Refined silver

Blick-feld, n. field of vision, -gold, n. refined gold still containing silver. -silber, n. (Metal.) refined silver still containing impurities. 

Raffinat-kupfer, n. refined copper, -silber, n. refined silver. 

About 2.47 million kg of silver are lost each year to the domestic biosphere, mostly (82%) as a result of human activities. As discussed later, the photography industry accounts for about 47% of all silver discharged into the environment from anthropogenic sources. In 1990, about 50% of the refined silver consumed domestically was used to manufacture photographic products 25% in electrical and electronic products 10% in electroplated ware, sterlingware, and jewelry 5% in brazing alloys and 10% in other products and processes. 

To this end, continued Father de Acosta, they did build small furnaces in places whereas the wind did commonly blow, and with wood and cole made their- refining, the which furnaces in Peru they call huayras. Since the Spaniards entred, besides this manner of refining which they vse to this day, they likewise refine silver with qvick-silver, and draw more by this means then [sic] in refining it by fire. For there is some kind of silver mettal found which can by no means be purged and refined by fire, but onely with quicksilver. . . (45). 

The largest decrease in imported silver was from the United Kingdom and Switzerland. For these two countries import levels fell by 18.1 million ounces, primarily in the form of refined bullion. A total of 125.4 million troy ounces of refined silver were imported in 1986 with only 9.5 million troy ounces accounted for in other forms. 

For a description of the process of refining silver with Testscherben, see ibid., 85-88. 

When this kind of diaphragm is used the composition of both anolyte and catholyte is the same. Similar conditions hold good for tho electrolytical refining of certain metals when the slime formed on the anode which contains precious metals is caught in a cloth bag covering the anode (e. g. when refining silver). 

Refining.—Various methods are employed in refining silver. The process of parting it from gold is described on p. 326. In addition to gold, the principal impurities are copper, iron, lead, and zinc. 

Refined silver, purged from other metals. 

Borcher s process. An electrolytic method for refining silver by using silver sheet cathodes and dilute nitric acid electrolyte. 

Chemical glassware is sufficiently resistant to concentrated alkali hydroxide solutions at room temperature that it can be used without adversely affecting the purity of the products. However, hot, concentrated alkali hydroxide solutions attack any glass so strongly that the latter can be used at high temperatures only for short periods of time, if at all. Such experiments must therefore be run in refined silver containers, which resist even concentrated boiling alkali hydroxide solutions. While pure nickel containers are also suitable, they are not cheaper than silver. 

Very pure CuO (15 g.) is dissolved in a clear, carbonate-free solution of 500 g. of NaOH in 330 ml. of HsO (brief refluxing). The dark-blue solution is cooled to 110 C and carefully diluted by adding 140 ml. of H3O through the reflux condenser (use a funnel). The small quantity of unreacted CuO is then filtered off, collecting the filtrate in a preheated Erlenmeyer flask of refined silver. The Erlenmeyer flask is protected by a Peligot tube (filled with 50% KOH) and kept in an electric drying oven for six days at TO C to allow the filtrate to crystallize. The mixture is then filtered the crystals are washed with some 50% and 45% sodium hydroxide (once each) at room temperature and dried on a clay plate over H3SO4. Yield 13 g. 

The end products are refined lead, lead alloys, refined silver and dore bullion. Refined lead of >99.99% purity is produced fi-om the Mt. Isa refinery and 99.985% and 99.97% purity grades are moulded in the BRM refinery. A wide range of lead alloys is produced, particularly for the battery, lead sheet and cable industries. With the progressive increase in the silver and... 

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