JPS589131B2 - How do you know what to do? - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for extracting and separating copper from metal sludge containing copper and other metals by solvent extraction.

It is generally known that extraction methods using solvents are effective for the separation and recovery of metals. ) or a liquid ion exchanger (JP-A-49-46501) has already been reported.

However, all of these known extraction solvents do not have a sufficiently high extraction rate of the target metal, or they are expensive due to their use life recycling treatment, so they are not necessarily suitable for extraction and recovery of metals on a practical scale. It wasn't suitable.

The present inventor focused on the physical and chemical properties of β-diketone compounds as metal chelating agents, and as a result of researching the practical application of these compounds in the extraction and separation of useful metals from metal sludge, the inventor found that a specific β-diketone compound It was discovered that by using a diketone, copper in particular can be separated and recovered from metal sludge with an excellent extraction rate, and based on this knowledge, the present invention was completed.

Furthermore, it has been unexpectedly discovered that the extraction rate can be significantly improved by performing the above-mentioned extraction process by using vertical stirring instead of the rotation conventionally used in the prior art.

The method of extracting and separating copper using β-diketone in the present invention combines this with a conventionally known copper amine forming step and further recovers the extracted copper through a back extraction step and an electrolytic recovery step, which are also known, resulting in extremely excellent effects. This can be an industrial method for separating and recovering copper.

That is, according to another method of the present invention, as shown in the flow diagram of FIG. 1, (1) a metal sludge containing copper and other metals is dissolved in an ammonia aqueous solution in the presence of an oxidizing agent such as air; Copper amine complexes etc. are formed, (2) an organic solvent solution of β-diketone is stirred and mixed with the ammonia aqueous solution containing these complexes to chelate copper, and selectively extracted into the organic solvent; ) Add a sulfuric acid aqueous solution to the above organic solvent phase to back-extract copper as copper sulfate, and then (4)
This aqueous copper sulfate solution is electrolyzed to recover copper as metal steel.

The high extraction rate of copper obtained by carrying out the present invention as described below is due to the extremely high distribution ratio of the chelate compound between β-diketone and copper, in other words, the solubility ratio of the chelate compound in the organic solvent phase and the aqueous phase. This is thought to be due to.

Alkyl substituted β- represented by the general formula RCOCH2COR
Regarding diketones, only a few methods have been used so far, such as the method of Adams et al. (American Journal of Chemistry, Vol. 66 (1944), 1
(see page 220), the synthesis was only attempted in the laboratory.

Only acetyl ketone with R=CH3 is commercially available as an analytical reagent, but its distribution ratio is not necessarily good, so β-diketones are generally not used for practical extraction and recovery of metals. has not been considered at all in the prior art.

The inventors have discovered that β-
When a diketone was synthesized and used for extraction and separation of copper,
It has been discovered that copper can be separated and recovered with particularly good extraction efficiency using β-diketones having a straight chain or branched alkyl group having 3 to 5 carbon atoms.

Among the alkyl-substituted β-diketones represented by the general formula RCOCH2COR, when R is an alkyl group having 2 or less carbon atoms, the solubility ratio is low, so the desired extraction rate cannot be obtained, and the carbon atoms If the number is 6 or more, even if the solubility ratio is sufficient, it is not preferable because the time required to reach extraction equilibrium increases.

The organic solvent used as the extraction solvent in the present invention may be any solvent as long as it has sufficient solubility for β-diketone and allows good separation of the organic phase and the aqueous phase.

Examples of such solvents include common organic solvents such as alkyl hydrocarbons, dichloroalkyl hydrocarbons, aromatic hydrocarbons, and halides thereof.

Table 1 below shows specific examples of β-diketones and organic solvents used as their solvents, along with experimentally measured solubility.

The ammonium compound for producing the copper amine complex may be any ammonium compound that produces NH4+ in an aqueous solution.
4Cl, NH4OH, (NH4)2CO3, etc.

By adjusting the pH of the aqueous solution to ammonia alkaline note, nickel, cobalt, zinc, cadmium, iron, etc.
Selective extraction of copper from aluminum etc. can be obtained.

The high extraction rate of copper obtained in the present invention is basically due to β
- Extraction of copper with diketones This is thought to be due to the high distribution ratio at equilibrium, that is, the molar concentration ratio of copper in the aqueous phase and the organic solvent phase.

Hereinafter, a case will be discussed in which DIBM is used as a chelating agent and toluene is used as an organic solvent.

In the present invention, various factors affecting the copper extraction rate,
For example the concentration of copper and ammonium ions in the aqueous phase,
pH value, organic phase/aqueous phase.

In order to examine the influence of volume ratio, etc., experiments were conducted by changing these conditions in the extraction process.

The results are shown below as Reference Examples 1 to 6.

The feature of the present invention is that a specific β-diketone is used for extraction and separation of copper, and the implementation of the present invention is not limited to the conditions shown in the following examples.

In each of the following examples, diimptyrylmetal (DIBM) prepared according to the method of Adams et al. was used as an extraction reagent, and this was used as a 1 molar solution in toluene as an organic solvent.

The sample containing copper to be extracted was an aqueous solution of cupric chloride to which NH4Cl and NH4OH were added and diluted with water.

Hydrochloric acid and sodium hydroxide were used to adjust the pH to avoid changes in ammonium ion concentration.

PerkinElma 13 for copper and pH quantification and measurement
A 9-spectrophotometer (manufactured by Hitachi, Ltd.) and an HM8 type pH glass electrode (manufactured by Toa Denpa) were used.

Reference example 1 The volume ratio of organic phase to aqueous phase (VO/VW) is the extraction rate of copper (
%), DIBM (diisoptyrylmethane) concentration 1. 20ml of 0M toluene solution
1, an ammonia aqueous solution having a copper concentration of 0.302 mol and an ammonium ion concentration of 113.55 mol and having a pH of 9.5 was added at a VO/VW ratio of 1/1 to 1/5.

Each liquid mixture was shaken for 30 minutes, and after standing still, the concentration of copper in the organic phase and aqueous phase was measured.

The results are shown in Figure 3.

In the figure, a is a graph showing the relationship between VO/VW and copper processing amount (mg), and b is a graph showing the relationship between VO/VW and copper extraction rate (%).

The larger the VO/VW, that is, the larger the volume of the organic phase, the greater the number of extracted fibers, but the larger the volume of the aqueous phase, the higher the copper throughput, that is, the concentration of copper in the organic phase.

When VO/VW=1/5, the copper concentration in 20 ml of the organic phase is approximately 200 mg (0.157 mol/l).

Therefore, in order to increase the extraction rate and processing amount of copper, it is desirable to increase the concentration of copper in the aqueous phase and further set VO/VW to 1/1.

Reference example 2 Stirring time of organic phase and aqueous phase in extraction process and extraction rate E
(%), 40 ml of an ammonia aqueous solution containing 0.0455 mol of copper was added to 10 ml of a 1 molar solution of DIBM in toluene and shaken for various times.

The results are shown in Figure 4.

The pH is 8.7 and the molar concentration of ammonium ions is 1.
It was set at 50.

As is clear from the figure, substantial equilibrium was reached approximately 5 minutes after the start of the experiment.

Reference Example 3 In order to examine the relationship between the ammonium ion concentration in the aqueous phase and the extraction rate in the amine complex compound formation step, DIBM
The concentration of ammonium ions in the aqueous ammonia solution added to a 1 molar solution of 1 molar solution in toluene was varied, and the extraction rate of copper after shaking for 30 minutes was determined for each case.

The source of ammonium ion formation is NH4O to stabilize the pH.
H and NH4Cl.

The molar concentration of copper is 0.0302 mol, and VO/VW is 1.
:1 and 1:4 and the pH is 9.5-9.9 and 9.
The results of 1 to 9.9 are shown in FIG.

In the figure, a indicates VO/VW=1:1 and b indicates VO/VW=1:
4 is a graph.

As is clear from the figure, the extraction rate decreases as NH4+ increases.

Therefore, when VO/VW = 1/1, the molar concentration of NH4+ is 1.5 or less, and when VO/VW = 1/4, it is 0.
．． It is preferable to set it to 4 or less.

Reference Example 4 DIBM is expressed as HA, and the reaction with copper ions is [Cu2+
]w+2[HA]o→←[CuA2]o+2H+.

w represents an aqueous phase and o represents an organic phase. [HA] concentration of o, pH
The larger the value, the greater the copper chelate formation.

In order to confirm this, a similar extraction operation was performed in the pH range of 3 to 13.

Furthermore, in this example, the molar concentrations of NH4+ and copper in the aqueous phase and the VO/VW ratio were each changed in two stages to examine their effects on the extraction rate.

The results are shown in Figure 6. Each graph (a), (b), (
c), (d) and (e) respectively show experimental results based on the following factors.

Organic phase Aqueous phase NH4+ Molar concentration Cu Molar concentration VO/VW (a) 1 molar solution of DIBM in toluene 10 ml 1.78
0.03 1/4(b)
〃 〃 3.20
0.03 1/4(c) 〃
15ml 3.20
0.03 1/1(d) 〃
10ml 1.78
0.15 1/4(e) 〃
15ml 1.78
0.15 1/1 As shown in the diagram, the extraction rate is VO/
The larger the VW is, the lower the NH layer concentration is, the higher it becomes.

Therefore, the pH (aqueous phase) is preferably 8 to 8 and less than 5.

Note that the reason why the extraction rate increases again at pH 9.5 or higher is due to the increase in the anion concentration in the aqueous phase of the chelating agent (DIBM).

For this reason, pH adjustment is also an important factor.

However, assuming that copper exists at a high ammonia concentration in the aqueous phase, and assuming that 4 mol of amine is coordinated to 1 mol of copper under the ammonia concentration conditions used here, [Cu(NH3)42+]w+2[ HA〕o→←〔Cu
Since it is expressed as A2]o+2H++4[NH3]w,
Regarding the factors of ammonium and pH that affect the distribution ratio, that is, the extraction rate, adjusting the ammonium concentration is more effective than adjusting the pH.These factors influence the distribution ratio D by the square of pH and the fourth power of ammonium concentration. do.

However, as shown in Figure 6, the copper concentration is 0.15 molNH
In the case of 4+1.78 mol, if the pH is attempted to be lower than 8, copper will be hydrolyzed and it will be difficult to adjust the pH.

Reference Example 5 In order to determine the relationship between the copper ion concentration in the aqueous phase and the extraction rate, in the extraction experiment, VO/VW = 1/4, pH = 8.9
Changes in the extraction rate were confirmed by varying the content of copper in water and the phase, with the NH4+ molar concentration being 1.50.

The results are shown in FIG. In the figure, graph a shows the relationship between the concentration of copper initially present in the aqueous phase (mg/40ml) and the copper extraction rate (%), and graph b shows the relationship between the above copper concentration and the amount of copper extracted in the organic phase (mg/40ml). 10ml).

As is clear from the figure, the copper concentration in the aqueous phase is 160mg/
Below 40 ml, the copper extraction rate is about 95% (graph a), but as the copper concentration increases beyond that, the extraction rate decreases rapidly.

The maximum amount of copper extracted in the organic phase is approximately 170 mg/10 ml.
(graph b) corresponds to approximately 0.27 mol, thus indicating that 54% of the theoretical amount of the chelating agent DIBM used was coordinated to copper.

Note that in the case of pH = 9.5, NH4 + molar concentration = 3.55, and VO/VW = 1/1, the copper concentration in the organic phase increases as the copper concentration in the aqueous phase increases. No major change was observed in the extraction rate, which was approximately 42% (Figure 8).

Reference Example 6 In order to determine the relationship between the number of repetitions of the extraction process required to obtain the desired extraction rate and various factors, the lower aqueous phase that has reached extraction equilibrium is separated and a new organic material is added to it. Further extraction was performed by adding a solvent, and this operation was repeated.

The results are shown in Figure 9. In the figure, each graph (a), (b),
(c) and (d) show the results when factors such as the VO/VW ratio, the molar concentration of copper and ammonium ions in the aqueous phase, and the pH value were changed in two steps and combined.

Organic phase NH4+ molar concentration Copper molar concentration pH VO/VW (a) DIBM
15 ml of a 1 molar solution in toluene of 3.55
0.302 9.53 1/1(b)
〃 10ml 3.55
0.302 9.53 1/4(c)
〃 10ml 1.50
0.300 10.07 1/4(d)
〃 15ml 1.50
0.300 10.07 1/1 As shown, for a nearly constant copper concentration, the higher the ammonium ion concentration, the lower the extraction rate and therefore the more iterative cycles required to obtain the required extraction rate.

The smaller the volume ratio VO/VW, the higher the extraction rate and the fewer repetitive cycles required.

When separating and extracting copper according to the present invention, an ammonia aqueous solution containing a copper complex amine compound and an organic solvent solution containing β-diketone are stirred and mixed. It has been discovered that a far superior extraction rate can be obtained compared to rotary stirring.

This is thought to be due to the fact that the liquid to be stirred, which is caused to flow in countercurrently by vertical stirring, is subdivided into droplets that are much smaller than in the case of rotary stirring, and the contact area between them increases.

The present invention also provides an extremely excellent stirring device for use in such a solvent extraction method, which will be explained below with reference to the drawings.

In FIG. 2, reference numeral 5 denotes an extraction column, which is equipped with inlets 6 and 7 for countercurrent stirring of organic solvents and aqueous solutions, and outlets 8 and 9 for them after phase separation.

Inside the column 5, stirring disks 11 having a substantial stirring surface in the counter-current direction are arranged in multiple stages at a constant pitch, and a stirring device 10 is connected in the column length direction. It has been inserted into.

The upper end of the operating shaft 12 projects above the extraction tower 5 and is connected to an operating direction changing member such as a crank 14, and is connected to a motor 15 via a pulley 13.

In the illustrated example, the interstage pinch of the rotor blade disk 11 is 50 mm.
On the other hand, the vertical stroke given by the crank is 25 mm, but this pitch can be changed as appropriate.

Based on the results of Reference Examples 1 to 6, the pH, VO/VW, and other factors were appropriately determined, and the method of the present invention was carried out using the extraction column equipped with the above-mentioned vertical stirring device.

The results are shown in Examples 1 and 2 below.

Example 1 An aqueous solution of cupric chloride and an aqueous solution of ammonium chloride and ammonia were mixed to form a 0.06 molar concentration of copper and 0.
．． An aqueous solution containing 30 molar NH4+ was prepared and HC
1 and NaOH were added to bring the pH to 10.0.

On the other hand, a 1 molar solution of DIBM in toluene was prepared, and the ammonia aqueous solution and organic solvent solution were respectively introduced from the top and bottom of the extraction column shown in the second diagram at a rate of 20 ml/min (ie, VO/VW = 1).

Stirring was performed by vertical movement of 25 mm three times per second, and the separated organic and aqueous phases were taken out, and the organic phase was sent to an electrolytic cell via a back extraction device using an aqueous sulfuric acid solution, where it was deposited as metallic copper around the copper electrode and recovered. .

The aqueous phase was recycled and used to prepare the ammonia aqueous solution.

The copper extraction rate reached 99.82%. Example 2 The same procedure as in Example 1 above was repeated with a copper concentration of 0.19 molar and an NH4+ concentration of 1.98 molar and a pH of 9.73.

The copper extraction rate was 95.43%.

[Brief explanation of drawings]

FIG. 1 is a flow diagram showing the steps of the method of the present invention, FIG. 2 is a vertical sectional view schematically showing the extraction apparatus used in the method of the present invention, and FIGS. It is a graph which shows the relationship between the various conditions used and extraction rate, respectively. In the figure: 1... Ammonia complexation process, 2... Extraction process, 3... Back extraction process, 4... Electrolytic recovery process, 5...
・Extraction column, 6... DIBM toluene solution inlet, 7.
... Ammonia aqueous solution inlet, 8... Copper chelate liquid outlet, 9... Ammonia aqueous solution outlet, 10... Stirring member, 11... Stirring disk, 12... Operating shaft, 13
...Pulley, 14...Crank, 15...Motor.

Claims (1)

[Claims] 1. In a method for extracting and separating copper from a metal sludge containing copper and other metals, the metal sludge is treated with an aqueous solution containing ammonium ions, and the resulting aqueous solution is treated with the following formula: represents an alkyl group having 3 to 5 carbon atoms) in an organic solvent, and the mixture is stirred and mixed. 2. A method for extracting and separating copper from a metal sludge containing copper and other metals, including (a) an amine complex formation step in which an ammonia aqueous solution is added to the metal sludge while introducing air; (b) the amine To the aqueous solution from step (a) above containing the complex compound is added a solution of a β-diketone in an organic solvent having the following general formula: where R represents an alkyl group having 3 to 5 carbon atoms. a copper extraction step, (c) a back extraction step in which an aqueous sulfuric acid solution is added to the organic solution containing copper extracted as a chelate compound in step (b) to extract copper as copper sulfate; and (d) a back extraction step in which copper is extracted as copper sulfate. A method characterized by comprising an electrolytic recovery step of electrolyzing the copper sulfate extracted in c) to produce metallic copper. 3. In an apparatus for extracting and separating copper from metal sludge containing copper and other metals, each alkyl group contains 3 to 5
An aqueous solution obtained by treating a metal sludge containing copper and other metals with an aqueous solution containing ammonium ions is extracted from the bottom of a vertical extraction tower. an operating member for stirring, which is supplied from the upper part of the extraction tower in an inflow direction that contacts each other countercurrently, and is configured to move up and down inside the extraction tower along the inflow direction; 1. An apparatus characterized in that a stirring plate is provided in multiple stages relative to an operating member, and each stage is provided with a stirring plate that has a substantial stirring surface in the direction of vertical movement.