the sludge can be relatively increased. it can.

(Invention of Claim 5) By using the suspension separated by the concentration treatment for the precipitation treatment or the precipitation retreatment, nickel ions contained in this suspension can be reduced to metallic nickel. Can be efficiently collected.

[Brief description of drawings]

FIG. 1 is a flowchart of a ferric chloride waste liquor regeneration treatment process incorporating the first embodiment of the present invention.

FIG. 2 is a conceptual diagram of an apparatus showing a flow of a recycling process of ferric chloride waste liquid.

FIG. 3 is a flowchart showing a second embodiment of the present invention.

[Explanation of symbols]

2 ... precipitation treatment, 2a ... precipitation retreatment, 3 ... concentration treatment,
4 ... Collection process.

Claims (5)

[Claims] 1. A method for recovering metallic nickel from a ferric chloride waste liquid containing nickel ions, which comprises adding metallic iron to a liquid to be treated consisting of ferric chloride waste liquid and stirring the mixture with heating to contain nickel. A precipitation treatment (2) in which ions are reduced to metallic nickel and ferrous chloride liquid is generated, and a suspension containing the ferrous chloride liquid is separated from sludge containing a deposit of the metallic nickel; Adding new metallic iron to the separated sludge
Without by injecting new ferric waste chloride was stirred warming, Sula
Tsu by dissolving iron component in di reacted with ferric waste chloride
After increasing the concentration of the nickel component in the sludge, the high
A second chloride process characterized by performing a concentration process (3) for separating the concentrated sludge and the suspension and a recovery process (4) for taking out the separated high-concentration sludge after the concentration process (3). Method for recovering metallic nickel from iron waste liquid. 2. The method for recovering metallic nickel from a ferric chloride waste liquid according to claim 1, wherein the ferric chloride waste liquid is injected and hydrochloric acid is added in the concentration treatment (3). 3. After the precipitation treatment (2), a liquid to be treated consisting of a new ferric chloride waste liquid is injected into the separated sludge, and metallic iron is added to the treated liquid and the mixture is heated and stirred to generate. Precipitation retreatment (2a) that separates the suspension containing ferrous chloride liquid and the precipitated sludge is performed one or more times to increase the concentration of nickel components in the sludge, and then concentration treatment (3) and recovery treatment The method for recovering metallic nickel from the ferric chloride waste liquid according to claim 1 or 2, wherein (4) is performed. 4. The high concentration sludge separated after the concentration treatment (3) is again subjected to the concentration treatment (3) one or more times, according to any one of claims 1 to 3. Item 1. A method for recovering metallic nickel from the ferric chloride waste liquid according to item 1. 5. The suspension obtained by the concentration treatment (3) is used as the liquid to be treated in at least one of the precipitation treatment (2) and the reprecipitation treatment (2a). The method for recovering metallic nickel from the ferric chloride waste liquid according to any one of claims 1.