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Description: Metallurgy of pure metals is concerned with the refining and preparation of high-purity substances, with special emphasis not only on the high degree of chemical purity attainable by chemical or physical methods (hydrometallurgy, sorption, extraction, crystallisation from aqueous solutions, electrolysis) and also by pyrometallurgical methods (crystallisation from melts, evaporation, condensation and transport reactions, electrotransfer, diffusion separation of substances, removal of gases from metals, and vacuum refining of metals). The main material parameter which is in fact a measure of the separation of impurities during crystallisation processes is the distribution coefficient. Special attention is given in the book to the determination of this coefficient, its properties and correlation with the proton number. An appendix contains the values of distribution coefficients and binary diagrams, mainly for copper, aluminium, iron and its transformation, selected noble, refractory, radioactive metals, lanthanides, and semiconductors.
Contents: INTRODUCTION • PURE METALS AND CLASSIFICATION OF THE METHODS OF PREPARATION OF PURE SUBSTANCES • Purity, properties and significance of pure substances • Methods of the description of purity • Effect of impurities on the properties of substances • GENERAL CHARACTERISTICS AND CLASSIFICATION METHODS OF SEPARATION AND REFINING OF SUBSTANCES • Main methods of production of pure metals and substances • SORPTION • Significance of sorption processes in the separation and refining of substances • Adsorption • Ion exchange, ion exchangers • Chromatography • EXTRACTION • Physico-chemical nature of extraction and its importance • Mutual solubility of two liquids • Separation laws • Isothermal equilibrium in a ternary liquid system • Extraction methods • Extraction systems • Application of extraction in the metallurgy of pure substances • CRYSTALLISATION • Crystallisation from solutions. Equilibrium, mechanism and kinetics of crystallisation • Solubility of salts • Isothermal evaporation and crystallisation • Cyclic separation of salts by crystallisation from solutions • Freezing-out • CRYSTALLISATION FROM MELTS • Distribution coefficients in crystallisation • Determination of the equilibrium distribution coefficient from phase diagrams. • The distribution coefficients of admixture in copper • Correlation dependence of distribution coefficients • Interphase (kinetic) distribution coefficient • The effective distribution coefficient • Criteria of the stability of the crystal—melt interface • Directional crystallisation • Zone melting • Mass transfer in crystallisation • Crystallisation methods of refining and production of single crystals of metals, alloys and special materials • General class • The Bridgman method • Zone melting methods • Drawing the crystal from the melt • Preparation of single crystals with a homogeneous or given distribution of admixtures • Verneuil method • Preparation of single crystals from the solid phase-recrystallisation methods • Preparation of crystals in zero gravity conditions • Rapid solidification • EVAPORATION, CONDENSATION, TRANSPORT REACTIONS • The theory of separation of compounds by evaporation and condensation • The relationship between the composition of the vapour and the solution • Change of the composition of solutions and vapours in relation to temperature and composition—boiling temperature and composition— vapour pressure diagrams • The physical—chemical nature of sublimation and distillation processes • The removal of admixtures by evaporation in vacuum • Principle of the rectification process • Using rectification for the refining and separation of metals and compounds • Distillation by means of chemical transport reactions • Distillation of metals by means of a reversible endothermic exchange reaction • Distillation of metals through sub-compounds • Distillation by synthesis and dissociation of volatile compounds. Iodide reaction • Suitabilityof the iodide process for different groups of metals • ELECTROLYSIS • Significance of electrolytic method of separation and refining of metals • The rate of the electrode process. Electrochemical and diffusion kinetics • Polarisation curves of reduction of cations • Simultaneous discharge of the ions of the main metal and admixtures • Conditions for the removal of admixtures in electrolysis • Removal of nonmetallic admixtures from cathodic metals in electrolysis • Anodic dissolution, Electrolytic refining of metals • Amalgamation method of separation and refining of metals • ELECTROTRANSPORT • Refining of admixtures from solid metals by electrotransport • Refining of admixtures from metallic melts by electrotransport • Refining of metals by electrotransport through the oxide layer • Applications of electrotransport in zone melting • DIFFUSION • Separation of gas substances by diffusion and thermal diffusion • High-voltage electrodialysis • SELECTIVE PRECIPITATION, OXIDATION AND REDUCTION • DEGASIFICATION OF METALS • Gases in metals • Vacuum refining of metals • METHODS OF TESTING PURE METALS • Analytical methods • Gravimetry and titration • Polarography • Emission spectral analysis • Absorption spectrophotometry • Atomic absorption spectrometry (AAS) • Fluorescence spectroscopy • Local microanalysis • Radiometric methods • Determination of gases in metals • Evaluation of analytical methods of determination of pure metals • Resistance of metals and semiconductors • Methods of examination of the structure and perfection of crystals • REFERENCES • SYMBOLS • APPENDICES • INDEXISBN - 9788130910949
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Pages : 242
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