Silver is the most common precious metal, are more than 60 of its minerals.It occurs predominantly in hydrothermal deposits and in the zone of sulfide deposits.Sometimes money can be found in sedimentary rocks and alluvial deposits, among sandstones, which contain carbonaceous material.
for silver is typical face-centered cubic lattice.In the compounds is usually monovalent.This metal is at the end of the electrochemical voltage series.Silver has the highest thermal conductivity among metals.
At ordinary temperatures this metal does not react with oxygen, nitrogen and hydrogen.Under the action of free halogens and sulfur on the surface protective film occurs halides and silver sulfide, which is a gray-black crystals colors.
hydrogen sulfide present in the atmosphere contributes to the appearance on the
surface of articles made of silver thin film, this is due to their darkening with time.Acting on hydrogen sulfide soluble salt of this metal, it is possible to obtain silver sulfide.
As a result, the adsorption of oxygen, which increases with increasing temperature and pressure at the surface of metal oxide silver appears as a thin film.The suspension of silver oxide has antiseptic properties.Carbon monoxide, hydrogen and other metal oxide is reduced to metallic silver.
Silver is dissolved in nitric acid at room temperature, resulting in the formation of silver nitrate.At ordinary temperatures, unless the presence of oxidants, perchloric acid, hydrogen bromide and silver do not react due to the formation on its surface a protective film of sparingly soluble halides.Silver complex compounds of various forms, most of which is soluble in water.
About 80% of mined silver is extracted from ores, and ores of copper and gold.To obtain gold ores used by cyanidation - silver is dissolved in an alkaline solution of sodium cyanide in the presence of air.It was then recovered from the solutions of complex cyanides applying reconstitution aluminum or zinc.
silver alloys of lead concentrates in the processing of lead-zinc ores, it is recovered by the addition of metallic zinc, which forms a refractory compound, a pop-up on the surface as a foam.Whereupon zinc is distilled off at a temperature of 1250 ° C.Silver is also melted copper ores, it is isolated from the anode slime produced during the electrolytic purification of copper.
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