Appeal No. 2000-1019
Application No. 08/623,852
lines 23 through 24, column 19, lines 30 through 45).3 While the
precipitation of such metals occurs downstream, we note that
Bender’s process is continuous (id, column 19, line 5). Thus,
reducing agents from the leaching zone would be present during
the precipitation of the above mentioned metals. Additionally,
Bender teaches that lead can be precipitated in the presence of a
sulfidizing reagent (id, column 19, lines 40 through 42).
Furthermore, Bender discloses that a sulfidic material may be a
reductant (id, column 8, lines 42 through 43). Therefore, we are
of the opinion that Bender satisfies the claim 1 requirement of
“a reducing agent to render a metal value insoluble,” because
Bender discloses the use of a reducing agent wherein, ultimately,
a metal is being precipitated.
For example, the manganese in Bender is initially reduced
from Mn4+ to Mn2+ by a reducing agent, enabling it to form a
soluble compound (Bender, column 5, lines 60 through 62).
Subsequently, the manganese is precipitated with lime (id, column
15, lines 23 through 25). As addressed two paragraphs prior, a
reducing agent need only have an indirect involvement with the
3Iron can be precipitated in the presence of a monovalent cation, such
as H+, Na+, K+, or NH4+ (id, column 13, lines 49 through 52). Manganese and
zinc can be precipitated with lime (id, column 17, lines 23 through 25, column
19, lines 30 through 39). Lead can be precipitated in the presence of a
sulfidizing reagent (id, column 19, lines 40 through 42).
19
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