Ore Beneficiation by Direct Reduction

Today, essentially all of North America’s iron mine production is sold to steel plants in the form of dry concentrates or agglomerized blast furnace pellets. Final concentrator products sold contain Fe in the range 60 to 67%, the balance being oxides and gangue. These iron concentrate products are designed to charge conventional oxygen blast furnaces at good melting efficiency, where iron oxides are reduced with carbon into steel.

Minesite Direct Reduced Iron (DRI)

Direct reduction processes are designed to more efficiently reduce low grade iron ores, dry concentrates and/or iron oxide pellets using a reductant (CO gas, natural gas, hydrogen, coal, coke etc.) to produce a metallic iron product grading better than 90% Fe and gaining carbon in the process. Usually, to conserve energy, the DRI product is immediately briquetted into hot briquetted iron (HBI; 90 to 92% Fe) or steel quality pig iron (+92% Fe).

Examples of new DRI processes that use variations of onsite DRI include the ACCAR and SL/RN processes employing rotary kiln furnaces directly fired with hydrocarbon fuels (primarily coal, but sometimes oil and natural gas).

Others processes such as Midrex and HYL generate a reducing gas with steam and hydrogen that is continuously recycled through a vertical shaft reduction furnace. In all cases, the metallic DRI product is uniform in composition and virtually free of tramp elements. It is used primarily in electric arc furnace steelmaking, itself often a minesite addition over time.

The unique process-flow development for beneficiating the Clear Hills ore is ongoing, with the Company currently refining the Grain Enlargement Process in order to optimize process efficiencies and recovery rates of metallic iron, with the additional of custom circuits for vanadium and precious metals recovery.

Ironstone is performing pilot plant work from Q2 2011 through Q4 2012 with the intent of demonstrating potential production of DRI/HBI/MPI from the iron deposit while also targeting recovery of vanadium pentoxide.

Ironstone gratefully acknowledges the generous research support being provided by the Industrial Research Assistance Program of the National Research Council of Canada (NRC-IRAP).