Production of chromium iron alloys directly from chromite ore

Abstract

A process for producing chromium iron alloys suitable for steel making directly from chromite ore wherein fines of chromite ore with additions of carbon fines, and accelerant and a binder are agglomerated and the dry agglomerates are fed into a reaction vessel with natural gas as a reducing agent at elevated temperatures adequate for reduction for thereby producing a chromium iron alloy suitable for steel making. The preferred accelerant is an alkali in the form of an oxide, hydroxide or carbonate, sodium hydroxide being preferred.

I claim: 
     
         1 . A process for producing chromium iron alloys suitable for steel making directly from chromite ore, comprising;
 agglomerating fines of chromite ore with additions of carbon fines, an accelerant and a binder, and drying the agglomerates; and   feeding the agglomerates into a reaction vessel with natural gas as a reducing agent at elevated temperatures adequate for reduction for thereby producing a chromium iron alloy suitable for steel making.   
     
     
         2 . The process of  claim 1 , wherein said accelerant is an alkali in the form of an oxide, hydroxide or carbonate. 
     
     
         3 . The process of  claim 2 , wherein said accelerant is sodium hydroxide. 
     
     
         4 . The process of  claim 2 , wherein said accelerant is included in an amount sufficient for the stoichiometric formation of sodium silicate of silica encapsulating the chromite fines and reacting with the chrome oxide present in the chromite. 
     
     
         5 . The process of  claim 4 , wherein said accelerant is included in each agglomerate in the approximate range of 2% to 15% by weight. 
     
     
         6 . The process of  claim 4 , wherein carbon is included in an amount sufficient for reduction of the reducible metal oxides of chromium and iron contained in the agglomerate. 
     
     
         7 . The process of  claim 6 , wherein carbon is included in each agglomerate in the approximate range of 15% to 25% by weight. 
     
     
         8 . The process of  claim 1 , wherein said agglomerates are dried with furnace off gas. 
     
     
         9 . The process of  claim 1 , wherein said elevated temperatures within the reaction vessel are in the approximate range of between 750° and 1,150° C. 
     
     
         10 . The process of  claim 1 , wherein said agglomerates are formed as pellets. 
     
     
         11 . The process of  claim 1 , wherein said reducing agent is reformed natural gas. 
     
     
         12 . The process of  claim 1 , wherein said elevated temperatures are in the range of 800° C. to 1,150° C. and said agglomerates are swept into the reaction vessel by reformed natural gas. 
     
     
         13 . The process of  claim 1 , said chromite ore fines and carbon fines are between 50 and 250 microns in size. 
     
     
         14 . The process of  claim 1 , wherein said binder is selected as bentonite or an organic alternative and is included in the amount of 0.5% to 1.5% of the agglomerate mass. 
     
     
         15 . The process of  claim 1 , wherein the chromite ore is from the ROF. 
     
     
         16 . The process of  claim 1 , wherein said reaction vessel is a vertical moving bed reactor, a rotary gas kiln, a fixed bed batch reactor or a moving conveyor belt sealed muffle furnace. 
     
     
         17 . A chromium iron alloy manufactured in accordance to the process of  claim 1 .