Classifications

• • 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

Definitions

• the briquetting process consists of compression agglomeration of the materials through the use of roller presses in which depending on the characteristics of the materials it will be necessary to use binders that help to form a briquette that meets the appropriate resistance characteristics for its handling in subsequent processes.
• the dimensions and shape of the briquette also depend on the end use that will be given.
• Patent with registration number EP 1425427 A4 which describes a method to produce cooked briquettes to be used as a charge in Blast Furnaces or Direct Reduction Furnaces from the mixture of hydrated iron ore and fluxes, being the mineral of iron preferably Goethite and fluxes preferably limestone which makes the difference from the present invention where pellet fines, DRI sludge, DRI fines and powders from DRI dedusting systems are used and no limestone is added.
• the firing of the briquettes of the referred patent is to harden them and facilitate their use by using firing furnaces with temperatures of at least 1200 ° C and more preferably at least 1380 ° C for at least 15 minutes, which makes the difference with With respect to the present invention, where the briquette hardening is achieved with a cure at room temperature.
• Patent US 2865731 A in which a method is described for producing cylindrical briquettes with a hydraulic piston from iron ore and paper pulp as a binder, the iron ore being hematite flotation concentrates which makes the difference with respect to The present invention wherein pellet fines, DRI sludge, DRI fines and powders from DRI dedusting systems are used using inorganic binders to form the roll press briquette.
• US patent 2012/0210824 Al in which it is described describes a method for producing cold-cured agglomerates in the form of pellets or micro-pellets in a pelletizing disk or drum from iron minerals with fine particle size preferably 80% below 325 mesh or also using by-products from the steel industry such as EAF and BOF powders, sinter feed or sinter fines, or iron ore concentrate fines using portland cement or clinker or binders as binder organic as acrylamides or carboxymethylcelluloses and having as final use for micro-pellets sintering plants and for pellets the Blast Furnaces, which makes the difference with respect to the present invention where briquettes are manufactured from pellet fines, DRI sludge , DRI fines and DRI dedusting system powders on roller presses using bentonite and liquid sodium silicate as binder and having as use end for briquette direct reduction plants.
• Figure 1 refers to the flow diagram of the process for obtaining briquettes from pellet fines, DRI sludge, DRI fines and powders from DRI dedusting systems.
• the present invention relates to a process for manufacturing briquettes from the following by-products from the steel industry;
• Pellet fines Obtained from the screening of the iron oxide pellets that are used as cargo to the Blast Furnaces or Direct Reduction reactors.
• DRI sludge Obtained from the dust collection systems by gas scrubbing of the feed zone and the reaction zone in Direct Reduction reactors.
• DRI fines Obtained from the screening of Direct Reduction Iron (DRI).
• the end use of the briquettes is to partially replace the iron oxide pellet charge in both HyL and Midrex Direct Reduction reactors with their physical, chemical and metallurgical characteristics for the final production of Direct Reduction iron (DRI) and comprising the following stages; a) Screening and crushing of pellet fines
• Pellet fines are screened by a 1/8 inch (3.17 mm) opening size mesh to obtain particles of primary pellet fines smaller than 1/8 inch (3.17mm) size, which are placed on a conveyor belt, and pellet fines particles larger than 1/8 inch (3.17 mm) in size are crushed by using a preferably jaw crusher (1) to obtain secondary pellet fines particles with sizes smaller than 1/8 inch (3.17 mm) which are subsequently placed together with the primary pellet fines particles smaller than 1/8 inch (3.17 mm) in the conveyor belt and obtain final pellet fines particles with sizes less than 1/8 inch (3.17 mm) b) DRI sludge screening and crushing
• DRI sludge which with humidity less than 10% and preferably less than 5% is screened by a mesh with opening size of 1/8 inch (3.17 mm) to obtain primary DRI sludge particles smaller than one size 1/8 inch (3.17mm), which are placed on a conveyor belt, and DRI sludge particles larger than 1/8 inch (3.17 mm) size are shredded using a preferably jaw crusher (2) to obtain secondary DRI sludge particles smaller than 1/8 inch (3.17 mm) which are subsequently placed together with the primary DRI sludge particles smaller than 1/8 inch ( 3.17 mm) on the conveyor belt and obtain final DRI sludge particles smaller than 1/8 inch (3.17 mm) in size c) DRI fine screening
• the DRI fines are a material that has already gone through a screening process in the plant that generates them and, to guarantee uniformity in size, they are again screened by a mesh (3) with an opening size of 1/4 inch (6.34). mm) to obtain final DRI fines particles smaller than 1/4 inch (6.34 mm) in size, which are placed on a conveyor belt for use in the briquetting process, and larger DRI fines particles At a size of 1/4 inch (6.34 mm) they are set aside for use as-is as load a in Electric Steel Mill furnaces. d) Dust storage from DRI dedusting systems
• Powders from DRI dedusting systems are stored in hoppers or silos (4) so that they can be used in the briquetting process by means of a dosing system.
• Final particles of pellet fines smaller than 1/8 inch, from DRI sludge smaller than 1/8 inch, from DRI fines smaller than 1/4 inch and dust from DRI dusts are mixed with liquid and powder binders, preferably 1 to 12% for liquid sodium silicate (5) and preferably 1 to 10% for bentonite powder (6), and with water (7 ) necessary to obtain adequate humidity in a mixer, preferably in a horizontal double-shaft mixer (8), to obtain a final mixture to be used in the briquetting stage.
• liquid and powder binders preferably 1 to 12% for liquid sodium silicate (5) and preferably 1 to 10% for bentonite powder (6)
• water (7 ) necessary to obtain adequate humidity in a mixer, preferably in a horizontal double-shaft mixer (8), to obtain a final mixture to be used in the briquetting stage.
• the combination of these liquid and powder binders provides the produced briquette with the porosity and physical strength characteristics necessary for favorable performance in both HyL and Midrex Direct Reduction reactors.
• pellet fines smaller than 1/8 inch and DRI sludge smaller than 1/8 inch are mixed in proportions from 10% pellet fines-90% DRI sludge up to 90 % fine pellets- 10% DRI sludge with liquid and powder binders to obtain a final mix to be used in the briquetting stage
• composite Portland cement is used as a binder, preferably from 1 to 10% instead of powdered bentonite.
• the final mixture obtained is passed to a feeding hopper of a roller press (9) to be briquetted with a specific compression force by means of a system of hydraulic pistons, preferably 0-147 kN / linear cm of roller (equivalent to 0- 15 ton / linear roller cm) and thus obtain fresh spheroidal briquettes, preferably with a diameter that is somewhat wider than 3.2 cm and with a volume preferably less than 7.5 cm3.
• a system of hydraulic pistons preferably 0-147 kN / linear cm of roller (equivalent to 0- 15 ton / linear roller cm)
• Fresh spheroidal briquettes pass a 1-inch, single bed, inclined vibrating screen (10) to remove edges and residue from fresh briquettes smaller than 1/4 inch (6.34 mm) in size and obtain in this way a sieved fresh briquette.
• the edges and residues of fresh briquettes with sizes smaller than 1/4 of an inch pass to a crumbling system (11) to then be reincorporated to the feed hopper of the roller press and to be briquetted together with the final mixture in step f) .
• the sieved fresh briquettes are cured in closed warehouses (12) at ambient conditions for at least 24 hours to improve the resistance properties, during which time the briquettes acquire resistance so that they do not degrade during their handling and thus obtain cured briquettes.
• a porosity 18 to 28% by volume and preferably from 21 to 25% by volume to improve its reduction properties within the reactors of the Direct Reduction iron production processes.
• the improvement in the properties of both strength and porosity influence the metallurgical behavior of the briquette, so that industrial tests carried out in HyL Direct Reduction reactors have given metallization results greater than 92.5%, understanding the percentage of metallic Fe with respect to metallization. the percentage of total Fe obtained by processing these briquettes in the Direct Reduction reactors.
• the fresh briquettes are cured in an accelerated manner in straight grill type drying ovens that operate at temperatures higher than ambient, preferably from 80 to 100 ° C with a residence time preferably longer than 2 hours, during which time briquettes are obtained cured and with adequate resistance for subsequent handling.
• the cured briquette is sent to both HyL and Midrex Direct Reduction iron production processes for consumption.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (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)
• Manufacture And Refinement Of Metals (AREA)

Priority Applications (2)

Applications Claiming Priority (1)

Publications (1)

Family

ID=71075524

Family Applications (1)

Country Status (2)

Cited By (1)

Citations (8)

Family Cites Families (5)

• 2018
  • 2018-12-12 WO PCT/MX2018/050029 patent/WO2020122701A1/es active Application Filing
  • 2018-12-12 CN CN201880100650.XA patent/CN113366128A/zh active Pending

Patent Citations (9)

Also Published As

Similar Documents

Legal Events