US 12,000,017 B2
Method and system for producing low carbon ferroalloy from chromite ore
Daniel Shaw, Haverford, PA (US); James Saville, Easton, MD (US); John Williams, Oxfordshire (GB); and Trevor N. Mustoe, Playa del Carmen (MX)
Assigned to MM Metals USA, LLC, West Conshohocken, PA (US)
Filed by MM Metals USA, LLC, Plymouth Meeting, PA (US)
Filed on Nov. 10, 2021, as Appl. No. 17/523,087.
Application 17/523,087 is a continuation of application No. PCT/US2020/035842, filed on Jun. 3, 2020.
Application PCT/US2020/035842 is a continuation of application No. 16/454,283, filed on Jun. 27, 2019, granted, now 10,508,319, issued on Dec. 17, 2019.
Prior Publication US 2022/0064756 A1, Mar. 3, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. C22B 5/04 (2006.01); C21D 1/74 (2006.01); C21D 6/00 (2006.01); C21D 8/12 (2006.01); C21D 9/00 (2006.01); C22B 1/24 (2006.01); C22C 33/04 (2006.01); C22C 38/18 (2006.01)
CPC C22B 5/04 (2013.01) [C21D 1/74 (2013.01); C21D 6/002 (2013.01); C21D 8/1205 (2013.01); C21D 9/0025 (2013.01); C21D 9/0068 (2013.01); C22B 1/24 (2013.01); C22C 33/04 (2013.01); C22C 38/18 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A method for recovering a ferroalloy from chromite ore comprising:
feeding a mixture of feed materials comprising chromite ore and aluminum granules into a plasma arc furnace, said chromite ore including chromium oxide and an iron oxide, said feed materials being in a proportion for reduction of said chromium oxide and iron oxide to form said ferroalloy;
heating said feed materials in said plasma arc furnace to a temperature in the range of approximately 1,650° C. to 1850° C. wherein said aluminum granules act as a reducing agent to produce an exothermic reaction reducing said chromium oxide and iron oxide in said chromite ore to produce a molten ferroalloy with molten slag floating on top of said molten ferroalloy;
extracting said molten ferroalloy from said plasma arc furnace; and
wherein the amount of aluminum granules used in said mixture of feed materials is equivalent to approximately 105% to 120% of the stoichiometric quantity of aluminum required to react with said chromite ore in said mixture of feed materials.