US2005126343A1PendingUtilityA1

Iron ore briquetting

27
Assignee: ROBE RIVER MINING COMPANY PTYPriority: Aug 2, 2001Filed: Aug 2, 2002Published: Jun 16, 2005
Est. expiryAug 2, 2021(expired)· nominal 20-yr term from priority
Inventors:Geoffrey BerosJohn Gannon
B30B 11/16C22B 1/248C22B 1/243C22B 1/2413C22B 1/24C22B 1/14
27
PatentIndex Score
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Cited by
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References
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Claims

Abstract

A method of producing an iron one briquette that is suitable for use as a blast furnace or other direct reduction furnace feedstock which includes the steps of: (1) mixing: (i) ore having a predetermined particle size distribution with a top size of 4.0 mm or less; and (ii) a flux; to form an ore/flux; (2) adjusting the water content of the ore prior to or during mixing step (1) to optimise briquette quality and product yield; (3) pressing the ore/flux mixture into a green briquette; and (4) indurating the green briquette to from a fured briquette.

Claims

exact text as granted — not AI-modified
1 . A method of producing an iron ore briquette that is suitable for use as a blast furnace or other direct reduction furnace feedstock which includes the steps of: 
 (a) mixing: (i) ore having a predetermined particle size distribution with a top size of 4.0 mm or less; and (ii) a flux; to form an ore/flux mixture;    (b) adjusting the water content of the ore prior to or during mixing step (a) to optimise briquette quality and product yield;    (c) pressing the ore/flux mixture into a green briquette; and    (d) indurating the green briquette to form a fired briquette.    
     
     
         2 . The method defined in  claim 1  further includes crushing and screening ore to form the predetermined particle size distribution that is mixed with flux in step (a).  
     
     
         3 . The method defined in  claim 1  wherein the top size of the predetermined particle size distribution of ore that is mixed with flux in step (a) is 3.5 mm.  
     
     
         4 . The method defined in  claim 3  wherein the top size is 3.0 mm.  
     
     
         5 . The method defined in  claim 3  wherein the top size is 2.5 mm.  
     
     
         6 . The method defined in  claim 3  wherein the top size is 1.5 mm.  
     
     
         7 . The method defined in  claim 3  wherein the top size is 1.0 mm.  
     
     
         8 . The method defined in  claim 1  wherein the predetermined particle size distribution of ore that is mixed with flux in step (a) includes less than 50% passing a 45 μm screen.  
     
     
         9 . The method defined in  claim 8  wherein the predetermined ore particle size includes less than 30% passing the 45 μm screen.  
     
     
         10 . The method defined in  claim 8  wherein the predetermined ore particle size includes less than 10% passing the 45 μm screen.  
     
     
         11 . The method defined in  claim 1  wherein the ore is a hydrated iron ore.  
     
     
         12 . The method defined in  claim 11  wherein the hydrated ore is a goethite-containing ore.  
     
     
         13 . The method defined in  claim 1  wherein the flux has a particle size distribution that is predominantly less than 100 μm.  
     
     
         14 . The method defined in any one of the preceding claims wherein the particle size distribution of the flux includes more than 95% passing a 250 μm screen.  
     
     
         15 . The method defined in any  claim 1  wherein the ore/flux mixture produced in step (a) is selected so that the basicity of the fired briquette produced in step (d) is greater than 0.2.  
     
     
         16 . The method defined in  claim 15  wherein the basicity is greater than 0.6.  
     
     
         17 . The method defined in  claim 1  wherein there is no binder in the ore/flux mixture.  
     
     
         18 . The method defined in  claim 1  wherein step (b) includes adjusting the water content of the ore so that the moisture content of the ore/flux mixture is 2-12% by weight of the total weight of the ore/flux mixture.  
     
     
         19 . The method defined in  claim 18  wherein step (b) includes adjusting the water content of the ore so that the moisture content of the ore/flux mixture is 2-5% by weight of the total weight of the ore/flux mixture for ores that are dense hematite ores.  
     
     
         20 . The method defined in  claim 18  wherein step (b) includes adjusting the water content of the ore so that the moisture content of the ore/flux mixture is 4-8% by weight of the total weight of the ore/flux mixture for ores containing up to 50% goethite.  
     
     
         21 . The method defined in  claim 18  wherein step (b) includes adjusting the water content of the ore so that the moisture content of the ore/flux mixture is 6-10% by weight of the total weight of the ore/flux mixture for ores that are predominantly, ie contains more than 50% , goethite.  
     
     
         22 . The method defined in  claim 1  wherein pressing step (c) produces briquettes that are 6 cc or less in volume.  
     
     
         23 . The method defined in  claim 22  wherein the briquettes are 8.5 cc or les in volume.  
     
     
         24 . The method defined in  claim 22  wherein the briquettes are 6.5 cc or less in volume.  
     
     
         25 . The method defined in  claim 1  wherein pressing step (c) includes pressing the ore/flux mixture using a low roll pressure.  
     
     
         26 . The method defined in  claim 25  wherein the low roll pressure is sufficient to produce briquettes having a green compressive strength of at least 2 kgf.  
     
     
         27 . The method defined in  claim 25  wherein the low roll pressure is generated by a roll pressing force of 10-140 kN/cm on the mixture of ore/flux.  
     
     
         28 . The method defined in  claim 25  wherein the roll pressing force is 10-40 kN/cm.  
     
     
         29 . The method defined in  claim 1  wherein indurating step (d) includes heating the briquette to a firing temperature within 40 minutes.  
     
     
         30 . The method defined in  claim 29  wherein step (d) includes heating the briquette to the firing temperature within 35 minutes.  
     
     
         31 . The method defined in  claim 29  wherein step (b) includes heating the briquette to the firing temperature within 30 minutes.  
     
     
         32 . The method defined in  claim 29  wherein step (d) includes heating the briquette to the firing temperature within 20 minutes.  
     
     
         33 . The method defined in  claim 29  wherein step (d) including heating the briquette to the firing temperature within 15 minutes.  
     
     
         34 . The method defined in  claim 29  wherein the firing temperature is at least 1200° C.  
     
     
         35 . The method defined in  claim 34  wherein the firing temperature is at least 1260° C.  
     
     
         36 . The method defined in  claim 34  wherein the firing temperature is at least 1320° C.  
     
     
         37 . The method defined in  claim 34  wherein the firing temperature is at least 1350° C.  
     
     
         38 . The method defined in  claim 34  wherein the firing temperature is at least 1380° C.  
     
     
         39 . The method defined in  claim 1  wherein the fired briquette has a crush strength of at least 200 kgf.  
     
     
         40 . A fired briquette produced by the method according to any one of the preceding claims which has a crush strength of at least 200 kgf.

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