A combustion method for the determination of total sulphur in limestones

Abstract

A method is described for the determination of total sulphur in limestones. The sample is mixed with tungsten trioxide and quartz flour and placed in a boat of refractory material. The boat and contents are inserted into an aluminous porcelain combustion tube maintained at a temperature of about 1200 °C in a resistance-type tube furnace. The combustion tube carries a coil of copper gauze at the outlet end to reduce sulphur trioxide. Nitrogen is used as carrier gas and the sulphur dioxide evolved is absorbed in dilute hydrochloric acid containing potassium iodide and starch as indicator, titration with standard potassium iodate solution being carried out as the analysis proceeds.