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SELENIUM (Se) -------------------------------------------------------------------------------- Selenium is a non-metallic element recovered as a by-product of electrolytic copper refining. It is a member of the sulfur family and exhibits a number of unique chemical and physical properties. Asarco produces selenium at its Amarillo Copper Refinery in Texas. Stringent quality control procedures assure that Asarco's selenium is uniformly high in quality. This sheet describes Asarco's standard products. Asarco is ready to work with individual customers to provide products that meet special requirements. The most important uses for selenium are in the production of a light-sensitive surface on photocopier machine drums, decolorizing of container glass, and tinting of architectural glass. Selenium is also used in pigments for plastics, glass, ceramics, and paint, where in combination with other elements it provides durable colors ranging from orange to deep red. In metallurgy, selenium is a trace additive that improves the free-machining characteristics of stainless steel. The electronics industry uses selenium to manufacture semiconductors and rectifiers. Selenium is an essential trace element in human nutrition. It is also valued as a dietary supplement in animal feed and is added to pharmaceutical preparations for controlling dandruff and dermatitis. Commercial Grade Asarco's commercial grade selenium is normally produced in powder form to purities of 99.5% and 99.9%. Selenium powder can be ordered as minus 200 mesh (minimum 99% purity through 200 mesh) and minus 325 mesh (minimum 90% purity through 325 mesh). Powder is shipped in 50-pound polyethylene-lined pails. A typical chemical analysis of Asarco's commercial grade selenium is shown on the next page. Selenium Alloys Asarco produces ferroselenium in random-sized chunks averaging 3" to 4" across and granules (minus 20 mesh). Ferroselenium contains 50% to 60% selenium and is shipped in 500-pound steel drums. Special packaging is available for smaller orders. -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- Handling Recommendations Elemental selenium is not generally considered to be a hazardous material in typical commercial applications. Under certain conditions, however, selenium and its compounds can react to form toxic fumes or gases. Contact with mineral acids under reducing conditions can produce toxic gases unless proper precautions are taken. Containers of selenium and its compounds should be stored in a cool dry area. Selenium should be stored and handled at an ambient temperature not exceeding 75°F in order to minimize lumping and crystallization. Any accidental spillage should be cleaned up immediately in a manner that does not create dust. Powders should be vacuumed. Fully effective dust control systems should be operated at all stages of in-plant handling where selenium powder may become airborne. When melted, temperature should be kept as low as is practical. Protective clothing and NIOSH-certified respiratory equipment should be worn at all stages where airborne selenium concentrations cannot be kept within government-established limits by mechanical ventilation equipment. Good sanitary procedures should be followed. Eating, drinking, and smoking should not be allowed in work areas. Hands and face should be washed before eating, drinking, and smoking. Workers should shower and change clothes before leaving the plant. Work clothes should not be worn home. Return to Products & Locations <- Last Page | Selenium | Next Page -> -------------------------------------------------------------------------------- Asarco Specialty Metals For sales and technical information: Chris Strand phone: (602) 977-6527 fax: (602) 977-6701 e-mail: cstrand@asarco.com About Our Products News Center Financial Information Environmental & Safety Careers Our Locations Management Company History Contact Us Job OpportunitiesAmarillo Refinery Asarco Mineral Discovery Center Corporate Offices El Paso Plant Hayden Smelter Mission Mine Ray Mine Silver Bell MineGeneral Information El Paso SiteCopper Products Index Precious MetalsAsarco's Copper Business Copper Products SpecsNews ReleasesHeadlines of current year News ArchiveMining Operations Mineral Processing Smelting and Refining Environmental Management & Remediation Products Photo usage PolicyASARCOAsarco's Environmental, Health & Safety Policy Environmental Management Practices Toxic Release Inventory Safety Performance ASARCO and the EnvironmentOperating Facilities Closed Plant SitesJob Opportunities Friday, January 26, 2007 2:45:36 PM SILVER (Ag) -------------------------------------------------------------------------------- By far the largest use for silver is in the photographic industry where light-sensitive silver salts are used to produce the image on film and photosensitive papers. Next in importance is the electronics industry where silver's superior electrical conductivity is used to advantage in contacts and other conductive devices. Sterling flatware, electroplated ware, holloware and jewelry, brazing alloys and solders, batteries, coins, medallions, catalysts, dental and medical supplies, mirrors and bearings for aircraft all consume significant amounts of silver. Asarco refines silver to two different levels of purity: 99.9% and 99.95%. Each of these grades meets or exceeds the ASTM specifications shown in the table on the next page. Asarco casts refined silver into 1,000-troy-ounce bars which are eligible for delivery on all major world commodity markets and exchanges. -------------------------------------------------------------------------------- †Chemical analyses for various grades of silver as specified under ASTM-B413-89 (Reapproved in 1989). *Oxygen is known to be present in refined silver. When calculating the purity of refined silver by difference, oxygen will be considered as silver. **For the purpose of determining conformance with this specification, an observed value obtained from analysis shall be rounded off "to the nearest unit" in the last right-hand place of figures used in expressing the limiting value, in accordance with the rounding method of ASTM Practice E29. By agreement between purchaser and manufacturer, analysis may be required and limits established for elements other than those listed. <- Last Page | Precious Silver | Next Page -> -------------------------------------------------------------------------------- ASARCO LLC • Commercial Department Contact: James Watts phone: 602-977-6573 • fax: 602-977-6701 email: jwatts@asarco.com About Our Products News Center Financial Information Environmental & Safety Careers Our Locations Management Company History Contact Us Job OpportunitiesAmarillo Refinery Asarco Mineral Discovery Center Corporate Offices El Paso Plant Hayden Smelter Mission Mine Ray Mine Silver Bell MineGeneral Information El Paso SiteCopper Products Index Precious MetalsAsarco's Copper Business Copper Products SpecsNews ReleasesHeadlines of current year News ArchiveMining Operations Mineral Processing Smelting and Refining Environmental Management & Remediation Products Photo usage PolicyASARCOAsarco's Environmental, Health & Safety Policy Environmental Management Practices Toxic Release Inventory Safety Performance ASARCO and the EnvironmentOperating Facilities Closed Plant SitesJob Opportunities Friday, January 26, 2007 2:45:36 PM SILVER (Ag) -------------------------------------------------------------------------------- By far the largest use for silver is in the photographic industry where light-sensitive silver salts are used to produce the image on film and photosensitive papers. Next in importance is the electronics industry where silver's superior electrical conductivity is used to advantage in contacts and other conductive devices. Sterling flatware, electroplated ware, holloware and jewelry, brazing alloys and solders, batteries, coins, medallions, catalysts, dental and medical supplies, mirrors and bearings for aircraft all consume significant amounts of silver. Asarco refines silver to two different levels of purity: 99.9% and 99.95%. Each of these grades meets or exceeds the ASTM specifications shown in the table on the next page. Asarco casts refined silver into 1,000-troy-ounce bars which are eligible for delivery on all major world commodity markets and exchanges. -------------------------------------------------------------------------------- †Chemical analyses for various grades of silver as specified under ASTM-B413-89 (Reapproved in 1989). *Oxygen is known to be present in refined silver. When calculating the purity of refined silver by difference, oxygen will be considered as silver. **For the purpose of determining conformance with this specification, an observed value obtained from analysis shall be rounded off "to the nearest unit" in the last right-hand place of figures used in expressing the limiting value, in accordance with the rounding method of ASTM Practice E29. By agreement between purchaser and manufacturer, analysis may be required and limits established for elements other than those listed. <- Last Page | Precious Silver | Next Page -> -------------------------------------------------------------------------------- ASARCO LLC • Commercial Department Contact: James Watts phone: 602-977-6573 • fax: 602-977-6701 email: jwatts@asarco.com About Our Products News Center Financial Information Environmental & Safety Careers Our Locations Management Company History Contact Us Job OpportunitiesAmarillo Refinery Asarco Mineral Discovery Center Corporate Offices El Paso Plant Hayden Smelter Mission Mine Ray Mine Silver Bell MineGeneral Information El Paso SiteCopper Products Index Precious MetalsAsarco's Copper Business Copper Products SpecsNews ReleasesHeadlines of current year News ArchiveMining Operations Mineral Processing Smelting and Refining Environmental Management & Remediation Products Photo usage PolicyASARCOAsarco's Environmental, Health & Safety Policy Environmental Management Practices Toxic Release Inventory Safety Performance ASARCO and the EnvironmentOperating Facilities Closed Plant SitesJob Opportunities Friday, January 26, 2007 2:45:36 PM SILVER (Ag) -------------------------------------------------------------------------------- By far the largest use for silver is in the photographic industry where light-sensitive silver salts are used to produce the image on film and photosensitive papers. Next in importance is the electronics industry where silver's superior electrical conductivity is used to advantage in contacts and other conductive devices. Sterling flatware, electroplated ware, holloware and jewelry, brazing alloys and solders, batteries, coins, medallions, catalysts, dental and medical supplies, mirrors and bearings for aircraft all consume significant amounts of silver. Asarco refines silver to two different levels of purity: 99.9% and 99.95%. Each of these grades meets or exceeds the ASTM specifications shown in the table on the next page. Asarco casts refined silver into 1,000-troy-ounce bars which are eligible for delivery on all major world commodity markets and exchanges. -------------------------------------------------------------------------------- †Chemical analyses for various grades of silver as specified under ASTM-B413-89 (Reapproved in 1989). *Oxygen is known to be present in refined silver. When calculating the purity of refined silver by difference, oxygen will be considered as silver. **For the purpose of determining conformance with this specification, an observed value obtained from analysis shall be rounded off "to the nearest unit" in the last right-hand place of figures used in expressing the limiting value, in accordance with the rounding method of ASTM Practice E29. By agreement between purchaser and manufacturer, analysis may be required and limits established for elements other than those listed. <- Last Page | Precious Silver | Next Page -> -------------------------------------------------------------------------------- ASARCO LLC • Commercial Department Contact: James Watts phone: 602-977-6573 • fax: 602-977-6701 email: jwatts@asarco.com About Our Products News Center Financial Information Environmental & Safety Careers Our Locations Management Company History Contact Us Job OpportunitiesAmarillo Refinery Asarco Mineral Discovery Center Corporate Offices El Paso Plant Hayden Smelter Mission Mine Ray Mine Silver Bell MineGeneral Information El Paso SiteCopper Products Index Precious MetalsAsarco's Copper Business Copper Products SpecsNews ReleasesHeadlines of current year News ArchiveMining Operations Mineral Processing Smelting and Refining Environmental Management & Remediation Products Photo usage PolicyASARCOAsarco's Environmental, Health & Safety Policy Environmental Management Practices Toxic Release Inventory Safety Performance ASARCO and the EnvironmentOperating Facilities Closed Plant SitesJob Opportunities Friday, January 26, 2007 2:46:32 PM GOLD (Au) -------------------------------------------------------------------------------- While monetary uses for gold exceed all other uses, a number of important industrial applications exist. Lustrous, easily fashioned, and tarnish-resistant, gold is a favorite material in the jewelry industry. More gold is used for jewelry than for any other industrial application. The next largest industrial use for gold is in electronics where its tarnish-resistance makes it the material of choice for reliability in printed circuitry and various electrical devices. Other applications include: dental supplies, where gold is used in fillings and orthodontic devices; aerospace, where gold-containing brazing alloys are important to jet engine assembly; and in glass manufacturing, where gold and gold oxide are used in heat-insulating windows and to decorate glass and porcelain dinnerware. Gold leaf is employed in commercial architecture for decorative purposes, and parts cast from gold alloys are used in chemical process equipment and synthetic fiber production machinery. A relatively small amount of gold is made into medallions and small bars for purchase as an investment. Asarco produces 99.95% pure gold in 400-troy-ounce bars. Asarco gold meets the ASTM specifications shown in the table on the next page. Asarco's 400-troy-ounce bars qualify for delivery on the London Bullion Market. †Chemical analyses for 99.95 grade gold as specified under ASTM-B562-95 (Reapproved in 1995). *For the purpose of determining conformance with this specification, an observed value obtained from analysis shall be rounded off "to the nearest unit" in the last right-hand place of figures used in expressing the limiting value, in accordance with the rounding method of ASTM Practice E29. By agreement between purchaser and manufacturer, analysis may be required and limits established for elements other than those listed. ASARCO LLC • Commercial Department Contact: James Watts phone: 602-977-6573 • fax: 602-977-6701 email: jwatts@asarco.com CAcT HomePage Chemistry of Batteries Skills to develop Explain: the chemistry in a battery operation; oxidation and reduction reactions; the technique used to represent a battery; the various parts of a battery. Classify chemical reactions as oxidation, reduction or other types. Chemistry of Batteries Chemistry is the driving force behind the magics of batteries. A battery is a package of one or more galvanic cells used for the production and storage of electric energy by chemical means. A galvanic cell consists of at least two half cells, a reduction cell and an oxidation cell. Chemical reactions in the two half cells provide the energy for the galvanic cell operations. Each half cell consists of an electrode and an electrolyte solution. Usually the solution contains ions derived from the electrode by oxidation or reduction reaction. We will make this introduction using a typical setup as depicted here. The picture shows a copper zinc galvanic cell (battery). A galvanic cell is also called a voltaic cell. The spontaneous reactions in it provide the electric energy or current. Two half cells can be put together to form an electrolytic cell, which is used for electrolysis. In this case, electric energy is used to force nonsponaneous chemical reactions. Oxidation Reduction Reactions Many difinitions can be given to oxidation and reduction reactions. In terms of electrochemistry, the following definition is most appropriate, because it let us see how the electrons perform their roles in the chemistry of batteries. Loss of electrons is oxidation, and gain of electrons is reduction. Oxidation and reduction reactions cannot be carried out separately. They have to appear together in a chemical reaction. Thus oxidation and reduction reactions are often called redox reactions. In terms of redox reactions, a reducing agent and an oxidizing agent form a redox couple as they undergo the reaction: Oxidant + n e- ® Reductant Reducant ® Oxidant + n e- An oxidant is an oxidizing reagent, and a reductant is a reducing agent. The reductant | oxidant or oxidant | reductant Two members of the couple are the same element or compound, but of different oxidation state. Copper-Zinc Voltaic Cells As an introduction to electrochemistry let us take a look of a simple Voltaic cell or a galvanic cell. When a stick of zinc (Zn) is inserted in a salt solution, there is a tendency for Zn to loose electron according to the reaction, Zn = Zn2+ + 2 e-. The arrangement of a Zn electrode in a solution containing Zn2+ ions is a half cell, which is usually represented by the notation: Zn | Zn2+, Zinc metal and Zn2+ ion form a redox couple, Zn2+ being the oxidant, and Zn the reductant. The same notation was used to designate a redox couple earlier. Similarly, when a stick of copper (Cu) is inserted in a copper salt solution, there is also a tendency for Cu to loose electron according to the reaction, Cu = Cu2+ + 2 e-. This is another half cell or redox couple: Cu | Cu2+. However, the tendency for Zn to loose electron is stronger than that for copper. When the two cells are connected by a salt bridge and an electric conductor as shown to form a closed circuit for electrons and ions to flow, copper ions (Cu2+) actually gains electron to become copper metal. The reaction and the redox couple are respectively represented below, Cu2+ + 2 e- = Cu, Cu2+ | Cu. This arrangement is called a galvanic cell or battery as shown here. In a text form, this battery is represented by, Zn | Zn2+ || Cu2+ | Cu, in which the two vertical lines ( || ) represent a salt bridge, and a single vertical line ( | ) represents the boundary between the two phases (metal and solution). Electrons flow through the electric conductors connecting the electrodes and ions flow through the salt bridge. When [Zn2+] = [Cu2+] = 1.0 M, the voltage between the two terminals has been measured to be 1.100 V for this battery. A battery is a package of one or more galvanic cells used for the production and storage of electric energy. The simplest battery consists of two half cells, a reduction half cell and an oxidation half cell. Oxidation and Reduction Reactions -- a review The overall reaction of the galvanic cell is Zn + Cu2+ = Zn2+ + Cu Note that this redox reaction does not involve oxygen at all. For a review, note the following: Oxidant + n e- = Reductant Example: Cu2+ + 2 e = Cu Cu2+ is the oxidizing agent and Cu the reducing agent. Reductant = n e- + Oxidant Example: Zn = Zn2+ + 2 e-. Zn is the reducing agent, and Zn2+ the oxidizing agent. Theoretically, any redox couple may form a half cell, and any two half cells may combine to give a battery, but we have considerable technical difficulty in making some couples into a half cell. Links to Some Battry Companies Batteries play an important role in our lives. These links are provided so that you can visit some of the battery companies on the internet. Because these are links, and they are subject to change over time. Cellular Phone Batteries Eveready Battery Company, Inc Energizer GNB, The Global Battery Company M & M Battery Company NEXcell Battery Co Trojan Batteries Links to Fuel Cell Companies A fuel cell differs from a battery in that the fuel is continuously supplied. To find out more about fuel cells, here are some links to fuel cell companies. Fuel Cell World An overall view of fuel cell technology with many links to other sources. Ballard Power Systems, Inc. A very informative page about fuel cell technology. Nice diagrams and photographs are available from the website. Ballard Power Systems, Inc. is located in Vancouver, Canada. Solid Oxide Fuel Cell of Global Thermoelectric of Calgary, Canada Fuelcell Technologies, Kingston, Canada The Hydrogen and Fuel Cell Letter A publication related to fuel cell development. Solid oxide fuel cell Fuelcell energy Epyx: the future of energy Confidence Building Questions In the reaction: Zn -> Zn2+ + 2 e- Is Zn oxidized or reduced? Hint . . .Zinc is oxidized. Skill - Identify and explain redox reactions. Loss of electrons by Zn means Zn is oxidized, Leo. In the reaction: Zn + Cu2+ = Zn2+ + Cu Which is reduced, Cu2+, Cu, Zn2+, or Zn? Hint . . .Copper ion, not the metal is reduced. Skill - Identify and explain oxidized and reduced species. The Cu2+ ions gain electrons to become Cu (metal) atoms. Thus Cu2+ is reduced. Which one has a stronger tendency to loose electrons when they are in contact with an electrolyte, Cu2+, Cu, Zn2+, or Zn? Hint . . .Zinc has a strong tendency to loose electrons. Discussion - The Zn metal is more reactive than copper. In an acidic solution, Zn atoms loose electron to H+ ions, but copper atoms will not. The tendency is measured in terms of standard reduction potential. What is responsible for the conduction of electricity in the solution? Hint . . .Ions of the electrolyte in the solution is responsible. Skill - Explain conductance of solution. The positive and negative ions move in opposite directions in a solution leading to conduction of electricity. The salt-bridge is the path for what to move? Hint . . .The salt bridge is the path for the ions in the solution to move. Skill - Next page: Oxidation states © by cchieh@uwaterloo.ca