Chemical engineering . e salts, and then with sodium sul-phide to remove the base metals, which is presumed to belargely zinc. If copper is present in the solution the same isremoved by electrolysis before the solution is passed to thezinc boxes for precipitation of the gold values, zinc cathodesbeing used, whereby the cyanogen is transformed into a zinccyanide with precipitation of the copper. The solution is thenrun through the zinc boxes, where the gold is removed, andthe solution is then treated as above. The cyanide is recoveredfrom the waste solutions by adding an excess of zinc chloride
Chemical engineering . e salts, and then with sodium sul-phide to remove the base metals, which is presumed to belargely zinc. If copper is present in the solution the same isremoved by electrolysis before the solution is passed to thezinc boxes for precipitation of the gold values, zinc cathodesbeing used, whereby the cyanogen is transformed into a zinccyanide with precipitation of the copper. The solution is thenrun through the zinc boxes, where the gold is removed, andthe solution is then treated as above. The cyanide is recoveredfrom the waste solutions by adding an excess of zinc chlorideand precipitating the cyanide as zinc cyanide. The same is re-moved either by filtration or decantation and returned to theworking solutions as desired: recovery being made in theabove manner. The technical modus operandi has not beenmade public by Mr. Orr, and therefore detailed results aremeager. Dairis Method.—This method of recovery of the c>anogendepends upon the use and action of :ui alternating electric mr-. FIG. 2.— P1,.\NT SM LGGLER-UNION MINING CO. rent. The solution is treated as a whole, without segregation,which is accomplished by placing suitable electrodes in thesolution storage vat, the same to contain approximately thevolume, in tons, which is used in the plant per 24 hours. Bythis the time of threatnient of the solution is 24 lime is added to the solution, each time a pumpingfrom the sump occurs, and in the same manner as the cyanideis added, e. g., by placing in some receptacle and allowing thepumped solution to flow over the alkali whereby the alkali isdissolved and added to the storage solution. The electrodes are preferably lead, as slight action occurs,although a set of lead electrodes will last but little more thanhalf a year. They then l)ecome honeycombed and lose themetallic property of lead to some extent. The distance of theelectrodes apart, is, with wooden tanks, the diameter of thetank, the object being to get equal fl
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectmetallu, bookyear1902
