Mitigating sulphide self-heating using hygroscopic agents: Case study with pyrrhotite

Spontaneous heating of sulphides can occur under certain ambient conditions, including moisture content. Hypothesizing that reducing moisture would mitigate self-heating hygroscopic reagents were tested on a strongly self-heating pyrrhotite-rich sample. A self-heating test was used to assess the impact of three inorganic chemicals, sodium hydroxide, sodium chloride and drierite, and two polymers, silica gel and poly (acrylic acid sodium salt). Silica gel and poly (acrylic acid sodium salt) were the most successful, attributed to holding the water firmly inside the structure. However, the amounts required argue against this as a practical approach.