Finishing stage

The bulk of commercial styrene is prepared by the Dow process or some similar system. The method involves the reaction of benzene and ethylene to ethylbenzene, its dehydrogenation to styrene and a final finishing stage. It is therefore useful to consider this process in each of the three stages. 

Corrosion also occurs where only one metal is involved. Here variations in oxidation potential caused by surface chemistry differences (such as irregularities in the metal s crystalline structure or stresses caused during the finishing stages of manufacture) create microanodes and microcathodes. 

Batch size The batch sizes in the preparation stage and in the polymerization stage are variable as batches may be split in the preparation stage and mixed in the polymerization stage. However, the concept of batches does not apply in the finishing stage. 

The Aerosol Fluorination process [42] (Aerosol) is operated on the principle that the substrate is absorbed onto the surface of fine sodium fluoride particles in the fluorination apparatus in which the fluorine concentration and the temperature increases along the length of the reaction vessel. A U.V. photo-fluorination finishing stage completes the perfluorination process which has the advantage that it is a continuous flow method. 

Perfluoropolyethers have found widespread use as high-performance lubricants and several companies manufacture a range of these materials (Krytox , Du Pont Fomblin , Montefluos Demnum , Daikin). The Fomblin fluids and Krytox require the use of fluorine in the finishing stages [81] whilst Demnum is synthesised by polymerisation of the fluorooxetane 16 followed by per-fluorination using fluorine (Fig. 27) [82]. 

Rubber grades with high molar mass to which oil is added during the finishing stage of the raw rubber production cycle. By the incorporation of oil the viscosity of the raw rubber is reduced and rubber processing is facilitated. 

Up to this point, we have a reasonable interpretation of definite evidence, beyond this, imagination must come into play. It is fair to assume that the process of evolution was extremely slow, and that each element was developed gradually and passed from an unfinished to a finished stage. The chemical atoms are now known to be extremely complex structures, each with an electropositive nucleus surrounded by electrons in rapid motion. That such a structure could have been developed instantaneously, with no previous preparation, is hardly probable, for the process was one of condensation, from lighter to heavier, and that, it would seem, must have acquired time. The process was one from relative simplicity of structure to relative complexity, and with the maximum condensation, as shown by uranium and thorium, a minimum of stability was reached. That is, so far as we now know for less Stable atoms may have been formed, to exist for a brief period and then vanish. Some of the radioactive elements which appear as products of the decay of uranium are of this kind. On that theme, more later. 

Further investigation is needed in order to clarify better the role of the long-life oxidants produced in the bulk solution and to establish their fate during oxidative treatment. Moreover, the specific composition of the waste has to be considered in order to evaluate if, rather than as main process, the electrochemical treatment with diamond anodes can be more efficiently used in combined processes in which this technology may be used as a pre-treatment or a finishing stage. 

Use In the final or finishing stages of manufacture of a product, usually textiles and leather, to make them suitable for specific purposes. 

The finishing stages for strontium separation are shown in Fig. 4. The main separation of the rare earths from the alkaline earths is made by ammonia gas precipitation of the rare earths as hydroxides in a carbonate-free medium. The alkaline earths pass into the filtrate and are removed in the next step as the carbonates. Since the separation of rare earth hydroxides and the only moderately soluble alkaline earth hydroxides is not clean, a re-precipitation step is required. The alkaline carbonates are then passed to packaging, either as the dried carbonates, or are first converted to sulfates, oxides, or fluorides for subsequent packaging in multiple-walled, weld-sealed, containers for storage. The... 

Various additives can be incorporated at the beating, refining or finishing stage, i.e. the paper can be modified to suit specific uses (improve opacity, printability, etc.). 

Tokach, M.D. J.E. Pettigrew L.J. Johnston M. Overland J.W. Rust S.G. Cornelius. Effect of adding fat and(or) milk products to the weanling pig diet on performance in the nursery and subsequent grow-finish stages./. Anim. Sci. 1995, 73, 3358-3368. 

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