Copper impurity element

The output from brass mills in the United States is spHt nearly equally between copper and the alloys of copper. Copper and dilute copper alloy wrought products are melted and processed from electrically refined copper so as to maintain low impurity content. Copper alloys are commonly made from either refined copper plus elemental additions or from recycled alloy scrap. Copper alloys can be readily manufactured from remelted scrap while maintaining low levels of nonalloy impurities. A greater proportion of the copper alloys used as engineering materials are recycled than are other commercial materials. 

Next, let the example of vanadium, which, in the as-reduced condition, may contain a variety of impurities (including aluminum, calcium, chromium, copper, iron, molybdenum, nickel, lead, titanium, and zinc) be considered. Vanadium melts at 1910 °C, and at this temperature it is considerably less volatile than many of the impurity metals present in it. The vapor pressure of pure vanadium at this temperature is 0.02 torr, whereas those of the impurity elements in their pure states are the following aluminum 22 torr calcium 1 atm, chromium 6 torr copper 23 torr iron 2 torr molybdenum 6 1CT6 torr nickel 1 torr lead 1 torr titanium 0.1 torr and zinc 1 atm. However, since most of these impurities form a dilute solution in vanadium, their actual partial pressures over vanadium are considerably lower than the values indicated. Taking this into account, the vaporization rate, mA, of an element A (the evaporating species) can be approximated by the following free evaporation equation (Langmuir equation) ... 

Many hydrometallurgical processes or process steps are used to upgrade concentrates, process recycled scrap metal, or purify aqueous process steams. Examples are (I) the leaching of molybdenite concentrate to remove Knpurities ,ft (2) leaching of tungsten carbide and molybdenum scrap-, (3) removal of copper impurities in nickel anolyte by cementation on metallic ruckel and (4) various methods for treating nuclear fuel elements. 

FIGURE 40.21 Comparison of the depth profiles of a copper impurity by trace element accelerator mass spectrometry (TEAMS) and secondary ion mass spectrometry (SIMS). Reprinted from McDaniel, ED, Datar, S.A., Nigam, M., Ravi Prasad, G.V. (2002) Impurity measurements in semiconductor materials using trace element accelerator mass spectrometry. Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms, 190 1-A), 826-830. Copyright (2002), with permission from Elsevier Science. 

Corrosion problems will arise in the use of recycled aluminum. For instance, most recycled aluminum is contaminated with impurity elements such as iron, silicon and copper. The contaminated aluminum usually has low corrosion resistance, because of its poor oxide film layer. As the use of recycled aluminum becomes more widespread, corrosion problems will increase in importance in many industrial fields. These considerations lead to the conclusion that corrosion engineering of aluminum and its alloys will be one of the most important subjects to be studied in the next century. 

Au, Ag, and Cu, which have low electrical resistance, are appropriate as conductors for use in LTCCs. Table 3-1 shows the value of resistance of Cu and Au when various impurities are dissolved at 1 at. %. The value of resistance of the main material changes markedly depending on the impurity element. For example, if Ti is dissolved at 1 at. % in Cu, the value of resistance is 10 times that of pure copper [29, 30, 31, 32, 33]. Furthermore, if the copper reacts with the other metal and an intermetallic compound is formed, it is in most cases more than 10 pl2 cm. The following compounds are less than 10 pQ cm [34, 35]. 

Ge et al. from our group, used NAA as a non-destructive standard method to quantify metallic impurities in carbon nanotubes (CNTs). Considerable amounts of iron, nickel, molybdenum, and chromium in the CNTs were found, which implies that these elements were dominantly used in the synthesis process. Small amounts of other impurity elements like manganese, cobalt, copper, zinc, arsenic, bromine, antimony, lanthanum, scandium, samarium, tungsten, and thorium are also found, which are presumed to have come from sources in chemical and physical manipulations used during the production process or in the precursors of the synthesis (Table 11.1). Although these commercial CNTs have been processed to reduce metal and amorphous carbon, even these as-purified samples still contain significant quantities of residual metals, which maybe contribute to the potential toxicological effects of CNTs. 

Germanium tetrachloride refined for use in making optical fibers is usually specified to contain less than 0.5 to 5 ppb of each of eight impurities vanadium, chromium, manganese, iron, cobalt, nickel, copper, and zinc. Limits are sometimes specified for a few other elements. Also of concern are hydrogen-bearing impurities therefore, maximum limits of 5 to 10 ppm are usually placed on HCl, OH, CH2, and CH contents. 

The lead—copper phase diagram (1) is shown in Figure 9. Copper is an alloying element as well as an impurity in lead. The lead—copper system has a eutectic point at 0.06% copper and 326°C. In lead refining, the copper content can thus be reduced to about 0.08% merely by cooling. Further refining requites chemical treatment. The solubiUty of copper in lead decreases to about 0.005% at 0°C. 

Although some changes occur in the melting furnace, cathode impurities are usually reflected directly in the final quaUty of electrorefined copper. It is commonly accepted that armealabiUty of copper is unfavorably affected by teUurium, selenium, bismuth, antimony, and arsenic, in decreasing order of adverse effect. Silver in cathodes represents a nonrecoverable loss of silver to the refiner. If the copper content of electrolyte is maintained at the normal level of 40—50 g/L, and the appropriate ratio of arsenic to antimony and bismuth (29) is present, these elements do not codeposit on the cathode. 

The Fermentation Process The process by which this antifungal substance is produced is an aerobic fermentation of an aquaous nutrient medium inoculated with a pimaricin-producing strain of Streptomycesgihrosporeus. The nutrient medium contains an assimilable source of carbon such as starch, molasses, or glycerol, an assimilable source of nitrogen such as corn steep liquor and Inorganic cations such as potassium, sodium or calcium, and anions such as sulfate, phosphate or chloride. Trace elements such as boron, molybdenum or copper are supplied as needed in the form of impurities by the other constituents of the medium. 

Few general statements can be made regarding the effect on corrosion resistance of alloying elements or impurities. A useful summary of the information has been prepared by Whitaker. Copper is usually harmful causing increased susceptibility to intercrystalline or general attack, so that alloys... 

The discussion so far has been limited to the structure of pure metals, and to the defects which exist in crysteds comprised of atoms of one element only. In fact, of course, pure metals are comparatively rare and all commercial materials contain impurities and, in many cases also, deliberate alloying additions. In the production of commercially pure metals and of alloys, impurities are inevitably introduced into the metal, e.g. manganese, silicon and phosphorus in mild steel, and iron and silicon in aluminium alloys. However, most commercial materials are not even nominally pure metals but are alloys in which deliberate additions of one or more elements have been made, usually to improve some property of the metal examples are the addition of carbon or nickel and chromium to iron to give, respectively, carbon and stainless steels and the addition of copper to aluminium to give a high-strength age-hardenable alloy. 

A.4 Identify all the chemical properties and changes in the following statement Copper is a red-brown element obtained from copper sulfide ores by heating them in air, which forms copper oxide. Heating the copper oxide with carbon produces impure copper, which is purified by electrolysis. ... 

Fig. 16.5. An overview of the minimum temperature of the different elements of the system. An estimate is made on the heat flows Q due to conduction between the different stages that are all connected with stainless steel rods or tubes. The total heat leak on the mixing chamber is estimated to be 45pW. This heat leak decreases in time and comes from the sphere and copper masses. We will see further on that this can be explained by ortho-para conversion of 70 ppm hydrogen impurities in the copper (courtesy of Leiden Cryogenics).

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