The advances made in the field of chemical engineering as applied to the processing of metals and other inorganic materials are reviewed. The reactions involved in this field are heterogeneous in nature, the fluid-solid noncatalytic reactions being the most important group of examples. In these heterogeneous reactions, interfacial chemical reactions are always accompanied by the transfer of mass and heat between the reaction interface and the bulk fluid. The interplay of these steps determines the overall characteristics and analysis of the reaction rate. The review examines the developments in the quantitative rate analysis of various fluid-solid reaction systems. Examples are largely drawn from the work of the author and coworkers, which has led to the formulation of the Law of Additive Reaction Times and its application to a wide range of fluid-solid reactions. The serious effects of thermodynamics on fluid-solid reaction with small equilibrium constants, in terms of the overall rate and the falsification of activation energy, have been examined based on a careful quantitative analysis.