US PATENT SUBCLASS 75 / 496
.~.~.~.~.~.~.~ With reformation of reducing gas in separate furnace (e.g., Midrex process, etc.)

Current as of: June, 1999
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75 /   HD   SPECIALIZED METALLURGICAL PROCESSES, COMPOSITIONS FOR USE THEREIN, CONSOLIDATED METAL POWDER COMPOSITIONS, AND LOOSE METAL PARTICULATE MIXTURES

330  DF  PROCESSES {9}
392  DF  .~ Producing or treating free metal {10}
414  DF  .~.~ At 300 degrees C or greater (e.g., pyrometallurgy, etc.) {7}
433  DF  .~.~.~ Iron(Fe) {18}
488  DF  .~.~.~.~ Reduction to metallic Iron(Fe) within shaft furnace {2}
489  DF  .~.~.~.~.~ Externally supplied gas reductant {1}
490  DF  .~.~.~.~.~.~ Solid Iron(Fe) produced within shaft furnace {4}
496.~.~.~.~.~.~.~ With reformation of reducing gas in separate furnace (e.g., Midrex process, etc.) {2}
497  DF  .~.~.~.~.~.~.~>.~ With plural reformers (e.g., Purofer process, etc.)
498  DF  .~.~.~.~.~.~.~>.~ With addition of steam to reformer (e.g., Armco process, etc.)

DEFINITION

Classification: 75/496

With reformation of reducing gas in separate furnace (e.g., Midrex process, etc.):

(under subclass 490) Process in which a reducing gas is reacted in a separate furnace to change its chemical composition prior to being introduced into the shaft furnace.

(1) Note. As an example, Methane is reacted with Carbon dioxide to yield Carbon monoxide and Hydrogen.