In this subclass, groups for obtaining metals include obtaining the metals by non-metallurgical processes, and obtaining metal compounds by metallurgical processes. Thus, for example, group C 22 B 11/00 covers the production of silver by reduction of ammoniacal silver oxide in solution, and group C 22 B 17/00 covers the production of cadmium oxide by a metallurgical process. Furthermore, although compounds of arsenic and antimony are classified in C 01 G, production of the elements themselves is covered by C 22 B, as well as the production of their compounds by metallurgical processes.

Processes using enzymes or micro-organisms in order to:

liberate, separate or purify a pre-existing compound or composition, or to

treat textiles or clean solid surfaces of materials

In this group, it is desirable to add the indexing codes relating to the metals obtained. The indexing codes, which are chosen from the main groups (only) of groups C 22 B 11/00 to C 22 B 25/00, from group C 22 B 19/34 or from any of the groups C 22 B 26/00 to C 22 B 61/00, have the same numbers as the classification symbols, but a colon is used instead of the oblique stroke, and should be unlinked. [5]

Attention is drawn to Chapter IV of the Guide which sets forth the rules concerning the application and presentation of the different types of indexing code. [6]

in the absence of an indication to the contrary, compounds are classified in the last appropriate place;

when two or more compounds are used successively, each compound is classified as such;

mixtures containing two or more compounds covered individually by the same one of groups C 22 B 3/28 to C 22 B 3/38, are classified only in that group. [5]