Sulphur Refining of Gold
Refining with Sulphur A more speedy method of removing iron, copper, lead and base metals from bullion is to add sulphur to the molten metals. Although gold sulphides may be readily formed in the wet way, they are decomposed into gold and sulphur by merely heating them to a temperature below 300 deg. C. If […]
Refining Gold with Oxidizing and Chlorinating Agents
Nitre Refining When the molten gold is obviously impure nitre is added, and as a rule its main action is to eat the pot away, for as fast as metals are oxidised they are again reduced by the carbon of the pots. Where fireclay crucibles are used the nitre does effect a small amount of […]
Simple Methods of Gold Purification
The purification of such alluvial gold alloys is a simple matter. The high specific gravity of the metal allows of separation from most admixed materials by some process of elutriation, or water concentration, or, in arid regions, by dry blowing. The coarser particles are readily picked out, but the finer are usually admixed with heavy […]
How to Operate a Merrill Crowe Precipitation Process
Efficient Merrill Crowe precipitation of gold and silver is dependent upon the proper control of certain physical and chemical properties of the solution. The most important of these properties are listed below: SUSPENDED SOLIDS, such as ore slime and precipitates of calcium carbonate, with hydrates of aluminum, magnesium and iron, present in the pregnant solution […]
Merrill Crowe Process & Equipment
Here is described the essential features of the Merrill Crowe Process and its equipment/apparatus used for the Simultaneous Clarification, De-aeration and Precipitation of cyanide solutions. Limited space has prevented a full description of all of the details involved but we have pointed out the application of the various types of equipment and the advantages to be […]
Gold Solubility in Nitric Acid of Copper-Bullions-Alloys
In a paper, entitled A Uniform Method for the Assay of Copper Material for Gold and Silver, A. R. Ledoux invited the assayers of this country to contribute to a symposium, in which the results of their assays of given samples of copper-matte and metallic copper would be made comparable. This symposium appeared about one […]
Operating Costs of Gold Processing Plant
A small gold mine flowsheet is shown below together with cost data which clearly shows the results that can be ‘obtained when handling a low grade ore by a simple process. There are many commendable features in such a set up and no complicated machines or practices are embodied in this plan. In fact, its […]
Hydraulic Dredging for Gold-Bearing Gravels
Repeated failures in attempts to work gold-bearing gravels by means of suction-dredges have created the impression that this method is impracticable. The suction-dredges have failed from three special causes: excessive wear and frequent breakage of pump-shell, runners and liners; inability to dredge compact gravel which would not readily move towards the intake; and, most important […]
Gold Ore Chlorination
Experience has shown how difficult it is to obtain information regarding laboratory-tests in connection with the gold ore chlorination process for the extraction of gold from its ores, and I therefore present the following method, somewhat in detail, for the benefit of those who may desire to pursue research work in this field. The ore […]
Gold Bromination & Gold Chlorination= F(Silver)
When dry chlorine gas is made to act in the cold upon finely-divided gold, it converts the latter with evolution of heat into auro-auric chloride, Au2Cl4, a hard, dark-red, hygroscopic salt. Moisture splits this salt into aurous and auric chloride, Au2Cl4 = AuCl + AuCl3 ; treatment with water converts it into auric chloride and […]