Classification of silver
Silver is mainly existed in silver ore, silver concentrate, coarse silver and silver products. Silver powder is an important material for electronic and electrical industry, the basic functions materials of thick film, resistors, ceramic, medium and other electronic slurry.
The content of silver is very low in nature. According to the distribution of elements in the crust, silver belongs to the trace elements, only about 20 to 30 times higher than gold on average. Silver ore resources can be divided into independent silver ore and associated silver ore, silver ore is mainly existed in the form of sulfide. Industrial minerals of silver are mainly having natural silver, argentite, stromeyerite, dyscrasite, stephanite and so on. While silver has many industrial minerals, they are rarely integrated into single silver deposit, usually distributed in polymetallic ore, copper and gold mine in a dispersed state. More than half of the silver outputs are from the comprehensive recovery of polymetallic ore. All of the assay methods of analytical chemistry have been applied to the silver determination, including gravimetry, titration, spectrophotometry, fluorescence method, chemical power method and so on, in which the advantages of atomic absorption spectrometry are the most prominent. Atomic absorption spectrometry measures silver is sensitive, accurate, fast, simple and less interference. Therefore, it obtains a wide range of applications.
Silver concentrate is the intermediate product of the nonferrous metals industry's production process, to determine the quality silver and the content of the relevant elements have an important role in the transaction of supply and demand sides and the production process determined. The main determination elements except for silver, there also have gold, copper, arsenic, bismuth, lead, zinc, sulfur, aluminum and magnesium.
Currently, the determination of silver and gold content mainly use the most classic fire assay gravimetric method, generally has secondary gold recovery; determination of copper content, high levels adopt iodimetry, low levels adopt atomic absorption spectrometry; determination of lead and zinc, high levels adopt EDTA titration, low levels adopt atomic absorption spectrometry; determination of arsenic content, high levels adopt potassium bromate titration, low levels adopt atomic fluorescence spectrometry; determination of sulfur content, adopt barium sulfate gravimetric method and combustion method; determination of bismuth content, mainly the atomic fluorescence spectrometry; determination of aluminum, there is spectrophotometry and EDTA titration; determination of magnesium, generally using atomic absorption spectrometry.
Coarse silver mainly refers to the silver ore which contains 30%-99.9% of the silver, smelting primary silver products and recycling silver. The crude silver scope is relatively wide, resulting in diversity and complexity of the product species. In the crude silver, except for those relatively simple composition and known quality recycled silver products can be directly used, others are usually required by refined, concentrated integration of corresponding value metal elements. In addition to a variety of precious metal components which coexist with coarse silver, it also contains a lot of metal and non-metal compounds and other substances which have the recovery value. Furthermore, due to its quality spans are getting bigger, it both have silver concentrates, monetary silver and all kinds of relatively low quality silver mining as well as industrial intermediate products.
Pure silver is produced by a variety of silver-containing materials, which the silver content is 99.90%-99.99%. Pure silver is mainly used in photography, chemical reagents, chemical materials, medicine, electronics, decor, jewelry and silver products and other industries. Silver is the most widely used metal powder in the electronics industry. In recent decades, with the progress of science and technology, especially the rapid development of the electronics industry, the preparation of silver was made considerable progress in both the technology and equipment, it was already quite mature.
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