Appeal No. 1997-0664
Application No. 08/280,945
FeO + 2HCl 6 FeCl + H O (brief, pages 3-4).2 2
The appellants further explain that the consumed or spent
pickling acid and the iron chloride contained therein can be
decomposed by a thermal decomposition process (usually spray
roasting or the fluidized bed process) according to the
following reaction:
2FeCl + 2H O 0.5O 6 Fe O + 4HCl (brief, page 4).2 2 2 23
However, the appellants also state that undesirable
pollutants, namely oxides of nitrogen (NO ) and chlorine, may
x
be formed during the thermal decomposition process (id.).
Thus, the present invention is directed to a process which
avoids the formation of pollutants, such as chlorine and NO ,
x
during the thermal decomposition by mixing the spent pickling
acid with at least one compound containing nitrogen having a
low oxidation number, for example ammonium compounds such as
ammonium chloride, ammonia, ureas, or amides (id.).
The prior art references relied upon by the examiner as
evidence of obviousness are:
Michels et al. (Michels) 3,399,964 Sep.
03, 1968
Jackson et al. (Jackson) 3,755,090 Aug.
28, 1973
4
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