| Company Name: |
Sigma-Aldrich Gold
|
| Tel: |
021-61415566 800-819-3336(Tel) 400-620-3333(Mobile) |
| Email: |
orderCN@sial.com |
| Products Intro: |
Product Name:Silver wire, diam. 2.0 mm, 99.9% trace metals basis
CAS:7440-22-4
Purity:wire, diam. 2.0 mm, 99.9% trace metals basis Package:1389.96RMB/1EA Remarks:ALDRICH |
| Company Name: |
Rush Metal Gold
|
| Tel: |
021-60516075 |
| Email: |
info@rushmetal.com |
| Products Intro: |
Product Name:Silver Wire/Dia.2.00mm/99.95%
CAS:7440-22-4
Purity:99.95% Package:960RMB/ 5m Remarks:Ag107 |
|
| Product Name: | Silver | | Synonyms: | Silver wire, 0.05mm (0.002 in.) dia., Annealed;Silver powder, spherical, APS 0.6 to 2μm;Silver foil, 0.025mm (0.001 in.) thick, annealed;Silver Thinfoil, 0.005mm (0.0002 in.) thick, Not certified pinhole free;Silver wire, 0.127mm (0.005 in.) dia., Hard, Temper: as drawn;Silver sputtering target, 50.8mm (2.0 in.) dia. x 3.18mm (0.125 in.) thick;Silver nanoparticles, 0.02mg/mL, supplied in 2mM sodium citrate, 425nm absorption;Silver sputtering target, 76.2mm (3.0 in.) dia. x 3.18mm (0.125 in.) thick | | CAS: | 7440-22-4 | | MF: | Ag | | MW: | 107.87 | | EINECS: | 231-131-3 | | Product Categories: | Analytical/Chromatography;Spectroscopy;Electrode MaterialsMetal and Ceramic Science;Organic Electronics and Photonics;Substrates and Electrode Materials;AA Standard SolutionsSpectroscopy;AAS;Matrix Selection;NitrateAlphabetic;Reference/Calibration Standards;S;SA - SMSpectroscopy;Single Solution;Standard Solutions;Inorganics;Chemical Synthesis;SilverMetal and Ceramic Science;Catalysis and Inorganic Chemistry;Nanoparticles: Metals and Metal AlloysChemical Synthesis;47: Ag;Nanoparticles: Metals and Metal AlloysMetal and Ceramic Science;Nanopowders and Nanoparticle Dispersions;SilverNanomaterials;Materials Science;Nanomaterials;Metal and Ceramic Science;Metals;Silver;Elemental AnalysisMetal and Ceramic Science;metal or element | | Mol File: | 7440-22-4.mol |  |
| | Silver Chemical Properties |
| Melting point | 960 °C(lit.)
| | Boiling point | 2212 °C(lit.)
| | density | 1.135 g/mL at 25 °C
| | vapor density | 5.8 (vs air)
| | vapor pressure | 0.05 ( 20 °C)
| | refractive index | n20/D 1.333
| | Fp | 232 °F
| | storage temp. | 2-8°C
| | solubility | H2O: soluble
| | form | wool
| | color | Yellow | | Odor | Odorless | | resistivity | 1-3 * 10^-5 Ω-cm (conductive paste) &_& 1.59 μΩ-cm, 20°C | | Water Solubility | insoluble | | Sensitive | Light Sensitive | | Merck | 13,8577 | | Stability: | Stable. Substances to be avoided include strong acids and strong bases, tartaric acid, oxalic acid. Blackened by contact with ozone, hydrogen sulfide, sulfur. Powder is highly flammable. | | CAS DataBase Reference | 7440-22-4(CAS DataBase Reference) | | NIST Chemistry Reference | Silver(7440-22-4) | | EPA Substance Registry System | Silver(7440-22-4) |
| | Silver Usage And Synthesis |
| History | Silver is one of the oldest metals, known since ancient times. It is a precious metal worldwide, used in ornaments, coins, and utensils. The symbol Ag for this element is derived from the Latin word, argentum. Silver occurs in nature in native form, commonly associated with gold. It is found in most lead and copper ores. The principal mineral of silver is argentite, Ag2S [1332-04-3]. Some other silver minerals include pyrargyrite, Ag3SbS3 [15123-77-0]; proustite, Ag3AsS3 [15152-58-4]; polybasite, Ag16Sb2S11 [53810-31-4]; cerargyrite, AgCl [14358-96-4]; stephanite, Ag5SbS4 [1302-12-1]; and tetrahedrite, Cu3(AsSb)S3. Abundance of silver in the earth’s crust is estimated to be 0.075 mg/kg and its average concentration in sea water is 0.014 µg/L.
| | Uses | Silver and its alloys and compounds have numerous applications. As a precious metal, silver is used in jewelry. Also, one of its alloys, sterling silver, containing 92.5 weight % silver and 7.5 weight % copper, is a jewelry item and is used in tableware and decorative pieces. The metal and its copper alloys are used in coins. Silver-copper brazing alloys and solders have many applications. They are used in automotive radiators, heat exchangers, electrical contacts, steam tubes, coins, and musical instruments.
Some other uses of silver metal include its applications as electrodes, catalysts, mirrors, and dental amalgam. Silver is used as a catalyst in oxidation-reductions involving conversions of alcohol to aldehydes, ethylene to ethylene oxide, and ethylene glycol to glyoxal.
| | Production Methods | Many processes are known for recovery of silver from its ores. These depend mostly on the nature of the mineral, its silver content, and recovery of other metals present in the ore. A few processes are briefly outlined below.
Silver is usually extracted from high-grade ores by three common processes that have been known for many years. These are amalgamation, leaching, and cyanidation. In one amalgamation process, ore is crushed and mixed with sodium chloride, copper sulfate, sulfuric acid, and mercury, and roasted in cast iron pots. The amalgam is separated and washed. Silver is separated from its amalgam by distillation of mercury.
In the cyanidation process the ore is crushed and roasted with sodium chloride and then treated with a solution of sodium cyanide. Silver forms a stable silver cyanide complex, [Ag(CN)2]–. Adding metallic zinc to this complex solution precipitates silver. Several leaching processes are known. One such process, known as the Patera process, developed in the mid 19th century, involves roasting ore with sodium chloride followed by leaching with sodium thiosulfate solution. Silver 834 SILVERis precipitated as silver sulfide, Ag2S, by adding sodium sulfide to the leachate. In the Clandot process, leaching is done with ferric chloride solution. Addition of zinc iodide precipitates silver iodide, AgI. AgI is reduced with zinc to obtain silver.
The above processes are applied for extraction of silver from high-grade ores. However, with depletion of these ores, many processes were developed subsequently to extract silver from low-grade ores, especially lead, copper, and zinc ores that contain very small quantities of silver.
Low grade ores are concentrated by floatation. The concentrates are fed into smelters (copper, lead, and zinc smelters). The concentrates are subjected to various treatments before and after smelting including sintering, calcination, and leaching. Copper concentrates are calcined for removal of sulfur and smelted in a reverberatory furnace to convert into blister copper containing 99 wt% Cu. The blister copper is fire-refined and cast into anodes. The anodes are electrolytically refined in the presence of cathodes containing 99.9% copper. Insoluble anode sludges from electrolytic refining contain silver, gold, and platinum metals. Silver is recovered from the mud by treatment with sulfuric acid. Base metals dissolve in sulfuric acid leaving silver mixed with any gold present in the mud. Silver is separated from gold by electrolysis.
Lead and zinc concentrates can be treated in more or less the same manner as copper concentrates. Sintering lead concentrates removes sulfur and following that smelting with coke and flux in a blast furnace forms impure lead bullion. The lead bullion is drossed with air and sulfur and softened with molten bullion in the presence of air to remove most impurities other than silver and gold. Copper is recovered from the dross and zinc converts to its oxide and is recovered from blast furnace slag. The softened lead obtained above also contains some silver. The silver is recovered by the Parkes Process. The Parkes process involves adding zinc to molten lead to dissolve silver at temperatures above the melting point of zinc. On cooling, zinc-silver alloy solidifies, separating from the lead and rising to the top. The alloy is lifted off and zinc is separated from silver by distillation leaving behind metallic silver.
The unsoftened lead obtained after the softening operation contains silver in small but significant quantities. Such unsoftened lead is cast into anode and subjected to electrolytic refining. The anode mud that is formed adhering to these anodes is removed by scraping. It contains bismuth, silver, gold, and other impurity metals. Silver is obtained from this anode mud by methods similar to the extraction of anode mud from the copper refining process discussed earlier.
If the low–grade ore is a zinc mineral, then zinc concentrate obtained from the flotation process is calcined and leached with water to remove zinc. Silver and lead are left in leach residues. Residues are treated like lead concentrates and fed into lead smelters. Silver is recovered from this lead concentrate by various processes described above.
| | Chemical Properties | lustrous soft white metal;silvery metallic solid; insoluble in water.
| | Chemical Properties | Silver is a white lustrous metal that is extremely ductile and malleable. | | History | Slag dumps in Asia Minor
and on islands in the Aegean Sea indicate that man learned
to separate silver from lead as early as 3000 B.C. Silver occurs
native and in ores such as argentite (Ag2S) and horn silver
(AgCl); lead, lead-zinc, copper, gold, and copper-nickel ores
are principal sources. Mexico, Canada, Peru, and the U.S.
are the principal silver producers in the western hemisphere.
Silver is also recovered during electrolytic refining of copper.
Commercial fine silver contains at least 99.9% silver. Purities
of 99.999+% are available commercially. Pure silver has a brilliant
white metallic luster. It is a little harder than gold and is
very ductile and malleable, being exceeded only by gold and
perhaps palladium. Pure silver has the highest electrical and
thermal conductivity of all metals, and possesses the lowest
contact resistance. It is stable in pure air and water, but tarnishes
when exposed to ozone, hydrogen sulfide, or air containing
sulfur. The alloys of silver are important. Sterling silver
is used for jewelry, silverware, etc. where appearance is paramount.
This alloy contains 92.5% silver, the remainder being
copper or some other metal. Silver is of utmost importance
in photography, about 30% of the U.S. industrial consumption
going into this application. It is used for dental alloys.
Silver is used in making solder and brazing alloys, electrical
contacts, and high capacity silver–zinc and silver–cadmium
batteries. Silver paints are used for making printed circuits.
It is used in mirror production and may be deposited on glass
or metals by chemical deposition, electrodeposition, or by
evaporation. When freshly deposited, it is the best reflector
of visible light known, but is rapidly tarnishes and loses much
of its reflectance. It is a poor reflector of ultraviolet. Silver
fulminate (Ag2C2N2O2), a powerful explosive, is sometimes
formed during the silvering process. Silver iodide is used in
seeding clouds to produce rain. Silver chloride has interesting
optical properties as it can be made transparent; it also
is a cement for glass. Silver nitrate, or lunar caustic, the most
important silver compound, is used extensively in photography.
While silver itself is not considered to be toxic, most
of its salts are poisonous. Natural silver contains two stable
isotopes. Fifty-six other radioactive isotopes and isomers are known. Silver compounds can be absorbed in the circulatory
system and reduced silver deposited in the various tissues of
the body. A condition, known as argyria, results with a greyish
pigmentation of the skin and mucous membranes. Silver has
germicidal effects and kills many lower organisms effectively
without harm to higher animals. Silver for centuries has been
used traditionally for coinage by many countries of the world.
In recent times, however, consumption of silver has at times
greatly exceeded the output. In 1939, the price of silver was
fixed by the U.S. Treasury at 71￠/troy oz., and at 90.5￠/troy
oz. in 1946. In November 1961 the U.S. Treasury suspended
sales of nonmonetized silver, and the price stabilized for a
time at about $1.29, the melt-down value of silver U.S. coins.
The Coinage Act of 1965 authorized a change in the metallic
composition of the three U.S. subsidiary denominations to
clad or composite type coins. This was the first change in U.S.
coinage since the monetary system was established in 1792.
Clad dimes and quarters are made of an outer layer of 75%
Cu and 25% Ni bonded to a central core of pure Cu. The composition
of the oneand five-cent pieces remains unchanged.
One-cent coins are 95% Cu and 5% Zn. Five-cent coins are
75% Cu and 25% Ni. Old silver dollars are 90% Ag and 10% Cu.
Earlier subsidiary coins of 90% Ag and 10% Cu officially were
to circulate alongside the clad coins; however, in practice they
have largely disappeared (Gresham’s Law), as the value of the
silver is now greater than their exchange value. Silver coins of
other countries have largely been replaced with coins made of
other metals. On June 24, 1968, the U.S. Government ceased
to redeem U.S. Silver Certificates with silver. Since that time,
the price of silver has fluctuated widely. As of January 2002,
the price of silver was about $4.10/troy oz. (13￠/g); however
the price has fluctuated considerably due to market instability.
The price of silver in 2001 was only about four times the cost
of the metal about 150 years ago. This has largely been caused
by Central Banks disposing of some of their silver reserves and
the development of more productive mines with better refining
methods. Also, silver has been displaced by other metals
or processes, such as digital photography. | | Uses | silver can provide color to a product or serve as a deodorant. This metal is a good example of when nanotechnology may be used to increase an ingredient’s compatibility with a cosmetic formulation, and in this form may be also used as a preservative. | | Uses | This malleable white metal is found as argentite (Ag2S) and
horn silver (AgCl) or in lead and copper ore. Copper plates
coated with a thin layer of elemental silver and fumed with
iodine were used by Niépce and Daguerre. Aside from the
heliograph and physautotype, silver halide compounds were
the basis of all photographic processes used in the camera and
most of the printing processes during the 19th century. | | Definition | Metallic element, atomic number 47, group IB of the
periodic table, aw 107.868, valence of 1, two stable
isotopes.
| | Uses | For coinage, most frequently alloyed with copper or gold; for manufacture of tableware, mirrors, jewelry, ornaments; for electroplating; for making vessels and apparatus used in manufacture of medicinal chemicals, in processing foods and beverages, in handling organic acids; as catalyst in hydrogenation and oxidation processes; as ingredient of dental alloys. Has been used for purification of drinking water because of toxicity to bacteria and lower forms of life. Some salts used in photography. | | Reactivity Profile | Silver reacts violently with chlorine trifluoride (in the presence of carbon) [Mellor 2 Supp. 1 1956]. Bromoazide explodes on contact with Silver foil. Acetylene forms an insoluble acetylide with Silver [Von Schwartz 1918 p. 142 ]. When Silver is treated with nitric acid in the presence of ethyl alcohol, Silver fulminate, which can detonated may be formed. Ethyleneimine forms explosive compounds with Silver, hence Silver solder should not be used to fabricate equipment for handling ethyleneimine. Finely divided Silver and strong solutions of hydrogen peroxide may explode [Mellor 1:936 1946-47)]. Incompatible with oxalic acid and tartaric acid [Nav Aer. 09-01-505 1956]. Silver can form explosive salts with azidrine. ("Ethyleneimine" Brocure 125-521-65, Midland (Mich.), Dow Chemical Co., 1965). Ammonia forms explosive compounds with gold, mercury, or Silver. (Eggeman, Tim. "Ammonia" Kirk-Othmer Encyclopedia of Chemical Technology. John Wiley & Sons, Inc. 2001.). Acetylene and ammonia can form explosive Silver salts in contact with Ag. (Renner, Hermann, Gunther Schlamp. “Silver, Silver Compounds, and Silver Alloys." Ullmann's Encyclopedia of Industrial Chemistry. Wiley-VCH Verlag GmbH & Co. KGaA. 2001.) | | Hazard | Toxic material.
| | Health Hazard | The acute toxicity of silver metal is low. The acute toxicity of soluble silver
compounds depends on the counterion and must be evaluated case by case. For
example, silver nitrate is strongly corrosive and can cause burns and permanent
damage to the eyes and skin.
Chronic exposure to silver or silver salts can cause a local or generalized darkening
of the mucous membranes, skin, and eyes known as argyria. The other chronic
effects of silver compounds must be evaluated individually. | | Fire Hazard | Silver and most soluble silver compounds are not combustible. However, silver
nitrate and certain other silver compounds are oxidizers and can increase the
flammability of combustible materials.
Silver acetylide, azide, fulminate, oxalate mixtures, styphnate, tartarate mixtures,
and tetrazene are all explosives and must be handled as such. | | Fire Hazard | Dust is flammable. | | Safety Profile | Human systemic effects by inhalation: skin effects. Inhalation of dusts can cause argyrosis. Questionable carcinogen with experimental tumorigenic data. Flammable in the form of dust when exposed to flame or by chemical reaction with C2H2, NH3, bromoazide, ClF3 ethyleneimine, H2O2, oxalic acid, H2SO4, tartaric acid. Incompatible with acetylene, acetylene compounds, aziridine, bromine azide, 3-bromopropyne, carboxylic acids, copper + ethylene glycol, electrolytes + zinc, ethanol + nitric acid, ethylene oxide, ethyl hydroperoxide, ethyleneimine, iodoform, nitric acid, ozonides, peroxomonosulfuric acid, peroxyformic acid. See also POWDERED METALS and SILVER COMPOUNDS. | | Potential Exposure | Silver may be alloyed with copper, aluminum, cadmium, lead, or antimony. The alloys are used in the manufacture of silverware, jewelry, coins, ornaments, plates, commutators, scientific instruments; automobile bearing; and grids in storage batteries. Silver is used in chromenickel steels, in solders and brazing alloys; in the application of metallic films on glass and ceramics, to increase corrosion resistance to sulfuric acid, in photographic films, plates and paper; as an electroplated undercoating for nickel and chrome; as a bactericide for sterilizing water; fruit juices; vinegar, etc.; in bus bars and windings in electrical plants; in dental amalgams; and as a chemical catalyst in the synthesis of aldehydes. Because of its resistance to acetic and other food acids, it is utilized in the manufacture of pipes, valves, vats, pasteurizing coils and nozzles for the milk, vinegar, cider, brewing, and acetate rayon silk industries. | | First aid | If this chemical gets into the eyes, remove any contact lenses at once and irrigate immediately for at least 15 minutes, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts the skin, remove contaminated clothing and wash immediately with soap and water. Seek medical attention immediately. If this chemical has been inhaled, remove from exposure, begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR if heart action has stopped. Transfer promptly to a medical facility. When this chemical has been swallowed, get medical attention. Give large quantities of water and induce vomiting. Do not make an unconscious person vomit. | | storage | Most silver compounds should be protected from light during
storage or while in use. | | Purification Methods | For purification by electrolysis, see Craig et al. [J Res Nat Bur Stand 64A 381 1960]. For purification of crude, or silver residues to pure silver see Glemser & Sauer in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol I pp 1028-1030 1963, and for the preparation of colloidal silver see ibid (Ed. Brauer) p 1034. | | Flammability and Explosibility | Silver and most soluble silver compounds are not combustible. However, silver
nitrate and certain other silver compounds are oxidizers and can increase the
flammability of combustible materials.
Silver acetylide, azide, fulminate, oxalate mixtures, styphnate, tartarate mixtures,
and tetrazene are all explosives and must be handled as such. | | Incompatibilities | Dust may form explosive mixture with air. Powders are incompatible with strong oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides May react and/or form dangerous or explosive compounds, with acetylene, ammonia, halogens, hydrogen peroxide; bromoazide, concentrated or strong acids, oxalic acid, tartaric acid, chlorine trifluoride, ethyleneimine. | | Waste Disposal | Recovery, wherever possible, in view of economic value of silver. Techniques for silver recovery from photoprocessing and electroplating wastewaters have been developed and patented. |
| | Silver Preparation Products And Raw materials |
|