Mining Intelligence.

Lake Wakatip Mail, Issue 1580, 11 March 1887, Page 5

Mining Intelligence.

THE EXTRACTION OP GOLD FROM PYRITES.

(TO THE EDITOR OP THE LAKE WAKATIP MAIL.)

Dear Sir.—l have much pleasure in forwarding the following on the abovenamed subject, feeling sure it will interest the mining public. A plant for the extraction of gold from pyrites, recently perfected by Messrs Cosmo, Ncwliery and Vautin, may now be seen working daily at the Langland'B Foundry, Yarratank, Melbourne. The 1 roasted pyrites is first treated in the chloiinator. This is an iron cylinder, provided with a gas valve and manhole, capable of sustaining a pressure of about 60lhs to the square inch. Into this vessel about three or four hundredweight of pyrites are placed with one per cen*. of sulphuric acid and one per cent of chloride of lime. A sufficient quantity of water is then added, the manhole is closed, and air to a pressure of 50U>8 to the square inch is pumped in. The chloiinator is then resolved, and by the action of the sulphuric acid upon the chloride of lime chlorido gas is produced. The effect of the air under pressure is to keep the chlorine in a liquid state, in which it acts most powerfully, and by the revolution of the cylinder it is allowed to haxe free aciion upon the gold. Chemical combination takes place and chloride of gold is formed and dissolved l>y the water. The length of time necessary to complete the process is regulated by the coarseness or fineness of th* ore, and when the operation is deemed to be complete the chlnrinator is stopped and the gas liberated. The manhole is then opened, and the charge sent down a shoot into a sand filter. The liquid is drawn off from the filter by a suction pump, water King added when necessary, so that all the chl ride of gold may be dissolved and carried orl' from the ore. After passing through a vat, where the in purities settle, the liquid flows into a charcoal filter. Here a r mirkable chemical reaction takes place, by wh-ch the gold is liberated from the chlorine, and the latter continues with the hydrogen of the wattr to form dydiochloriu acid. Tbe free gold is deposited on the char o-1 of the filter, and when a sufficient quantity of ilt« metal has been the charcoal is dried and ignited, and pure g'»l«l remains behind. If the water is used o»cr and over agiin the hyihochlnric acid becomes gradually more concentrated, and renders the use of >o nnicii sulphuric acid in the chluritiator unnecessary. The chloiinator now liein? employed can be resolved by about half a hoise power, and tho whole pro-ess is so simple that one man is able to siipciintei.il all the operations. 'lhe cost of treatment by this process does not exceed from 10s to 12s per ton. I am, etc., Ar.FRKD MORKISBY. Invincible Mine, Bees Valley, March 8, 1887.