Silver separation from gold

Methods of wet analysis were slow to develop as lack of acids made it difficult to bring many materials into solution. Mineral acids were not available until the Middle Ages, then first prepared by unknown alchemists. Nitric acid was first mentioned in the thirteenth century as aqua fortis (strong water) by which silver could be separated from gold. It was the availability of mineral acids that enabled wet methods of analysis to be developed for a wide range of materials. 

Molybdenite [1309-56 ] M0S2, normally floats with the copper sulfides. Therefore, the copper concentrate from the cleaner cells frequently has to be separated from molybdenite in a separate flotation circuit before the copper concentrate goes to the smelter. Gold, silver, selenium, and tellurium are collected with the copper concentrate. 

The mud or slime from the silver separation is processed to form impure gold anodes. These anodes are then electroly2ed to yield purified gold and to separate platinum and palladium for subsequent recovery (31). 

Potassium cyanide is primarily used for fine silver plating but is also used for dyes and specialty products (see Electroplating). Electrolytic refining of platinum is carried out in fused potassium cyanide baths, in which a separation from silver is effected. Potassium cyanide is also a component of the electrolyte for the analytical separation of gold, silver, and copper from platinum. It is used with sodium cyanide for nitriding steel and also in mixtures for metal coloring by chemical or electrolytic processes. 

Many of the metals used by ancient man— coppei (cuprum, Cu), silver (argentum, Ag), gold (aurum, Au), tin (stannum, Sn), and lead (plumbum, Pb)—are in relatively short supply. Ancient man found deposits of the first three occurring as the elementary metals. These three may also be separated from their ores by relatively simple chemical processes. On the othei hand, aluminum and titanium, though abundant, are much more difficult to prepare from their ores. Fluorine is more abundant in the earth than chlorine but chlorine and its compounds are much more common—they are easier to prepare and easier to handle. However, as the best sources of the elements now common to us become depleted, we will have to turn to the elements that are now little used. 

The alchemists of the Middle Ages were no strangers to acids. In fact, aqua fortis, which literally means "strong water," is basically nitric acid. Alchemists used aqua fortis to dissolve certain metals. Specifically, they used it to separate silver (which would dissolve in aqua fortis) from gold (which would not). 

Thum A variation of the Balbech process for separating silver from gold in which the electrodes are held vertically. The anodes are contained in cloth bags to retain the shmes silver deposits at the cathodes and is periodically scraped off. 

If the ratio be unity, the concentrations of the solute in each solvent will be the same if the ratio be far removed from unity, a correspondingly large proportion of the solute will be found in the one solvent which can be utilized to extract the Soln. from the other solvent. E.g. ether will remove ferric chloride from its aq. soln., and since many other chlorides are almost insoluble in ether, the process is utilized in analysis for the separation of iron from the other elements the solubility of cobalt thiocyanate in ether is utilized for the separation of cobalt perchromic acid is similarly separated from its aq. soln. by ether molten zinc extracts silver and gold from molten lead the extraction of organic compounds from aq. soln. by shaking out with ether or other solvent is much used in organic laboratories. 

The separation of the elements from metals is a process in which you should provide yourself with good apparatus, and with experienced manipulation and workmanship. First make an aqua fortis thus take of alum, vitriol, sal-nitri, equal parts, distil to a strong aqua fortis, return that to the residue and distil a second time in a glass flask. Dissolve in this silver and afterwards dissolve in it sal ammoniac. After this is done take the metal in thin plates and dissolve it in the water. When that has taken place separate it in the water bath (balneo mar is), pour it over again until an oil is found at the bottom from gold almost brown, from silver almost bluish, from iron red to almost black, from mercury quite white, from lead lead-colored, from copper quite green, from tin, yellow. 

Thus you have again quicksilver. The following descriptions of the separation of gold and silver, and silver from copper, closely resemble similar processes in the Probier-buchlein, but the descriptions are less complete. 

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