Reduction Processing of Metal-Containing Ores in The Presence of Microwave and RF Energy

Abstract

A process for reducing a metal-containing material, the process comprising: providing a metal-containing material ( 5 ), heating said metal-containing material by convective and/or conductive and/or radiative means ( 2 ), exposing said metal-containing material to microwave (MW) energy ( 3 ), exposing said metal-containing material to radio frequency (RF) energy ( 4 ), and exposing said metal-containing material to a reducing agent ( 8 ). The method, which does not involve dielectric heating during exposure to MW and RF energy, enables more energy-efficient chemical reduction of metal-containing ores and ore concentrates and increases metallization yield.

1 - 19 . (canceled) 
   
   
       20 . A process for reducing a metal-containing material, the process comprising:
 providing a metal-containing material, heating said metal-containing material by convective and/or conductive and/or radiative means,   exposing said metal-containing material to microwave (MW) energy,   exposing said metal-containing material to radio frequency (RF) energy, and exposing said metal-containing material to a reducing agent,   wherein exposing the metal-containing material to MW and/or RF energy does not significantly heat said material.   
   
   
       21 . The process according to  claim 20 , wherein the metal-containing material comprises an ore or a concentrate. 
   
   
       22 . The process according to  claim 20 , wherein the metal-containing material comprises iron. 
   
   
       23 . The process according to  claim 22 , wherein the ore is selected from the group consisting of ilmenite, titaniferous magnetite, iron ore, limonitic laterites, magnetite, maghemite, hematite and saprolitic laterites. 
   
   
       24 . The process according to claim  1 , wherein the metal-containing material is heated by said convective and/or conductive and/or radiative means to a temperature that does not exceed approximately 1,200° C. 
   
   
       25 . The process according to  claim 24 , wherein the metal-containing material is heated by said convective and/or conductive and/or radiative means to a temperature that does not exceed 850° C. 
   
   
       26 . The process according to  claim 24 , wherein the metal-containing material is heated by said convective and/or conductive and/or radiative means to a temperature in the range of from 400 to 850° C. 
   
   
       27 . The process according to  claim 26 , wherein exposing the metal-containing material to MW and/or RF energy heats said material less than 10° C. 
   
   
       28 . The process according to  claim 20 , wherein the peak electric field strength of the MW energy applied to the cavity is in the range of from 300 to 5,000 Vm −1 . 
   
   
       29 . The process according to  claim 20 , wherein the peak electric field strength of the RF energy applied to the cavity is in the range of from 3,000 to 100,000 Vm −1 . 
   
   
       30 . The process according to  claim 20 , wherein the reducing agent comprises a gas selected from carbon monoxide and/or hydrogen. 
   
   
       31 . The process according to  claim 20 , wherein the reducing agent comprises a solid material comprising carbon. 
   
   
       32 . The process according to  claim 20 , wherein the reducing agent is comprised in the metal-containing material. 
   
   
       33 . The process according to  claim 20 , wherein the metal-containing material is heated by said convective and/or conductive and/or radiative means before exposing said material to MW energy and/or RF energy. 
   
   
       34 . The process according to  claim 20 , wherein the metal-containing material is exposed to MW and/or RF energy while heating said material by said convective and/or conductive and/or radiative means. 
   
   
       35 . The process according to  claim 20 , wherein the metal-containing material is exposed to MW energy and RF energy simultaneously. 
   
   
       36 . An extractive metallurgical process for the chemical reduction of an iron-containing ore or concentrate, the process comprising:
 providing an iron-containing ore or concentrate,   heating said ore or concentrate by convective and/or conductive and/or radiative means,   exposing said ore or concentrate to a reducing agent, whereby some or all of said ore or concentrate is reduced to iron,   characterised in that said ore or concentrate is also exposed to microwave (MW) energy and radio frequency (RF) energy concurrently with said heating of said ore or concentrate, the MW and RF energy levels being selected so that there is little or no additional heating of said ore or concentrate, and in that the temperature of said ore or concentrate does not exceed 850° C. during the reduction process.   
   
   
       37 . The extractive metallurgical process of  claim 36  wherein the temperature of said ore or concentrated does not exceed 650° C. 
   
   
       38 . A product obtainable by a process as defined in  claim 20 .