Melt purification

High or ultrahigh product purity is obtained with many of the melt-purification processes. Table 22-1 compares the product quality and product form that are produced from several of these operations. Zone refining can produce very pure material when operated in a batch mode however, other melt ciystallization techniques also provide high purity and become attractive if continuous high-capacity processing is desired. Comparison of the features of melt crystalhza-tion and distillation are shown on Table 22-2. 

Brodie, J. A. Mech. Chem. Trans. Inst. Engrs. Australia 7 (1971) 1, 37-44. A continuous multistage melt purification process. 

Brodie crystallizer-purifier, 545, 547 Kureha purifier, 545,547 multistage, 543 MWB process, 543,545 Phillips process, 544-546 Schilaknecnt column, 543,544,546 TNO bouncing ball process 545.547 Melt purification. See Melt crystallization Membranes, 631,632,641 applications, 632 cellulose acetate, 635 equipment configurations, 632 gas permeation,633,644 hollow fiber, 632,633,641,643 performance, 646 Permasep, 641 olate and frame, 638 Prism, 633,643 properties, 635,636 structures, 632 tubular, 638,639 types, 635, 636... 

Al-Zn-Mg-Cu alloys with additions of Fe, as well as with combinations of Fe, Mn, Zr and Sc, were produced by induction melting using ceramic crucibles and supplementary methods of melt purification, which included ceramic filters and blowing the melt with argon. Rods of 6 mm in diameter were manufactured by extrusion at 400 C with extrusion ratio A.=84. The T6 treatment consisted in water quenching from 465 °C and aging at 120 °C for 24 h. The alloy compositions and the properties of rods in the T6 condition are given in Table 1. 

Their acidic and basic regions are determined conditionally with respect to the initial concentration of oxide ions in the melts, which, in its turn, is dependent on the concentration of oxygen admixtures in the pure solvent and, subsequently, on the quality of the melt purification from oxygen-containing impurities. 

High or ultrahigh product purity is obtained with many of the melt purification processes. Table... 

J, A. Brodie, A Continuous Multi-Stage Melt Purification Process, p. 37, The Mechanical and... 

The Brodie purifier (Brodie, 1971) is a countercurrent melt purification system with the added feature of an imposed temperature gradient between the residue and product outlets. The unit thereby acts as a countercurrent multistage fractionator with partial melting and recrystallization occurring along its length. 

Brodie, J.A. (1971) A continuous multistage melt purification process. Mechanical and Chemical Engineering Transactions, Institute of Engineers Australia, 7, (1), 37-44. 

Fuel chlorination 700 C Preliminary electrolysis 68QPC Precipitation crystallization 680°C Electrolysis-additional 700 C Melt purification 700°C... 

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