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Publication numberUS3617254 A
Publication typeGrant
Publication dateNov 2, 1971
Filing dateMar 12, 1969
Priority dateMar 12, 1969
Publication numberUS 3617254 A, US 3617254A, US-A-3617254, US3617254 A, US3617254A
InventorsImperato Louis George Jr
Original AssigneeBlocked Iron Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method of making ore agglomerates
US 3617254 A
Abstract  available in
Previous page
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Claims  available in
Description  (OCR text may contain errors)

United States Patent [72] inventor Louis George lrnperato, Jr.

' Tenafly,N.J.

[21] Appl. No. 806,672

[22] Filed Mar. 12, 1969 V Continuation-impart of Ser. No. 672,003, Oct. 2, 1967, Continuation-impart Ser. No. 374,191, June 10, 1964, Pat. No. 3,382,063.

[45] Patented Nov. 2, 1971 [73] Assignee Blocked Iron Corporation The portion of the term of the patent subsequent to May 7, 1985, has been dlsclallned.

[54] METHOD OF MAKING ORE AGGLOMERATES 501 Field of Search .111. 75/3 Primary Examiner-Allen 8. Curtis Auomey- Buell, Blenko & Ziesenheim ABSTRACT: A method is provided for producing lump metal ores by admixing the finely divided ore with an alkaline earth oxide or hydroxide and a carbonaceous material, forming the mixture into lumps and reacting it with carbon dioxide in the presence of moisture to form alkaline earth carbonates in situ in the lumps.

METHOD OF MAKING OlRlE AGGLOMERATES This application is a continuation-in-part of my copending application Ser. No. 672,003, filed Oct. 2, 1967, which is a continuation-in-part of my application Ser. No. 374,191, filed types of pellets heretofore made and is a very distinct advantage to be gained by the practice of this invention. l have found that this can be accomplished within the range of coal concentration set out hereinabove, although I prefer to use June 10, 1964 now U.S. Pat. No. 3,382,063. This invention re- 5 about l percent minus l00-mesh coal when forming specular lates to ore agglomerates and methods of making the same and hematite balls or pellets. particularly to high strength and at least partially self-reducing The amount of alkaline earth oxide or hydroxide, e.g. lime, iron ore agglomerates and methods of making such agpreferably lies in the range from about to 20 percent by glomerates. weight of the admixture.

The need for a satisfactory method of agglomerating iron Iprefer to add a small amount (up to about 2 per ent) )of and other ores, particularly oxide ores. has long been recogsolubilizing agent for calcium and magnesium, as disclosed in nized. As the high purity, lumpy ores of the Mesabi and other y p e a .9 u s a uga n a ning ranges have been exhausted it has been necessary to turn to material. -gblaCkStfaP molasses. g fructose. dextrose, ore concentrates recovered from less pure ore deposits and to sy p the llkfi og he h a Small m n of a min ral fine ores not heretofore considered suitable for steel making. 5 acid Salt of an alkali lin earth me l h as C ium in order to make these ores suitable for handling and use in Chloride in all amount 1858 1 about 10 percent 1 ay also add steepmelting furnaces i h b necessary to agglomerate a small amount of an alkali metal oxide or hydroxide such as these ores into larger pieces. This has conventionally been Sodlum hydroxldet P y the range of about done by pelletizing or briquetting the fine ores and sintering or about p f I fusing the pellets or briquettes to form the solidified ag- The Practlce of my Invention Produces a resumng Pmducl glomerates. Sintering requires extremely high temperatures Whlch 1135 high strength after b81118 sublecled to elevated and large capital outlays in temperature-resistant equipment. Pefatures. 'g- 1900' and WhlCh Shows a gh p r- 1 have invented an ore agglome ate d h d f ki centage of reduced iron after such heating indicating that the such agglomerates which is much less expensive than these t'noclll iS self-reducing. Both of these properties are highly sintered agglomerates and is at least partially self-reducing. gh after n fi -l t0 hl i in the preferred practice of my invention 1 admix ore fines The practice of my invention can perhaps best be explained with an oxide or hydroxide of an alkaline earth metal, a finely y r ren to he f llo ing examples which how the sigdivided carbonaceous material of the group consisting of coal l'llficances 0f the p a ice my in n i n- (both bituminous and anthracite), coke, graphite, charcoal, EXAMPLE] coke breeze and optionally with a small amount of a mineral Pellets were made by admixing lime hydrated and specular acid salt of an alkali metal, or an alkaline earth metal and/or a hematite or taconite concentrates with coal. The resulting pelsmall amount of an alkali hydroxide together with sufficient lets were subjected to carbon dioxide sufficient to form water to permit the formation of agglomerates such as pellets, recrystallized limestone in situ. The carbonated pellets were briquettes or blocks. These agglomerates are then subjected to then divided into two parts, one heated to l.600 F., and the an atmosphere of carbon dioxide for a time sufficient to conother to 1,700 F. in an atmosphere containing carbon monox- Vert a major portion of the alkaline earth oxide or hydroxide ide such as would be encountered in a blast furnace or like to carbonate. iron-handling furnace. The pellets were removed and analyzed 1 have found that the moisture level for most effective for reduced iron. The results are tabulated in Tablel. operatron of my process ls below 10 percent by weight of'the 40 TABLE I CARBONATE BONDED PELLET SUMMARY total admlxture and preferably in the neighborhood of 5 per- Cent or less. Percent reduction Preferably the carbonaceous material used in my process is 1,600 F. 1,700 F. finely divided bituminous coal and I shall hereafter dlscuss the Taconite concentrate: invention in terms of iron ores the bituminous coal. I prefer Gperccnt lime hydrate"... 38.7 44.8 the size range of 4-mesh and under for the coal used and good %3i volume 49 1 81 5 results have been attained at both ends of the range as well as Specular hematite Canasta-m; D H with mixtures of varying particle size coal. 1 have found that gg ig 39's 45.6 amounts between about 1 percent and 15 percent of coal by 23%regroulnddsplicultgrl1?ln'lr;1titel(?i325 M+ {28.3 74.1 weight are most satisfactory for my purposes, although larger 50 s g fs a g g z g f i fi fi amounts to 25 percent have been satisfactorily used in practlchydrate+l0% high volatile coal 49.1 37. 1

- ing my process. I have found that the use of minus l00-mesh coal makes it possible to ball or pelletize conventional as EXAMPLE ll received"specular hematite concentrate without the addition An additional series of pellets were made as in Example I ofreground hematite or without the addition ofany other fine and after removal from the heating furnace at l,600 and ore. Prior to my invention, it had been impossible to form balls l,700 F., respectively, were screened to determine the or pelletize specular hematite by usual balling or pelletizing amount above 4-mesh and the amount below 20-mesh. They methods without regrinding or adding another fine ore. This were then jarred for 15 minutes in a container and again has been one of the very real problems in the heat-indurated screened. The test results appear in Table ll.

T ABLE II Screen test from furnace at Screen test after jarring at- 1,600" F. 1,700 F. 1,600 F. 1,700 F. +4M 20M +4M 20M +4M 20M +4M -20M Taconite:

6% lime hydrate 96. 7 1. 67 96.9 1. 48 43.7 51. 8 9% lime hydra 99.9 0.1 99.87 0.13 77.82 21:96 78.28 21.62 12% lime hydrate 99. 6 0.3 99. 5 0.2 83. 9 15. 9 82.8 16. 8 9% lime hydrate+10% high volatile coal 8 M) 99. 2 0. 38 97.6 0. 13 80. 64 17.30 80.09 15.0 9% lime hydrated-8% high volatile coal (-8 M) and 2% low Volatile coal (-8 98. 62 0.61 99.47 0.23 81.00 16. 98 84.17 14. 24 9% lime hydrate+8% high volatile coal (-8+150 M) and 2% low volatile coal (-8+150 M) 96.69 0. 56 98. 57 0.42 81.77 14.23 78.77 17. 37 Specular hematite:

25% reground (-325 M)+5% lime hydrate+ 15% high Volatile coal (-100 M) 99.60 0. 35 96.80 2. 54 76.77 20.17 57.12 36. 61 Venezuelan ore:

Plus 1.76 lime hydrate 97. 59 0. 87 60. 43 32. 41 6% lime hydrnte+15% high volatile coal 3,617,254 3 4 EXAMPLE 111 TABLE v1 A series of tests were made on pellets produced by mixing together lime hydrate, specular hematite ore in both the as received and the reground" forms as in Example I but sub- Green B ll Physical Characteristics stituting various other types of carbonaceous material for coal 5 Im an Resistance lines and omitting the molasses and chloride. The resulting 5 pellets were subjected to an atmosphere of carbon dioxide as Number of Drops from in Example I to form recrystallized limestone in situ. These Heightorliv'onm A 1 Pl R a hardened pellets were tested as were the pellets in Example ll. l

to The results of the tests appear in T ble III Pellet Moisture Fracture an Individually "1 By Weight. Dry Dropped Ball ball Sample Number Basis Average) 1 12.10 11 TABLE IIL-ROOM TEMPERATURE STRENGTH DATA l5 :1, Pellet composition:

Specular hematite as received, percent, 17 Specular hematite reground, percent, 70 I Lime hydrate, percent, 9 The pellets were d1'1ed prior to exposure and treatment w1th carbonacems materials must percent 4 20 carbon dioxide to the levels of moisture set out in Table Vll.

Tumble test, Compression 0/0+% 280 TABLE V" carbonaceous materials, type test, lbs. rev.

Coke breeze 161 96 ?;g$ Before exposure and treatment with carbon dioxide charcoal: 173 96 gas. the green wet pellets were dried to a moisture N content indicated below:

Sample Number Dried Pellet Moisture, i

Dry Basil lRun 1 4.72 EXAMPLE 1v Run 1 11 Rub 1 4.17 Pellets made for Example ill were then treated in the heated I jg;

, un furnace as in Examples l and ii. The test results appear in Run 2 6 Table IV.

TABLE IV Pellet composition:

Specular hematite as received, percent, 17 Specular hematite reground, percent, 70

Lime hydrate, percent 9 carbonaceous materials, various, percent, 4

Screen test from furnace at- Screen test after jarring at- 1600 F. 1, 700 F. 1, 600 F. 1, 700 F. carbonaceous materials, types +4 M -20 M +4 M -20 M +4 M -20 M +4 M -20 M Coke breeze 99. G Anthracite 99. 8 Graphite- 99. 7 CharcoaL 99. 6 Heat-lndurated taconite pellet 91.67

EXAMPLE V TABLE ViiI.-CARBONATED PELLE'I STRENGTH I CHARACTERISTICS Copper concentrates were m1xed with dolom1t1c fines and C h, ml coal fines to form three different compositions. These were i f 5 pelletized and tested. The compositions are set out in Table V. ball e) ball e) Abrasion Sample Number %z"+ resistance TABLE V I Run 1- 67 104 52. 4 IRun 2- 80 91 66.2 11 Run 1- 90 117 81.0 lgIIRRuiJ 2i 77 96 7g. 0 un "U 92 7 0 Test Sample, ldent1ficat1on and composltlon 111 n 2 10 61, 40. 6 sample Numb" Composition 1 Measured as the average total load in pounds required to fracture an individual pellet; with the size consist indicated.

2 Measured as the percent by Weight 01 material remaining in u five pound test sample of pellets which had previously been rotated in an I 5: 2:2 f zzfg ASTM coke tumbling drum for 200 revolutions. ll 93% by weight Copper Concentrate P"" A sample of pellets were heated in nitrogen from room temm 5:52;:ggsgzr perature to l,600 F. in approximately 60 minutes and the 4% COM sample remalned 1n the n1trogen atmosphere at l,600 F. for 5% Dolomitlc Hydra" an additional hour. The specimens were cooled in nitrogen to room temperature, removed from the furnace, and tested as follows: The green ball physical characteristics of these pellets of Crushing Strength: Ten pellets were removed from the samcopperconcentratesare setoutin Table VI. ple and the average load required to fracture an individual pellet was determined.

Abrasion Test: The remainder of the sample was placed on a 4-mesh sieve screen which was then put into a Ro-Tap shaker apparatus and jarred for 15 minutes. The percent by weight of the material remaining on the 4-mesh screen 5 after jarring was determined.

Thetesfi-esults are set out in ism e IX While I have described certain preferred practices and products according to my invention, it will be understood that this invention may be otherwise embodied within the scope of the following claims. 1. The method of producing a high strength, self-reducing lump ore from finely divided metalcontaining materials comprising the steps of admixing the finely divided metal ore containing material with at least one of the group consisting of the oxides and hydroxides of alkaline earth metals and with a carbonaceous material from the group consisting of coal, coke, graphite, coke breeze and charcoal, forming the mixture into lumps and reacting the lumps with carbon dioxide in the presence of moisture to form alkaline earth carbonates in situ in the lumps.

2. The method as claimed in claim 1 wherein the carbonaceous material is coal having a fineness of 4-mesh and under.

3. The method as claimed in claim 1 wherein the metal ore is copper concentrates.

TABLE [X Sample Crushing Strength, +4M After 10 Number in pounds Jarring l RUN 2 s 31.7 ll Run l 101 51.9 m Run 1 27 48.5

it will be evident from the foregoing tables and examples that a high strength pellet capable of a high level of self-reduction can be achieved by the practice of my invention.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,617,254 D te November 2. 1971 Invent0r(s) L It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, Example V, Table V, Sample Number II, "22% percent Coal Fines, should read 2% Coal Fines Signed and sealed this 24th day of October 1972.

(SEAL) Attest:


Commissioner of Patents Attesting Officer USCOMM-DC 60376-P69 RM PO-IOSO (10-69) h u 5 GOVERNMENT Pmmm; OFFICE was o:ss-:134

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2805141 *May 24, 1954Sep 3, 1957Univ MinnesotaPelletizing process
US2844457 *Nov 22, 1954Jul 22, 1958Blocked Iron CorpLump ores and methods of producing them
US3235371 *Sep 10, 1962Feb 15, 1966Control Of Michigan College OfAgglomerated mineral products and method of making same
US3382063 *Jun 10, 1964May 7, 1968Blocked Iron CorpOre agglomerates and methods of making the same
US3437474 *Oct 2, 1967Apr 8, 1969Blocked Iron CorpMethod of making ore agglomerates
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3942974 *Feb 10, 1975Mar 9, 1976Kennecott Copper CorporationManganese nodule pelletizing
US4093448 *Sep 27, 1976Jun 6, 1978Stanislav Borisovich EliseevMethod of producing pellets from ore concentrates
US4199348 *Jun 7, 1978Apr 22, 1980International Minerals & Chemical CorporationMineral ore pellets
US5066327 *Jun 11, 1990Nov 19, 1991Nkk CorporationMethod for manufacturing cold bonded pellets
US5186742 *Nov 27, 1991Feb 16, 1993Chemical Lime CompanyMethod and composition for use in recycling metal containing furnace dust
US5286278 *Aug 29, 1990Feb 15, 1994Karl HeckelDry process for the cold briquetting of metallurgical dusts
US5685524 *Jan 16, 1996Nov 11, 1997Chaparral Steel CompanyDirect ironmaking or steelmaking apparatus using self-reducing iron oxide pellets
US7896963Mar 1, 2011Hanqing LiuSelf-reducing, cold-bonded pellets
US20040058433 *Sep 17, 2003Mar 25, 2004Yu Yeung SiuElectrochemical test strip for use in analyte determination
US20050061207 *Sep 23, 2003Mar 24, 2005Hanqing LiuSelf-reducing, cold-bonded pellets
U.S. Classification75/771, 75/773
International ClassificationC22B1/242, C22B1/14
Cooperative ClassificationC22B1/242
European ClassificationC22B1/242