US PATENT SUBCLASS 423 / 172
.~.~.~.~ With steam or at specified temperature

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}
170  DF  .~.~ Treating impure sulfate (e.g., barite, etc.) {1}
171  DF  .~.~.~ Calcining gypsum {1}
172.~.~.~.~ With steam or at specified temperature

DEFINITION

Classification: 423/172

(under subclass 171) Processes in which the heat for removing the water of hydration is supplied by steam or water vapor, or the particular heating temperature, or range thereof, is specified.