US3416778A - Apparatus for thermal treatment of minerals - Google Patents

Apparatus for thermal treatment of minerals Download PDF

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Publication number
US3416778A
US3416778A US626736A US62673667A US3416778A US 3416778 A US3416778 A US 3416778A US 626736 A US626736 A US 626736A US 62673667 A US62673667 A US 62673667A US 3416778 A US3416778 A US 3416778A
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United States
Prior art keywords
grill
kiln
chamber
gases
chambers
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Expired - Lifetime
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US626736A
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English (en)
Inventor
Chabaglian Henri Fernand
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ThyssenKrupp Industrial Solutions AG
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Polysius AG
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Publication date
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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
    • C22B1/24—Binding; Briquetting ; Granulating
    • C22B1/2413—Binding; Briquetting ; Granulating enduration of pellets
    • 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
    • F27B7/00—Rotary-drum furnaces, i.e. horizontal or slightly inclined
    • F27B7/20—Details, accessories, or equipment peculiar to rotary-drum furnaces
    • F27B7/2016—Arrangements of preheating devices for the charge
    • F27B7/2066—Arrangements of preheating devices for the charge comprising a band transporter
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D15/00—Handling or treating discharged material; Supports or receiving chambers therefor
    • F27D15/02—Cooling
    • F27D15/0206—Cooling with means to convey the charge
    • F27D15/0266—Cooling with means to convey the charge on an endless belt

Definitions

  • the known apparatus utilizes one or more traveling grills which transport the material toward a rotary kiln where the roasting itself is conducted, while on the grill, preceding the kiln, the material is heated by hot gases discharged from the kiln.
  • the kiln is preceded with a traveling grill through which the gas makes two passes, i.e., the ⁇ grill is separated into two parts, the hot gases recuperated from the downstream part being supplied to the upstream part of the grill.
  • the kiln is preceded by two grills in cascade, the first serving as a recuperator for the heat radiated from the kiln and from the cooler, and the second serving as recuperator for the heat of the gases discharged from the kiln.
  • the circuit of the gas is independent and forms a simple gas passage.
  • the object of the invention is to provide a heat treatment apparatus of the type hereinbefore described in 'which the circulation and the recuperation of the hot gases permits greater flexibility of treatment by separating the functions of drying and preheating and assuring an improvement in the efficiency of heating on the grills, as well as an increase in capacity which is difiicult to obtain by merely increasing the dimensions of the grills.
  • the invention then comprises apparatus for thermal treatment of minerals characterized in that it comprises a first traveling grill for drying on which the material is heated by gases which have passed through a second preheating grill on which the material is heated partly by gases discharged from the kiln and partly by burners which are supplied with secondary air of combustion consisting of hot air discharged from a cooler which follows the kiln, a burner in the kiln being also supplied with secondary air consisting of part of the hot air discharged from the cooler.
  • FIGURE 1 is a schematic view of an apparatus according to the invention.
  • FIGURE 2 is a schematic view of a modification of the apparatus according to the invention which is shown in FIGURE 1.
  • the apparatus for thermal treatment shown in FIGURE 1 comprises a conveyor 1 which conducts the material to be treated into a hopper 2 which distributes it upon a first traveling grill 3, which transports the material across a drying chamber 4 and discharges it into a hopper 5 which distributes the dry material upon a second traveling grill 6.
  • This intermediate hopper 5 The role of this intermediate hopper 5 is to form a reservoir of material between the two grills 3 and 6 in order that the grill 6 may be suitably covered with the material.
  • this hopper 5 on the one hand tends to cause the material to be turned over in the course of its transfer, thus permitting better equalization of the temperatures in the mass of the material, and on the other hand tends to stir the material so as to cause segregation of the fine particles or small fragments of material, the elimination of which, When necessary, can be obtained by using a hopper wall 7 consisting of a screen.
  • This hopper 5 thus makes possible a speed of travel of the material which is different on the two grills, so that the thickness of the layer of the material may be different on each grill, the height of the layer upon the grill 6 being determined by an adjustable regulator 8, while a level detector 9, which may consist of a sound transmitter and a sound receiver, for example, permits the determination of the quantity of material in the hopper 5.
  • the difference in the speed of travel of the material on the two grills which is made possible by the hopper thus permits adjustment of the duration of treatment in accordance with the requirements of the material being treated.
  • Material on the grill 6 then passes through the precalcination chamber 10 and is transferred into a rotating kiln 11, where the actual roasting takes place, after which the material is discharged upon a grill 12 where it is cooled while passing through three successive chambers, 13, 14 and 15.
  • the air which is used for final cooling in the exit chamber '15 is discharged to the exterior at a temperature of about to 200 C.
  • the air which is used for intermediate cooling in the intermediate chamber 14 at about 200400 C. is withdrawn by a fan 16 and conducted to the chamber 10, where it is used as air of combustion for the burners 17.
  • Gases at about 1000-1200 C. from the kiln 11 pass into the chamber 10, where they are mixed with the gases flowing from the burners 17, and pass through the bed of material to bring the material to an average temperature of 700 C. at which the principal reactions for changing the state of the material commence (between 500 and 900 0., according to the material) such as decarbonation, dehydration, oxidation or others.
  • the gases discharged by the fan 21 then pass through the bed of material disposed upon the grill 3, to penetrate into a chamber 22 at a temperature of 80120 C., from which they are withdrawn by a fan 23 which discharges them to the exterior by a stack 24.
  • the apparatus according to the invention permits great flexibility of the thermal treatment.
  • the requirements in the kiln 11 are of the order of 140 Th.
  • the thermal requirements in the chambers 4 and 10 are of the order of 310 Th.
  • the requirements in the kiln 11 are of the order of 128 Th.
  • the thermal requirements in the chambers 4 and 10 are of the order of 200 Th.
  • the requirements in the kiln 11 are of the order of 190 Th.
  • the requirements in the chambers 4 and 10 are of the order of 540 Th.
  • the requirements in the kiln 11 are of the order of 520 Th.
  • the requirements in the chambers 4 and 10 are of the order of 550 Th.
  • the thermal requirements in the kiln are substantially less than those necessary in the chambers 4 and 10.
  • the thermal requirements are substantially the same in the kiln 11 and in the chambers 4 and 10.
  • the distribution makes it possible to limit the gas flow between the kiln 11 and the chamber 10, to prevent raising dust.
  • the treatment of the material requires high temperatures, and in order not to treat the material too long in the rotary kiln where the material is subjected to agitation which impairs the cohesion, one may carry the material on the second grill to an elevated temperature of about 1200" C., in which case it is desirable, for mechanical and economical reasons, to employ a second grill which is short.
  • the material arriving upon this second grill should already be at a temperature which is relatively high, about 600 to 900 C., so that it is desirable to employ a modification of the abovedescribed apparatus, which modification is represented by the form of the apparatus illustrated in FIGURE 2.
  • the first grill 3 is a grill which is subjected to two passes of the gas
  • FIGURE 2 thus all of the relative advantages of FIGURE 2 are retained, while the cost of the installation is reduced substantially by comparison with continuous installations which employ only one grill.
  • Apparatus for thermal treatment of minerals comprising a rotary kiln preceded by traveling grills for drying and preheating, wherein the improvement comprises a first traveling grill for drying; a second traveling grill for preheating, the inlet end of which is arranged to receive material discharged from the exit end of the first grill, and the exit end of which is arranged to discharge material into the inlet of the kiln; an enclosed cooler arranged to receive material discharged from the exit of the kiln; two separate chambers adjacent to the two ends of the first grill, which are bounded by the upper surface of the grill; two separate chambers adjacent to the two ends of the first grill which are bounded by the lower surface of the grill; a separate chamber bounded by the upper surface of the second grill; a separate chamber bounded by the lower surface of the second grill; a burner in the kiln; an inlet for supplying air to the cooler; a recuperating system for withdrawing the air which has been heated in the cooler and supplying a portion thereof as secondary combustion
  • Apparatus for thermal treatment of minerals comprising a rotary kiln preceded by traveling grills for drying and preheating, wherein the improvement comprises a first traveling grill for driving; a second traveling grill for preheating, the inlet end of which is arranged to receive material discharged from the exit end of the first grill, and the exit end of which is arranged to discharge material into the inlet of the kiln; an enclosed cooler which is divided into an inlet chamber arranged to receive material discharged from the exit of the kiln, an intermediate chamber which receives material from the inlet chamber, and an exit chamber which receives material from the intermediate chamber; a separate chamber bounded by the upper surface of each of the grills; a separate chamber bounded by the lower surface of each of the grills; a burner in the kiln; inlets for supplying cooling air to all three chambers of the cooler; a recuperating system for withdrawing, from the intermediate chamber of the cooler, air which has been heated to an intermediate temperature, and for supplying such air to one
  • Apparatus according to claim 2 wherein a hopper is arranged to receive the material passing from the first grill to the second grill, for controlling the thickness of References Cited UNITED STATES PATENTS 1,468,168 9/1923 Pike 26332 3,254,882 6/1966 Helming 26332 3,313,534 4/1967 Frans 26332 FREDERICK L. MATTESON, JR., Primary Examiner.

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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)
  • Muffle Furnaces And Rotary Kilns (AREA)
  • Furnace Details (AREA)
US626736A 1966-05-06 1967-03-29 Apparatus for thermal treatment of minerals Expired - Lifetime US3416778A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR60648A FR1484823A (fr) 1966-05-06 1966-05-06 Dispositif de traitement thermique pour matières minérales

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FR (1) FR1484823A (fr)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3539336A (en) * 1968-08-20 1970-11-10 Eveleth Taconite Co Ore pelletizing process and apparatus
US3671027A (en) * 1970-09-24 1972-06-20 Hanna Mining Co Heat processing of minerals
US3782888A (en) * 1972-10-04 1974-01-01 Allis Chalmers Method and apparatus for heat treating with heat recuperation from material cooling and auxiliary heat during startup
US3891383A (en) * 1972-12-06 1975-06-24 Ishikawajima Harima Heavy Ind Rotary kiln apparatus with suspension preheater having burner for calcining
US3940241A (en) * 1974-01-25 1976-02-24 F. L. Smidth & Co. Rotary kiln plant
US4174004A (en) * 1977-02-15 1979-11-13 Chloride Group Limited Electric storage batteries
US4332551A (en) * 1980-01-23 1982-06-01 Voest-Alpine Aktiengesellschaft Process and equipment for firing pellets
US4884969A (en) * 1985-11-16 1989-12-05 Ludwig Riedhammer Gmbh Tunnel kiln
US20150153107A1 (en) * 2012-07-19 2015-06-04 Tenova S.P.A. Plant and relative procedure for the continuous feeding of heated metallic material to a melting furnace for the production of steel

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4065320A (en) * 1975-05-13 1977-12-27 Allis-Chalmers Corporation System for handling high sulfur materials
DE2630895A1 (de) * 1976-07-09 1978-01-12 Readymix Cement Eng Gmbh Vorrichtung zum brennen oder sintern und anschliessendem kuehlen von zementklinker, kalk, magnesit, dolomit oder aehnlichen stoffen

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1468168A (en) * 1922-07-05 1923-09-18 Robert D Pike Apparatus for calcining and clinkering
US3254882A (en) * 1962-12-10 1966-06-07 Polysius Gmbh Method of and arrangement for dressing moist raw materials with solid undesired inclusions
US3313534A (en) * 1965-07-21 1967-04-11 Allis Chalmers Mfg Co Method and furnace for heat treating minerals

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1468168A (en) * 1922-07-05 1923-09-18 Robert D Pike Apparatus for calcining and clinkering
US3254882A (en) * 1962-12-10 1966-06-07 Polysius Gmbh Method of and arrangement for dressing moist raw materials with solid undesired inclusions
US3313534A (en) * 1965-07-21 1967-04-11 Allis Chalmers Mfg Co Method and furnace for heat treating minerals

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3539336A (en) * 1968-08-20 1970-11-10 Eveleth Taconite Co Ore pelletizing process and apparatus
US3671027A (en) * 1970-09-24 1972-06-20 Hanna Mining Co Heat processing of minerals
US3782888A (en) * 1972-10-04 1974-01-01 Allis Chalmers Method and apparatus for heat treating with heat recuperation from material cooling and auxiliary heat during startup
US3891383A (en) * 1972-12-06 1975-06-24 Ishikawajima Harima Heavy Ind Rotary kiln apparatus with suspension preheater having burner for calcining
US3940241A (en) * 1974-01-25 1976-02-24 F. L. Smidth & Co. Rotary kiln plant
US4174004A (en) * 1977-02-15 1979-11-13 Chloride Group Limited Electric storage batteries
US4332551A (en) * 1980-01-23 1982-06-01 Voest-Alpine Aktiengesellschaft Process and equipment for firing pellets
US4884969A (en) * 1985-11-16 1989-12-05 Ludwig Riedhammer Gmbh Tunnel kiln
US20150153107A1 (en) * 2012-07-19 2015-06-04 Tenova S.P.A. Plant and relative procedure for the continuous feeding of heated metallic material to a melting furnace for the production of steel

Also Published As

Publication number Publication date
FR1484823A (fr) 1967-06-16
DE1508510B2 (de) 1972-10-19
DE1508510A1 (de) 1969-10-30

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