Copper, pure metal

Copper. The recovery of copper [7440-50-8] Cu, from ore leach Hquors as a stage in the hydrometallurgical route to the pure metal is one of the... 

The largest consumption of beryUium is in the form of aUoys, principally the copper—beryUium series. The consumption of the pure metal has been quite cycHc in nature depending on specific governmental programs in armaments, nuclear energy, and space. The amount of beryUium extracted from bertrandite has tanged between 200 and 270 metric tons pet year since 1986 (14). SmaU quantities of beryl were also processed during this period. 

When electrons traverse an alloy rather than a pure metal, tire scattering of electrons is different at tire ion core of each chemical species and so the conductivity reflects a mixture of the effects due to each species. In a series of copper alloys it was found that the resistance, which is the reciprocal of the conductivity, is a parabolic function of tire concentration of the major element... 

Some metals are soluble as atomic species in molten silicates, the most quantitative studies having been made with Ca0-Si02-Al203(37, 26, 27 mole per cent respectively). The results at 1800 K gave solubilities of 0.055, 0.16, 0.001 and 0.101 for the pure metals Cu, Ag, Au and Pb. When these metal solubilities were compared for metal alloys which produced 1 mm Hg pressure of each of these elements at this temperature, it was found drat the solubility decreases as the atomic radius increases, i.e. when die difference in vapour pressure of die pure metals is removed by alloy formation. If the solution was subjected to a temperature cycle of about 20 K around the control temperamre, the copper solution precipitated copper particles which grew with time. Thus the liquid metal drops, once precipitated, remained stable thereafter. 

Examples of this procedure for dilute solutions of copper, silicon and aluminium shows the widely different behaviour of these elements. The vapour pressures of the pure metals are 1.14 x 10, 8.63 x 10 and 1.51 x 10 amios at 1873 K, and the activity coefficients in solution in liquid iron are 8.0, 7 X 10 and 3 X 10 respectively. There are therefore two elements of relatively high and similar vapour pressures, Cu and Al, and two elements of approximately equal activity coefficients but widely differing vapour pressures. Si and Al. The right-hand side of the depletion equation has the values 1.89, 1.88 X 10- , and 1.44 X 10 respectively, and we may conclude that there will be depletion of copper only, widr insignificant evaporation of silicon and aluminium. The data for the boundaty layer were taken as 5 x lO cm s for the diffusion coefficient, and 10 cm for the boundary layer thickness in liquid iron. 

Silver is a white metal it is softer than copper and harder than gold. One use of the pure metal (about 99.99%) is as a liner bonded to stronger or cheaper metals. The metallic bond is usually of high thermal conductivity. 

Resistance thermometers are made of a pure metal, such as platinum, nickel, or copper. The electrical resistance of such a material is almost linearly dependent on temperature. Resistance thermometers are stable, having a small drift. A widely used and the best-known resistance probe is the IW-100 probe, which is platinum, having a resistance of 100 ohms at the temperature of 0 °C. Other resistance values for PT probes are available. The resistance versus temperature values as well as tolerances for platinum probes are standardized. The shape and size of a resistance probe can vary considerably, resulting in changes in probe dynamics. 

The hardness of such coatings may reach a maximum of about 400 Hy as compared with approximately 50 Hy for a soft gold deposit. A series of corrosion studies in industrial and marine atmospheres by Baker" has indicated that the protective value of hard gold coatings is comparable with that of the pure metal, and that a thickness of only 0-002 5 mm gives good protection to copper base alloys during exposure for six months. 

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. 

Many elements are familiar to all of us. The charcoal used in outdoor grills is nearly pure carbon. Electrical wiring, jewelry, and water pipes are often made from copper, a metallic element. Another such element, aluminum, is used in many household utensils. 

The impure copper from either process is refined electrolytically it is made into anodes and plated onto cathodes of pure copper. Other metals may be present in the impure copper and those with highly positive electrode potentials also are reduced. The rare metals—most notably, platinum, silver, and gold—obtained from the anode sludge are sold to recover much of the cost of the electricity used in the electrolysis. 

Bimetallic nanoparticles, either as alloys or as core-shell structures, exhibit unique electronic, optical and catalytic properties compared to pure metallic nanopartides [24]. Cu-Ag alloy nanoparticles were obtained through the simultaneous reduction of copper and silver ions again in aqueous starch matrix. The optical properties of these alloy nanopartides vary with their composition, which is seen from the digital photographs in Fig. 8. The formation of alloy was confirmed by single SP maxima which varied depending on the composition of the alloy. 

C04-0103. Write the balanced redox reactions for the formation of each of the following oxides from the reaction of molecular oxygen with pure metal (a) chromium(VI) oxide (b) zinc oxide (c) copper(I) oxide. 

C16-0059. Using copper as an example, draw a molecular picture illustrating that the concentration of atoms in a pure metal is independent of the volume of the sample. 

For relatively simple matrices, such as pure metallic CRMs synthetic reference materials for direct calibration were prepared and used, for example Bi, Cd, Hg, Pb and T1 in high purity gallium (HUtenkamp and Jackwerth 1988), Ag in copper (Pau-wels et al. 1990) and Au and Pd in silver (Hinds 1993). Direct calibration by solid biological materials with added analyte belongs also to these quite successfully applied techniques (Hofmarm et al. 1992). 

For equipment handling acetylene the pure metals, or alloys containing copper, silver, mercury, gold, must be avoided to prevent the formation of explosive acetylides. 

Copper is attacked by mineral acids, except cold, dilute, unaerated sulphuric acid. It is resistant to caustic alkalies, except ammonia, and to many organic acids and salts. The brasses and bronzes have a similar corrosion resistance to the pure metal. Their main use in the chemical industry is for valves and other small fittings, and for heat-exchanger tubes and tube sheets. If brass is used, a grade must be selected that is resistant to dezincification. 

Early in the history of crystal dislocations, the lack of resistance to motion in pure metal-like crystals was provided by the Bragg bubble model, although it was not taken seriously. By adjusting the size of the bubbles in a raft, it was found that the elastic behavior of the raft could be made comparable with that of a selected metal such as copper (Bragg and Lomer, 1949). In such a raft, it was further found that, as expected, the force needed to form a dislocation is large. However, the force needed to move a bubble is too small to measure. 

Low-temperature (T < 1K) heat conduction of a pure metal, like copper of our experiment (Cu Debye temperature 0D 340K), is mostly electronic [27] and the phonon contribution should be negligible. With the latter hypothesis, in the 30-150 mK temperature range ... 

In substitutional metallic solid solutions and in liquid alloys the experimental data have been described by Epstein and Paskin (1967) in terms of a predominant frictional force which leads to the accumulation of one species towards the anode. The relative movement of metallic ion cores in an alloy phase is related to the scattering cross-section for the conduction electrons, which in turn can be correlated with the relative resistance of the pure metals. Thus iron, which has a higher specific resistance than copper, will accumulate towards the anode in a Cu-Fe alloy. Similarly in a germanium-lithium alloy, the solute lithium atoms accumulate towards the cathode. In liquid alloys the same qualitative effect is observed, thus magnesium accumulates near the cathode in solution in bismuth, while uranium, which is in a higher Group of the Periodic Table than bismuth, accumulated near the anode in the same solvent. 

Figure 3. An example of correlation between the abundance of low volatile metals in a random set of Karabash snow samples (C) and the calculated volatility of the same pure metals at the temperature of blister copper formation (12600 C). Vertical points correspond to the selected samples K(A)j the data for Si, Cu, and Fe are not considered.

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