US PATENT SUBCLASS 423 / 173-- .~.~ Treating impure carbonate (e.g., oyster shells, etc.)

US PATENT SUBCLASS 423 / 173
.~.~ Treating impure carbonate (e.g., oyster shells, etc.)

Current as of: June, 1999
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423 /	HD	CHEMISTRY OF INORGANIC COMPOUNDS

1	DF	TREATING MIXTURE TO OBTAIN METAL CONTAINING COMPOUND {15}
155	DF	.~ Alkaline earth metal (Mg, Ca, Sr, or Ba) {11}
173		.~.~ Treating impure carbonate (e.g., oyster shells, etc.) {2}
174	DF	.~.~.~> Forming calcium carbide
175	DF	.~.~.~> Calcining {2}

DEFINITION

Classification: 423/173

(under subclass 155) Processes wherein the original mixture contains the carbonate of an alkaline earth metal.

(1) Note. Limestone, magnetite, oyster shells, etc., are assumed to be impure since they are naturally occurring carbonates. Patents which claim treating calcium carbonate which is disclosed as being limestone, for example, are classified here. Processes for treating dolomite or oyster shells are classified here when no separation of the calcium and magnesium from each other is made.

SEE OR SEARCH THIS CLASS, SUBCLASS:

169, for treating impure carbonates, such as dolomite, to separate magnesium and calcium from each other, and subclass 167, for treating phosphate rock which contains some calcium carbonate.