US3908972A - Installation for treatment of minerals on a continuous circular grill - Google Patents

Installation for treatment of minerals on a continuous circular grill Download PDF

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Publication number
US3908972A
US3908972A US394513A US39451373A US3908972A US 3908972 A US3908972 A US 3908972A US 394513 A US394513 A US 394513A US 39451373 A US39451373 A US 39451373A US 3908972 A US3908972 A US 3908972A
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United States
Prior art keywords
grid
beams
radial
plant
accordance
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Expired - Lifetime
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US394513A
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English (en)
Inventor
Edouard Bonnaure
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Creusot Loire Enterprises SA
Creusot Loire SA
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Creusot Loire SA
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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
    • C22B1/00—Preliminary treatment of ores or scrap
    • C22B1/14—Agglomerating; Briquetting; Binding; Granulating
    • C22B1/16—Sintering; Agglomerating
    • C22B1/20—Sintering; Agglomerating in sintering machines with movable grates
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B21/00—Open or uncovered sintering apparatus; Other heat-treatment apparatus of like construction
    • F27B21/06—Endless-strand sintering machines

Definitions

  • the present invention relates to a plant for heat treatment by gas flows of pelletised ores, using a Continuous, circular grid.
  • it is more particularly applicable to the reduction of iron ores with pure hydrogen or with a mixture of hydrogen and carbon monoxide, for the production of solid, deoxidized products.
  • This reduction process was the object of French Patent application No. 72-15245 of 28th April 1972 and its Addition No. 72-30196 of 24th August 1972, filed by the same Applicant.
  • the grid passes successively through zones with different functions of which the zones for treatment by through-passage of a gas flow are generally the longest and the hottest.
  • the grid in these zones is subject to high thermal stresses which are of long duration and are deleterious to the good condition of its elements.
  • the gases used for the treatment of ore are often expensive and inflammable and it is therefore important to control the leaks which take place, firstly between the fixed boxes and the elements of the grid, secondly between the various elements of the grid and lastly between the various gas circulation boxes.
  • the present invention provides a solution to these various problemsand is applicable to a plant for heattreatment by gas flows of pelletised ores, using a continuous, circular grid with a fixed base, formed of a series of radial beams forming cradles supporting the bars of the grid, and including a loading Zone,'at least one treatment zone, a discharge zone and neutral zones, the grid passing in the or each treatment zone, between a fluid-tight upper and a fluid-tight, fixed lower box.
  • the ends of the radial beams forming the grid extend beyond the boxes on either side and rest on two circular, concentric rings rotating at the same angular velocity.
  • the supports for the radial beams on the circular rings permit their free radial expansion and the vertical, lateral sides of the radial beams are connected by flexible, fabricated members which are able to accommodate tangential expansion of the radial beams.
  • FIG. 1 gives a diagrammatic plan of a plant, in accordance with the invention, where a circular grid is used for the reduction of the ore in two successive stages, firstly with a mixture of carbon monoxide and hydrogen and then with pure hydrogen.
  • FIG. 2 gives a more detailed view of the plant along a radial section aa of FIG. 1 and of FIG. 4, i.e., along the axis of the hydrogen supply to a secondary reduction zone.
  • the lower portion of FIG. 2 shows the lower box along a radial section bb of FIG. I, along the axis of the outlet for the hydrogen after reduction.
  • FIG. 3 shows a view of the plant along a section cc of FIG. I, in the products evacuation zone.
  • FIG. 4 shows in principle in lateral view on line eev of FIG. 2 the assembly of the radial beams, the flexible, fabricated sides and the portions of the seals rigidly attached to the mobile grid.
  • FIG. 5 shows a vertical view along the section d-d of FIG. 1, through a neutral zone arranged between two zones for treatment with different gases.
  • FIG. 6 is a plan view of the beams on the line ff of FIG. 4.
  • the circular, horizontal and continuous grid moves in the direction indicated by arrow 1.
  • the grid receives the sized and inert products for lining the bottom and the sides to form a protection for the grid.
  • the green pellets are brought onto the grid at 3.
  • Zones 4 and 5 are zones for predrying and drying of the pellets, which are then roasted in zone 6. Separated by a first neutral zone at 7, is a primary reduction zone at 8, while secondary reduction is effected in zones 9 and 10.
  • Neutral zone 11 precedes a cooling zone 12, itself followed by another neutral zone 13.
  • Product evacuation is carried'out at 14 by means of a shovelling wheel.
  • Zone 15 is a clear zone to enable repairs to be carried out and is served by a handling machine 16 for this purpose.
  • Assembly 17 groups the fans, scrubbers, combustion chambers, flues and other apparatus linked with the circuit of the drying and roasting gases of zones 4, 5 and 6.
  • the unit for preparation of the mixture of carbon monoxide and hydrogen which supplies primary reduction zone 8.
  • Conditioning units 19 and 20 supply reduction zones 9 and 10 with hydrogen.
  • At 21 is shown the unit for circulation and cooling of the neutral gas which passes through zone 12.
  • Fan 22, for the cooling air of unit 21, sends back hot air to zones 4, 5 and 6 through conduits 23.
  • the hot gas leaving primary reduction zone 8 can be passed as fuel, through conduits 24, either to roasting zone 6 or to the hydrogen heater of the adjacent conditioning unit 19.
  • the materials extracted from the grid at 14 are evacuated by conveyer 25 to treatment unit 26, where the recovery takes place of the grid protector, which is returned to the grid at 2 by means of conveyer 27.
  • Conveyer 28 transfers the iron sponges to the treatment storage and shipping assembly.
  • Conveyer 29 brings'the green pellets onto the grid.
  • FIG. 1 does not show the ore storage and homogenization depots or the drying, crushing and pelletizing plants, or the attached plants, the positioning of which, relative to the grid itself is relatively unimportant.
  • the hot reducing gas is passed into upper box 31 by conduit 30.
  • Conduit 30 and box 31 are of fabricated construction and covered inside with an insulating and refractory lining. They are suspended from upper beams not shown in the figure.
  • Fabricated cases 32 with water circulation, are rigidly attached to box 31 and have the triple task of providing thermal insulation for the .upper mechanical seal, of providing a lower anchorage for the refractory lining of the box and, lastly, of limiting the empty space between the fixed box and the tops of the sides of the mobile grid.
  • Fluid-tightness between the box and the grid is produced by seals 33 which are applied to the fabricated' cases 34 rigidly attached to the mobile grid and cooled by circulation of water.
  • the shape of cases 32 and 34 forms a baffle to shield seals 33 from the radiation of the box and from the materials arranged on the grid.
  • Each radial beam consists of two hollow, vertical sides 35 at the ends supporting cases 34 and connected by two hollow struts, 54 or 55.
  • the longitudinal bars of grid '36 rest on the struts of two consecutive radial beams.
  • the internal, vertical faces of sides 35 are lined with an insulating and refractory layer 37.
  • the layer of sized and inert products forming the protection for the grid is arranged at 38 over the bars of the grid.
  • the radial beams rest freely, by their struts 54 and 55 and through two roller supports 40 which permit expansion, on two large beams 41, in the form of circular, horizontal and concentric rings which rotate at the same angular velocity, which is adjustable according to the conditions of use.
  • the two circular beams 41 run on rails 44 of fixed frame 42 by means of wheels 43 and are guided radially by centering rollers 45. So as not to overcrowd the figure, the mechanical apparatus for driving beams 41, which can be of a quite conventional type, has not been shown.
  • FIG. 2 shows diagrammatically in solid lines the cold water supply circuit and in broken lines the hot water return circuit.
  • a seal is formed between lower box 46 and the mobile grid by vertical plates 52, which are rigidly attached to the radial beam and immersed in fixed waterholders 53.
  • FIG. 3 shows, at 54 and 55 respectively, the two radial struts of two consecutive beams. Bars 36 rest freely on water-cooled cross-pieces 54 and 55. Cross-pieces 54 and 55 are coated with a special layer 56, which limits gas-metal contact and heat-exchange.
  • a shovelling wheel 58 which is provided with buckets 59 and rotates in the direction of arrow 60 about a horizontal axis 61; the materials are deposited on a conveyer belt 62 in the centre of the shovelling wheel, and conveyer 62 then tips them onto conveyer 25, which can be seen in FIG. 1.
  • any metallised pellets which may have escaped discharge shovelling wheel 28 can be evacuated further on by a simple, magnetic apparatus, not shown in the figure; the remaining grid protection layer 38 is then levelled before receiving the further addition necessary to reform the required thickness.
  • FIGS. 4 and 6 shows the two vertical sides 35 at the ends of two consecutive radial beams.
  • the sides of these beams are connected by flexible, fabricated sides 75.
  • Fabricated cases 34 rest on the sides 35 of extremities of the radial beams and are connected to the beams by vertical axes 80.
  • the vertical joints between adjacent cases are cylindrical.
  • Vertical plate 52 which is immersed in lower hydraulic seal 53, is fastened to the lower portion of sides 35 and fabricated sides 75.
  • empty space between the upper level of the ironbearing materials 39 and the arch 63 is divided into three chambers 64, 65 and 66 by four registers 67, the lower portions of which are as close as possible to the top of layer 39.
  • inert gas is injected by piping 68, at a pressure very slightly greater than that in the adjacent treatment zones.
  • the mixtures of this inert gas and the other gases escape from chambers 64 and 66 through water-cooled purges 69; the flow rate, pressure and composition of these gaseous mixtures are controlled to maintain the proper operation of the plant.
  • a similar apparatus is used for the lower portion of the grid, where water-cooled cases 70 are applied at a controlled pressure to the lower faces and struts 54 and 55 of radial beams 35.
  • Central piping 71 is used for the supply of inert gas, while the gaseous mixtures are exhausted through purges 72. It will be noted that purges 69 and 72 can also act as possible dispersion purges for the treatment gas circuits running on either side of the neutral zone in question.
  • the plant may have a different number of primary and secondary reduction zones to the one described by way of example.
  • an advantageous modification could be formed by the use of two successive shovelling wheels to evacuate the materials, instead of one, the first removing the upper portion of layer 39 (with a high degree of reduction) and the second removing the lower portion of the layer (with a lower degree of reduction), together with a small proportion of grid protector 38.
  • a plant for heat-treatment of pelletised ores with gas flows comprising a continuous, circular rotary grid, a fixed base for said grid, a series of radial beams in the form of cradles supporting the bars of the grid, a loading zone, at least one treatment zone, a discharge zone and neutral zones for said grid, said grid passing, in each treatment zone, between an upper box and a lower boxsaid boxes being fixed and fluid-tight, said radial grid-support beams extending beyond said boxes on either side, means for cooling said beams by internal water circulation, two circular, concentric rings rotating at the same angular velocity supporting said beams and mounted on said base, roller supports for said radial beams on said circular rings permitting free radial expansion of said beams and flexible, fabricated members flexing to allow tangential expansion of said radial beams connected to vertical, lateral sides of the ends of said beams adjacent said supports.
  • a plant in accordance with claim 1 having neutral zones between different active zones, the ceiling of each neutral zone being lower than the ceiling of adjacent active zones, the space below the ceiling being divided into three transverse chambers by means of four vertically adjustable registers, an inert gas being introand evacuation means in accordance with claim 7.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Geology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Materials Engineering (AREA)
  • Environmental & Geological Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • General Engineering & Computer Science (AREA)
  • Tunnel Furnaces (AREA)
  • Manufacture And Refinement Of Metals (AREA)
US394513A 1972-09-15 1973-09-05 Installation for treatment of minerals on a continuous circular grill Expired - Lifetime US3908972A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7232751A FR2199556B1 (enrdf_load_stackoverflow) 1972-09-15 1972-09-15

Publications (1)

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US3908972A true US3908972A (en) 1975-09-30

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US394513A Expired - Lifetime US3908972A (en) 1972-09-15 1973-09-05 Installation for treatment of minerals on a continuous circular grill

Country Status (7)

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US (1) US3908972A (enrdf_load_stackoverflow)
AU (1) AU6006173A (enrdf_load_stackoverflow)
BE (1) BE804870A (enrdf_load_stackoverflow)
BR (1) BR7306822D0 (enrdf_load_stackoverflow)
DE (1) DE2341096A1 (enrdf_load_stackoverflow)
FR (1) FR2199556B1 (enrdf_load_stackoverflow)
NL (1) NL7312026A (enrdf_load_stackoverflow)

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2977106A (en) * 1957-05-08 1961-03-28 Selas Corp Of America Furnace closure
US3172936A (en) * 1965-03-09 Sliding seals for sintering machines
US3302936A (en) * 1964-11-23 1967-02-07 Mcdowell Wellman Eng Co Circular traveling grate machine
US3367644A (en) * 1966-02-07 1968-02-06 Mcdowell Wellman Eng Co Liquid trough seal
US3452972A (en) * 1966-06-23 1969-07-01 Donald Beggs Furnace hearth
US3460818A (en) * 1966-05-31 1969-08-12 Mckee & Co Arthur G Apparatus for treatment of particulate material on moving support
US3536307A (en) * 1968-11-08 1970-10-27 Dravo Corp Circular traveling grate machine
US3589691A (en) * 1968-10-07 1971-06-29 Mckee & Co Arthur G Treatment of material on a moving support
US3614076A (en) * 1968-08-10 1971-10-19 Dravo Corp Open burner machines for sintering ores
US3638928A (en) * 1969-08-28 1972-02-01 Koppers Co Inc Pallet heat rib shield
US3761359A (en) * 1970-11-23 1973-09-25 Hippel H Von Method and apparatus for heat treating materials
US3774891A (en) * 1971-06-10 1973-11-27 N Plotkin Annular roasting machine for loose materials

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1940935A (en) * 1931-06-03 1933-12-26 Matthiessen & Hegeler Zinc Co Method of sintering ores and apparatus therefor

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3172936A (en) * 1965-03-09 Sliding seals for sintering machines
US2977106A (en) * 1957-05-08 1961-03-28 Selas Corp Of America Furnace closure
US3302936A (en) * 1964-11-23 1967-02-07 Mcdowell Wellman Eng Co Circular traveling grate machine
US3367644A (en) * 1966-02-07 1968-02-06 Mcdowell Wellman Eng Co Liquid trough seal
US3460818A (en) * 1966-05-31 1969-08-12 Mckee & Co Arthur G Apparatus for treatment of particulate material on moving support
US3452972A (en) * 1966-06-23 1969-07-01 Donald Beggs Furnace hearth
US3614076A (en) * 1968-08-10 1971-10-19 Dravo Corp Open burner machines for sintering ores
US3589691A (en) * 1968-10-07 1971-06-29 Mckee & Co Arthur G Treatment of material on a moving support
US3536307A (en) * 1968-11-08 1970-10-27 Dravo Corp Circular traveling grate machine
US3638928A (en) * 1969-08-28 1972-02-01 Koppers Co Inc Pallet heat rib shield
US3761359A (en) * 1970-11-23 1973-09-25 Hippel H Von Method and apparatus for heat treating materials
US3774891A (en) * 1971-06-10 1973-11-27 N Plotkin Annular roasting machine for loose materials

Also Published As

Publication number Publication date
FR2199556B1 (enrdf_load_stackoverflow) 1975-01-03
NL7312026A (enrdf_load_stackoverflow) 1974-03-19
FR2199556A1 (enrdf_load_stackoverflow) 1974-04-12
DE2341096A1 (de) 1974-03-21
BR7306822D0 (pt) 1974-07-11
BE804870A (fr) 1974-03-14
AU6006173A (en) 1975-03-06

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