Animal charcoal is produced by calcining bones in vessels from which the air is excluded, whereby the glue-yielding tissue is converted into carbon, which is distributed upon the bone-earth. Since the value of animal charcoal depends on the quantity of carbon it contains, a product prepared from bones highly steamed, will evidently be of little value, as a considerable portion of the glue-yielding substance has been converted into glue.
If the bones are to be used for the production of animal charcoal they should be subjected to the action of high-pressure steam only long enough to extract the fat, but the resulting glue-liquor is very thin and difficult to work. The watery glue-liquor is first drawn off, and the fat which comes last is caught by itself. The thin glue-liquor is evaporated in vacuum.
3. EXTRACTION OF BONES.
To avoid the loss of glue-yielding substance which is unavoidable in steaming bones, even if only for a short time, in many plants the fat is now extracted by treating the bones with benzine or carbon disulphide. No loss of glue-yielding substance being involved by this process, bones thus treated yield the best quality of animal charcoal.
The fat obtained by extraction with carbon disulphide has such a disagreeable odor as to render it almost worthless. In addition this solvent is very volatile, consequently very inflammable, and is also very poisonous. For these reasons its use for the extraction of fat has been almost entirely abandoned.
Figs. 31 and 32 show an apparatus for the use of benzine which is the invention of Messrs. Wm. Adamson and Charles F. A. Simonis, of Philadelphia, Pa. It is for the purpose of treating animal and vegetable substances with hydrocarbons for extracting therefrom oily, fatty and resinous matter; and the object of this invention is to cause hydrocarbons to trickle through such substances instead of flooding the same, so that it will take up the oily, fatty and resinous matter without any of the albuminous or gelatinous ingredients.
Fig. 31 is a vertical section of apparatus wherewith this invention may be carried into effect; Fig. 32, an inverted plan view of part of Fig. 31.
Fig. 31.
Fig. 32.