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
  • C22B15/0028—Smelting or converting
  • C22B15/003—Bath smelting or converting
  • C22B15/0041—Bath smelting or converting in converters
  • C22B15/0043—Bath smelting or converting in converters in rotating converters
• • 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
  • C22B11/00—Obtaining noble metals
  • C22B11/02—Obtaining noble metals by dry processes
• • 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
  • C22B23/00—Obtaining nickel or cobalt
  • C22B23/02—Obtaining nickel or cobalt by dry processes
  • C22B23/025—Obtaining nickel or cobalt by dry processes with formation of a matte or by matte refining or converting into nickel or cobalt, e.g. by the Oxford process
• • 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
  • C22B5/00—General methods of reducing to metals
  • C22B5/02—Dry methods smelting of sulfides or formation of mattes

Definitions

• the turbulent supernatant bath ofcopper sulfide is converted to liquid copper which is substantially saturated with oxygen by surface blowing with free oxygen-containing gas.
• At least one impurity from the group consisting of lead, selenium, sulfur, tellurium and tin are volatilized from the molten copper and the molten copper is thereafter treated with a reducing gas to lower the oxygen content to at least about 0.1 percent.
• the present invention relates to the fire refining of cupriferous materials to produce high-grade copper, and more particularly to an integrated process for treating copper sulfide which may contain nickel.
• Another object of the invention is to provide an integrated process for recovering high-grade copper and nickel from copper sulfide containing nickel by a combination of pyrometallurgical and vapometallurgical techniques.
• the present invention contemplates establishing a turbulent bath containing copper sulfide and having a copper to nickel ratio of more than about 7:3, maintaining the bath in a turbulent state without forming a metal phase to volatilize more than about 50 percent of at least one impurity selected from the group consisting of bismuth, lead, tin and zinc, then surface blowing the turbulent bath with a free-oxygen-containing gas to convert a controlled minor portion of the copper sulfide to an immiscible metal phase in which at least one element from the group consisting of antimony, arsenic, bismuth, lead, tin and the precious metals is concentrated, removing the immiscible metal phase, then surface blowing the turbulent supernatant bath of copper sulfide with a free-oxygen-containing gas to convert copper sulfide to liquid copper, to substantially saturate the liquid copper with oxygen and to oxidize and volatilize at least one impurity selected from the group consisting
• Copper mattes or copper sulfide concentrates which contain significant amounts of iron, nickel, cobalt, lead, bismuth, tin, arsenic, antimony, selenium, tellurium, zinc and the precious metals can be treated by the process of the present invention.
• Cupriferous scrap to which sufficient sulfur has been added to combine with all the copper contained therein can also betreated in accordance with the present invention.
• precious metals refers to the platinum group metals and gold.
• the nickel content in the sulfide feed material must be controlled so that the copper to nickel ratio is more than about 7:3 to insure production of the immiscible liquid metal phase for the concentration of precious metals present and of impurities.
• the copper to nickel ratio in the cupriferous material is controlled at a level greater than about 10: 1 since at ratios of copper to nickel of greater than about 10:] arsenic, in addition to bismuth, lead, tin and zinc, can be volatilized from both the sulfide phase and the metal phase and the concentration of precious metals in the immiscible metalphase is remarkably more effective.
• the matte of controlled sulfur content can then be slow cooled to provide a solidified mass of three readily separable phases-a precious-metals-containing magnetic fraction which is about 5 percent to 15 percent of the solidified mass, a nickel sulfide fraction of low copper content and a copper sulfide fraction with a nickel content such that the copper to nickel ratio is greater than about 10:1, e.g., 15:1.
• This process for separation of nickel sulfide from copper sulfide isdescribed in Canadian Pat. Nos. 452,861 and 452,862.
• the precious-metals-containing magnetic fraction is ad vantageously melted, treated with.
• a free-oxygen-containing gas to lower the sulfur content to between about 0.5 percent and 4 percent and the iron content to less thanabout 3 percent, granulated by drastic quenching to uniformly distribute the remaining sulfur throughout the granules and then treated with carbon monoxide at elevated pressure, advantageously below about atmospheres, to carbonylate and remove substantially all of the nickel as nickel carbonyl, as described in U.S. Pat. No. 1,067,638, leaving a residue containing copper, sulfur and the precious metals which can be treated by leaching to remove copper, sulfur and other contaminants from the precious metals.
• the sulfur deficien cy of the matte is slight and is controlled so that only a nickel sulfide phase containing the precious metals and a copper sulfide phase are produced upon slow cooling.
• the sulfur deficiency is controlled to produce less than about 2 percent metallics, e.g., about 0.5 percent to 1 percent metallics.
• the nickel sulfide phase is then treated in a manner similar to that described for the precious metals magnetic fraction in order to concentrate the precious metals and to produce nickel carbonyl.
• the nickel sulfide fraction can advantageously be blown to nickel metal as described in Canadian Pat. No. 655,210.
• the copper sulfide fraction with a copper to nickel ratio greater than about 10:1, can be treated in accordance with the process of the present invention.
• An advantageous feature of the present invention is maintenance of a turbulent copper sulfide bath while avoiding formation of a metal phase to maximize the volatilization of impurities from the liquid copper sulfide.
• the bath should be held at temperatures above 1,300 C., more than about 1,400 C., in order to increase the rate and the extent of impurity volatilization.
• Table l which were obtained by surface blowing copper mattes with air at temperatures of 1,200 and 1,340C. and with nitrogen containing less than about 1 percent oxygen at a temperature of 1,500" C.
• this part of the process is conducted in a top-blown rotary converter, e.g., a Kaldo converter, equipped with a burner, which converter provides great flexibility in operation by provision of gaseous atmospheres of optimum oxidizing potential, independent control of bath temperature and independent mechanical generation of a turbulent bath for excellent gas-liquid-solid contact.
• a top-blown rotary converter e.g., a Kaldo converter
• a burner which converter provides great flexibility in operation by provision of gaseous atmospheres of optimum oxidizing potential, independent control of bath temperature and independent mechanical generation of a turbulent bath for excellent gas-liquid-solid contact.
• the absence of submerged tuyeres in such converters allows them to be operated at high temperatures unattainable in the standard converters of the nonferrous industry.
• the sulfide bath is a low-grade matte, some of the impurities can be volatilized during the oxidation and slagging of iron.
• impurities such as arsenic, bismuth, lead, tin and zinc are advantageously volatilized by maintaining the copper-containing sulfide bath in a turbulent state by either pneumatic or mechanical means and without forming a metal phase by maintaining high temperature, neutral or only slightly oxidizing atmospheres above the turbulent bath.
• surface blowing a partially converted matte at 1,340 C. with nitrogen containing less than about 1 percent oxygen, by volume was effective in lowering the lead, arsenic and bismuth contents as shown in table Ill.
• the results in table lll also confirm that superior results are obtained by volatilizing impurities from the matte at temperatures above 1,400 C. The test conducted at 1,500 C.
• the atmosphere above the sulfide bath is controlled to have an oxidizing-reducing potential equivalent to a value between about 10 1 and 10 for the ratio of (CO)(SO )%(CO wherein the values of CO, 50 and CO are their respective partial pressures.
• Both the rate and extent of impurity volatilization from the matte can advantageously be improved by subjecting the matte, after iron removal, to a subatmospheric pressure treatment.
• the matte is advantageously transferred to a separate vessel wherein it is maintained in a turbulent state and at high temperatures, e.g., above l,400 C., and the pressure in the vessel is lowered to less than about 10 atmosphere.
• the turbulent sulfide bath is surface blown with free-oxygen-containing gas, such as air, oxygen-enriched air of commercial oxygen, to convert a controlled portion of the sulfide bath into a metal phase to collect substantially all the precious metals and substantial portions of other impurities remaining in the bath.
• free-oxygen-containing gas such as air, oxygen-enriched air of commercial oxygen
• antimony which is particularly difficult to eliminate by volatilization from the sulfide phase or by subsequent oxidation and volatilization from the metal phase, is highly concentrated and collected in the metal phase.
• substantial amounts of antimony can be eliminated at this point in the process without employing special slagging techniques at later processing stages.
• Strong agitation of the sulfide bath to insure efiective interphase liquid-liquid contact and resulting washing of the sulfide phase by the metal phase is important at this point to collect precious metals and other impurities in the metal phase.
• the metal is then allowed to settle into a liquid bottom and is removed for treatment, e.g., cast into anodes and treated electrolytically to recover the copper and the precious metals.
• a copper matte containing 42 percent copper, 28.5 percent iron, 25.9 percent sulfur, 0.11 percent arsenic and the balance essentially silica was surface blown with air at a temperature of 1,340 C. for 1 hour to lower the sulfur content to 24 percent, the iron content to 19.5 percent and the arsenic content to 0.035 percent.
• a matte containing 29.4 percent copper, 13.9 percent nickel, 27.6 percent iron, 26 percent sulfur, 0.103 percent arsenic and the balance essentially silica was surface blown with air at a temperature of l,340 C. for about 100 minutes to lower the iron content to l 1 percent, the sulfur content to 24.5 percent and the arsenic content to about 0.088 percent.
• the partially purified copper sulfide remaining in the converter e.g., a Kaldo or LD converter
• a free-oxygen-containing gas such as air, commercial oxygen or oxygen-enriched air
• Surface blowing is continued to convert the partially purified copper sulfide to copper and to substantially saturate the copper with cuprous oxide, e.g., an oxygen content of between about 0.5 percent and 1.5 percent.
• cuprous oxide e.g., an oxygen content of between about 0.5 percent and 1.5 percent.
• the surface of the turbulent liquid bath is kept reasonably clear of slag in order to assure efficient gas-liquid contact and the bath is maintained at a temperature between about l,l00 and l,500 C.
• the introduction of the aforementioned amounts of oxygen is effective in oxidizing the impurities remaining in the liquid copper bath and in volatilizing more than about 50 percent of at least one volatile oxide of elements such as arsenic, lead, selenium, sulfur, tellurium and tin.
• the oxidation and volatilization of the impurities is conducted at temperatures above l,300 C. in order to insure more rapid and complete elimination of the impurities.
• the oxygen contained in the copper bath is also effective in oxidizing substantially all of the nickel in the bath. Nickel removal is advantageously conducted at low temperatures, e.g., about l,l00 C., because at higher temperatures nickel removal is less efficient.
• the nickel content can be lowered to below 0.5 percent without a flux at a temperature of about l,l00 C.
• the nickel content can be further lowered by employing an acidic flux such as silica.
• an acidic flux such as silica.
• the nickel content in the copper bath can be lowered to about 0.1 percent
• the copper-containing bath is then brought to the proper pitch and cast.
• the purified liquid copper-containing bath containing up to about 1.5 percent oxygen is treated with an atmosphere reducing to cuprous oxide to lower the oxygen content to less than about 0.1 percent.
• the bath is held at a temperature of about 1,100 to about l,200 C. while maintaining the atmosphere above the bath to have a reducing potential equivalent to a COzCO ratio of at least one part of CO for each 1,000 parts of CO
• a turbulent bath is also employed therein in order to assure intimate gas-liquid contact.
• the oxygen content of the copper bath can be lowered during the subatmospheric pressure treatment described hereinafter by passing reducing gases having the aforedescribed reducing potentials through the copper bath.
• the copper-containing bath is cast into commercial shapes such as wire bars or cast into anodes for further purification.
• the copper-containing bath is advantageously subjected to a subatmospheric pressure treatment to degas the bath.
• the copper-containing bath is introduced to a vacuum chamber which is maintained at a pressure of less than about 10 atmosphere.
• the subatmospheric pressure treatment will be more efficient if the copper-containing bath is maintained in constant state of circulation or turbulence by well-known means, e.g., electromechanical.
• the subatmospheric pressure treatment has the further advantage of further lowering the level of impurities such as sulfur, arsenic, bismuth, lead, selenium, sulfur, tellurium, tin and zinc by volatilization.
• impurities such as sulfur, arsenic, bismuth, lead, selenium, sulfur, tellurium, tin and zinc by volatilization.
• the effectiveness of the subatmospheric pressure treatment in lowering the level of the various impurities is partly dependent on the oxygen content of the liquid copper.
• the lead content can be lowered in the absence of oxygen but the elimination of sulfur and arsenic is facilitated by the presence of sufficient oxygen as cuprous oxide to form the volatile oxides of the respective impurities.
• the copper-containing bath with oxygen contents up to about 1.5 percent can be directly transferred to the vacuum chamber without deoxidation; and after these impurities have been lowered to acceptable levels, reducing gases having a reducing potential equivalent to COzCO ratios of at least one part of CO for each 1,000 parts ofCO are then passed through the liquid copper.
• the subatmospheric pressure treatment is effective in lowering the impurity levels at conventionally employed temperatures for casting copper, it has been found particularly advantageous to subject the copper bath to the subatmospheric pressure treatment at temperatures of at least about 1,200 C. Even bismuth, which is considered difficult or impossible to eliminate by conventional pyrometallurgical techniques, can be readily removed by the subatmospheric pressure treatment.
• EXAMPLE I A turbulent bath of copper matte, the composition of which is given in table Vll, was established and surface blown with oxygen for 1% hours at l,340 C. and then a sample was taken for analysis. Surface blowing of the turbulent bath with oxygen was then discontinued and was replaced by surface blowing with nitrogen containing less than about 1 percent oxygen for 2 hours at l,340 C. after which a sample was taken for analysis. Surface blowing of the turbulent bath with oxygen at l,340 C. was resumed for 1 hour to produce a metal phase which, along with a sample of matte, was removed and analyzed. After 70 minutes of surface blowing with oxygen at 1,340 C. another metal phase was produced and was again removed along with a sample of the matte for analysis.
• the remaining matte was converted to blister copper and saturated with oxygen after blowing with oxygen for 80 minutes.
• the blister copper was subjected to a subatmospheric pressure of less than about 1O atmosphere at 1,500 C.
• the results of the chemical analyses at different stages of the process are reported in table Vll together with an analysis of commercially produced cathode copper for comparative purposes.
• the results in table Vll confirm that copper produced in accordance with the process of the present invention is comparable with electrolytic copper.
• the tellurium content which was 0.l percent in the head sample, was lowered to less than 0.01 percent after the vacuum treatment whereas a similar vacuum treatment at l,260 C. only lowered the tellurium content to 0.05 percent.
• one of the blister copper samples contained 0.3 percent selenium; and after the vacuum treatment at 1,500 C., the selenium content was lowered to less than about 0.002 percent.
• lence can be induced by pneumatic or electromagnetic means.
• the efficiency of volatilizing impurities from the matte is greatly increased by a turbulent bath since the turbulence constantly exposes fresh surfaces from which volatilization occurs.
• the use of a rotary furnace during the converting operation is advantageous since the rotating furnace avoids the establishment of localized areas of lower temperature where magnetite and other accretions can build up and eventually lower the capacity of the converter.
• the turbulence induced by a rotary converter provides a rapid approach to equilibrium conditions by rapid decrease of concentration gradients and, thus, for instance, the problem of slag foaming is minimized.
• the turbulence mechanically induced by a rotary furnace also provides excellent liquid-liquid contact between the impure copper sulfide phase and the controlled metal portion, which contact greatly increases the amount and rate of concentration of impurities in the controlled metal portion.
• the highly efficient gas-liquid contact realized by conducting the process in a top blown furnace provides greater control of the production of the controlled metal portion, the converting of the partially purified copper sulfide and the subsequent oxidation of the remaining impurities in the coppercontaining bath.
• a rotary furnace permits required tempera ture control including efficient heat exchange between the liquid bath and the furnace wall refractory.
• the furnace is equipped with a lance for delivering freeoxygen-containing gas to the'surface of the turbulent bath and with a burner for supplying heat to, and for controlling the atmosphere above, the turbulent bath.
• the burner gases serve the additional function of continually flowing over the surface of the turbulent bath thereby flushing residual gases and lowering the partial pressures of volatile impurities whereby volatilization efficiency is increased.
• Top blowing by directing a stream of free-oxygen-containing gas on the surface of the agitated bath is another advantageous feature of the present invention.
• a free-oxygen-containing gas is directed to the surface of a molten copper-containing sulfide bath, liquid copper is formed in the vicinity of impingement of the free-oxygcn-containing gas and by gravitational forces descends through the molten sulfide phase which provides even greater liquid-liquid contact between the liquid sulfide phase and the liquid copper to further increase the effectiveness of the concentration of impurities in the liquid copper.
• the surface blowing permits the use of commercial oxygen or oxygen-enriched air during the converting operation whereby the offgases are rich in sulfur dioxide which facilitates sulfur recovery.
• a turbulent bath is one of the advantageous features of the process variables.
• the present invention contemplates, in an advantageous embodiment, establishing a turbulent bath containing copper sulfide and having a copper to nickel ratio of more than about 10:1, maintaining the bath in a turbulent state without forming a metal phase to volatilize more than about 50 percent of at least one impurity selected from the group consisting of arsenic, bismuth, lead, tin and zinc, then surface blowing the turbulent bath with a free-oxygen-containing gas to convert a controlled minor portion of the copper sulfide to an immiscible metal phase in which at least one element from the group consisting of antimony, arsenic, bismuth, lead, tin and the precious metals is concentrated, removing the immiscible metal
• a method for recovering copper from cupriferous materials which comprises establishing a bath containing copper sulfide and having a copper to nickel ratio of more than about 7:3, maintaining said bath containing copper sulfide in a turbulent state without forming a metal phase to volatilize more than about 50 percent of at least one impurity selected from the group consisting of bismuth, lead, tin and zinc, then surface blowing the turbulent bath containing copper sulfide with a free-oxygen-containing gas to convert a controlled minor portion of the copper sulfide to an immiscible metal phase in which at least one element from the group consisting of antimony, arsenic, bismuth, lead, tin and the precious metals is concentrated, removing the immiscible metal phase, then surface blowing the turbulent supernatant copper sulfide with a free-oxygen-containing gas to convert copper sulfide to liquid copper, to substantially saturate the liquid copper with oxygen and to oxidize and volat
• a method for recovering copper from cupriferous materials which comprises establishing a bath containing copper sulfide and having a copper to nickel ratio of more than about 10:1, maintaining said bath containing copper sulfide in a turbulent state without forming a metal phase to volatilize more than about 50 percent of at least one impurity selected from the group consisting of arsenic, bismuth, lead, tin and zinc, then surface blowing the turbulent bath containing copper sulfide with a free-oxygen'containing gas to convert a controlled minor portion of the copper sulfide to an immiscible metal phase in which at least one element from the group consisting of antimony, arsenic, bismuth, lead, tin and the precious metals is concentrated, removing the immiscible metal phase, then surface blowing the turbulent supernatant bath of copper sulfide with a free-oxygen-containing gas to convert copper sulfide to liquid copper, to substantially saturate the liquid copper with oxygen and
• immiscible metal phase then surface blowing the turbulent supernatant bath of copper sulfide with a free-oxygen-containing gas to convert copper sulfide to liquid copper, to substantially saturate the liquid copper with oxygen and to oxidize and volatilize at least one impurity from the group consisting of arsenic, lead, selenium, sulfur, tellurium and tin and then treating the liquid copper with an atmospherp reducing to cuprous oxide to lower the oxygen content to less than about 0.1 percent.
• a process for recovering copper, nickel and precious metals from nickeland copper-containing materials which comprises establishing a turbulent molten bath of a sulfide material, directing a stream of a free-oxygen-containing gas upon the surface of the turbulent bath to produce a sulfur deficient matte, slowly cooling the sulfur deficient matte to produce a solidified mass of readily separable crystals of nickel sulfide which contains precious metals and copper sulfide crystals having a copper to nickel ratio greater than about 10:1, comminuting the solidified mass, separating the nickel sulfide and copper sulfide phases in the comminuted mass by flotation, melting and then surface blowing the nickel sulfide phase to produce a nickel bath containing about 0.5 percent to about t percent sulfur and less than about 3 percent iron, drastically quenching the nickel bath to form nickel granules with sulfur uniformly distributed, carbonylating the nickel granules at elevated pressures to produce nickel carbonyl and a precious metal concentrate, establishing
• copper sulfide with a free-oxygen-containing gas to convert copper sulfide to liquid copper, to substantially saturate the liquid copper with oxygen and to oxidize and volatilize at least one impurity from the group consisting of arsenic, lead, selenium, sulfur, tellurium and tin and then treating the liquid copper with an atmosphere reducing to cuprous oxide to lower the oxygen content to less than about 0.1 percent.
• a process as described in claim 2 wherein the immiscible metal phase is from about 5 percent to about percent, by weight, of the molten copper sulfide.
• liquid copper substantially saturated with oxygen is subjected to a subatmospheric preaure treatment to further lower the level of at least one impurity selected from the group consisting of arsenic, bismuth, lead, selenium, sulfur, tellurium, tin and zinc before treating the liquidcopper with an atmosphere reducing to cuprous oxide.

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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 (5)

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• 1968
  • 1968-05-02 CA CA867672A patent/CA867672A/en not_active Expired
• 1969
  • 1969-04-04 US US813769A patent/US3615361A/en not_active Expired - Lifetime
  • 1969-04-26 ZM ZM56/69A patent/ZM5669A1/xx unknown
  • 1969-04-28 SE SE6905999A patent/SE355603C/xx unknown
  • 1969-04-29 NO NO1786/69A patent/NO125733B/no unknown
  • 1969-04-30 ES ES366656A patent/ES366656A1/es not_active Expired
  • 1969-05-01 JP JP44033918A patent/JPS505130B1/ja active Pending
  • 1969-05-01 NL NL6906699A patent/NL6906699A/xx unknown
  • 1969-05-02 FR FR6914149A patent/FR2007723A1/fr not_active Withdrawn
  • 1969-05-02 BE BE732418D patent/BE732418A/xx unknown
  • 1969-05-02 FI FI1298/69A patent/FI49731B/fi active
  • 1969-05-02 GB GB22632/69A patent/GB1218167A/en not_active Expired

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