EP0003665A1 - A method of producing cold agglomerates for use in iron making - Google Patents

A method of producing cold agglomerates for use in iron making Download PDF

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Publication number
EP0003665A1
EP0003665A1 EP79300171A EP79300171A EP0003665A1 EP 0003665 A1 EP0003665 A1 EP 0003665A1 EP 79300171 A EP79300171 A EP 79300171A EP 79300171 A EP79300171 A EP 79300171A EP 0003665 A1 EP0003665 A1 EP 0003665A1
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EP
European Patent Office
Prior art keywords
agglomerates
resulting
steam
mixture
iron
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP79300171A
Other languages
German (de)
English (en)
French (fr)
Inventor
Hideyuki Yoshikoshi
Achim Deja
Hiroshi Fukuyo
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.)
JFE Engineering Corp
Original Assignee
Nippon Kokan Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nippon Kokan Ltd filed Critical Nippon Kokan Ltd
Publication of EP0003665A1 publication Critical patent/EP0003665A1/en
Withdrawn legal-status Critical Current

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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
    • 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
    • C22B1/242—Binding; Briquetting ; Granulating with binders
    • C22B1/243—Binding; Briquetting ; Granulating with binders inorganic

Definitions

  • This invention relates to a method of producing cold or unburned agglomerates used for iron making, from pulverized or fine iron ores or other iron containing materials.
  • the present invention is intended to provide methods of producing cold agglomerates used for iron making, whereby cold pellets or briquettes of high strength may be obtained continuously with a high operational efficiency. It also has the advantage of providing methods of producing cold agglomerates used for iron making, which can be practiced continuously with high safety without the necessity of using high pressure steam.
  • a method according to the invention of producing cold agglomerates for use in iron making is characterized in that to 100 weight parts of fine or pulverized iron containing material are added 3 to 10 weight parts of a hydraulic bonding agent and optionally a desired amount of other additives, the resulting mixture is added with water and homogenized, the so homogenized mixture is then mechanically processed into green briquettes or pellets, and the resulting briquettes or pellets are cured by the steps of
  • the step a) may be carried out at an ambient temperature up to 60° C in an atmosphere of from 80 to 100% relative humidity during not more than 3 days, and the step b) may be carried out at a temperature from 90°C to 100°C.
  • cold agglomerates of a high compressive strength may be obtained within a relatively short time.
  • iron containing materials which can be used as starting material for a process according to the invention are iron sand, iron dusts produced and recovered in iron making plants and fine iron ores.
  • iron sand iron dusts produced and recovered in iron making plants
  • fine iron ores are most preferred as starting materials.
  • fine iron ores are used as the starting material.
  • the fine iron ore is mixed with a hydraulic bonding agent and optionally with other known additives, then homogenized with water, and the resulting homogenized product is mechanically formed into green briquettes or pellets.
  • a hydraulic bonding agent and optionally with other known additives
  • the resulting homogenized product is mechanically formed into green briquettes or pellets.
  • a method according to the invention enables an improved compressive strength of the agglomerates to be achieved notwithstanding the fact that the amount of the hydraulic bonding agent is kept to lower than 10 wt. percent related to the weight of the fine iron ore. It should be noted that an increase in the amount of the hydraulic bonding agent in such cold agglomerates may give rise to increased slag formation during iron making. On the other hand, the compressive strength of the agglomerates will not be sufficient if the hydraulic bonding agent is present in amounts less than 3 wt. percent related to the weight of fine iron ore.
  • Typical examples of hydraulic bonding agents are agents such as pulverized portland cement clinkers and blast furnace slags.
  • the marketed portland cement such as standard portland cement and rapid-hardening portland cement, belongs to a category of said crushed portland cement clinker.
  • the blast furnace slags are used as hydraulic bonding medium, use is made of 2 to 12 wt. percent of slaked lime related to the weight of slags used as accelerator for the hardening reaction.
  • modulators for adjusting the basicity of the slags such as converter slags and slaked lime, and improvers for the properties of the agglomerates may be mentioned besides reaction accelerators as stated above.
  • the fine iron ores are mixed uniformly with bonding agents and the optional additives and the resulting mixture is added to and further mixed with O.5 to 20 wt. percent of water.
  • the resulting product is formed into green briquettes or pellets.
  • the green pellets are formed by rolling, while the green briquettes are formed by compression moulding using a suitable mould.
  • the resulting green pellets or briquettes are subjected to a curing process which represents the most important feature of the present invention and comprises setting, steam treating and heating steps.
  • the present inventors have found that the total curing time can be advantageously reduced by the curing process of green briquettes or pellets which comprises these three steps under specific conditions.
  • the present inventors have also made investigations into the effects of the individual steps of setting, steam treating and heating on curing and have found that different reactions take place for each of these steps and act in concert to improve the overall curing effect.
  • the pelleted or briquetted material is allowed to stand at ambient temperature for less than three days, or within an atmosphere of relative humidity of 80 to 100% for less than three days at an ambient temperature up to 60°C.
  • the green briquettes thus obtained were maintained in an atmosphere at 15°C with 70% relative humidity, at 15°C with 100% relative humidity, and at 30, 50 and 70°C with.100% relative humidity, for determining the relation between the treating time duration and the compressive strength of the ultimate briquettes.
  • the subsequent steps of steam treating and heating were carried out in steam at 100°C at atmospheric pressure for three hours and in air at 350°C for 1 hour, respectively.
  • the results of these test runs are shown in Figure 1. It can be seen from Figure 1 that the strength of the ultimate briquettes prepared without passing through the setting step is no more than about 100 kg/cm 2 , whereas that of the ultimate briquettes obtained by passing through the setting step may be increased markedly.
  • the strength of the ultimate briquettes is slightly increased for the setting time of over three days, if the setting temperature of less than about 60°C was used. However, the increase in the strength is that small. With the setting temperature over 60 0 C, an increase in the compressive strength may be attained for a shorter setting time, however, the strength starts to decrease within three days with lapse of the setting time.
  • the upper limit of the setting time has been selected to be three days, in view of the object of the invention of producing briquettes or pellets continuously within a relatively short time so as to be usable as starting material for iron making.
  • the relative humidity of the setting atmosphere should be increased for preventing evaporation of moisture added as water to the ore and clinker mixture. This may be attained effectively by using a relative humidity over 80%.
  • the step of steam treating is conducted in steam at 90 to 100°C and atmospheric pressure.
  • Figure 2 shows the results of an experiment conducted for determining the effects of the treating temperature and treating time duration on the property of the ultimate briquettes.
  • the starting green briquettes as used in this experiment were the same as in the preceding experiment for setting.
  • the green briquettes were set for 1 day at 50°C and 100% relative humidity, treated in steam at 100°C atmospheric pressure for various treating time intervals and heated in air at 300°C for 1 hour.
  • the compressive strength of the ultimate briquettes which have not undergone steam treating is that low, whereas that of the ultimate briquettes which have undergone steam heating is increased markedly.
  • the duration of steam treating should be less than 5 hours, and the steam treating of 1 to 5 hours is preferred.
  • the steam treating temperature of more than 100°C cannot be maintained under an atmospheric pressure
  • the upper limit of the steam treating temperature is selected to 100°C.
  • the steam treating temperature of more than 90°C gives good results at a sufficient curing velocity.
  • the lower limit for steam treating is selected to 90°C.
  • the heating step is carried out in air at 100°C to 500°C.
  • Figure 3 shows the result of an experiment conducted for determining the effects of various treating conditions on the strength of the ultimate briquettes.
  • the starting green briquettes as used in the preceding experiments for setting and heat treating were used in the present experiment. These briquettes were subjected to setting at 50°C with 100% relative humidity for 48 hours, then to steam treatment in steam kept at 100°C and atmospheric pressure for 5 hours, and finally to heating under various heating temperatures and heating time intervals.
  • those briquettes which have not undergone any heating viz, those with zero heating time have a compressive strength of no more than 280 kgjcm 2 , whereas heating imparts sufficient strength to the briquettes to enable them to be used as furnace burdens.
  • the heating time should be selected appropriately according to various heating temperatures.
  • a set of optimum operating parameters can be conveniently selected under the operating conditions of setting, steam treating and heating as described above.
  • ultimate agglomerates with a practically sufficient compressive strength can be produced in about 3 days by selecting the time intervals for setting, steam treating and heating 3 days, five hours and 3 hours respectively.
  • ultimate agglomerates with practically sufficient compressive strength can be produced in less than 3 days treating time, and a set of desired operating parameters may be selected depending on the required treating time and in accordance with the operating conditions for the three steps as described above. It is to be noted that, with conventional curing, about one month of curing time will be required for producing the ultimate product with the compressive strength comparable to that obtained by the present invention.
  • the curing method of the present invention has been described in the above with reference to curing of briquettes. It has been confirmed that substantially similar results may likewise be realized with pellets.
  • the compressive strength of the ultimate pellets obtained by the present method amounts to about 150 to 230 kg per pellet, while that of the ultimate briquettes obtained by the invention amounts to about 200 to 700 kg/cm 2 . Both of these values are sufficient for practical application.
  • the green pellets or briquettes which have passed through the above preliminary steps are supplied into a bin 2 via line 1.
  • the bin 2 is a device for setting and supplied by injection via line 3 with air saturated with steam generated in device 4 at certain temperature.
  • the pellets or briquettes After retention in the bin 2 for a predetermined time, the pellets or briquettes are delivered to a steam treating unit 6 via line 5. The pellets or briquettes descend by gravity through the unit 6 and are discharged therefrom after retention of a predetermined time.
  • a steam inlet 7 is connected to the bottom of the unit 6. Saturated steam from generator 8 at atmospheric pressure is injected into the unit 6 to flow through the pellets or briquettes accommodated therein and be discharged through an upper opening of the unit 6.
  • the pellets or briquettes are supplied via line 9 into a heating unit 10.
  • the unit 10 is similar to the unit 6 and has a hot air inlet 11 from a hot air generator 12 connected thereto in place of the steam inlet 7.
  • the pellets or briquettes are heated by the hot air to a predetermined temperature in the course of gradual descent through the unit and, after a retention for a prescribed duration, are discharged through a lower discharge opening onto a conveyor 13 to be thereby transported to a storing place.
  • inventive method can be practiced continuously by a simple device without using high pressure steam. According to the present invention, not only the operating efficiency may be improved, but the costs of various equipment may be reduced markedly.
  • Goldsworthy ores (II) and portland cement clinkers were used respectively as ores and binders as shown in Tables 1 and 2. 96 weight percents of Goldsworthy ores (II) and 4 weight percents of portland cement clinkers were mixed and to the resulting mixture was added water in an amount corresponding to 10 weight percents based on the weight of the ore cement clinker mixture. The resulting mixture was then homogenized and mechanically worked under pressure into briquettes each weighing 10 g and 18.1 mm in diameter.
  • the green briquettes thus obtained were allowed to stand for 1 day at ambient temperature and then subjected to a steam treating for 5 hours using 100°C steam and to heating at 350°C for 1 hour.
  • the briquettes thus obtained showed a high compressive strength of 280 kg/cm 2 inspite of the small amount of the binder present in the starting mixture.
  • the briquettes thus obtained were subjected to a reduction test prescribed in JIS M 8713.
  • the compressive strength of these briquettes following the test amounted to 58.6 kg/cm 2 and the swelling of these briquettes amounted only to 5.3%, showing that these briquettes may be safely used as furnace burden material.
  • CBP No. 1 and CBP No. 2 Two pellet samples (CBP No. 1 and CBP No. 2) were prepared.
  • portland cement clinker and calcium carbonate were used respectively as binder or bonding medium and basicity moderator.
  • CBP No. 2 granulated slag of blast furnace were used as main binder, whereas slaked lime was used as reaction accelerator and basicity modulator and light burned dolomite as moderator for improving mechanical properties in high temperature of ultimate briquettes .
  • Goldsworthy ores (I) and MBR ores were used as iron containing material.
  • Table 1 and 2 These constituents were mixed together in a weight parts ratio as shown in Table 3.
  • the ultimate product can be produced in about 3 days from the starting mixture.
  • the ultimate product has sufficient compressive strength to be usable as starting material for iron making.
  • the amount of the binders and other additives can be reduced to generally less than 10 weight percents based on the weight of the material, thus there being no fear of increasing the amount of slags during smelting.
  • the inventive method can be practiced continuously by using a simplified device without the necessity of using high pressure steam, thus promoting operating efficiency and reducing the cost of equipment.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Geology (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Manufacture And Refinement Of Metals (AREA)
EP79300171A 1978-02-03 1979-02-02 A method of producing cold agglomerates for use in iron making Withdrawn EP0003665A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP10508/78 1978-02-03
JP1050878A JPS54103702A (en) 1978-02-03 1978-02-03 Method of producing non-baked pelletized ore for making pig iron

Publications (1)

Publication Number Publication Date
EP0003665A1 true EP0003665A1 (en) 1979-08-22

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ID=11752148

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EP79300171A Withdrawn EP0003665A1 (en) 1978-02-03 1979-02-02 A method of producing cold agglomerates for use in iron making

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EP (1) EP0003665A1 (enrdf_load_stackoverflow)
JP (1) JPS54103702A (enrdf_load_stackoverflow)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2520756A1 (fr) * 1982-02-02 1983-08-05 Nippon Kokan Kk Procede et appareil de production continue de pastilles non frittees
US4432788A (en) * 1981-04-23 1984-02-21 Nippon Kokan Kabushiki Kaisha Method for manufacturing non-fired iron-bearing pellet
FR2541688A1 (fr) * 1983-02-28 1984-08-31 Nippon Kokan Kk Procede et appareil metallurgiques pour produire en continu des boulettes non cuites
EP0118149A1 (de) * 1983-02-25 1984-09-12 Metallgesellschaft Ag Verfahren zum Hartbrennen von Grünpellets auf einer Pelletbrennmaschine
EP0204355A1 (de) * 1985-06-01 1986-12-10 Metallgesellschaft Ag Verfahren zum Hartbrennen von Eisenerzpellets auf einem Wanderrost
US9347109B2 (en) * 2003-02-28 2016-05-24 Vale S.A. Combined pre-treatment process for enabling feed material to be charged in direct reduction processes
CN114525402A (zh) * 2022-04-22 2022-05-24 唐山金沙燃烧热能股份有限公司 一种高炉免烧结冷固球团的制备方法及应用

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS55100940A (en) * 1979-01-25 1980-08-01 Nippon Kokan Kk <Nkk> Preparation of unsintered ore pellet for iron manufacture
JPS5999940A (ja) * 1982-11-26 1984-06-08 三菱自動車工業株式会社 車両用発電機制御装置
KR100321620B1 (ko) * 1997-07-10 2002-05-13 이구택 슬래그를첨가한비소성펠릿의제조방법
JP5181485B2 (ja) * 2007-02-05 2013-04-10 Ｊｆｅスチール株式会社 造粒焼結原料の製造方法
JP6414903B2 (ja) * 2016-04-20 2018-10-31 Ｊｆｅスチール株式会社 炭素内装鉱の製造方法

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1085701A (fr) * 1952-12-31 1955-02-07 Metallgesellschaft Ag Procédé de fabrication d'agglomérés
GB990672A (en) * 1963-02-01 1965-04-28 Kennedy Van Saun Mfg & Eng Improvements in method of pelletizing finely divided solid materials
FR2111711A1 (enrdf_load_stackoverflow) * 1970-10-19 1972-06-09 Cold Bound Pellets Ab
FR2192172A1 (enrdf_load_stackoverflow) * 1972-07-06 1974-02-08 Gutehoffnungshuette Sterkrade
US3895088A (en) * 1971-01-14 1975-07-15 Control Michigan Technological Method for agglomerating steel plant waste dusts
FR2308688A1 (fr) * 1975-04-21 1976-11-19 Univ Michigan Tech Procede d'agglomeration de dechets poussiereux d'acierie
US4049435A (en) * 1976-04-22 1977-09-20 Valery Efimovich Lotosh Method for obtaining a lump product

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS51931A (ja) * 1974-06-20 1976-01-07 Tokyo Shibaura Electric Co Rokuonbaiasukyokyukairo
JPS515962A (enrdf_load_stackoverflow) * 1974-07-04 1976-01-19 Tokyo Shibaura Electric Co

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1085701A (fr) * 1952-12-31 1955-02-07 Metallgesellschaft Ag Procédé de fabrication d'agglomérés
GB990672A (en) * 1963-02-01 1965-04-28 Kennedy Van Saun Mfg & Eng Improvements in method of pelletizing finely divided solid materials
FR2111711A1 (enrdf_load_stackoverflow) * 1970-10-19 1972-06-09 Cold Bound Pellets Ab
US3895088A (en) * 1971-01-14 1975-07-15 Control Michigan Technological Method for agglomerating steel plant waste dusts
FR2192172A1 (enrdf_load_stackoverflow) * 1972-07-06 1974-02-08 Gutehoffnungshuette Sterkrade
FR2308688A1 (fr) * 1975-04-21 1976-11-19 Univ Michigan Tech Procede d'agglomeration de dechets poussiereux d'acierie
US4049435A (en) * 1976-04-22 1977-09-20 Valery Efimovich Lotosh Method for obtaining a lump product

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4432788A (en) * 1981-04-23 1984-02-21 Nippon Kokan Kabushiki Kaisha Method for manufacturing non-fired iron-bearing pellet
FR2520756A1 (fr) * 1982-02-02 1983-08-05 Nippon Kokan Kk Procede et appareil de production continue de pastilles non frittees
DE3303164A1 (de) * 1982-02-02 1983-08-18 Nippon Kokan K.K., Tokyo Verfahren und vorrichtung zur kontinuierlichen herstellung von ungesinterten pellets
US4468253A (en) * 1982-02-02 1984-08-28 Nippon Kokan Kabushiki Kaisha Method and apparatus for continuously manufacturing non-sintered pellet
EP0118149A1 (de) * 1983-02-25 1984-09-12 Metallgesellschaft Ag Verfahren zum Hartbrennen von Grünpellets auf einer Pelletbrennmaschine
FR2541688A1 (fr) * 1983-02-28 1984-08-31 Nippon Kokan Kk Procede et appareil metallurgiques pour produire en continu des boulettes non cuites
GB2141699A (en) * 1983-02-28 1985-01-03 Nippon Kokan Kk Method and apparatus for continuously manufacturing non-fired pellets
US4636342A (en) * 1983-02-28 1987-01-13 Nippon Kokan Kabushiki Kaisha Method for continuously manufacturing non-fired pellets
EP0204355A1 (de) * 1985-06-01 1986-12-10 Metallgesellschaft Ag Verfahren zum Hartbrennen von Eisenerzpellets auf einem Wanderrost
US9347109B2 (en) * 2003-02-28 2016-05-24 Vale S.A. Combined pre-treatment process for enabling feed material to be charged in direct reduction processes
CN114525402A (zh) * 2022-04-22 2022-05-24 唐山金沙燃烧热能股份有限公司 一种高炉免烧结冷固球团的制备方法及应用

Also Published As

Publication number Publication date
JPS54103702A (en) 1979-08-15
JPS5715652B2 (enrdf_load_stackoverflow) 1982-03-31

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