Appeal No. 1998-2133
Application No. 08/448,585
The claims relate to a method and apparatus for ozone
bleaching of cellulose pulp involving the use of a plurality
of fluidizing mixers directly connected in series where ozone
is introduced only into the first fluidizing mixer. Claim 14
is representative of the subject matter on appeal:
14. A method of ozone bleaching cellulose pulp having a
consistency of 5-25% using first and second fluidizing mixers,
comprising the steps of sequentially:
(a) in the first fluidizing mixer at a pressure of 6-15 bar
mixing cellulose pulp having a consistency of 5-25% with a
mixture of ozone gas in carrier gas in an amount of 2-5 cubic
meters per air dried ton of the cellulose pulp to form a
fluidized mixture of pulp, ozone and carrier gas so that some
ozone reacts with pulp to effect bleaching but non-reacted
ozone remains;
(b) transferring the mixture of pulp, non-reacted ozone, and
carrier gas from the first fluidizing mixer directly to the
second fluidizing mixer;
(c) in the second fluidizing mixer, without introducing any
additional ozone therein, refluidizing the mixture of pulp,
non-reacted ozone, and carrier gas from the first fluidizing
mixer, the ozone further reacting with the pulp to effect
bleaching, but some residual ozone and carrier gas remaining
mixed with the pulp, and discharging the mixture of residual
ozone, carrier gas, and pulp from the second fluidizing mixer;
(d) maintaining the residual ozone in contact with the pulp
for a time sufficient for further reaction of ozone with the
pulp to effect bleaching to take place; and
(e) separating carrier gas and unreacted ozone from the pulp.
The following references are relied upon by the examiner
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