Process for producing iron ore agglomerate for use in direct reduction reactors, and the agglomerate product

Abstract

A process for producing iron ore agglomerates for use in direct reduction furnaces involving dispersing nanomaterial in a binder, combining it with iron ore fines and/or steelmaking by-products along with additives, adjusting moisture, carrying out agglomeration, curing the agglomerate, and applying a surface coating to mitigate the sticking effect within direct reduction furnaces.

1 . A process for producing iron ore agglomerate for use in direct reduction furnaces, the process comprising:
 a) dispersing 0.05-2% per weight of nanomaterial in a binder in order to obtain a binding mixture;   b) mixing 1-10% per weight of the binding mixture from a) with 70-99% per weight iron ore fines and/or steelmaking by-products and 0-5% per weight additives in an intensive mixer to provide a mixture;   c) adjusting a moisture of the mixture of b) to obtain 0-25% per weight of water;   d) performing an agglomeration process via briquetting or extrusion to provide an agglomerate;   e) curing the agglomerate;   f) applying a coating agent at a surface of the agglomerate to reduce a sticking effect in direct reduction furnaces.   
     
     
         2 . The process according to  claim 1 , wherein the nanomaterial used in a) is selected from the group consisting of carbon nanotubes, exfoliated graphite, functionalized microsilicate, tubular nanosilica, tubular halloysite, carbon nanofiber, and graphene. 
     
     
         3 . The process according to  claim 1 , wherein the binder used in a) is selected from the group consisting of sodium silicate, vegetable tar, pitch, starch, phenolic resins, and molasses. 
     
     
         4 . The process according to  claim 1 , wherein the iron ore fines and/or steelmaking by-products employed in b) have Fe total  contents >60%, SiO 2 <5%, Al 2 O 3 <2%, and granulometry 98%<6 mm. 
     
     
         5 . The process according to  claim 1 , wherein the additives used in b) are selected from the group consisting of bentonite, pitch, tar, hydrated lime, phenolic resins, glucose, starch, molasses, glycerin, carboxy methyl cellulose, and biomass. 
     
     
         6 . The process according to  claim 1 , wherein the mixing in b) is carried out in an intensive mixer for no more than 4 minutes. 
     
     
         7 . The process according to  claim 1 , wherein the agglomeration in d) is performed in extruders producing extrudates in a shape of cylindrical rods of size 5-50 mm in diameter and 50-200 mm in length. 
     
     
         8 . The process according to  claim 1 , wherein the agglomeration in d) is performed in a roller press producing briquettes in pillow format with dimensions 15-50 mm×10-40 mm×5-25 mm. 
     
     
         9 . The process according to  claim 1 , wherein the agglomeration in d) is performed in a roller press producing briquettes with a packing degree <50%, bulk density <3.8 g/cm 3 , and porosity >40%, with connected pores. 
     
     
         10 . The process according to  claim 1 , wherein the agglomeration in d) is performed in a briquetting machine controlling a linear force in the range of 15 to 30 KN/cm. 
     
     
         11 . The process according to  claim 1 , wherein curing in e) is carried out in gas, electric, infrared, electromagnetic furnaces or at room temperature. 
     
     
         12 . The process according to  claim 11 , wherein curing in gas, electric, or infrared furnaces is carried out at a temperature of 100 to 550° C. for 10 to 30 minutes. 
     
     
         13 . The process according to  claim 11 , wherein curing in electromagnetic furnaces is carried out for 2 to 15 minutes. 
     
     
         14 . The process according to  claim 11 , wherein curing at room temperature is carried out for up to 15 days. 
     
     
         15 . The process according to  claim 1 , wherein applying the coating agent in f) is done by immersion or spraying a chemical or mineral additive with surface covering properties selected from the group consisting of bauxite, bentonite, serpentinites, cement, magnesium hydroxide, limestone, and combinations thereof. 
     
     
         16 . The process according to  claim 1 , wherein a dosage of the coating agent is 1 to 10 kg per ton of agglomerate in f). 
     
     
         17 . Iron ore agglomerates produced from the process according to  claim 1 , wherein the iron ore agglomerates comprise Fe>60%, deleterious content of Na 2 O, SiO 2 , and Al 2 O 3 <10%, disintegration <10%, metallization content >90%, degree of packing <50%, bulk density <3.8 g/cm 3 , and porosity >40%, with connected pores. 
     
     
         18 . The iron ore agglomerates according to  claim 17 , comprising one or more of an Fe content in the range of 65.1 to 67.5%, deleterious content of Na 2 O, SiO 2 , and Al 2 O 3 <5%, disintegration <5%, and metallization content in the range of 91.2-99.5%.