US3674463A - Continuous gas-atomized copper smelting and converting - Google Patents

Continuous gas-atomized copper smelting and converting Download PDF

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Publication number
US3674463A
US3674463A US60793A US3674463DA US3674463A US 3674463 A US3674463 A US 3674463A US 60793 A US60793 A US 60793A US 3674463D A US3674463D A US 3674463DA US 3674463 A US3674463 A US 3674463A
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matte
copper
smelting
converting
slag
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US60793A
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English (en)
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John C Yannopoulos
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Newmont Exploration Ltd
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Newmont Exploration Ltd
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    • 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
    • C22B15/0047—Smelting or converting flash smelting or converting

Definitions

  • a process for smelting copper sulfide concentrates and simultaneously converting the thus-produced matte to form blister copper, slag and an efiluent gas unusually rich in sulfur dioxide is characterized by continuous operation in which both smelting and converting are carried out in suspension over a common furnace hearth body of molten blister copper, matte and slag from which the matte to be converted is supplied.
  • This invention relates to the smelting and converting of copper sulfide concentrates and, more particularly, to a process for carrying out these two operations simultaneously and continuously primarily in a gas-atomized state.
  • the matte produced is converted batchwise in a Peirce- Smith converter and therefore the overall copper making operation cannot qualify as continuous.
  • the flash smelting process as presently operated cannot be adjusted to volume of the client converting, and thus produce metallic copper, by increasing the amount of oxygen admitted with the concentrate because the resulting oxidized slag is extremely high in magnetite and tends to solidify. It appears, therefore, that during flash smelting a matte and/or white metal phase is necessary to avoid a slag extremely high in copper and magnetite and to accommodate the matte collected during any slag cleaning treatment.
  • the present invention is thus an improvement in a continuous process for smelting a copper sulfide concentrate wherein a stream of an intimate mixture of particulate copper sulfide concentrate and siliceous fluxing material is charged downwardly into a suspension smelting zone and an oxidizing gas is charged at high velocity in a direction converging downwardly and inwardly against the falling stream of concentrateflux mixture so as to disperse the stream into a particulate smelting-promoting phase suspended in and carried downwardly in the oxidizing gas and thus form at the bottom of the vessel a molten body of blister matte and a supernatant layer of molten slag.
  • the improvement in such a process comprises (a) introducing into the lower portion of the falling particulate smeltingproducing phase a jet stream of reducing material at a rate sufficient to maintain the partial pressure of oxygen below about l0 mm.
  • FIG. 1 is a schematic drawing of the process in which both smelting and converting are carried out in a common zone;
  • FIG, 2 is a cross-sectional detail view of the upper charging end of the apparatus shown in FIG. 1;
  • FlG. 3 is a side elevation of the furnace used in the process shown schematically in FIG. I;
  • FIG. 4 is a plan view of the furnace hearth taken along line 44 in FIG. 3;
  • FIG. 5 is a crosssectional view of the furnace hearth taken in the direction of the arrows 5 along line AA in FIG. 4;
  • FIG. 6 is a cross-sectional view of the furnace hearth 3 taken in the direction of the arrows 6 along the line A-A in FIG. 4',
  • FIG. 7 is a detailed material flow balance imposed on the schematic drawing of FIG. 1 pursuant to a specific example of operation of the process;
  • FIG. 8 is a schematic drawing of a modification of the process of the invention in which the smelting and converting zones are separate.
  • FIG. 9 is a schematic drawing of another modification of the process in which the smelting and converting zones are separate.
  • the ratio of oxygen to copper sulfide concentrate is adjusted to transform from 35 to 75% of the copper into blister copper and the rest into high grade matte. All of the silica required for a good slag is added with the concentrate at the top of the furnace shaft. The proportion of the silica charged, and the operating temperature, can be higher than in the Peirce-Smith converter inasmuch as the reactions are taking place in suspension and not in contact with the refractory walls. A fraction of the copper sulfide concentrate is also added near the bottom of the shaft as a temperature control and safeguard against a high partial pressure of oxygen which would otherwise cause magnetite formation.
  • Copper and high grade matte are continuously tapped at one end of the furnace hearth, and slag is skimmed at the other end.
  • the matte is recycled into the process, at the rate that it is produced, and is sprayed pneumatically down wardly into the top of the shaft. This recycled matte is converted exothermically to blister copper by the appropriate air flow.
  • a thin column of the incoming matte is encircled, as shown in FIG. 2, with a cylindrical ring charge of well mixed fine concentrate and fine fluxes which, in turn, are splashed, atomized and dispersed by a number of powerful jets of air or oxygen-enriched air.
  • the violent action of the atomizing nozzles at the top of the shaft produces an intimate mixture of the reactants in the form of a co-current gravitational flow of a gasliquid suspension of the concentrate fiux-matte mixture moving downwardly through the shaft.
  • the proportion of the flux charged per unit of concentrate and the operating temperature of the mixture can be higher than in the conventional Peirce-Smith converter.
  • an appropriate fraction of the fine dry concentrate is blown with Garr guns or the like through four auxiliary entrances near the bottom of the shaft and using recycled flue gas or any conventional reducing gas as the carrier (FIG. 1).
  • the resulting dispersion of fine concentrate among the falling droplets serves as a reducing agent to control the oxygen partial pressure of the gases in this portion of the smclt ing and converting none to an extremely low level and at the same time controls the temperature and formation of magnetite.
  • This low oxygen partial pressure at the bottom of the shaft in the atmosphere adjacent the surface of the supernatant slag layer. generally below 10 and preferably below 10- min. of mercury. is an indispensable condition in the practice of the invention and can be achieved by one or more of the following expendients:
  • Control of the temperature and magnetite formation in the lower portion of the furnace shaft is effected by the secondary smelting of the concentrate charged at this point which consumes part of the heat produced in the shaft by the converting reaction and thus cools the liquidgas interface at the furnace hearth to the appropriate temperature.
  • This cooling can be regulated by preheating (or not) the concentrate and by controlling the temperature of the carrier gas of the secondary smelting operation so that the temperature of the supernatant slag immediately below the shaft will permit the dissolving of any magnetite formed and not previously reduced as the reactants move downwardly through the low-oxygen atmosphere immediately above the surface of the slag layer.
  • the partial pressure of oxygen at the bottom of the shaft can be always controlled to an extremely low level in spite of inadvertent random feed variations.
  • a cleaning treatment of the slag is advantageously provided through smelting of pyrite or pyrrhotite introduced by Garr gun blowers, or the like, into the low-oxygen containing atmosphere immediately above the surface of the slag layer in the furnace hearth.
  • This along with the countercurrent flow of slag versus matte in the settler as the result of separate withdrawal of the slag and matte from opposite ends of the furnace hearth, reduces copper losses and magnetite content in the slag.
  • a copper concentrator middling product low in copper and high in sulfur and iron, can be used in lieu of the pyrite or pyrrhotite for the overall economy of the copper extraction process.
  • FIG. 3 The general configuration of the furnace for carrying out the foregoing procedure is shown in FIG. 3 with its accompanying liquid.
  • the primary smelting zone 10 and the converting zone 11 are located within the furnace shaft 12, and the concentrate-flux mixture is supplied through a solid feeder 13 which air is supplied through nozzle 14 at the top wall of the shaft 12 in an arrangement such as that shown in FIG. 2.
  • a solid feeder 13 which air is supplied through nozzle 14 at the top wall of the shaft 12 in an arrangement such as that shown in FIG. 2.
  • openings 15 provided for supplying the auxiliary concentrate for smelting in the secondary smelting none 10a.
  • a conventional tap 16 for blister copper 17 is provided at the bottom of the furnace hearth l8, and another conventional matte tap 19 is provided at the deep end of the hearth for drawing off the matte 20.
  • the matte is collected in a recycling ladle 21 which is capable of being raised by a cable 22 to its upper dotted position where the ladle is tilted to pour its contents into a tundish 23 at the top of the furnace shaft 12.
  • Pyrite, or pyrrhotite, for cleaning the slag is introduced through obliquely arranged openings 24 in the roof 25 of the furnace hearth.
  • the supernatant slag layer 26 is drawn off through a conventional slag tap hole 27 located at the end of the furnacc hearth opposite the matte tap 19.
  • the process gas ellluent is collected in an uptake section 28 and is removed through a flue 29.
  • the furnace hearth is provided with different cross-sectional shapes under the smelting-converting zone and under the settling zone represented, respectively, by the arrows 55 and 66 at the transverse hearth line AA in FIG. 4.
  • the hearth shape under the smelting-converting zone is shown in FIG. 5 and is substantially trough-shaped so that the interfaces between the hearth atmosphere and slag, the slag and the matte, and the matte and the blister copper progressively decrease in area.
  • the hearth shape in the settler zone, shown in FIG. 6, is substantially rectangular.
  • Blister copper, matte of different grades up to white metal, slag, unreacted solids, and a gas phase with extremely low oxygen concentration enter the settler system defined by the furnace hearth 18 at the bottom of the shaft.
  • these products falling through the shaft and still continuously reacting, hit the surface of the liquid slag 26 in the molten bath, a sharp deceleration occurs which causes coagulation of similar phases and sinking of the heavier liquids.
  • Three liquid phases blister copper 17, matte 20 and slag 26 thus form and settle as three distinct layers.
  • the concentrations of copper, sulfur, iron and oxygen in the matte are far from being uniform throughout the matte layer due to their dilferent origins in the shaft reaction zone and in the different reaction times of the individual droplets.
  • Matte is continuously tapped into the ladle which is vertically moved into the heated tundish whereby the matte is continuously recycled to the top of the shaft at the rate that it is produced.
  • the main control on the matte production is the rate of secondary smelting of concentrate introduced through the auxiliary supply openings near the lower portion of the shaft.
  • the optimum depth of the matte layer is advantageously controlled by continuously monitoring the density of the molten phases in the furnace with conventional gamma-ray density gages.
  • Chalcopyrite concentrate of the following composition is the charged copper sulfide concentrate:
  • NoTu.Molstn1-e 1% (dry basis).
  • the flux materials admixed with the copper concentrate are made up of quartzite of the following composition:
  • the pyrite concentrate for the auxiliary flash operation to control copper losses in the slag has the following composition:
  • the average linear velocity of the gas downwardly through the shaft is about 11 feet per minute at an average temperature of 1200 C.
  • the matte which is formed and recycled to the top of the furnace shaft contains 75% Cu, 20.9% S, 3.8% Fe and 0.25% 0 and 70% of the copper in the concentrate charged is converted to blister in the first pass.
  • the process is autogenous except for a minor quantity of fuel (12.7 standard cubic feet of natural gas/ton of copper concentrate) which is burned for the auxiliary pyrite smelting.
  • the process of the invention thus consists in effect of two systems represented by the numerals I and II in FIG. I:
  • FIGS. 8 and 9 Two modifications of the process of the invention are shown in FIGS. 8 and 9.
  • an auxiliary furnace shaft is provided for gas-atomized converting of the recycled matte to blister copper.
  • the smelting of the copper sulfide concentrate in suspension takes place in the main shaft in which no matte is recycled, and a minor fraction of the concentrate is blown through Garr guns at the bottom of this shaft as in the operation shown in FIG. 1.
  • the recycled matte is suspension-converted in an adjacent shaft, and both shafts are in direct communication at their lower ends directly above the furnace hearth.
  • the suspension-smelting of the copper sulfide concentrate is effected obliquely in a direction such that, as in FIG.
  • the discharge ends of the converting and smelting suspension zones are in direct communication above the furnace hearth.
  • a distinct step of matte-converting in suspension is combined with a suspension-smelting step in a manner such that a very low partial pressure of oxygen prevails at the point where the products of the two-steps emerge and fall into the common molten phases in the single furnace hearth.

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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)
US60793A 1970-08-04 1970-08-04 Continuous gas-atomized copper smelting and converting Expired - Lifetime US3674463A (en)

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JP (1) JPS5126887B1 (enrdf_load_stackoverflow)
AU (1) AU462635B2 (enrdf_load_stackoverflow)
CA (1) CA942068A (enrdf_load_stackoverflow)
ZA (1) ZA714951B (enrdf_load_stackoverflow)
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Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3759501A (en) * 1971-12-13 1973-09-18 Kennecott Copper Corp Cyclonic smelting apparatus
US3767383A (en) * 1971-11-15 1973-10-23 Int Nickel Co Refining copper pyrometallurgically by two-stage subatmospheric treatment
US3849120A (en) * 1973-06-25 1974-11-19 T Norman Smelting of copper-iron or nickel-iron sulfides
US3905807A (en) * 1971-07-30 1975-09-16 Commw Scient Ind Res Org Recovery of tin from slags
US4073645A (en) * 1975-04-09 1978-02-14 Klockner-Humboldt-Deutz Aktiengesellschaft Process of smelting sulphidic copper ore concentrates
US4165979A (en) * 1978-02-21 1979-08-28 The International Nickel Company, Inc. Flash smelting in confined space
US4236700A (en) * 1978-10-13 1980-12-02 Outokumpu Oy Device for suspension smelting of finely-divided _oxide and/or sulfide ores and concentrates
EP0053595A1 (en) * 1980-12-01 1982-06-09 Boliden Aktiebolag A method for recovering the metal content of complex sulphidic metal raw materials
US4337086A (en) * 1978-12-21 1982-06-29 Queneau Paul Etienne Method for decreasing metal losses in nonferrous smelting operations
GB2161835A (en) * 1984-07-18 1986-01-22 Outokumpu Oy Processing sulphide concentrates into raw material
US4695317A (en) * 1985-01-31 1987-09-22 Sumitomo Metal Mining Company Limited Method of treating silicate ore containing gold and silver
US4802916A (en) * 1985-03-20 1989-02-07 Inco Limited Copper smelting combined with slag cleaning
US4802917A (en) * 1985-03-20 1989-02-07 Inco Limited Copper smelting with calcareous flux
AU640527B2 (en) * 1990-09-26 1993-08-26 Johannesburg Consolidated Investment Company Limited Pyrometallurgical process for treating a feed material
WO2003100412A3 (en) * 2002-05-23 2004-04-01 Innovative Met Products Pty Lt Method of ore treatment
EP2785885A4 (en) * 2011-11-29 2015-12-09 Outotec Oyj METHOD OF CONTROLLING SUSPENSION IN A SUSPENSION MELTING OVEN, SUSPENSION MELTING OVEN AND CONCENTRATE BURNER
US9725784B2 (en) 2012-06-21 2017-08-08 Lawrence F. McHugh Production of copper via looping oxidation process
US10852065B2 (en) 2011-11-29 2020-12-01 Outotec (Finland) Oy Method for controlling the suspension in a suspension smelting furnace

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5512262U (enrdf_load_stackoverflow) * 1978-07-10 1980-01-25

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3905807A (en) * 1971-07-30 1975-09-16 Commw Scient Ind Res Org Recovery of tin from slags
US3767383A (en) * 1971-11-15 1973-10-23 Int Nickel Co Refining copper pyrometallurgically by two-stage subatmospheric treatment
US3759501A (en) * 1971-12-13 1973-09-18 Kennecott Copper Corp Cyclonic smelting apparatus
US3849120A (en) * 1973-06-25 1974-11-19 T Norman Smelting of copper-iron or nickel-iron sulfides
US4073645A (en) * 1975-04-09 1978-02-14 Klockner-Humboldt-Deutz Aktiengesellschaft Process of smelting sulphidic copper ore concentrates
US4165979A (en) * 1978-02-21 1979-08-28 The International Nickel Company, Inc. Flash smelting in confined space
US4236700A (en) * 1978-10-13 1980-12-02 Outokumpu Oy Device for suspension smelting of finely-divided _oxide and/or sulfide ores and concentrates
US4337086A (en) * 1978-12-21 1982-06-29 Queneau Paul Etienne Method for decreasing metal losses in nonferrous smelting operations
EP0053595A1 (en) * 1980-12-01 1982-06-09 Boliden Aktiebolag A method for recovering the metal content of complex sulphidic metal raw materials
US4388110A (en) * 1980-12-01 1983-06-14 Boliden Aktiebolag Method for recovering the metal content of complex sulphidic metal raw materials
GB2161835A (en) * 1984-07-18 1986-01-22 Outokumpu Oy Processing sulphide concentrates into raw material
DE3525710A1 (de) * 1984-07-18 1986-01-30 Outokumpu Oy, Helsinki Verfahren und vorrichtung zum verarbeiten von sulfidkonzentraten und sulfiderzen zu rohmetallen
US4599108A (en) * 1984-07-18 1986-07-08 Outokumpu, Oy Method for processing sulphide concentrates and sulphide ores into raw material
US4695317A (en) * 1985-01-31 1987-09-22 Sumitomo Metal Mining Company Limited Method of treating silicate ore containing gold and silver
US4802916A (en) * 1985-03-20 1989-02-07 Inco Limited Copper smelting combined with slag cleaning
US4802917A (en) * 1985-03-20 1989-02-07 Inco Limited Copper smelting with calcareous flux
AU640527B2 (en) * 1990-09-26 1993-08-26 Johannesburg Consolidated Investment Company Limited Pyrometallurgical process for treating a feed material
WO2003100412A3 (en) * 2002-05-23 2004-04-01 Innovative Met Products Pty Lt Method of ore treatment
EP2785885A4 (en) * 2011-11-29 2015-12-09 Outotec Oyj METHOD OF CONTROLLING SUSPENSION IN A SUSPENSION MELTING OVEN, SUSPENSION MELTING OVEN AND CONCENTRATE BURNER
US9677815B2 (en) 2011-11-29 2017-06-13 Outotec Oyj Method for controlling the suspension in a suspension smelting furnace, a suspension smelting furnace, and a concentrate burner
US10852065B2 (en) 2011-11-29 2020-12-01 Outotec (Finland) Oy Method for controlling the suspension in a suspension smelting furnace
US9725784B2 (en) 2012-06-21 2017-08-08 Lawrence F. McHugh Production of copper via looping oxidation process

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AU3185871A (en) 1973-02-01
CA942068A (en) 1974-02-19
ZM10571A1 (en) 1972-04-21
JPS5126887B1 (enrdf_load_stackoverflow) 1976-08-09
AU462635B2 (en) 1975-07-03
ZA714951B (en) 1972-04-26

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