Sponge purification

Refining. KroU-process hafnium sponge and electrowon hafnium do not meet the performance requirements for the two principal uses of hafnium metal. Eurther purification is accompHshed by the van Arkel-de Boer, ie, iodide bar, process (18) and by electron beam melting. 

The vanadium alloy is purified and consoHdated by one of two procedures, as shown in the flow diagram of the entire aluminothermic reduction process presented in Figure 1. In one procedure, the brittle alloy is cmshed and heated in a vacuum at 1790°C to sublime most of the aluminum, oxygen, and other impurities. The aluminum faciHtates removal of the oxygen, which is the feature that makes this process superior to the calcium process. Further purification and consoHdation of the metal is accompHshed by electron-beam melting of pressed compacts of the vanadium sponge. 

Several methods are employed for the purification of the single platinum metal salts, for instance re-crystallization of Na2[Pt(Cl)6] with oxidative hydrolysis of the impurities of Pd, Rh, Ir, etc. which together with base-heavy metals are removed as insoluble hydroxides. Generally the metals are obtained, initially as sponge or powder, by conversion of their salts through thermal decomposition or by reduction of aqueous solutions of the ammonium-chloro complexes. Os which has been oxidized to the volatile 0s04 and Ru have to be reduced by H2. 

The high-throughput purification in a discovery environment and the removal of transition metals using adsorption on or crystallization in the presence of activated carbon, glass-bead sponges, polymeric fibers, or silica-bound scavengers and the preparative isolation of radiolabeled compounds are out of the scope of this contribution. 

Iron oxide, spent, or Iron sponge, spent obtained from coal gas purification 1376... 

B. Lorenz, R. Batel, N. Bachinski, W. G. E. Muller and H. C. Schroeder (1995). Purification and characterization of two exopolyphosphatases from the marine sponge Tethya lyncurium. Biochim. Biophys. Acta, 1245, 17-28. 

K. Friedrich, V. Hacker, H. Fuchs, R, Fankhauser (1998) Solid Biomass Gasification for Fuel Cells Gas Purification - Sponge Iron Reactor. Summary. Technische Universitat, Graz/Austria... 

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