Heterogeneous solid-liquid reactions leading to crystallization of products are discussed. Different macro kinetics of reacting solid particles can be found due to the combination of the dissolution process of the solid reactant, the actual reaction and the crystallization kinetics. Thereby, a surface layer of the solid reactant which consists of the solid product being generated is the dominant problem. Various examples of solid-liquid reaction crystallizations are discussed in order to give an overview about this topic. Additionally, experimental work (production of boric acid and citric acid) with the aim to improve solid-liquid reaction crystallizations is presented. If hydrates are involved in solid-liquid reaction crystallizations their stability dominately influences the overall reaction. It is shown that the macro kinetics of solid-liquid reactions and their rates can be influenced trolled) by, e.g., an initially added amount of, e.g., the product or byproduct.