Appeal No. 2000-0002
Application 08/848,477
and a pressure of about 50-90 psi; and
(c) filtering the hematite complex from the metal-
rich solution.
Claim 21. An iron-rich solid residue
obtained by the process for the recovery of zinc
from electric arc flue dust while recycling flue
dust iron to the electric arc furnace, comprising
the steps of:
(a) at a pH
of about 2.6, leaching zinc in electric arc flue
dust into an aqueous solution using a calcium
chloride/hydrochloric acid leach mill solution;
(b) separating the aqueous solution from an
iron-rich solid residue remaining after the leach of
step (a); (c) recovering the zinc from the
aqueous solution by adding calcium hydroxide to the
aqueous solution at a pH of about 6-10 to create a
calcium-rich solution;
(d) regenerating the
calcium chloride/hydrochloric acid leach mill
solution by adding sulfuric acid to the calcium-rich
solution to precipitate gypsum; and (e)
separating the gypsum from the leach mill solution.
Claim 29. An iron complex obtained by the
process:
(a) reacting a slurry of the flue
dust and a calcium chloride/hydrochloric acid leach
mill solution to place the base metals in solution
while leaving essentially all of the iron complexed
with the sodium, potassium, and magnesium; and
(b) separating the
base metal solution from the iron complex.
THE REFERENCES
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