The encyclopædia britannica; a dictionary of arts, sciences, literature and general information . l surfaces, and a slope of 11 in. more or less per foot from centreto circumference; a common size is 17 ft. in diameter, and a commonspeed one revolution per minute. These tables treat material ofjJon and less in diameter coming from box classifiers. The principleon which the table works is that the film of water upon the smoothsurface rolls the larger grains (quartz) towards the margin of thetable faster than the smaller grains (heavy mineral) which are in theslow-moving bottom current. The revo
The encyclopædia britannica; a dictionary of arts, sciences, literature and general information . l surfaces, and a slope of 11 in. more or less per foot from centreto circumference; a common size is 17 ft. in diameter, and a commonspeed one revolution per minute. These tables treat material ofjJon and less in diameter coming from box classifiers. The principleon which the table works is that the film of water upon the smoothsurface rolls the larger grains (quartz) towards the margin of thetable faster than the smaller grains (heavy mineral) which are in theslow-moving bottom current. The revolution of the table thendischarges the quartz earlier at a, a, a, a, an intermediate middlingproduct next at b. and the heavy mineral last at c. Suitable laundersor troughs and catch-boxes are supplied for the three products. Thecapacity of such a table is 12 tons or more of pulp, dry weight, intwenty-four hours. Frames, ur?d in concentrating tin ore in Cornwall,are rectangular slime-tables which separate the waste from theconcentrates on the same principle as the circular tables, though they. Fig. 10.—Convex Revolving Slime-table. run intermittently. They treat very fine pulp, and after being fedfor a short period (about fifteen minutes) the pulp is shut off, theconcentrates are flushed off with a douche of water and caught in abox, and the feed pulp is again turned on. Canvas tables are rect-angular tables with plane surfaces covered with cotton duck (canvas)free from seams, they slope about IJ in. to the ioot. They are fedwith stamp-mill pulp, with the tailings of vanners, or, best of all,with very fine pulp overflowing from a fine classifier. The roughsurface of the duck is such an efficient catching surface that they canrun for an hour before the concentrates are removed—an operationwhich is effected by shutting off the feed pulp, rinsing the surfacewith a little clean water, and hosing or brooming off the concentratesinto a catch-box. The feed-pulp is then again turn
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Keywords: ., bookcentury1900, bookdecade1910, bookidencyclopdiab, bookyear1910
