What are the functions of the ingredients in the heat discs?
• Iron reacts with oxygen in the air to provide heat in a process called iron oxidation. • Sodium chloride (salt) speeds up the rate of reaction between iron and oxygen. • Sodium thiosulfate controls hydrogen generation. • Water is also necessary for the iron oxidation reaction. • Charcoal allows the iron powder to have a surface to react inside the heat discs. The surface of this charcoal has been treated (“activated”) to have special properties. • Sodium polyacrylate controls the level of water present in the heat cell.
