Reviews: J.S.J. van Deventer, Department of Chemical Engineering, The University of Melbourne, Australia
This book on metallurgical kinetics is the latest by the prolific author of textbooks, Fathi Habashi. By explaining the qualitative and quantitative principles of processes, illustrated by examples from the literature, Habashi is using the same easy-to-read educational style as in his previous books. In this respect the book will succeed in reaching the target audience of undergraduate metallurgy students.
The first part of the book introduces the principles of homogeneous reactions, the rate laws, the relationship between kinetics and the thermodynamic equilibrium, and the Arrhenius equation. Related aspects such as viscous flow, diffusion, adsorption, nucleation and radioactive decay are also introduced. This material is presented at a very basic level and will not be of direct use to the practising metallurgist. The boundary layer and the mechanism of rate control are discussed in the second part of the book. Habashiís explanation of a change in rate control with temperature is clearer than most other texts.
It is unusual to find sections on semiconductors, crystallinity, phase transformations, lattice energy, the common ion effect and galvanic effects in a text on reaction kinetics. Nevertheless, this information enhances the readerís understanding of the underlying processes instead of just discussing rate data as a mathematical relationship. The derivations for reacting solids with or without the formation of a porous or non-porous product layer are clear and easy to follow. Some researchers fit these standard heterogeneous rate expressions to kinetic data and then draw erroneous conclusions regarding the rate controlling mechanism. Unfortunately such pitfalls are not discussed by Habashi. Another aspect that is dealt with inadequately by most reaction engineering textbooks is the population balance approach, which allows for a distribution of particle sizes or reaction rates.
In most texts on reaction kinetics the source of experimental data is not discussed. Habashi devotes a short chapter to chemical and physical experimental methods, thermal analysis, surface analysis and phase analysis. The third part of the book gives an outline of a wide range of solid-solid reactions, solid-gas reactions, solid-liquid reactions, liquid-gas reactions, liquid-liquid reactions and electrode processes. Rate expressions are given for many of these reactions, but unfortunately typical values are not always provided for the rate constants.
Similar to most undergraduate textbooks on reaction engineering, Habashi devotes inadequate attention to the integration of mass transfer processes such as diffusion and adsorption with systems of rate equations. Unfortunately the emphasis of the book is on single homogeneous or heterogeneous reactions, so that practical kinetic problems involving combined chemical reactions, several diffusional steps, film transport and a shifting equilibrium are not addressed. Furthermore, Habashi does not mention how rate equations could be combined with mass conservation equations to simulate flow through various reactor types. With computational tools so freely available it is possible to pose and solve these problems as systems of differential equations even at the undergraduate level. In a more general sense it is also important to explain to students how to deal with kinetic problems for which the standard rate expressions are inappropriate. The standard textbooks on chemical reaction engineering deal with some of these problems in a more satisfactory manner than the metallurgical textbooks, but are still found lacking in providing the student with a methodology which could be used in real life situations. On the other hand, it is often difficult to apply the principles outlined in chemical reaction engineering textbooks directly to metallurgical problems. It is in this regard that Habashi succeeds in linking the theoretical aspects of rate processes to specific reactions and physicochemical phenomena.
Kinetics of Metallurgical Processes is recommended for undergraduate students and their lecturers interested in understanding the physicochemical basis of different metallurgical reactions. It is neither a substitute for the standard texts on chemical reaction engineering, nor does it have the level of sophistication required by the specialist metallurgist. However, this book is an excellent text for metallurgists and graduate students who require a refresher course on reaction kinetics.