US3652069A - Shaft furnace smelting of oxidic ores, concentrates or calcines - Google Patents

Shaft furnace smelting of oxidic ores, concentrates or calcines Download PDF

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Publication number
US3652069A
US3652069A US864051A US3652069DA US3652069A US 3652069 A US3652069 A US 3652069A US 864051 A US864051 A US 864051A US 3652069D A US3652069D A US 3652069DA US 3652069 A US3652069 A US 3652069A
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United States
Prior art keywords
carbonizing
columns
shaft
furnace
combustion chamber
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Expired - Lifetime
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US864051A
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English (en)
Inventor
Howard K Worner
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Conzinc Riotinto of Australia Ltd
Conzinc Riotinto Ltd
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Conzinc Riotinto Ltd
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Publication date
Priority claimed from AU44834/68A external-priority patent/AU402464B2/en
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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
    • C22B5/00—General methods of reducing to metals
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B11/00—Making pig-iron other than in blast furnaces
    • C21B11/02—Making pig-iron other than in blast furnaces in low shaft furnaces or shaft furnaces
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C21B13/02—Making spongy iron or liquid steel, by direct processes in shaft furnaces
    • C21B13/023—Making spongy iron or liquid steel, by direct processes in shaft furnaces wherein iron or steel is obtained in a molten state
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B5/00—Making pig-iron in the blast furnace
    • C21B5/008—Composition or distribution of the charge
    • 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
    • C22B19/00—Obtaining zinc or zinc oxide
    • C22B19/34—Obtaining zinc oxide
    • C22B19/36—Obtaining zinc oxide in blast or reverberatory furnaces
    • 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
    • C22B23/023—Obtaining nickel or cobalt by dry processes with formation of ferro-nickel or ferro-cobalt
    • 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
    • C22B25/00—Obtaining tin

Definitions

  • ABSTRACT Method and apparatus for direct shaft furnace smelting of oxidic ores, concentrates or calcines, the method comprising causing a pelletized or briquetted mixture of the ore or concentrate or calcines and coal to gravitate slowly downwards first through one or more carbonizing columns having holes or slots in the walls thereof and then through a main furnace shaft therebeneath, introducing oxygen-containing gas into a combustion chamber surrounding or partly surrounding the carbonizing column or columns to effect substantial combustion of tars and combustible gases emerging through the holes or slots from the descending material in the carbonizing column or columns, withdrawing the products of combustion from the combustion chamber, and withdrawing the metal or alloy produced from the main furnace shaft; and apparatus adapted therefor.
  • This invention makes possible the direct charging of composite pellets or briquettes containing caking coal and ensures that a. the pellets or briquettes remain strong during the handling into and the passage through carbonization stage, and
  • the tarry matter is liberated and combusted to a substantial degree in a heating-up open space within the top of the furnace and so does not foul-up the top of the shaft and gas offtaltes.
  • One advantage of the invention is that high cost low reactivity metallurgical coke, essential for good operation in conventional blast furnaces can be replaced by cheaper caking coal.
  • the principal requirement of the coal used is that it should develop a high fluidity when passing through the early stages of pyrolysis. If the coal available does not possess this quality in sufficient degree, the blend of the coal with the oxidic fines can be supplemented with tar, bitumen or other liquid form of hydrocarbon that will increase the capacity of the coal material to diffuse amongst and wet" the particulate oxidic components of the pellets (or briquettes) during heating through the temperature range 320 to 480 C.
  • Another advantage of the invention is that it permits continuous charging of pellets or briquettes into shaft furnaces in such a way that complex sealing and double or triple bell and hopper systems are not required.
  • the invention is applicable principally to the direct shaft furnace smelting of oxide ores and concentrates, such as iron, tin and nickel bearing lateritic ores and concentrates.
  • the invention is also applicable to the smelting of calcines or other oxidic metallurgical products.
  • the product of smelting may be a liquid metal or alloy which is tapped from the crucible of the shaft furnace or a metal vapour which may be withdrawn from the upper end of the shaft.
  • the zinc vapour leaves the top of the shaft rather than collecting with the less volatile lead-rich phase and/or slag in the crucible of the bottom of the furnace.
  • an oxidic furnace by-product is recovered out of the top of the shaft furnace.
  • the invention accordingly provides a method for the direct shaft furnace smelting of oxidic ores or concentrates or calcines which comprises causing a pelletised or briquetted mixture of the ore or concentrate or calcines and coal to gravitate slowly downwards first through one or more carbonizing columns having holes or slots in the walls thereof and then through a main furnace shaft therebeneath, introducing oxygen-containing gas into a combustion chamber surrounding or partly surrounding the carbonizing column or columns to effect substantial combustion of tars and combustible gases emerging through the holes or slots from the descending material in the carbonizing column or columns, withdrawing the products of combustion from the combustion chamber, and withdrawing the metal or alloy produced from the main furnace shaft.
  • the invention consists in a method of continuous integrated feeding, carbonizing and smelting of oxidic ores or concentrates or calcines in a shaft furnace involving the following steps:
  • the oxidic ore fines or concentrates or calcines are first blended with finely ground caking coal, and if desired other additives, at least one of which is a binder capable of forming a bond at near ambient temperatures, pelletizing or briquetting the blend, allowing the pellets or briquettes to harden by action of the binder or binders, charging the hardened but as yet uncoked pellets or briquettes via an appropriate hopper or hoppers into one or more substantially vertical hollow columns, having holes or slots in the walls thereof to allow escape of the tars and other gaseous hydrocarbons released from the coal component in the pellets or briquettes as they pass through the pyrolysis temperature range while moving slowly down the columns. On emergence from the columns the pellets or briquettes are in a semi-coked condition and descend further down the shaft furnace until smelting is completed.
  • additives at least one of which is a binder capable of forming a bond at near ambient temperatures, pelletizing or briquetting the blend
  • An oxygen-containing gas is blown via one or more ports or jets into the chamber or space surrounding the columns is order to achieve combustion of a substantial proportion of the tars and hydrocarbon gases emerging through the holes or slots and also part at least of the carbon monoxide and hydrogen emerging from the top of the burden in the furnace stack.
  • the combustion of these tars and gases in the space around the hollow columns provides ample heat to ensure autogenous coking of the coal matter in the pellets or briquettes as they slowly descend within the hollow columns.
  • the pellets or briquettes are heated by a combination of radiation, conduction and convection within the columns and emerge onto the top of the furnace stack burden at temperatures within the range 450 to 800 C. preferably within the range 550 to 750 C. and between 700 to 800 C.
  • the hot combusted gases leave the space or chamber around the hollow columns via one or more appropriately located vents to pass via heat exchangers and gas cleaners to exhaust fans.
  • High thermal efl'iciency may be secured by using these gases for various heating operations in metallurgical plants, such as for instance, the preheating of the air blown into the furnace via tuyeres or ports, moderate preheating of pellets or briquettes prior to charging into the hoppers at the top of the shaft furnace.
  • the tars and other volatile pyrolysis products are substantially combusted by reaction with oxygen-containing gases in a combustion chamber surrounding the column or columns and mounted above but substantially separate from the smelting shaft proper; the substantially devolatilized and partially coked pellets or briquettes emerge from the slotted column or columns finally into the smelting shaft in which rapid smelting to a metal vapour, slag and possibly another less volatile metal-rich phase takes place.
  • the invention also provides apparatus for the direct shaft furnace smelting of oxidic ores or concentrates or calcines which comprises one or more hollow carbonizing columns disposed above a main furnace shaft, a combustion chamber or space surrounding or partly surrounding the carbonizing column or columns, each carbonizing column having holes or slots in the wall or walls thereof, means for feeding a pelletised or briquetted mixture of ore or concentrate and coal to the upper ends of the carbonizing column or columns, so that the pellets or briquettes descend slowly under gravity first through the carbonizing column or columns and then through the main furnace shaft, means for introducing oxygen-containing gas into the combustion chamber or space, and means for withdrawing metal or alloy from the main furnace shaft.
  • the invention consists in apparatus for achieving semi-coking of the coal component in composite pellets or briquettes of oxidic ores, concentrates or calcines comprising substantially vertical hollow columns made of heat resisting alloy or refractory ceramic arranged within the space or chamber above the main shaft of the shaft furnace, the space or chamber being substantially sealed except for one or more gas offtakes, each column having holes or slots, of such size or arrangement that the pellets or briquettes will not be able to fall through them, and extending for at least the length of the bottom half of each column.
  • the columns permit the transfer of heat to the descending pellets or briquettes from the surrounding space in which the tars and gaseous hydrocarbons, plus any CO or I'I arising from the stack, are combusted by an oxygen-containing gas blown in via appropriately located ports or jets in the outer wall of the chamber or space.
  • the columns are of such length, cross-sectional area and wall thickness as to permit the progressive heating of the pellets or briquettes descending therein to a temperature within the range 450 to 800 C. preferably within the range 550 to 750 C. and preferably between 700800C. in zinc smelting before they emerge.
  • the combustion chamber is preferably removable from the main furnace shaft.
  • the oxygen-containing gas blown into the combustion space or chamber surrounding the carbonizing columns enters with sufficient velocity and pressure to ensure ample circulation and movement of flames and hot gases within it.
  • Baftles or other means may also be employed within the combustion space to assist uniform heating of each of the columns, as otherwise varying degrees of coking may result in the several columns.
  • vent or vents via which the hot combusted gases leave the combustion space or chamber surrounding the carbonizing columns are connected to hot gas mains which convey the hot gases to heat exchangers, gas cleaners and exhaust fans.
  • the combustion space or chamber surrounding the carbonizing columns is maintained at a slightly negative pressure in order to help draw the tarry matter and other hydrocarbons away from the pellets or briquettes through the slots or holes and into the space or chamber where combustion takes place.
  • FIG. 1 a shaft furnace 10 is shown in the upper part of which three perforated carbonizing columns 11, 12, 13 are located. Preferably the columns 11, 12, 13 increase slightly and gradually in cross-sectional area from top to bottom.
  • Composite pellets or briquettes 14 are fed into the upper ends of the columns 11, 12, 13 via hoppers 15.
  • Two inlets 16a, 16b for oxygen-containing gases and one ofitake 18 for the products of combustion are provided. Said inlets 16, 16a are placed along the sides of the combustion space or chamber 19 surrounding the carbonizing columns 11, 12, 13 in such a way so as to ensure optimum movement and distribution of the hot oxygen-containing gases.
  • the offtake 18 is connected to the upper end of the combustion chamber 19.
  • Slots or holes 20 are formed in the walls of the columns 11, 12, 13.
  • the said slots or holes 20 are of such size or arrangement that the pellets or briquettes cannot fall out through said slots or holes.
  • Tuyeres 21 are provided for the admission of oxygen-containing gas (e.g. air) at the bottom of the furnace.
  • the melt collects in the crucible 22 and is tapped at outlet 23.
  • FIGS. 2 and 3 are similar to FIG. 1 but embody modifications which are particularly suited to smelting processes in which volatile metal products are formed. Accordingly provisions are made for the condensation of such metal vapours by having vapour condensers 24 connected to the main shaft of the furnace 10.
  • the combustion chambers 19 are shown as separate removable units, that shown in FIG. 2 being of substantially rectangular vertical cross-section. Additional inlets 17 for oxygen-containing gases are located below the chamber 19.
  • the apparatus shown in FIG. 3 includes a waisted section 25 below the chamber 19 which serves to aid the flow of the volatile metal product into the vapour condenser 24 and also serves to direct the devolatilized-carbonized pellets or briquettes towards the center of the furnace.
  • Means may, if desired, be provided for controlled rotation or other actuation of the hollow carbonizing columns 11, 12, 13 in any of the forms of the invention to accelerate or case the descent of the pellets or briquettes in said columns.
  • Ore fines 50 Coal 44 Lime 5 Cement The mixture was pelletized in a disc pelletizer to produce pellets ranging from one-half inch to seven-eigths inch diameter.
  • the pellets 14 were allowed to dry out slowly over 24 to 40 hours and were hard enough to withstand the handling into the hoppers 15 at the top of a low shaft smelting furnace of the general type shown in FIG. 1.
  • About 3 percent extra lump limestone (plus one-fourth in. minus seven-eighths in.) was added to maintain reasonably high basicity in the slags.
  • the experimental furnace had a total internal shaft height of 8 ft. with a shaft diameter of 18 inches and a hearth diameter of 12 inches.
  • the vertically slotted carbonizing steel columns 11, 12, 13 were 3 feet long and the bed height in the shaft proper 24 was approximately 4 feet 6 inches.
  • the blast air was preheated to between 380 C. and 400 C. and blown in via six tuyeres 21.
  • the air blown in at lower pressure via ports 16 and 17 was preheated to only 200 C.
  • the furnace 10 used was the same as employed for Example 1 and the blast preheat temperature at 21 was the same, namely 380 to 400 C. However, the air blown in at inlets l6 and 17 was only at C. This was necessary to keep the temperature at the top of the burden in the shaft below 700 as otherwise excessive fume loss occurred.
  • the partially carbonized pellets emerged from the carbonizing columns 11, 12, 13 at a preferred just dull red heat (550 to 650 C.).
  • This molten alloy is suitable for continuous refining in a WORCRA type furnace with countercurrent flow of slag relative to that of the molten alloy as described in the process of our US. Pat. No. 3,326,672.
  • EXAMPLE 3 Smelting of a 50:50 Mixture of Nickeliferous Laterite and Gamieritic Weathered Serpentine Ore The ore mixture contained the following percentages of the more significant components on a dry basis:
  • the blast preheat temperature at 21 was 375 to 400 C. and the air blown in via inlets 16 and 17 was at approximately 250 C.
  • the alloy tapped at intervals via taphole 23 was of the following average chemical composition:
  • the calcium-magnesium-iron-aluminium silicate slag contained 0.06% Ni and 0.15% Cr.
  • Zinc calcines produced by calcining Broken Hill zinc sulphide concentrates in a fluid bed roaster.
  • the calcines had an average assay of:
  • the experimental furnace used had a total shaft height of 8 feet and a diameter of 18 inches with a crucible hearth diameter of 12 inches.
  • Six tuyeres 21 of heat resisting alloy were used.
  • the carbonizing columns 11, 12, 13 were 3 ft. 6 in. long, and the heat resistant alloy waist 25 directed the hot devolatilized pellets down into the shaft 10.
  • the pellets emerged from the bottom of the slotted columns 11, 12, 13 at 650 to 700 C. and were slightly hotter, 700 to 750 C., as they entered into the top of the shaft proper.
  • the calcium-iron-aluminium silicate slags tapped from the crucible were generally similar to those tapped from ISF furnaces. Zinc contents ranged from 5.0 to 9.6 percent.
  • Apparatus for the direct shaft furnace smelting of oxidic ores or concentrates or calcines which comprises one or more hollow carbonizing columns disposed above a main furnace shaft, a combustion chamber or space surrounding or partly surrounding the carbonizing column or columns, each carbonizing column having holes or slots in the wall or walls thereof, means for feeding a pelletized or briquetted mixture of ore or concentrate or calcine and coal to the upper ends of the carbonizing column or columns, so that the pellets or briquettes descend slowly under gravity first through the carbonizing column or columns and then through the main furnace shaft, means for introducing oxygen-containing gas into the combustion chamber or space, and means for withdrawing metal or alloy from the main furnace shaft.
  • Apparatus according to claim 1 wherein a plurality of carbonizing columns is provided and the combustion chamber extends between and around the carbonizing columns.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Manufacture Of Iron (AREA)
US864051A 1968-10-15 1969-10-06 Shaft furnace smelting of oxidic ores, concentrates or calcines Expired - Lifetime US3652069A (en)

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Application Number Priority Date Filing Date Title
AU44834/68A AU402464B2 (en) 1968-10-19 Shaft furnace smelting of oxidic ores concentrates or calcines

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US3652069A true US3652069A (en) 1972-03-28

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US (1) US3652069A (fr)
JP (1) JPS5027002B1 (fr)
DE (1) DE1951567B2 (fr)
FR (1) FR2020720A1 (fr)
GB (1) GB1261127A (fr)
MY (1) MY7300108A (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3953196A (en) * 1974-04-05 1976-04-27 Obenchain Richard F Process for the direct reduction of metal oxides
EP0796918A1 (fr) * 1996-03-18 1997-09-24 Kawasaki Steel Corporation Procédé d'alimentation d'un cubilot et ferraille et coke
US6517603B2 (en) * 2001-03-20 2003-02-11 Startec Iron Llc Method for recovery of metals having low vaporization temperature
US20060157899A1 (en) * 2005-01-15 2006-07-20 Lew Holdings, Llc Single vessel blast furnace and steel making/gasifying apparatus and process
CN105371653A (zh) * 2015-09-08 2016-03-02 刘建华 一种立式氧化锌冶炼炉
US20180030574A1 (en) * 2015-02-24 2018-02-01 Sumitomo Metal Mining Co., Ltd. Method for smelting saprolite ore

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB189412637A (en) * 1894-06-29 1895-06-29 John Edward Lloyd Barnes Improvements in Ore Roasters.
US637432A (en) * 1898-02-16 1899-11-21 Dimitris Tschernoff Gas blast-furnace.
AU132654A (en) * 1954-06-29 1955-01-06 Robertshaw-Fulton Controls Company Improvements in temperature regulator
US2857155A (en) * 1952-10-04 1958-10-21 Electrolyser Corp Ltd Apparatus for reducing ores

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB189412637A (en) * 1894-06-29 1895-06-29 John Edward Lloyd Barnes Improvements in Ore Roasters.
US637432A (en) * 1898-02-16 1899-11-21 Dimitris Tschernoff Gas blast-furnace.
US2857155A (en) * 1952-10-04 1958-10-21 Electrolyser Corp Ltd Apparatus for reducing ores
AU132654A (en) * 1954-06-29 1955-01-06 Robertshaw-Fulton Controls Company Improvements in temperature regulator

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3953196A (en) * 1974-04-05 1976-04-27 Obenchain Richard F Process for the direct reduction of metal oxides
EP0796918A1 (fr) * 1996-03-18 1997-09-24 Kawasaki Steel Corporation Procédé d'alimentation d'un cubilot et ferraille et coke
US5759232A (en) * 1996-03-18 1998-06-02 Kawasaki Steel Corporation Method of charging materials into cupola
US6517603B2 (en) * 2001-03-20 2003-02-11 Startec Iron Llc Method for recovery of metals having low vaporization temperature
US20060157899A1 (en) * 2005-01-15 2006-07-20 Lew Holdings, Llc Single vessel blast furnace and steel making/gasifying apparatus and process
US20180030574A1 (en) * 2015-02-24 2018-02-01 Sumitomo Metal Mining Co., Ltd. Method for smelting saprolite ore
US10301704B2 (en) * 2015-02-24 2019-05-28 Sumitomo Metal Mining Co., Ltd. Method for smelting saprolite ore
CN105371653A (zh) * 2015-09-08 2016-03-02 刘建华 一种立式氧化锌冶炼炉

Also Published As

Publication number Publication date
MY7300108A (en) 1973-12-31
DE1951567B2 (de) 1971-12-16
DE1951567A1 (fr) 1971-12-16
JPS5027002B1 (fr) 1975-09-04
FR2020720A1 (fr) 1970-07-17
GB1261127A (en) 1972-01-19

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