Appeal No. 2005-0374 Page 3
Application No. 09/891,780
Smith, like Appellants, is concerned with removing arsenic compounds from distillation
bottoms in a process of purifying hydrogen fluoride (Smith, col. 5, l. 17-22). According to
Smith, various processes of purifying hydrogen fluoride involve distillation (Smith, col. 2, ll. 48-
52). During distillation, impurities plus some hydrogen fluoride collect in the bottom of the
distillation column (Smith, col. 2, ll. 52-54). The bottoms typically contain, among other things,
hexafluoroarsenic acid or salt thereof (Smith, col. 2, ll. 52-59). The process of Smith is directed
to recovery of the hydrogen fluoride in the bottoms and conversion of the hexafluoroarsenic acid
or salt thereof to a form that can be rendered nonhazardous (Smith, col. 3, ll. 61-66).
Smith accomplishes recovery and conversion by steps of concentrating (Smith, col. 6, ll.
8-19), hydrolyzing the hexafluoroarsenic acid or salt thereof (Smith, col. 8, ll. 1-17), and reacting
the resulting arsenic acid with calcium oxide to render the waste nonhazardous (Smith, col. 8, ll.
30-44).3 In the concentration step, the bottoms are heated to a temperature of about 50° C to
about 150° C, more preferably, to about 70° C to 105° C such that hydrogen fluoride is
vaporized (Smith, col. 6, ll. 8-19).
Appellants argue that, “in the determination of patentability under 35 U.S.C. § 102(b),
the Examiner erred in concluding that Smith’s process step of applying a temperature range of
50° C to 150° C to a reaction mixture which is to be hydrolyzed in order to convert
hexafluoroarsenic acids or salts therefrom [sic: thereof] to arsenic acid or salts thereof anticipates
3Smith also discusses reacting the residual arsenic acid with calcium hydroxide (Smith, col. 8, ll. 46-52).
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