PublishedRarebooksclub.Com, May 2014 |
ISBN9781234124014 |
FormatSoftcover |
Dimensions24.6cm × 18.9cm × 0.3cm |
This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1921 edition. Excerpt: ...circuits are so excellent, that no general rules can be formulated.
Acid salt cake is used in place of sulphuric acid in some instances, notably where it is considerably cheaper or where there is a considerable amount of carbonate in the ore and treatment in an acid pulp seems to be necessary. It is not unlikely, however, that in the latter case, further investigation would reveal the fact that an acid pulp was unnecessary and that the use of both salt cake and sulphuric acid could be done away with. The great majority of ores that can be concentrated by flotation will give a good flotation result with a mixture of pine oil and coal-tar creosote, the pine oil forming from 5 to 50 per cent. of the mixture. In laboratory tests in a mechanical machine from one to two pounds per ton of ore of such a mixture is necessary and sufficient. The procedure for preliminary testing, then, should be as follows: 1. Grind the ore, best dry, so that all will pass the screen whose aperture corresponds to the average maximum size of grain of the mineral to be recovered, but in any case so that all will pass a 0.3-mm. screen. The grinding should further be such that at least 50 per cent. of the material will pass a screen whose aperture is one-quarter that of the limiting screen. 2. Use an agitation-type machine which will give a peripheral speed of impeller tip of from 1500 to 2500 f.p.m. in the case of a three-or four-inch impeller, slightly less in case of a larger machine. The machine should be one that can be easily and thoroughly cleaned. The Janney laboratory flotation machine rigged with the shaft extended through an overhead bearing (see Fig. 4) driven by a variable speed 4-h.p. motor is, in the writer's opinion, the best agitation-type laboratory...
