JPS6363638B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] This invention relates to a method for producing metallic copper and chlorine, and more specifically, it relates to a method for producing metallic copper and chlorine, and more specifically, it relates to a method for producing metallic copper and chlorine. The present invention relates to a method for producing metallic copper and chlorine from a cuprous chloride-containing solution obtained by treating a waste solution such as a cupric chloride-containing waste solution generated during pickling of an alloy. [Prior Art] In recent years, a large amount of etching agents containing an aqueous solution of cupric chloride, to which hydrochloric acid and hydrogen peroxide have been added, have come to be used in large quantities for etching printed wiring boards. The treatment of waste liquid containing cupric chloride discharged after etching wiring boards has become a major problem in terms of pollution prevention. Further, the waste liquid generated after washing copper-containing stainless steel produced in steel mills and the like with hydrochloric acid contains cupric chloride, and the treatment of this waste liquid has also become a problem. As a method for treating these waste liquids, a method for recovering copper by electrolysis using an electrolytic cell without a diaphragm or an electrolytic cell with a filter diaphragm is known. [Problems to be solved by the invention] However, in electrolysis using the non-diaphragm method or electrolysis using the filtration diaphragm method, the recovery rate of copper is low and the solution Depending on the acidity of
Problems arise when cuprous chloride precipitates on the cathode, making it difficult to adopt it industrially. As described above, there is still no suitable method for treating the cupric chloride waste liquid that is discharged in large quantities, and the current situation is that it is difficult to dispose of it. [Means for solving the problem] This invention was developed as a result of intensive research in view of the current situation.
Cupric chloride, such as waste fluid discharged after etching printed wiring boards or waste fluid generated during pickling of copper alloys, is easily reduced by metallic copper to become cuprous chloride. This method succeeded in recovering highly pure metallic copper and chlorine from a cuprous chloride solution easily and at a significantly low cost. That is, in this invention, an aqueous solution of hydrochloric acid or a metal chloride is supplied to the anode chamber of an electrolytic cell which is divided into an anode chamber and a cathode chamber by a cation exchange membrane, and first chloride is preliminarily supplied to the cathode chamber. Supplying a solution of a chlorinated complex of cuprous chloride obtained by reacting copper with chloride ions, or/and allowing chlorine ions to be present in the cathode chamber at least in a concentration sufficient to form a chlorinated complex of cuprous chloride. This is a method for producing metallic copper and chlorine, which is characterized in that cuprous chloride is supplied in a state in which copper chloride is dissolved, chlorine gas is generated from an anode by electrolysis, and metallic copper is electrodeposited on a cathode. Hereinafter, the electrolytic cell and electrolysis method used in the present invention will be described in more detail with reference to the attached drawings. FIG. 1 shows an electrolytic cell, ancillary equipment, and routes used in the present invention. Reference numeral 1 is an electrolytic cell composed of unit electrolytic cells, and the inside is connected to an anode chamber 2 by a cation exchange membrane 4. It is divided into cathode chamber 3. 5 is an anode, and 6 is a cathode. 7 is a supply route for a chlorinated complex solution of cuprous chloride and/or a cuprous chloride solution to be supplied to the cathode chamber 3; 8
is an extraction route for the cathode compartment solution which draws out the cathode compartment solution containing hydrochloric acid or metal chloride from the upper part of the cathode compartment 3 and leads to the production tank 12 for preparing the chlorinated complex solution of cuprous chloride via the introduction route 13. be. The generation tank 12 is connected to a supply path 7 that supplies a chlorinated complex solution of cuprous chloride and/or a cuprous chloride solution to the cathode chamber 3 as a cathode chamber liquid, and the end thereof is connected to the cathode chamber 3. . 9 branches off in the middle of the extraction path 8 and connects to the anode chamber 2.
10 is a discharge section for the chlorine gas generated in the anode chamber 2, 11 is a discharge section for fresh salt water containing unreacted substances discharged from the anode chamber, and 14 is a channel for discharging the cuprous chloride solution. An introduction section 15 into the generation tank 12 is a chlorine ion supply section that introduces hydrochloric acid or a metal chloride aqueous solution of monovalent and divalent ions into the generation tank 12 . Cuprous chloride is obtained, for example, by treating a waste liquid containing cupric chloride obtained from etching printed wiring boards with metallic copper. This cuprous chloride is supplied from an introduction section 14 attached to the electrolytic cell 1 to a production tank 12 for producing a chlorinated complex of cuprous chloride. In this generation tank 12, hydrochloric acid in the catholyte supplied via the introduction route 13, or a metal chloride aqueous solution of monovalent or divalent ions, or/and hydrochloric acid newly supplied separately from the supply section 15, or monovalent , and an aqueous metal chloride solution of divalent ions, and is introduced and supplied to the cathode chamber 3 through the supply path 7 as a chlorinated complex solution of cuprous chloride. The decopper-removed cathode chamber solution containing hydrochloric acid or metal chloride aqueous solution taken out from the cathode chamber 3 via the extraction path 8 is introduced and supplied to the anode chamber 2 through a supply path 9 branched from the extraction path 8. Ru. Note that 16 in the figure is a water supply section for concentration adjustment. The electrolysis operation using this electrolytic cell 1 can be a continuous operation. Specifically, the liquid to be supplied to each part of the electrolytic cell 1 and the liquid and gas to be discharged from the electrolytic cell 1 are continuously fed and discharged. The chlorinated complex solution of cuprous chloride supplied to the cathode chamber 3 has a sufficient concentration of 0.01 mol/l to 2.2 mol/l, but is not particularly limited. When the concentration of monovalent copper ions in the cathode chamber 3 is low, one or more of hydrochloric acid or metal chlorides may be added as an electrolyte in order to reduce electrolyte resistance. In this case, the hydrogen ion concentration (PH) is preferably 4 or less. The amount of cations transferred from the anode chamber 2 to the cathode chamber 3 through the cation exchange membrane 4 is determined by the applied current together with coordination water. On the other hand, the concentration of the hydrochloric acid or metal chloride aqueous solution supplied to the anode chamber 2 is preferably in the range of 0.5 mol/l to 5 mol/l. These feed materials are the cathode chamber solution containing hydrochloric acid or metal chloride after copper removal in the cathode chamber 3;
A part of the liquid may be supplied separately as a new liquid, or may be combined and supplied. As cationic species of hydrochloric acid and metal chlorides supplied to the anode chamber 2, to the cathode chamber 3, and to generate a chlorinated complex of cuprous chloride outside the electrode chamber 1, , H ⁺ , Li ⁺ , Na ⁺ ,
K ⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ , specifically
HCl, NaCl, KCl, _MgCl2 , _CaCl2 , _SrCl2 ,
Examples include BaCl ₂ and the like. The dilute acid or salt water discharged from the anode chamber 2 is
It is sufficient if it is 0.5 mol/l or more, and economically it is preferable to increase the decomposition rate. The current density of electrolytic cell 1 is 1A/dm ² to 30A/dm ²
The range is preferably 5A/dm ² to 20A/d, considering the electrolytic cell capacity, electrolysis time, copper precipitation form, etc.
m ² is particularly desirable. Regarding the cation exchange membrane 4 used in the electrolytic reaction, ordinary cation exchange membranes such as carboxylic acid membranes and sulfonic acid membranes can be used, but since the concentration of hydrogen ions in the electrolytic bath is high, strong acid type membranes such as A cation exchange membrane having sulfonic acid groups is preferred. If a weak acid type cation exchange membrane is used, the resistance of the membrane increases and the cell voltage tends to increase, which is not very preferable. In addition, since the electrolytic bath itself is acidic, damage to the exchange membrane is small even if polyvalent cations are present, but as polyvalent cations, metal ions with a deposition potential nobler than copper are not suitable for obtaining pure copper. Not desirable. For the anode, a dimensionally stable insoluble metal anode such as graphite, magnetite, peroxide, or titanium coated with a platinum group metal is used. As the cathode is electrodeposited at a higher potential than hydrogen generation, electrolysis at room temperature is possible even in acidic solutions, so even if nickel, copper, titanium, or titanium alloys are used, corrosion will not occur. is not a problem. In this invention, instead of the chlorinated complex solution of cuprous chloride supplied to the cathode chamber 3, a solution of raw material cuprous chloride is supplied from the introduction part 14 to the production tank 12 and the supply path 7.
Although the slurry of cuprous chloride is supplied to the cathode chamber 3 through the slurry, the cuprous chloride slurry may be directly supplied to the cathode chamber 3. However, in the case of direct supply, it is necessary that the supplied cuprous chloride solution contains chlorine ions at a concentration sufficient to form a chlorinated complex of cuprous chloride at least in the cathode chamber 3. Such chloride ions can be added directly to the cathode compartment 3 in parallel with the supply of the cuprous chloride solution to the cathode compartment 3, or
Alternatively, a chlorine ion-containing liquid such as hydrochloric acid may be added to the cuprous chloride slurry from the supply unit 15 to the generation tank 12 before being supplied to the cathode chamber 3. achieved by. In addition, in the generation tank 12, means for supplying a chlorinated complex solution of cuprous chloride prepared in advance to the cathode chamber 3 from the supply path 7, and means for directly supplying the cuprous chloride solution described above to the cathode chamber 3. may be carried out in combination. [Function] By energizing the anode 5 and cathode 6 in the illustrated electrolytic cell 1, the chlorinated complex aqueous solution of cuprous chloride in the cathode chamber 3 is reduced and deposited on the surface of the cathode 6 as metallic copper. be done. On the other hand, in the anode chamber 2, the hydrochloric acid or metal chloride aqueous solution dissociates and exists as cations (hydrogen ions or metal ions of the corresponding metal chloride), which pass through the cation exchange membrane 4 together with the coordinated water to the cathode. It moves into the chamber 3, and generates hydrochloric acid or metal chloride with chlorine ions in the cathode chamber 3. A part of the cathode chamber solution containing hydrochloric acid or metal chloride produced by copper removal and free hydrochloric acid etc. contained in the chlorinated complex solution of cuprous chloride is supplied from the extraction route 8. The liquid is supplied to the anode chamber 2 through a path 9 and is reused as a feed material to the anode chamber 2, and the remaining cathode chamber liquid is passed through an introduction path 13 to a production tank 12 for preparing a chlorinated complex of cuprous chloride. Supplied. In the anode chamber 2, generated chlorine ions are discharged out of the system from the discharge section 10 as chlorine gas. In the generation tank 12, the new cuprous chloride solution supplied from the introduction part 14 is replaced with hydrochloric acid or metal chloride in the cathode chamber solution from the introduction route 13, or/and newly introduced separately from the supply part 15. The mixture is mixed with hydrochloric acid or an aqueous solution of monovalent or divalent metal chloride, and reacts, and is supplied from the supply path 7 to the cathode chamber 3 as a chlorinated complex solution of cuprous chloride. [Examples] The method of the present invention will be explained in more detail below with reference to Examples. Example 1 Electrolysis was carried out in continuous operation as follows using the electrolytic cell structure and attached piping system shown in FIG. A cuprous chloride-containing liquid obtained by previously treating a waste liquid containing cupric chloride obtained by etching a printed wiring board with metal copper was used as a raw material cuprous chloride solution. This raw material cuprous chloride solution is sent as a new solution from the introduction part 14 to the generation tank 12, and is reacted with hydrochloric acid to form a chlorinated complex solution of cuprous chloride. The chlorinated complex solution was supplied from the bottom of the cathode chamber 3 of the electrolytic cell 1 through the supply path 7. The aforementioned hydrochloric acid used in the generation tank 12 is the hydrochloric acid from the introduction route 13 and the newly replenished amount in the supply section 15. While supplying the cathode chamber solution containing hydrochloric acid obtained from the extraction path 8 to the supply path 9 to the anode chamber 2, metal copper is electrodeposited in the cathode chamber 3, and chlorine gas is taken out from the discharge section 10. A liquid containing unreacted hydrochloric acid was discharged from the discharge section 11. In this case, the specifications of the supply and discharge of each part, the operating conditions, etc., and the operating results were as shown in Table 1.

【table】

[Table] Example 2 A cathode chamber decoppered containing sodium chloride from the cathode chamber 3 without newly replenishing hydrochloric acid from the supply section 15 in the production tank 12 of the chlorinated complex of cuprous chloride in Example 1. Liquid extraction route 8 and introduction route 1
3, and is combined with the cuprous chloride solution from the route 14 in the generation tank 12, and the supply route 9
A cathode chamber solution containing sodium chloride was supplied to the anode chamber 2, and a sodium chloride solution was separately introduced into the cathode chamber 3 for electrolysis. In this case, the specifications of the supply and discharge of each part, the electrolytic operation conditions, and the operation results are as shown in Table 2.

【table】

〔Effect of the invention〕

This invention involves supplying hydrochloric acid or an aqueous solution of a metal chloride to the anode chamber of an electrolytic cell in which both cathode and cathode chambers are formed by a cation exchange membrane, and reacting cuprous chloride with chloride ions in advance to the cathode chamber. The obtained chlorinated complex solution of cuprous chloride is supplied, or/and cuprous chloride is supplied in a state in which chlorine ions are present in the cathode chamber at a concentration sufficient to form a chlorinated complex of cuprous chloride. The purpose is to supply chlorine gas and electrolyze it to obtain chlorine gas from the anode and metallic copper from the cathode.
Through such electrolytic treatment, high purity metallic copper and chlorine can be easily obtained with high efficiency. In addition, at that time, a part of the cathode chamber solution decoppered by electrodeposition of metal copper is used as the aqueous solution of hydrochloric acid or metal chloride to be supplied to the anode chamber, and a part of the cathode chamber solution is electrolyzed. It is possible to recover high-purity metallic copper and chlorine with higher efficiency while saving the supply of chlorine as much as possible. The cuprous chloride solution used in the method of this invention is
Waste liquid obtained from etching printed wiring boards,
Alternatively, it can be obtained very easily by reducing a cupric chloride-containing liquid such as a waste liquid obtained from pickling copper-containing alloys at a steel mill. By electrolyzing such a cuprous solution as a raw material, it is possible to produce approximately the same amount of metallic copper using approximately half the electricity compared to directly electrolytically treating waste liquid containing cupric chloride. First, it does not generate oxygen from the anode or dissolve copper at the cathode, and can produce highly useful chlorine.
This can be said to be an economical method that allows sufficient profit recovery even when the cost of reduction treatment of waste liquid containing cupric chloride is considered.

[Brief explanation of drawings]

FIG. 1 is a structural diagram showing an example of an electrolytic cell and its ancillary equipment used in the method of the present invention. 1... Electrolytic cell, 2... Anode chamber, 3... Cathode chamber, 4... Cation exchange membrane, 5... Anode, 6... Cathode, 7... Cuprous chloride solution or/and chlorinated complex solution of cuprous chloride. Supply route to the cathode chamber, 8... Extraction route for the decoppered cathode compartment solution, 9... Supply route for the anode compartment solution for the decoppered cathode compartment solution, 10... Chlorine gas discharge section, 11... Contains unreacted materials. Fresh salt water discharge section, 12... Generation tank, 13... Cathode chamber liquid introduction path, 14... Cuprous chloride solution introduction section, 15... Chlorine ion supply section.

Claims (1)

[Claims] 1. An aqueous solution of hydrochloric acid or a metal chloride is supplied to the anode chamber of an electrolytic cell which is divided into an anode chamber and a cathode chamber by a cation exchange membrane, and the cathode chamber is preliminarily filled with chloride. A chlorinated complex solution of cuprous chloride obtained by reacting cuprous chloride with chloride ions is supplied, or/and chlorine ions are added to the cathode chamber at a concentration sufficient to form a chlorinated complex of cuprous chloride. A method for producing metallic copper and chlorine, which comprises supplying cuprous chloride in a state in which it exists, generating chlorine gas from an anode by electrolysis, and electrodepositing metallic copper on a cathode. 2. Production of metallic copper and chlorine according to claim 1, characterized in that the aqueous solution of hydrochloric acid or metal chloride supplied to the anode chamber is a cathode chamber solution decoppered by electrodeposition. Law. 3 The chlorinated complex solution of cuprous chloride is obtained by extracting the decoppered cathode chamber solution and supplying it to the anode chamber, and reacting the chlorine ions in the remaining cathode chamber solution with cuprous chloride that is supplied separately. A method for producing metallic copper and chlorine according to claim 1, characterized in that: 4 A chlorinated complex solution of cuprous chloride supplied to the cathode chamber and/or a cuprous chloride solution supplied with chlorine ions present in the cathode chamber at a concentration sufficient to at least generate a chlorinated complex of cuprous chloride. The cuprous chloride in copper is obtained by reducing cupric chloride in the waste liquid generated during etching of printed wiring boards, as described in claim 1 or 2. A method for producing metallic copper and chlorine.