Show keeping keepin 9 up I 1 A I 1 t wi cien e SC n erkle er e 0 science borvice service static electricity used commercially in separating ores new york every small boy who has ever eve r rubbed a p piece bece of scaling wax with c cats ats fur and attracted to it bits of paper knows that in the forces of static cleo electricity triciti tri city lies one means of sepa separating rating materials small boys grown up to become mining engineers long ago realized that somehow static electricity might be used commercially to separate valuable from worthless ores the idea Is old of course but it never has been applied widely and successfully to largo scale tion ot of ores as have the magnetic methods the trouble in those early days daya was that the sources of electricity tho the old fashioned ma chines and so on were ineffective later the use of transformers transform rs and mechanical rectifiers flers ot of current arrived and some improvement camo came also but as II 11 D johnson reports to the american institute of mining and metallurgical engineers there thera has been little development in tho the lost last 10 years despite great ad vances in the radio and vacuum tube art in that decade how tho the separator works mr johnson hns has studied the ele elec tro static separation ot of over 00 dit ferent elements with a simple and ingenious apparatus the mineral mixture to bo be separated feeds down a hopper on to the surface of a rotating cylinder charged electrically positive nearby this cylinder is another one charged with electricity of the opposite sign by using a n full wave high voltage rec tidying tube the voltage created out of line in their vertical fall and makes them drop on tho the other side of a suitable vertical dividing sheet of material thus one component of tho the mixture falls on the ono one side and the particles on tho the other mineral granules of tho the size obtained in commercial grin grinding ding machos were used in the tests ono one difficult separation achieved was the removal of bituminous s coal dust from anthracite dust among the difficult separations mode made possible were those of separating galena from pyrite muscovite from both micas and calcino from dolomite |