Show the electro chemical system dyste r n ELMER ELLSWORTH CAREY IN engineering MAGAZINE continued from last issue mercury wells such as are described in the second volume of richards work on ore dressing can be connected and the their r efficiency greatly increased some tests were made some years ago in south africa with mercury wells in which the baffle plates were connected as anodes and I 1 am informed that a similar construction is now being successfully used in california there are several methods of constructing ting electrochemical mercury wells and many experiments have shown that tha t the electrolytic mercury well is a very efficient gold saver there is no fouling or flouring floering flou ring and no scum or coating of sulphur ets collects on the mercury electrolytic mercury wells will extract values from slimes and will recover gold that cannot be amalgamated by the usual methods acney require no skilled attention and possess many advantages over plates in pan amalgamation anodes are suspended from the stirrers and the mercury 15 I 1 5 connected with the negative wire various systems of pan amalgamation have been described especially in connection with eya parks clerici cler I 1 i ci molloy hannay etc but there is no essential difference in these various processes the patent numbers of several devices are given in a previous paragraph and more extended descriptions appear in the books mentioned above turning to electrochemical z the claim is made that under electrochemical conditions the cyanide solution is much more active than usual values pass into the solution which are lost in the ordinary systems the time of treatment is reduced and the extraction increased while there is a decrease in the operating cost precipitation pi tation by electro deposition goes on simultaneously with the le leaching adling process and the usual troubles are eliminated a molecule of after taking up a particle of gold is released as nascent having greatly increased affinity for gold and silver the solution is constantly regenerated the loss of being negligible li the larger particles of gold are amalgamated directly without passing into the solution in electro the pulp and solution are agitated in a shallow tank having the bottom covered with quicksilver cathode revolving stirrers cause the pulp to travel with a circular motion over the quicksilver quick silver for an hour or two this is equivalent to passing the pulp over several miles of mercury surface during this period the values are amalgamated directly or pass into the solution andare and are precipitated by electrolysis the extraction averaging 97 per cent all ores so far as known are capable of successful treatment by means of electro within the next few years I 1 expect to see the electrochemical process perfected to such an extent that it will become automatic and continuous pulp from the ithe mill will continuously enter a series of tanks and from the lower end of the system the tailings will be continuously discharged in fact plans for such a continuous system have already been prepared at present electro is in the experimental state although it was once used quite successfully employed in many mines in south africa let us consider again amalgamation ga mation taking as a text the so called base or rebellious ore when low grade ore is crushed to or mesh practically all the gold is released as free gold but bult only a small percentage of the assay value can be recovered by the usual mill plate gold when in a very finely divided state quickly becomes coated with argillaceous talcose sulphurous or arse filous coverings and it will not amalgamate very ane fine gold easily acquires coatings gaseous or otherwise which eff effectually actually prevent the amalgamation amalgam tion contact values in slimes cannot be extracted by the usual mill plate particles of gold in placer deposits sometimes become coated by local galvanic action and we have rusty or coating which effectually prevent amalgamation with electrochemical electro chemical conditions dit ions all these difficulties art automatically overcome and the broad statement can be made without fear of successful challenge that all values not encased are recovered including platinum and the values associated socia soca ted with black sand in electrochemical amalgamation and a few pounds of common salt should be added to every ton of ore or pulp by electrolysis the chloride of sodium is reduced to nascent chlorine and nascent sodium of mercury is also added to the water or solution this salt under electrolytic action evolves nascent chlorine and mercury As a result of these reactions an alloy of nascent sodium and mercury is formed this alloy absorbs nascent hydrogen produced by the ithe decomposition of the water and the resulting compound known as hydrogen sodium amalgam has a powerful affinity for gold in fact no compound known to science has a more powerful amalgamating action the water and solutions become charged with nascent chlorine and hydrogen these gases instantly destroy foul or greasy substances in the pulp rusty or coated gold is quickly cleaned the gases menta mentioned ned reducing all oxides nascent hydrogen reduces oxides at normal temperature As a result of this cleaning and reducing action gold particles have been freed from all substances that would prevent amalgamation and amalgamation takes place at the first contact with the mercurial surface electrochemical action keeps the mercury in a perfect state and it also prepares the gold for amalga mation malion in the mercury riffle or well we have the necessary fall to bring every particle of gold into intimate contact with the mercury surface and as the quickened mercury surface is at all times exposed to the passing 0 pulp we have the most perfect conditions possible for effective amalgamation we have therefore all the specifications which would be called for in an ideal amalgamation device simplicity low cost ease of installation and operation absence of skilled attendance large capacity and high percentage of extraction those who wish a more detailed account of the chemical and electrochemical processes are referred to a paper on electrochemical amalgamation ga mation in the may 1909 issue of the electrochemical and metallurgical industry to the mining journal london for june 12 1909 and also to vol I 1 page of the proceedings of the london institution of mining and metallurgy in using the electrolytic system in placer and dredge operations the auriferous material is at first passed through throng g h a series of screens until a ten or twelve mesh concentrate is obtained the coarser particles of gold will be saved by the usual usuff riff riffle le system the twelve mesh concentrate containing the values ordinarily lost is ihnen passed over the con necked plates or riffles fiffles of suitable length and 95 per cent of all values not encased are re recovered covered at a trifling expense the successful application of the electrolytic system on gold dredges would double the net savin savins savings el s under the present system the fine tailings of the dredges generally contain greater assay values per ton than the amount of gold recovered that is on ground where fifteen cents per yard is recovered it will generally be found that the assay value of the tailings is 25 or 30 cents per ton in ten years I 1 estimate that gold and platinum to the amount of have passed through ithe tail sluices juices of california dredges and have been forever lost within the next ten years the value of the lost gold in the dredge tai ings nl s will exceed unless some new system of ex tr acting these elusive values successfully is discovered |