Ex Parte Pekarovic et al

Board of Patent Appeals and Interferences

Mar 4, 2010

11103265 (B.P.A.I. Mar. 4, 2010)

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
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Ex parte JAN PEKAROVIC and
ALEXANDRA PEKAROVICOVA
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Appeal 2009-008953
Application 11/103,265
Technology Center 1700
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Decided: March 4, 2010
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Before CHUNG. K. PAK, CHARLES F. WARREN, and
TERRY J. OWENS, Administrative Patent Judges.

OWENS, Administrative Patent Judge.

DECISION ON APPEAL
STATEMENT OF THE CASE
The Appellants appeal under 35 U.S.C. § 134(a) from the Examiner’s
rejection of claims 1-12, which are all of the pending claims. We have
jurisdiction under 35 U.S.C. § 6(b).

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The Invention
The Appellants state that their “invention relates to a method of
removing silica from a cellulosic raw material, such as bamboo, bagasse,
reed and straw, prior to the cellulosic raw material being converted into a
pulp by a chemical or mechanical delignification processes” (Spec. ¶ 0001).
Claim 1 is illustrative:
1. A method of removing silica from a cellulosic raw material
prior to a delignification step comprising the steps of:

impregnating the cellulosic raw material with a solution comprising
sodium carbonate to form a silica-containing impregnation liquor and an at
least partially desilicated raw material;

separating the silica-containing impregnation liquor from the at least
partially desilicated raw material;

causticizing the separated silica-containing impregnation liquor to
precipitate silica-enriched calcium carbonate; and

separating the precipitated silica-enriched calcium carbonate from the
causticized impregnation liquor.

The References
Thomas M. Grace, Chemical Recovery Technology – A Review, 247 IPC
Technical Paper 1-28 (1987) (hereafter Grace).

Jan Pekarovic et al., Desilication of Agricultural Residues – the First Step
Prior Pulping, TAPPI 2003 Fall Technical Conference Paper FAL0311 1-10
(2003) (hereafter Pekarovic).

The Rejection
Claims 1-12 stand rejected under 35 U.S.C. § 103 over Pekarovic in
view of Grace.
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OPINION
We affirm the Examiner’s rejection.
Issue
Have the Appellants indicated reversible error in the Examiner’s
determination that the applied prior art would have rendered prima facie
obvious, to one of ordinary skill in the art, causticizing, prior to a
delignification step, a separated silica-containing impregnation liquor to
precipitate silica-enriched calcium carbonate?
Findings of Fact
Pekarovic discloses that high silica content in wheat straw is a
problem during wheat straw delignification (¶¶ 27, 30).1 Prior to
delignification, Pekarovic leaches silica from wheat straw by impregnating
the wheat straw with a sodium carbonate solution (¶¶ 1, 24, 27-30; Table 3;
drawing in Appellants’ Evidence Appendix). Pekarovic indicates that the
sodium carbonate is recovered (¶ 26), but does not disclose a method for
doing so.
Grace discloses silica removal from pulping process chemical
recovery systems by precipitating the silica with lime (¶¶ 1, 75). Grace
teaches that “[t]he ideal point for silica removal is from weak black liquor
immediately after fiber separation” (¶ 75) and that “[d]esilication can also be
carried out on the green liquor.” See id.

1 The Pekarovic and Grace paragraph numbers are those added by the
Examiner.
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Application 11/103,265

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Analysis
The Appellants argue that Pekarovic “contains no disclosure with
respect to causticizing the separated silica-containing impregnation liquor”
(Br. 3-4) and that Grace “does not even hint to performing desilication on a
cellulosic raw material prior to delignification” (Br. 6).
That argument is not well taken because “[n]on-obviousness cannot
be established by attacking references individually where the rejection is
based upon the teachings of a combination of references.” In re Merck &
Co., 800 F.2d 1091, 1097 Fed. Cir. 1986). The Examiner relies upon
Pekarovic for a disclosure of performing desilication on a cellulosic raw
material prior to delignification, and Grace for a suggestion to causticize
Pekarovic’s silica-containing impregnation liquor with lime (Ans. 3-4).
The Appellants argue that black liquor generated by a delignification
step and the Appellants’ silica-containing black liquor are qualitatively
different, and that Grace only suggests the use of carbonation to effect silica
precipitation in black liquor (Br. 4-6).
As pointed out by the Examiner (Ans. 9), the Appellants improperly
based that argument upon Grace’s disclosed kraft process which uses
sodium sulfide (¶ 4) rather than basing it upon Graces’ disclosed soda
process which uses sodium carbonate (¶ 33) and, therefore, is more similar
to Pekarovic’s process (¶¶ 1, 24).
Grace discloses causticizing weak black liquor or green liquor with
lime (¶ 75). The Appellants disclose that they use calcium oxide (lime)
and/or calcium hydroxide “to causticize the separated silica-containing
impregnation black liquor” (Spec. ¶ 0023). Pekarovic’s desilication of
wheat straw by impregnation with sodium carbonate also partially
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delignifies the wheat straw (Table 3) and, therefore, appears to produce a
black liquor. The Appellants do not explain, and it is not apparent, why one
of ordinary skill in the art would have expected Grace’s causticization with
lime to be effective on a weak black liquor immediately after fiber
separation but not on Pekarovic’s silica-containing impregnation liquor
which also appears to be a black liquor. The Examiner argues that “a person
of ordinary skill in the art would reasonably expect that the reaction which
removes silica from one type of pulping liquor would remove it from other
pulping liquors even if the pulping liquors had slightly differing
compositions” (Ans. 8). The Appellants have not responded to that
argument and, accordingly, have not convinced us that the argument is in
error.
Conclusion of Law
The Appellants have not indicated reversible error in the Examiner’s
determination that the applied prior art would have rendered prima facie
obvious, to one of ordinary skill in the art, causticizing, prior to a
delignification step, a separated silica-containing impregnation liquor to
precipitate silica-enriched calcium carbonate.
DECISION/ORDER
The rejection of claims 1-12 under 35 U.S.C. § 103 over Pekarovic in
view of Grace is affirmed.
It is ordered that the Examiner’s decision is affirmed.

No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a).
AFFIRMED
Appeal 2009-008953
Application 11/103,265

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