Silver is chemical element I of group of periodic Mendeleev's system, it represents plastic metal of white color. In the nature silver is in a type of mix of two stable isotopes.
Instruction
1. Silver is the most widespread precious metal, more than 60 of its minerals are known. It meets mainly in hydrothermal fields and also in a zone of enrichment of sulphidic fields. Sometimes silver can be found in sedimentary rocks and scatterings, among sandstones which contain carbonaceous substance.
2. The face-centered cubic lattice is characteristic of silver. In connections it, as a rule, odnovalentno. This metal is in the end of electrochemical series. Silver has the highest specific heat conductivity among metals.
3. At a usual temperature this metal does not interact with oxygen, nitrogen and hydrogen. Under the influence of free halogens and sulfur on its surface there is a protective film of halogenides and sulfide of the silver representing crystals of gray-black color.
4. The hydrogen sulfide which is present at the atmosphere promotes emergence on a surface of products from silver of a thin film, their darkening is explained by it over time. Influencing hydrogen sulfide on salts of this metal are soluble, it is possible to receive silver sulfide.
5. As a result of oxygen adsorption which amplifies with increase in temperature and pressure on the surface of metal silver protoxide in the form of a thin film appears. Suspension of protoxide of silver has antiseptic properties. Carbon monoxide, hydrogen and other metals restore protoxide to metal silver.
6. Silver is dissolved in nitric acid at the room temperature therefore silver nitrate is formed. At a usual temperature if there are no oxidizers, chloric acid and bromovodorod do not interact with silver because of education on its surface of a protective film of slightly soluble halogenides. Silver forms various complex connections, the most part from them is soluble in water.
7. About 80% of the extracted silver are taken from polymetallic ores and also from ores of copper and gold. From gold ores apply a cyanation method to its receiving — silver is dissolved in alkaline solution of cyanide of sodium in the presence of air. Then it is allocated from solutions of complex cyanides, applying restoration by aluminum or zinc.
8. Silver concentrates in lead alloys when processing zinc-lead ores, it is taken addition of metal zinc which forms the refractory connection emerging on a surface in the form of foam. Then zinc is driven away at a temperature of 1250 °C. Silver is also melted from copper ores, it is emitted from the anode slime which is formed at electrolytic purification of copper.