Germany is now chiefly dependent on Bavarian flake graphite for crucibles. The efforts made during the war to get Ceylon graphite in through Holland and Switzerland indicate that the Bavarian supply is not wholly satisfactory. Amorphous graphite is supplied from Austria. Overproduction has made it possible at times to sell the products in America below cost.
Japan produces some flake graphite. Chosen has an abundant supply of the amorphous variety. In Chosen there have been recent discoveries of crystalline graphite which may be of importance.
[Figure 11] shows the changes in the annual output of graphite in the chief producing countries, and [Figure 12] shows the percentage of crucible graphites produced by the main sources of supply.
SUMMARY
Graphite occurs in nature in two forms, crystalline and amorphous, each form having its own peculiar uses. Crystalline graphite is used in the manufacture of crucibles, as a lubricant, and in paints. Amorphous graphite is used as a lubricant, for foundry facings, in pencils, in paints, as a polish for high explosives, in boiler compounds, in electrodes, in dry batteries, as a stove and shoe polish, and as a filler for fertilizers. Most of the above uses are essential and cannot easily be eliminated. Artificial graphite made from coal or other carbonaceous matter can be substituted for the natural amorphous graphite.
Fig. 11.—Annual output of graphite in chief producing countries, 1902-18. Full lines indicate crystalline graphite; dotted lines principally amorphous graphite.
Fig. 12.—Percentage of crucible graphite produced by main sources of supply, 1907-1917. Bavarian data since 1913 doubtful, but since completion of the graph it has been found that the 1917 production was much larger than shown.
Amorphous graphite may occur wherever coal or other carbonaceous beds have undergone regional or igneous metamorphism. Crystalline graphite, both flake and vein, is usually found in association with granitic intrusives. Since such rocks have not been thoroughly prospected in all parts of the world, it is probable that important new deposits of graphite will be discovered, especially in Canada, Siberia and parts of South America and Africa.