Purification of Gold by Electrolysis
The Moebius Process of Purification of Gold by Electrolysis is now in successful operation and is said to be specially suitable for refining copper bullion containing large proportions of silver and gold with small quantities of lead, platinum, and other metals, but is chiefly used in parting dore silver containing not more than 20 per 1,000 […]
Gold Refining Machine
The guard pot, with the clay pot in it containing 2 or 3 ozs. of fused borax, is placed in the furnace, and is heated gradually until the bottom of the clay pot is dull red. The ingots (of which the larger are slipper-shaped) to be refined, amounting in all to 650 to 720 ozs. […]
Miller Chlorine Process
The use of chlorine gas for the purification of molten gold was first proposed by L. Thompson, and the results of his investigations were published in the Journal of the Society of Arts two years later. He stated that “ it has long been known to chemists, that not only has gold no affinity to […]
Gutzkow Process to Refine Gold
This Gutzkow Process of parting by sulphuric acid was invented and patented by Mr. F. Gutzkow. It has been extensively worked in Germany and in San Francisco, and up to the year 1891 had been instrumental, on the authority of Mr. Gutzkow, in refining one hundred million dollars’ worth of silver. It is fully described in […]
Sulphuric Acid Parting of Gold & Silver
This process has now, in the majority of refineries, superseded the nitric acid method, which is much more expensive, owing to the higher cost of the acid used and of the plant required. The German chemist, Kunckel, who lived in the seventeenth century, is said to have been the first to employ sulphuric acid in […]
Silver Chloride Reduction
The silver chloride is then reduced in lead-lined tanks by means of granulated zinc and water acidulated with sulphuric acid. Thirty-three pounds of commercial granulated zinc are stated to be enough to reduce 100 lbs. of silver from the chloride. The reactions involved are as follows: 2AgCl + Zn = ZnCl2 + 2Ag Zn + […]
Gold Alloy Granulation
The gold to be parted must be approximately free from base metals, particularly from those which are not soluble in nitric acid, such as tin, arsenic, antimony. If these were present they would form insoluble oxides, which would remain with the gold, so that further refining operations would be necessary: they would, moreover, cause a […]
PARTING: Separate Gold and Silver by Melting
Parting is the separation of silver from gold and a process during which the base metals are separated from both, but, as the presence of a high percentage of these base metals is injurious to the successful conduct of the processes which are chiefly in use, a preliminary refining by one of the methods already […]
How Gold Bullion is Made
By whatever process gold may have been extracted from its ores, it is necessary to melt the crude bullion and cast it into bars so that its value may be ascertained, and that it may be put into a form convenient for transportation and sale. The name “ bullion ” may be conveniently restricted to […]
How to Make a Gold Bar by Casting Gold Bullion Ingot
The operation of refining by one of the methods described above is necessary before gold can be exactly valued. When base metals other than copper are present, segregation occurs and the solidified metal is not uniform in composition. The result is that the exact value of the bullion cannot be determined, and the buyer must […]