JPH0114317B2 - - Google Patents

Description

[Detailed description of the invention]

FIELD OF THE INVENTION The present invention relates to a copper electrolyte purification method, particularly in connection with an ion exchange-hydrochloric acid elution-sulfidation-electrowinning process for removing Sb and Bi contained in a copper electrolyte. , relates to a copper electrolyte purification method characterized in that hydrochloric acid is synthesized by reacting hydrogen sulfide with chlorine gas produced as a by-product during electrolysis, and the synthesized hydrochloric acid is reused in the elution step. BACKGROUND OF THE INVENTION In electrolytic refining of copper, electrolysis is carried out by suspending a large number of purified copper anodes and cathodes made of copper seed plates in an electrolytic tank. Sb, Bi, in copper anode
Most of the As is once eluted into the electrolytic solution by the electrolytic treatment, but Sb and Bi usually reach a saturation concentration, so they precipitate and become anode slime. In this way, the precipitated slime deposited from the electrolytic solution is fine and easily floats in the solution, and has an extremely high contribution rate to the contamination of electrodeposited copper compared to the deposited anode slime. In order to produce high-quality electrodeposited copper, it is necessary to prevent the concentration of impurities in the electrolyte from accumulating above a certain level, so a portion of the electrolyte is periodically extracted and purified. ing. Previous liquid purification methods have mainly focused on removing Cu, Ni, and As from the liquid, and Sb and Bi were removed together with the arsenization electrolysis to remove As. Therefore, Sb,
Removal of Bi depends on the amount of arsenization treatment liquid, and the removal of Sb and Bi using the current method is as follows:
Since the concentration in the electrolyte is 1/10 to 1/30 lower than that of As, there was a problem in terms of cost. Therefore, several methods have been proposed to remove Sb and Bi from the electrolyte solution, but one method uses a combination of ion exchange method and sulfidation/electrowinning method to selectively separate and recover Sb and Bi. has been developed and is attracting attention. The above method consists of a process in which Sb and Bi in a copper electrolyte from which Cu, Ni and As have been removed are adsorbed and separated using an ion exchange resin, and the adsorbed Sb and Bi are eluted from the resin with hydrochloric acid; by sulfiding
This is a combination of a sulfidation/electrowinning process in which Sb is separated and recovered as Sb ₂ S ₃ and the solution after Sb removal is subjected to Bi removal electrolysis to recover electrodeposited Bi. This Bi-removal electrolytic process is an electrowinning process of Bi from an acidic hydrochloric acid solution containing Bi, and chlorine gas is produced as a by-product during electrolysis. For work hygiene reasons, we have struggled to find countermeasures against the by-product chlorine gas, but no measures have been found that can be applied to actual industrial processes. Summary of the Invention As a result of repeated studies on the possibility of synthesizing hydrochloric acid from chlorine gas generated during electrowinning of an acidic solution of hydrochloric acid and reusing the synthesized hydrochloric acid, the inventor discovered that hydrogen sulfide could be added to the chlorine gas. It has been found that by synthesizing hydrochloric acid through reaction, hydrochloric acid recycling in the involved processes can be suitably carried out, and this greatly contributes to the economic efficiency of the process. Thus, the present invention comprises the steps of passing a copper electrolyte through an ion exchange resin adsorption bed capable of adsorbing Sb and Bi, and eluting the ion exchange resin adsorption bed adsorbing Sb and Bi with hydrochloric acid to remove Sb and Bi. an elution step to generate an eluent containing Sb, a step to sulfurize the eluent and separate Sb as Sb ₂ S ₃ , and a step to electrolytically win Bi by electrolyzing the solution after removing Sb to remove Bi; To provide a method for purifying a copper electrolyte, which includes a step of reacting hydrogen sulfide with hydrogen sulfide, which is sometimes a by-product, and a step of synthesizing hydrochloric acid, and a step of reusing the synthesized hydrochloric acid in the elution step. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 shows the Sb-Bi removal flow sheet of the copper electrolyte described above. The copper electrolyte is passed through the adsorption bed and Sb and Bi are adsorbed onto the ion exchange resin. The post-adsorption liquid and cleaning liquid are returned to the copper electrolysis process. Elution is effected with hydrochloric acid, producing an eluent containing Sb and Bi. The eluent was sulfurized by H ₂ S blowing, and Sb
is separated as Sb ₂ S ₃ and sold externally or subjected to an Sb recovery process. After removing Sb, the solution is desorbed to electrolytically extract Bi.
It is subjected to Bi electrolysis to obtain electrodeposited Bi. Electrodeposited Bi
is sent to the Bi purification process. At the same time, chlorine gas is produced as a by-product. The chlorine gas and the post-electrolysis solution are subjected to a hydrochloric acid synthesis step under H ₂ S injection. The hydrochloric acid synthesis reaction is Cl ₂ + H ₂ S → 2HCl + S°, and 2Cl ₂ + 2H ₂ S + 2H ₂ O + 3O ₂ → 2HCl + 2H ₂ SO ₄ occurs as a side reaction. Therefore, the hydrochloric acid produced contains a small amount of sulfuric acid. The generated hydrochloric acid is returned to the elution step and reused, but a desulfation step to remove sulfuric acid may be provided before that, or as a more convenient method, a portion of the generated hydrochloric acid, for example 5 to 15% By extracting the sulfuric acid from the system, the sulfuric acid concentration in the reused hydrochloric acid can be kept below the allowable level. The generated solid sulfur is removed from the system by filtration or the like. Since H ₂ S is used in the sulfurization step and the HCl synthesis step, it is convenient to use a common H ₂ S source. The HCl synthesis reaction using the Cl ₂ −H ₂ S−H ₂ O system makes it possible to synthesize HCl in high yield, as shown in the following experimental example. ) No. 1, No. 2, and No. 3 containers containing 200 c.c.
This was done by arranging two containers containing water (at room temperature) in series downstream. The arrangement of this test apparatus is shown in FIG. The HCl production rate was calculated using the following formula. HCl production rate = Cl increase amount in HCl liquid / Cl ₂ injection amount x 72 / 78 x 1
00(%) T・S゜ Generation rate = T・S amount in free sulfur / H ₂ S injection amount × 32 /
34×100(%) The results are summarized in the table below.

【table】

[Table] Example In the flow sheet shown in Figure 1, a quantity balance was established under the following conditions, and smooth operation could be continued for a long period of time: Preconditions for determining quantity (1) Amount of cut outside the system: Sb≒3t /M, Bi≒1.2t/M (2) Electrolyte concentration: Sb≒0.35g/, Bi≒0.20g/
(3) Resin adsorption capacity: Sb≒16g/, Bi≒6.4g/
(4) Eluent concentration: Sb≒20g/, Bi≒12g/ (A) Copper electrolyte: 10000m ³ /M Adsorption: Post-adsorption solution 10000m ³ /M Washing (water): Washing liquid 200m ³ /M Elution: Eluent 150m ³ /M Resin 6.3m ³ /M (B) Sulfurization (eluent 150m ³ /M, H ₂ S 1.5t/M):
Sb ₂ S ₃ 5t (dry weight) After Sb removal liquid 150m ³ /M (C) Bi removal electrolysis: After electrolysis liquid 150m ³ /M, chlorine gas
0.9T/M, electrodeposited Bi 1.2T/M (D) HCl synthesis: 0.44T/M H ₂ S, 150m ³ /M solution after electrolysis, 0.9T/M chlorine gas (E) 90% of HCl reused 10% removal outside the system (F) Effect of HCl replenishment invention Sb contained in copper electrolyte for copper electrolyte purification
and ion exchange to remove Bi - hydrochloric acid elution -
In connection with the sulfidation-electrowinning process, we have established a countermeasure for the chlorine gas produced as a by-product during electrolysis, which had previously been difficult to implement. By reacting hydrogen sulfide with hydrochloric acid to synthesize hydrochloric acid and reusing the synthesized hydrochloric acid in the elution step, we succeeded in making the process safer and more economical, and furthermore, we succeeded in making the process safer and more economical by reacting hydrogen sulfide with hydrogen sulfide. Since it can be used in common, there is no burden on process costs.

[Brief explanation of drawings]

FIG. 1 shows a flow sheet of the copper electrolyte purification process of the present invention, and FIG. 2 shows the hydrochloric acid synthesis experimental equipment.

Claims (1)

[Claims] 1. A step of passing a copper electrolyte through an ion exchange resin adsorption bed capable of adsorbing Sb and Bi, and eluting the ion exchange resin adsorption bed adsorbing Sb and Bi with hydrochloric acid to contain Sb and Bi. an elution stage to generate an eluent, a stage to sulfurize the eluent and separate Sb as Sb ₂ S ₃ , and a stage to electrolyze Bi to remove Bi from the solution after removing Sb. A copper electrolyte purification method comprising the steps of: reacting by-produced chlorine gas with hydrogen sulfide to synthesize hydrochloric acid; and reusing the synthesized hydrochloric acid in the elution step.