The concentration of germanium in coal

In this investigation, approximately 500 pounds of germaniferous coal was sampled and split into size and specific gravity fractions. The specific gravity fractions were analyzed for ash, volatile matter, fixed carbon, and germanium. Richer fractions of the coal were further treated by solvent extraction, and on the basis of these tests, extraction tests of varying times were conducted. In addition, a sample of the coal was tested by froth flotation and the effects of flotation on germanium concentration were noted.

Size and specific gravity separations have given products that contain two to three times as much germanium as the feed. Solvent extraction with suitable solvents was able to give products that contained as high as 250 times the germanium content of the feed. Froth flotation produced concentrations of the germanium that were only one and a half times greater than obtained in feed. The greatest concentration made by burning the coal was 50 to 1 when comparing the germanium in the ash to the germanium in the sample.