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 […]
Common & Technical Names of Rocks and Minerals
Characteristics of Bulk Materials
Useful Table contains the Angle of Repose, Bulk Density and other Characteristics of various materials.
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 […]
Wet Lead Assay Method
For a number of years I have used for the commercial wet assay of lead generally the ammonium molybdate, and occasionally the ferrocyanide method. These well-known methods need no detailed description here. In the ore-selling and ore-buying establishments of the West, 90%, of all wet lead-assays are made by one or the other, and at […]
Silver Sulphide Assaying
There has been considerable discussion of late as to the best assay method for determining the silver-contents of sulphides of silver resulting from the leaching of silver-ores, and also as to the relative merits of the crucible and the scorification-method for the determination of the silver-contents of ores. Owing to the great depression in the silver-market, these […]
Alundum Extraction-Thimble Used in the Copper Assaying
The photograph, Fig. 1, shows the apparatus a little less than half size, consisting of a filtering-flask fitted with rubber stopper through which passes a bent glass tube, and an extraction-thimble fitted with rubber stopper through which passes a glass tube of 0.25-inch bore. Both tubes are connected by a short piece of rubber tubing. […]
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 […]
Common & Basic Formulas for Mineral Processing Calculations
The control of a milling operation is a problem in imponderables: from the moment that the ore drops into the mill scoop the process becomes continuous, and continuity ceases only when the products finally come to rest at the concentrate bins and on the tailing dams. Material in process often cannot be weighed without a […]