Appeal No. 1997-0569
Application No. 08/150,559
heating iron minerals in view of the teachings of Wright to
use red mineral granules that have natural color throughout
and the teaching of Lewis to form red mineral particles (i.e,
iron oxide particles) by heating iron-containing minerals.
Appellants urge that the collective teachings of the
prior art references relied upon by the examiner teach or
suggest only that roasted iron oxide pigments may be used in a
surface coating like that described in Wright to provide the
desired coloration for roofing granules. From appellants’
perspective, nothing in the applied references teaches or
suggests a roofing material wherein coloration of the roofing
granules is obtained by using iron containing slag as the
roofing granules and oxidizing the iron to achieve the desired
coloration by the process set forth in the claims on appeal.
While it is true that the references relied upon by the
examiner do not teach appellants’ specific method of making
roofing granules by heating granulated iron-containing slag to
a temperature in the claimed range and for a period of time
sufficient to oxidize said iron and cause a color change of
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