Metallic charge

Coreless furnaces derive their name from the fact that the coil encircles the metal charge but, in contrast to the channel inductor described later, the cod does not encircle a magnetic core. Figure 8 shows a cross section of a typical medium sized furnace. The cod provides support for the refractory that contains the metal being heated and, therefore, it must be designed to accept the mechanical loads as well as the conducted thermal power from the load. 

Ferrous foundries consist of two types steel foundries in which electric furnaces (EAF and induction) are used, and iron foundries in which hot-blast cupolas and/or electric furnaces are used. Electric furnaces use virtually 100% scrap charges. Cupolas are shaft furnaces which use preheated air, coke, fluxes, and metallic charges. Scrap is over 90% of the metallic charge. Cupolas accounted for about 64% of total iron foundry scrap consumption in 1994 and electric furnaces accounted for about 34%. The balance was consumed by other furnaces, such as air furnaces. Iron foundry products have a high carbon content and the scrap charge usually contains a high percentage of cast iron or is used in combination with pig iron. 

Table 1 shows the average percentages of scrap and pig iron used in the metallic charges for each of the three principal furnace types. DRI consumption averaged about 2% in electric furnaces and only a fraction of 1% in BOFs and cupolas. These percentages do not include the scrap consumed in blast furnaces and certain other special furnaces which amounted to 1.9 million t in 1994. DRI consumption in blast furnaces totaled 490,000 t in 1994. 

Mn(acac)3 in the above mechanism undergoes an intramolecular photooxidation-reduction reaction arising from the ligand to metal charge transfer process (LMCT). 

These iridium(IV) complexes have UV-visible spectra dominated by intense absorptions around 500 nm (X = Cl) and 700 nm (X = Br) assignable to 7tx —> Ir(t2g) ligand-to-metal charge-transfer bonds. 

FIGURE 16.33 In a ligand-to-metal charge-transfer transition, an energetically excited electron migrates from a ligand to the central metal ion. This type of transition is responsible for the intense purple of the permanganate ion, MnCF,. ... 

This paper surveys several aspects of metal-to-metal charge-transfer transitions. Species of interest originate from non-molecular and molecular solids and from solutions. The parallel in the different approaches is stressed. In addition to the spectroscopy of these transitions, their influence or role in other phenomena is also discussed. 

Metal-to-Metal Charge Transfer (MMCT) Involving One Closed-Shell... 

In this paper we will describe and discuss the metal-to-metal charge-transfer transitions as observed in optical spectroscopy. Their spectroscopic properties are of large importance with regard to photoredox processes [1-4], However, these transitions are also responsible for the color of many inorganic compounds and minerals [5, 6], for different types of processes in semiconductors [7], and for the presence or absence of certain luminescence processes [8]. 

In this chapter we have shown that optical metal-to-metal charge-transfer transitions are of large importance in many fields and that they occur very generally. Not only their direct, but also their indirect influence is of great importance. A more unified approach in the different areas of research, and a stronger interaction between the different approaches is desirable. 

The case of polarized interfaces is usually described within the context of the metal-electrolyte interface where the metal charge dependence of the SH intensity is dramatic because of the strong interfacial electric field present at the interface [16]. It has long been a real challenge at the polarized liquid-liquid interface but has, however, been observed at charged air-water interfaces [48]. 

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