GOLD SAVING INVENTION.

Dominion, Volume 1, Issue 193, 9 May 1908, Page 8

GOLD SAVING INVENTION.

: Mr. J. C. Dromgool, B.Sc., master of . the secondary department of tho Tauranga- District High. School,' has patented an''inventionfor an improved method of filtering the'cya T nide solution from $hp .'-slimes. jn .^ l metal»: lurgy of 'gold.by. tlio cyanido process'.. ; ;Mr. Dromgool has just, received word; from the Registrar '..of- Patents, stating that his specifications hare been accepted. Tho improvement consists-mainly in' the application of thp centrifugal; principle in the. process of' filtering. Tho machine by ■ which'; the operations are carried .out is similar to the hydro extractor used, in laundry,work,for cleansing wool, and also in the manufacture of sugar.' It consists of a largo iron, cylinder, capable of holding several tons .''of slimes, x and of rotating at ; a high rate of speed upon a central- vertipal.axis; the vertical • peripheral sjirface of this - cylinder is 'perforated so ,as'■ to allow the passage outwards of the cyanide'solutionj while its inner surface is lined with • a filtering material-e canvas '-or felt. The high speed of rotation results in .a.'tendency in the 'whole: mass 'of the sjiriies 'to move outwards, but the layer offiltering . material retains the' solid r ;matter within the-cylinder,. so .that' only the/cyanide solution passes > through. ,-. The'' probess 5 of. washing from-, the . slimes the 'last graces of gold solution is carried 'oiyt on'tho satne principle by adding successive charges of water, and provision is also made for expeditiously discharging/ the. slimes from the machine when tlje operation of washing is'complete: , j