Appeal No. 2000-0002
Application 08/848,477
THE INVENTION
The appealed claims are directed to an iron-rich residue
prepared from dry electric arc flue dust by a series of
process steps. Broadly, the flue dust is acidified to
solubilize certain metals therein and the iron present is
oxidized to form insoluble iron oxides which precipitate at
certain acidic pHs from the solution and are recovered as an
"iron-rich" residue.
Claims 1, 21 and 29 are believed to be adequately
representative of the appealed subject matter and are
reproduced below for a more facile understanding of the
claimed invention.
Claim 1. An iron-rich residue obtained by
(a) mixing dry electric arc flue dust powder
with a calcium chloride/hydrochloric acid leach mill
solution to produce a slurry having a pH of about
2.6 and a solids content (pulp density) of about 15-
30 wt.%;
(b) oxidizing the base metals in
the slurry to produce a metal-rich solution
containing the base metals and an insoluble hematite
complex by heating the slurry in an oxygen
atmosphere at a temperature of about 90-120 deg C
2
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