Synthesis of tin (II) sulfide: Determination of the reaction kinetics through calorimetric techniques

In the last ten years, the search for new application materials has become one of the “must” in the field of powder technology. Particularly, as regards solid lubricants, concerns in the use of compounds containing Lead and Antimony have been raised, since the former is classified as a carcinogen and the second such as a suspect one. Therefore, as consequence of both more and more stringent law requirements for environmental emissions and low impact on human health, safe and cheap materials are strongly demanded. As the sake of example, Tin (II) Sulfide, SnS, has been widely tested and found to be not only technically superior with respect to other alternatives but also safer from the environmental point of view. Despite these properties, its development has been limited by the relatively high synthesis costs compared to its competitors. The aim of this work is to determine the kinetics of a safe “dry” batch process for the production of SnS using only cheap calorimetric techniques. The results obtained from this study (synthesized in a series of equations describing the dynamics of the process) have shown that a simple but complete calorimetric analysis is able to overcome the main criticality that characterizes a dry synthesis involving Sulfur and Tin: that is, the difficulty in the reactor temperature control (danger of thermal runaway) due to the extremely fast and high exothermicity of the reaction and the low thermal capacity of the reacting mixture.