Method to increase the adherence of coating materials on ferrous materials

Abstract

METHOD TO INCREASE THE ADHERENCE OF COATING MATERIALS ON FERROUS MATERIALS, comprising the step of: before the reduction of iron ores and/or on the agglomerates thereof, contacting same with a dispersion containing at least a particulate material, thus forming a composite coating of at least a material that cannot be substantially hardened in the aqueous mean and at least a material that can be hardened in the aqueous mean.

1 - 16 . (canceled)  
   
   
       17 . A method of increasing the adherence of non-hardenable coating materials on ferrous materials for a direct reduction furnace comprising contacting the ferrous material with an aqueous mixture of the non-hardenable coating materials and a material which hardens in the presence of water thereby forming a coating film on the ferrous material surface.  
   
   
       18 . The method of  claim 17  wherein the material used to harden the coating film is selected from the group consisting of Portland cements, pozzolanic cements, aluminous cements and mixtures thereof.  
   
   
       19 . The method of  claim 18  wherein the cements have particle size distribution between 0.01 micrometer and 100 micrometers.  
   
   
       20 . The method of  claim 18  wherein the weight ratio of cement to ferrous material is between 1 to 40 and 1 to 5.  
   
   
       21 . The method of  claim 17 , wherein the non-hardenable material used to coat the ferrous material surface is selected from the group consisting of bentonite clays, bauxite, aluminum containing clay and mixtures thereof.  
   
   
       22 . The method of  claim 21  wherein the non-hardenable material has particle size distribution between 0.01 micrometer and 500 micrometers.  
   
   
       23 . The method of  claim 21  wherein the non-hardenable material has particle size distribution between 0.05 micrometer and 100 micrometers.  
   
   
       24 . The method of  claim 21  wherein the non-hardenable material ranges from 0.01% by weight to approximately 2% by weight in relation to the dry weight of the ferrous material to be coated.  
   
   
       25 . The method of  claim 17 , wherein the ferrous material is pellet, briquette, sized or fine ore.  
   
   
       26 . The method of  claim 17 , wherein the sum of hardenable plus non-hardenable material in the water dispersion ranges from 1 to 80% by weight of the dispersion.  
   
   
       27 . The method of  claim 17 , wherein the contacting is by means of dipping, spraying or sprinkling.  
   
   
       28 . The method of  claim 17 , wherein the coat film hardening is achieved by the cure reaction of cement in air.  
   
   
       29 . In a method of reducing the formation of agglomerates of ferrous materials during reduction of such materials by coating the ferrous materials with an aqueous dispersion of a non-hardenable coating in a direct reduction furnace, the improvement comprising concurrently coating the ferrous material with a material which hardens in the presence of water.  
   
   
       30 . A coated ferrous material with significantly lower agglomeration formation during reduction produced by the process of  claim 17 .  
   
   
       31 . A coated ferrous material with low agglomeration formation during reduction in a direct reduction furnace as compared to uncoated ferrous material where the coating comprises a mixture of a non-hardenable coating material and a hardened coating material.  
   
   
       32 . The ferrous material of  claim 31  where the non-hardenable coating material is selected from the group consisting of bentonite clays, bauxite, aluminum containing clay and mixtures thereof and a hardened coating material is selected from the group consisting of Portland cements, pozzolanic cements, aluminous cements and mixtures thereof.