Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B15/00—Obtaining copper
  • C22B15/0026—Pyrometallurgy
  • C22B15/006—Pyrometallurgy working up of molten copper, e.g. refining
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B15/00—Obtaining copper
  • C22B15/0026—Pyrometallurgy
  • C22B15/0028—Smelting or converting
  • C22B15/0052—Reduction smelting or converting

Definitions

• the present invention relates to a pyrometallurgical refining process for copper.
• An object of the present invention is to provide an improved process for refining copper, which can economically be effected with a high reaction efiiciency.
• Another object of the present invention is to provide a new process for refining copper, wherein the maximum result in the heating, oxidation and reduction can be fully achieved solely through the feeding of fuel blended with air containing oxygen in various densities (hereinafter referred to as air).
• a further object of the present invention is to provide a new process wherein copper can be refined by appropriately adjusting the ratio of fuel to air respectively for each stage of heating, oxidation and reduction without the aid of any other additional fuel.
• the conventional pyrometallurigical process for copper refining includes the stages of anode refining into refined blister, followed by electrolytic refining into copper cathode, and subsequent melting and casting into wire bars. Similar processes are also widely practised in the treating and refining of copper scrap.
• These conventional processes generally comprise melting copper charge, heating in a reverberatory or any other type of suitable furnace, and removing impurities container in the said charge by oxidation with air, and finally reducing Cu O.
• Oxidation is effected by means of air being blown onto the surface of molten mass or into the molten mass, causing to separate Pb, Zn, S, As, Sb, Ni, Co, Mn, Bi and Fe contained in the molten mass from the molten copper.
• the volatile impurities are carried away in the waste gas, whilst those remaining in the slag floating on the surface of molten copper are skimmed out of the furnace.
• the molten copper remaining in the furnace is fully or almost saturated with Cu O.
• the said molten copper is reduced with a reducing agent to remove oxygen, the refining of copper will then be completed.
• the thus-refined copper is then cast in casting moulds to the desired form.
• the reducing operation as herein set forth is the so-called poling wherein green wood is considered as the most suitable as a reducing agent. Since the suitability of green wood referred to above depends on its water content, size and shape, its availability and cost offers an economic problem.
• the present invention is to provide an improved refining process which entirely overcomes these above-mentioned defects and disadvantages.
• the characteristic feature of the present invention lies in that the best results can be achieved in each stage of heating, oxidation and reduction by merely feeding fuel blended with air.
• the fuel used in the present invention may be liquid fuels such as heavy oil and light oil, or pulverized carbonaceous material including solid fuels such as coal, coke, charcoal, saw-dust and the like.
• these in the powdered form are mixed with air in the desired ratio and blown beneath the surface of the molten mass, by means of a combined mixing and feeding apparatus such as variable speed feeder with injector.
• a combined mixing and feeding apparatus such as variable speed feeder with injector.
• liquid fuels are similarly blown into the molten mass in atomized form by such means as an injection feeder.
• the refining reaction takes place in two stages, namely the oxidation and the reduction of the molten copper.
• the oxidation stage selective oxidation is effected at optimum temperature by utilizing the lower oxidizing tendency of copper than other impurities, while in the reducing stage, deoxidation is carried out at optimum temperature by a close contact of a reducing agent with oxygen in molten copper, and it is to be noted that optimum temperature is also required in subsequent casting operation.
• the oxygen ratio namely the ratio of the actually supplied amount of oxygen (b) to the theoretical amount of oxygen (a) necessary for combustion, that is, b/aXlOO (percent), within the ranges of approximately to 130% during heating, within the range of approximately to 200% during oxidation and within the range of approximately 20 to 100% during reduction, in order to effectively accomplish the respective objects.
• the desired refining can be advantageously and economically carried out by merely adjusting the above-mentioned oxygen ratio within the rang-e of 20 to 200%, without the aid of the additional or supplemental fuel such as heavy oil, as in the case of conventional known processes. Furthermore, because of its simple and inexpensive operation, the process of the present invention is superior to any of the conventional processes.
• the fuel used in this process may be one or a mixture of two or more kinds of fuels. Further, a different kind of fuel may respectively be used for each stage of oxidation, reduction and heating, or instead thereof, the oxygen density in the air may sometimes be varied with the kind of fuel used.
• Example 1 Type of charcoal Shiro-Zumr (whitlsh charcoal). Approximately 20 metric tons of molten copper (con- Size 5 mfish taming 0.02% and O 0.0%) from converter were p i t analyses; charged in a 40 metric ton cylindrical anode furnace, and c l ifi value 920 cal/kg slag floated on the surface of molten mass was skimmed 3 Volatile matter 5% off, and then pulverized coal was blown into the molten 0 Fixed carbon 4 Copper at the rate of 0.8 kg./min. and the oxygen ratio Ash maintained at 150%.
• the pulvenzed coal used was as follows' mixing ratio 'by weight of 50:50, was 0.8 kg./min. and the Type of coal Washed pulverized coal. oxygen ratio 140%, and in the next stage of 40 min. under Size -150 mesh. the conditions where the fuel feeding rate was 1.5 kg./min. Proximate analyses: and oxygen ratio 30%. After the second charging of Calorific value 7,910 cal./ kg.
• the pulverized charcoal used was similar to that in Example 2. Analyses of the wire bar obtained were as follows.
• Example 5 54 metric tons of electrolytic copper were charged into a 55 metric ton reverberatory furnace and melted by burning heavy oil. Scum was skimmed out. Then, saw-dust was blown into the molten mass under the conditions where the fuel feeding rate was approximately 5 kg./ min. and the oxygen ratio 27 to 30%. A portion of melt was taken out and analysed after blowing for 80 min. As the result was found satisfactory, the blowing was stopped and the finished product cast in the usual manner into wire bars.
• a pyrometallurgical refining process for copper wherein a molten bath of unrefined copper is subjected to consecutive stages of heating, oxidation and reduction, said process comprising the steps of blowing directly into the bath of unrefined copper a mixture of oxygen and a fuel selected from the group consisting of liquid oil and solid carbonaceous material while heating the bath, adjusting the volume of oxygen in the mixture to an oxygen-fuel ratio capable of oxidizing the copper, continuing the blowing of the adjusted mixture directly into the copper bath until the oxidation is completed, adjusting the volume of oxygen in the mixture to an oxygen-fuel ratio capable of reducing the copper, and then continuing the blowing of the adjusted mixture directly into the copper bath until the reduction is completed.
• unrefined copper is selected from the group consisting of blister copper, electrolytic copper and scrap copper.
• the unrefined copper consists of a mixture of two different substances selected from the group consisting of blister copper, electrolytic copper and scrap copper.
• a pyrometallurgical refining process for copper wherein a molten bath of unrefined copper is subjected to consecutive stages of heating, oxidation and reduction, said process comprising the steps of blowing directly into the bath of unrefined copper a mixture of oxygen and a fuel selected from the group consisting of liquid oil and solid carbonaceous material while heating the bath, the oxygen b/a ratio ranging between 80 and 130, adjusting the oxygen b/a ratio to one ranging between 100 and 200, continuing the blowing of the adjusted mixture directly into the copper bath until the oxidation is completed, adjusting the oxygen b/a ratio to one ranging between 20 and 100, and then continuing the blowing of the adjusted mixture directly into the copper bath until the reduction is completed, said oxygen b/a ratio being one hundred times the ratio of the actually supplied amount of oxygen to the theoretical amount of oxygen necessary for combustion.
• a pyrometallurgical refining process for copper wherein a molten bath of unrefined copper is subjected to consecutive stages of heating, oxidation and reduction, said process comprising the steps of blowing directly into the bath of unrefined copper a mixture of air and a fuel selected from the group consisting of liquid oil and solid carbonaceous material while heating the bath, the density of oxygen in the air being adjusted in accordance with the type of fuel, further adjusting the volume of oxygen in the air to a mixture ratio capable of oxidizing the copper, continuing the blowing of the adjusted mixture directly'into the copper bath until the oxidation is completed, further adjusting the volume of oxygen in the air to a mixture ratio capable of reducing the copper, and then continuing the blowing of the adjusted mixture directly into the copper bath until the reduction is completed,
• a pyrometallurgical refining process for copper wherein a molten bath of unrefined copper is subjected to consecutive stages of heating, oxidation and reduction, said process comprising the steps of blowing directly into the bath of unrefined copper a mixture of oxygen and a fuel selected from the group consisting of liquid oil and solid carbonaceous material while heating the bath, adjusting the volume of oxygen in the mixture to an oxygen-fuel ratio capable of oxidizing the copper, continuing the blowing of the adjusted mixture directly into the copper bath while violently stirring the bath until the oxidation is completed, whereby impurities are effectivelyseparated' and eliminated from the copper, adjusting the volume of oxygen in the mixture to an oxygenfuel ratio capable of reducing the copper, and then continuing the blowing of the adjusted mixture directly into the copper bath until the reduction is completed.
• a pyrometallurgical refining process for copper wherein a molten bath of unrefined copper is subjected to consecutive stages of heating, oxidation and reduction, said process comprising the steps of blowing-directly into the bath of unrefined copper a mixture of oxygen and a fuel selected from the group consisting Of liquid oil and solid carbonaceous material while heating the bath, adjusting the volume of oxygen in the mixture to an oxygen-fuel ratio capable of oxidizing the copper, continuing the blowing of the adjusted rnixture directly into the copper bath until the oxidation is completed, adjusting the volume of oxygen in the mixture to an oxygen-fuel ratio capable of reducing the copper, and then continuing the blowing of the adjusted mixture directly into the copper bath while stirring the bath until the reduction is completed.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Manufacture And Refinement Of Metals (AREA)

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Cited By (14)

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Citations (5)

• 0
  • BE BE622116D patent/BE622116A/xx unknown
• 1962
  • 1962-08-21 US US218434A patent/US3258330A/en not_active Expired - Lifetime
  • 1962-09-08 DE DEN22069A patent/DE1161034B/de active Pending

Patent Citations (5)

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