| 摘要 |
<p>Fine refuse coal, e.g. anthracite slush culm, is cleaned by classifying it into two or more size ranges and subjecting each size range separately to a froth flotation process, using a smaller amount of collector with the finer ranges than with the coarser ranges. The flotation of the coarser coal may be effected without or with only a small amount of frother, the preferred frother being the mixture of alcohols and hydrocarbons described in Specification 446,418. The collector is preferably a hydrocarbon, e.g. kerosene, and sodium silicate may be added. Slimes, e.g. of minus 100 mesh, may be removed before flotation by any known means, alkali metal silicate being preferably added to the pulp to facilitate the desliming.</p> |
