Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
  • C25C1/00—Electrolytic production, recovery or refining of metals by electrolysis of solutions
  • C25C1/12—Electrolytic production, recovery or refining of metals by electrolysis of solutions of copper
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S204/00—Chemistry: electrical and wave energy
  • Y10S204/08—AC plus DC
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S204/00—Chemistry: electrical and wave energy
  • Y10S204/09—Wave forms

Definitions

• the crude copper includes from 0.1 to 3.0 wt. percent of antimony and at least 0.1 wt. percent of arsenic.
• the present invention relates to a method for electrorefining crude copper containing antimony and arsenic in high concentrations to thereby obtain copper of high purity.
• the former is in the range of 0.002 to 0.09% or thereabout and the latter is in the range of 0.0003 to 0.06% or thereabout.
• the present invention is intended to provide a method for electrorefining crude copper including antimony and arsenic in such high concentrations as above to thereby yield a high-purity copper efficiently.
• the inventors of the present invention have electrolysed crude coppers including antimony and arsenic in high concentrations by applying various conditions for electrolysis and come to the findings as follows:
• the present invention has been accomplished on the basis of the foregoing findings obtained through electrolysis of crude coppers including 0.1% or more of arsenic and antimony in a high concentration under various conditions of electrolysis.
• the present invention relates to a method for electrorefining crude copper, which features a clever application of the process for a plating method known as the electroplating method of periodic reversal current to an electrorefining of those crude coppers of high antimony contents which have hitherto been considered to be difiicult or impossible to electrolyse by the known electrore'fining methods. That is, the process of making electric current flow in reverse directions at regular intervals, thereby efficiently producing a high-purity copper having a grade equal to that of the conventional electrolytic copper from said crude coppers through electrorefining.
• said regular flow of electric current means the case of applying an electric current by employing an electrode consisting of crude copper as the anode, that is, the case of impressing positive polarity on said electrode consisting of crude copper
• said reverse flow of electric current means the case of applying an electric current by employing an electrode consisting of crude copper as the cathode, that "is, the case of impressing negative polarity on said electrode consisting of crude copper.
• the arsenic content in a crude copper usually approximates the antimony content therein, it does not restrict the conditions of electrolysis so much as antimony in the operation of electrolysis under the foregoing various conditions.
• a crude copper including more than 3% of arsenic tends to lower the grade of products, and, therefore, it is desirable to use a crude copper including less than 3%, preferably less than 2%, of arsenic to be subjected to treatment by the method of the present invention.
• a rectifier capable of converting the polarity from positive to negative and vice versa, to set the ratio of the duration of the reverse current flow (seconds) to the duration of the regular current flow (seconds) at more than 4 preferably in the range of A to A and, in the case of the anode consisting of a crude copper including arsenic of not less than 0.1% and antimony in the range of from 0.1% to less than 0.4%, to set the duration of the reverse current flow preferably at less than 10 seconds, more preferably less than 5 seconds, while setting the duration of the regular current flow preferably at less than 200 seconds, and applying a current density of less than 400 amperes per square meter.
• the present invention is, as set forth above, a method capable of displaying an excellent effect in electrorefining of crude coppers including antimony and arsenic in high concentrations, a method capable of producing electrolytic copper in high efliciency particularly in the case of a crude copper including antimony of, say, less than 0.4% at as high a current density as 350 amperes per square meter.
• a crude copper including antimony of, say, less than 0.4% at as high a current density as 350 amperes per square meter.
• the grade of the resulting product electrolytic copper tends to be somewhat inferior to that obtained from a crude copper including less than 1% of antimony. Consequently, when the quality of the product is taken into consideration, a crude copper including less than 0.6% of antimony is most suitable to be treated by the method of the present invention.
• the distance between the crudecopper electrode (or anode) and the pure-copper electrode (or cathode) in an electrolytic cell is desirable to be maintained in the range of about 100 to 120 mm.
• the feeding of the electrolyte to the electrolytic cell in the present invention is operated in such a fashion that the electrolyte is put in said electrolytic cell through one end of the cell and discharged through the opposite end thereof for recycling.
• addition of a small quantity of the powder of an appropriate filtering assistant such as diatomaceous earth to the electrolyte to be filtered has the effect of not only keeping the function of the filter in good order for hours but also imparting fine appearance to the refined copper.
• the conditions for electrolysis other than those described in the foregoing are much the same as those for the conventional electrolysis, and yet, it is desirable that, in the electrolyte for use in the present invention, the concentration of Cut+ ion is in the range of about 40 to 50 g./l., the concentration of H 80 is in the range of about 170 to 210 g./l., and it is further advisable to add glue to the extent of from about 4 to 100 g./ton electrolytic copper and thiourea to the extent of from about 50 to 150 g./ton electrolytic copper to said electrolyte. As for Clion, it is appropriate to make its concentration in said electrolyte be less than 0.1 g./l.
• an electrolytic copper containing more than 99.99% of copper, less than 0.0002% of antimony and less than 0.0002% of arsenic.
• Example 1 Electrorefining was conducted by the use of a crude copper including 97.13% by weight of copper, 0.6% by weight of antimony and 1.6% by weight of arsenic as the anode.
• the electrolyte composed of 40 g./l. of copper and 200 g./l. of sulfuric acid (in concentration) was fed to the electrolytic cell by cycling at the rate of 18 to 20 l./min. while its temperature being held at 59 to 61 C.
• the electrolysis was effected by applying a current density of 200 to 220 amperes per square meter, there occurred an abnormal state about 45 hours after the start of electrolysis, whereby electrolytic dissolution of the anode became difficult and continuous operation of the electrolysis became impossible.
• the electrolysis was switched over to the method of the present invention. That is, upon setting the duration of the regular current flow to be 90 seconds and the duration of the reverse current fiow to be 3 seconds by means a polarity converter (a manufacture of Hirao Denki K.K.), electric current was flowed in opposite directions alternately. As a result, it became possible to perform the electrolysis very easily.
• a polarity converter a manufacture of Hirao Denki K.K.
• Example 2 When electrolysis was conducted by the use of a crude copper including 95.84% by weight of copper, 0.7% by weight of antimony and 2.6% by weight of arsenic as the anode and under the conditions for electrolysis of 220 am peres per square meter in current density, 59 to 61 C. in temperature of electrolyte, 100 mm. in electrodes distance, 18 to 20 l./min. in cycling rate of electrolyte, use of electrolyte consisting of 40 to 43 g./l. of copper, 190 to 200 g./l. of sulfuric acid, 0.2 g../l. of antimony and 1.3 g./l.
• the cell voltage for electrolysis in this case was 0.28 v. in the early stage and 0.28 v. at the end.
• the current efiiciency was 99.3% for the regular current fiow and 93.0% for the total current flow.
• the impurities among the deposited substances were more than 0.0001% of antimony and 0.0002% of arsenic.
• Example 3 When electrolysis was conducted by the use of a crude copper including 93.64% by weight of copper, 2.1% by weight of antimony and 3.4% by weight of arsenic as the anode and under the conditions for electrolysis of 220 amperes per square meter in current density, 59 to 61 C. in temperature of electrolyte, mm. in electrodes distance, 18 to 20 l./min. in cycling rate of electrolyte, use of electrolyte consisting of 40 to 43 g./l. of copper, 190 to 200 g./l. of sulfuric acid, 0.2 g./l. of antimony and 1.3 g./l.
• Example 4 As a result of continuous operation of electrolysis for about 2 months, using crude copper having copper content in the range of 99.0 to 99.2%, antimony content in the range of 0.1 to 0.19% and arsenic content in the range of 0.05 to 0.15% as the anode, under the conditions of 350 amperes per square meter in current density, 62 to 65 C. in temperature of electrolyte, 100 mm. in electrodes distance, 15 to 20 l./min. in cycling rate of electrolyte, use of electrolyte consisting of 38 to 42 g./l. of copper, 183 to 187 g./l. of H 80 0.01 to 0.037 g./l. of Cl and 0.3 g./l.
• the electrolytic copper obtained through this electrolysis contained less than 0.0001% of antimony and less than 0.0001% of arsenic. And, the current etficiency was 95.0% for the regular current flow and 86% for the total current fiow.
• a process for the electrolytic refining of crude copper which comprises subjecting to electrolysis a first electrode of crude copper containing from 0.1 to less than 0.4 Wt. percent of antimony and at leastO.1 wt. percent of arsenic to deposit purified copper onto a second electrode, employing as the electrolyte an aqueous solution containing sulfuric acid and copper ions and maintaining the temperature of the electrolyte in the range of about 55 to 65 C. during the electrolysis, the electrolysis being carried out by flowing a DC. current, at a current density of from to 400 a./m.
• a process for the electrolytic refining of crude copper which comprises subjecting to electrolysis a first electrode of crude copper containing from 0.4 to 3.0 wt. percent of antimony and at least 0.1 Wt. percent of arsenic to deposit purified copper onto a second electrode, employing as the electrolyte an aqueous solution containing sulfuric acid and copper ions and maintaining the temperature of the electrolyte in the range of about 55 to 65 C. during the electrolysis, the electrolysis being carried out by flowing a DC current, at a current density of from 150 to 250 a./m.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Electrolytic Production Of Metals (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=13861535

Family Applications (1)

Country Status (8)

Cited By (4)

• 0
  • BE BE790684D patent/BE790684A/xx unknown
• 1971
  • 1971-10-29 JP JP46085534A patent/JPS4850927A/ja active Pending
• 1972
  • 1972-10-24 DE DE2252036A patent/DE2252036A1/de active Pending
  • 1972-10-24 US US00299744A patent/US3824162A/en not_active Expired - Lifetime
  • 1972-10-27 CA CA155,021A patent/CA1003360A/en not_active Expired
  • 1972-10-27 SE SE7213968A patent/SE401529B/sv unknown
  • 1972-10-27 AU AU48228/72A patent/AU472070B2/en not_active Expired
  • 1972-10-30 ZM ZM170/72*UA patent/ZM17072A1/xx unknown

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