Appeal No. 96-1165
Application 08/060,422
Gorin and erroneously rejected claims 4, 18-21 and 24-26 on the basis of claim 1, step (b), over
Kertamus., i.e., the examiner has not considered the claims and references as a whole in determining
obviousness and has therefore engaged in hindsight reconstruction of the claimed subject matter; (iii) Gorin,
Kertamus and Wheelock taken alone or in combination fail to teach or suggest the claimed subject matter
because none of the references suggest using recycled carbon monoxide in the reduction of the metal
sulfate, neither Gorin nor Wheelock disclose reducing sulfur dioxide to form sulfur and carbon monoxide,
and Kertamus does not mention sulfate processing to obtain sulfur dioxide; and (iv) since “Gorin, Kertamus,
and Wheelock are directed to separate, distinct and complete invention [sic, inventions] with quite different
objectives, it would not be obvious to add, modify, subtract or substitute portions of apparatus or change
reactions schemes from any one reference to give the claimed invention” (brief: p. 26). We do not find any
of these arguments persuasive.
Gorin discloses a process of reducing calcium sulfate in reactor 42 to calcium sulfide with a
reducing agent which includes carbon monoxide, feeding the calcium sulfide to reactor 44 to oxidize the
sulfide to calcium oxide and sulfur dioxide, feeding the sulfur dioxide into reactor 56 and reducing the sulfur
dioxide to sulfur by subjecting the sulfur dioxide to a reducing gas and then to a Claus reaction (Fig. 2; col.
2, line 26-59; col. 4, lines 30-64). Gorin further teaches recovering gas from the conversion of sulfur
dioxide to sulfur and recycling the gas in the initial stages of the process for producing sulfur dioxide.
Reducing calcium sulfate with a reducing agent containing carbon monoxide is further taught by Wheelock
(col. 1, lines 44-52). Wheelock further teaches that the rate of the reaction is directly proportional to the
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