Appeal No. 1996-2566
Application No. 08/107,656
chloride which allegedly possesses improved flocculation
properties. See the specification at page 2, lines 13-20 and
pages 9 and 10. Claim 12 is representative and is reproduced
below:
12. A process of preparing a solution of basic
sulfate-containing polyaluminum chloride, said process
comprising the steps of:
a. digesting an aluminum-containing substance with
hydrochloric acid to form a resulting solution
and an insoluble residue;
b. filtering said resulting solution formed in step
a) to separate said insoluble residue therefrom
and
to form a solids-free solution;
c. concentrating said solids-free solution formed
in step b) by evaporation to form a concentrated
solution having an AlC1 content of about 30
3
percent by weight;
d. recovering AlC1 @6H O from said concentrated
3 2
solution formed in step c) by
crystallization;
e. thermally decomposing said AlC1 @6H O formed in
3 2
step d) to form a solid basic aluminum chloride
by heating at temperature from 150 to
200EC so
that said solid basic aluminum chloride
contains Al and OH in a molar ratio of OH/Al of
from 1.35:1 to 2.25:1;
f. feeding the solid basic aluminum chloride formed
in step e) into an aqueous sulfuric acid solution
and dissolving said solid basic aluminum
2
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