German Charcoal
After the Armistice was signed, Chaney took up the question of how the Germans made their charcoal. The German charcoal was made from coniferous wood and was reported to be as good as ours, in spite of the fact that they were using inferior materials. Inside of a month Chaney had found out how the German charcoal was made, had duplicated their material, and had shown that it was nothing like as good as our charcoal. The Germans impregnated the wood with zinc chloride, carbonized at red heat, and washed out most of the zinc chloride. When this zinc chloride was found in the German charcoal, it was assumed that it had been added after the charcoal had been made. It was therefore dissolved out with hydrochloric acid, thereby improving the charcoal against chloropicrin. The German charcoal was then tested as it stood, including the fines, against American charcoal, 8 to 14 mesh. The most serious error, however, was in testing only against a high concentration of chloropicrin. The German charcoal contains relatively coarse pores which condense gases at high concentrations very well but which do not absorb gases strongly at low concentrations. The result was that the German charcoal was rated as being four or five times as good as it really was.
German Charcoal. ×200.
Fig. 73.—Charcoal from Spruce Wood.
Comparison of Charcoal
The following table shows a comparison of charcoals from different sources. The method of activation was identical and the times of treatment were those approximately giving the highest service time. The results against chloropicrin, therefore, represent roughly the relative excellence of the charcoal obtainable from various raw materials, using this method of activation:
Comparison of Various Active Charcoals Activated in Laboratory
| Base Material | Apparent Density | Steam Treatment at 900° | Accelerated Chloropicrin Test Results | |||
|---|---|---|---|---|---|---|
| Primary Carbon | Activated Carbon | Time Min. | Weight Loss Per Cent | Weight Absorbed Per Cent | Service Time Min. | |
| Sycamore | 0.158 | 0.080 | 18 | 53 | 41 | 7.3 |
| Cedar | 0.223 | 0.097 | 60 | 88 | 78 | 16.0 |
| Mountain mahogany | 0.420 | 0.236 | 60 | 44 | 32 | 16.3 |
| Ironwood | 0.465 | 0.331 | 60 | 44 | 31 | 20.8 |
| Brazil nut | 0.520 | 0.316 | 120 | 71 | 46 | 32.2 |
| Ivory nut | 0.700 | 0.460 | 120 | 70 | 48 | 47.0 |
| Cohune nut | 0.659 | 0.502 | 120 | 48 | 51 | 53.4 |
| Babassu nut | 0.540 | 0.322 | 210 | 68 | 85 | 58.7 |
| Cocoanut | 0.710 | 0.445 | 120 | 60 | 61 | 58.4 |
| Cocoanut | 0.710 | 0.417 | 180 | 75 | 72 | 64.4 |
| Briquetted Materials | ||||||
| Sawdust | 0.542 | 0.365 | 120 | 66 | 53 | 40.0 |
| Carbon black | 0.769 | 0.444 | 240 | 64.3 | 53 | 50.5 |
| Bituminous coal | 0.789 | 0.430 | 165 | 61 | 58.3 | 46.8 |
| Anthracite coal | 0.830 | 0.371 | 480 | 81 | 53 | 40.7 |