Zinc Box for Gold Bullion Precipitation
It was generally believed at one time that the precipitation of gold and silver by zinc was effected by simple displacement, according to the equation: 2KAuCy2 + Zn = K2ZnCy4 + 2Au Some considerations have been adduced, however, which throw doubt on this view. It is well known that a considerable excess of free cyanide must […]
Effect of Potassium Cyanide on Gold & Metals
The discovery that metallic gold is soluble in potassium cyanide came after studying the action of cyanides on plates of gold, and announced that they were slowly dissolved. Metallurgists pointed out that gold-leaf is dissolved by a dilute solution of the salt, and also showed that if the gold floats on the surface of the […]
Gold Vat Leaching
Gold Leaching done in round vats, constructed of wood, concrete, or iron and steel. If wood is used it is covered by a coating of paraffin paint, or by a mixture of asphaltum and coal-tar. Concrete and brick vats are not now advocated owing to their great cost and less convenient working, and wooden vats suffer more […]
How to Prepare and Storage of Cyanide Solution
The cyanide is usually dissolved in a little water before being added to the stock solution, as the amount of KCy present is more easily determined in a strong solution than in any other form. A special dissolving vat of small size is often provided and is placed at a higher level than the large […]
How to Make Gold Bullion
Various gold bullion making methods have been suggested for effecting the elimination of the zinc and other base metals. The chief ones are: Direct fusion with fluxes. Roasting, followed by fusion. Treatment with sulphuric acid, followed by fusion. Lead fusion and cupellation (Tavener process). Volatilisation of the zinc, followed by fusion. Direct Fusion The method […]
Cleaning the Gold Precipitate Bullion Box
There is one precipitation house and refinery common to all the leaching buildings. The method of precipitation is by zinc shavings, which, with slight modifications, answers admirably for all strengths of solution, the strong solutions ranging from .70 per cent. KCy to .25 per cent. KCy; the weak from .25 per cent. KCy to .10 […]
Cyanide Solution Strength Test
The strength of the cyanide solutions is tested by silver nitrate, using 10 c.c. of the strong and weak solutions respectively (diluted to about 100 c.c. with water) and taking 100 c.c. of wash-water undiluted. In each case a few drops of a 5 per cent, solution of potassium iodide are added. When the titration […]
Chemical Precipitation on Mercury
The Chemical Precipitation on Mercury of the Gilmour – Young Process is a method that has been employed at the Santa Francisca Mine, Nicaragua. The ore contains a very large percentage of clay, the slimes amounting to 70 per cent, of the ore. The ore is crushed by a No. 5 Krupp ball mill through a […]
Electrical Precipitation on Mercury or Amalgamated Plates
In the Siemens-Halske Electrical Precipitation process, the gold is deposited from solution by the passage through the liquid of a current of electricity. Moreover, as the precipitation is as readily obtained in extremely dilute cyanide solutions as in those containing 0.1 per cent, or more, very weak solutions are used in dissolving the gold from […]
Cyanide in the Stamp Battery
Use of Cyanide in the Stamp Battery to treat the ore direct from the stamp milling battery instead of first passing it over amalgamated plates. Ore can be crushed with cyanide solution instead of water, and led at once into the filtering tanks. The results are stated to have shown that the coarse gold resisted the attack […]