Method of processing finely divided material incorporating metal based constituents
AssigneeArc Dust Processing (UK) Limited
InventorAllan Douglas Clark
Life of this patent
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Abstract
Finely divided material, such as flue dust from a steel making furnace, is processed to reclaim constituents. The material in hopper (11) is pelletized. The pellets are dried in a dryer (16) and fed to a first rotary kiln (21) where they are sintered to provide very hard pellets, during which process volatile constituents are driven off and collected. The sintered pellets are screened to remove finely divided material and fed with reductant, such as finely divided washed anthracite (35), to a second rotary kiln (31). Reduction of the pellets causes a second constituent to be driven off and the second constituent is then oxidized in the kiln and collected as finely divided oxide. The original pellets retain their integrity and become essentially sponge iron.
Claims14
A method of processing finely divided material incorporating a range of metal based constituents, the method comprising the steps of:
- forming the finely divided material into pellets;
- drying the pellets;
- heating the pellets in a first rotary kiln at a temperature and residence time sufficient to sinter the pellets and to drive off volatile first constituents from the pellets;
- removing any material in a finely divided form from the sintered pellets;
- and
- heating the sintered pellets in a second rotary kiln, in a reducing atmosphere, whereby one or more second constituents are reduced to a volatile form and driven off, leaving one or more reduced third constituents.
A method of processing finely divided material incorporating metal based constituents, the method comprising the steps of:
- forming the finely divided material into a plurality of pellets;
- drying the plurality of pellets;
- heating the plurality pellets in a continuous motion first rotary kiln, to provide continuous rolling motion of the plurality of pellets, at a temperature and for a residence time which is sufficient to sinter the plurality pellets and drive off substantially all of volatile first constituents from the plurality of pellets;
- removing any finely divided material from the sintered plurality of pellets;
- and
- heating the sintered plurality of pellets in a continuous motion separate second rotary kiln, in a reducing atmosphere which provides continuous rolling motion of the plurality of pellets, to reduce at least one second constituent to a volatile form and driven off the at least one second constituent from the sintered plurality of pellets thereby leaving at least one reduced third constituent in the second separate rotary kiln.
Dependencies are inferred from the claim text.