Ingot, solid

Component Separation by Progressive Freezing When the distribution coefficient is less than I, the first solid which ciystaUizes contains less solute than the liquid from which it was formed. As the frac tion which is frozen increases, the concentration of the impurity in the remaining liquid is increased and hence the concentration of impurity in the sohd phase increases (for k < 1). The concentration gradient is reversed for k > 1. Consequently, in the absence of diffusion in the solid phase a concentration gradient is estabhshed in the frozen ingot. 

The melt is heated by passing a large elecuical cunent between two electrodes, one of which is tire metal rod to be refined, and the otlrer is the liquid metal pool standing in a water-cooled copper hearth, which collects the metal drops as tlrey fall tluough the molten electrolyte. This pool tlrerefore freezes at the bottom, forming the ingot. Under optimum chcumstances tire product billet takes the form of a cylindrical solid separated from the molten salt by... 

Gray oxide can be produced by a milling process, which, strictly speaking, does not mill the material. A rotating drum is filled with solid balls or ingots of lead. 

Every pure liquid or solid has a characteristic density that helps distinguish it from other substances. To give one example, the density of pure gold is 19.3 g/cm, whether the sample is a nugget in a miner s pan or an ingot in a bank vault. Pyrite, an iron compound that resembles gold, has a much lower density of 5.0 g/cm. Table Ud lists... 

The position of the zone x is measured from the leading edge of the ingot. The distribution for multiple passes can also be emulated from a material balance, but in this case the leading edge of the zone encounters solid corresponding to the composition at the point in question for the previous pass. The multiple-pass distribution has been numerically calculated (Pfann, Zone Melting, 2d ed., Wiley, New York, 1966, p. 285) for many combinations of k, Ul, and n. Typical solute-composition profiles are shown in Fig. 20-6 for various numbers of passes. 

The extrusion process requires the use of a lubricant to prevent adhesion of the aluminum to the die and ingot container walls. In hot extrusion, limited amounts of lubricant are applied to the ram and die face or to the billet ends. For cold extrusion, the container walls, billet surfaces, and die orifice must be lubricated with a thin film of viscous or solid lubricant. The lubricant most commonly used in extrusion is graphite in an oil or water base. A less common technique, spraying liquid nitrogen on the billet prior to extrusion, is also used. The nitrogen vaporizes during the extrusion process and acts as a lubricant. 

This reactor contains at least two solid phases, two Hquid phases, and a gas phase. The flows are largely driven by gravity caused by the density differences of the soHd and Hquid phases. Taconite and coke are admitted at the top of the reactor and O2 at the bottom. Liquid Fe and slag are withdrawn at the bottom of the reactor. The Hquid iron is either cast into ingots in molds or directly passed from the reactor through rolling mills to process it into sheets. 

Subsurface Defects in Ingots, The precipitation of REpOpS and rH as solid pariicles in the liquid steel immediately after the adSi ion is conducive to inclusion clustering, the forming of large — up to inches in diameter — spatial networks of small —... 

Solidification. When the ingot or casting solidifies, there are three main possible microstructures that form (see Figure 7.5). We will describe here only the final structures the thermodynamics of the liquid-solid phase transformation have been described previously in Chapter 2. The outside layer of the ingot is called the chill zone and consists of a thin layer of equiaxed crystals with random orientation. 

Much has been written about the way in which the polymerization should be conducted. One finds references to dianhydride purification by complexing it with anisole [20, 23] or forming solid ingots of the dianhydride to insure high molecular weight formation just to name a few [24], Although some of this... 

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