De-icing salt works by lowering the freezing point of water. This is known as freezing point “depression”. When pure salt is mixed with water, it dissolves into separate sodium and chloride ions. These ions interfere with the formation of ice crystals, making it more difficult for water to freeze

Winter gritting is the process of spreading salt or grit on roads, car parks, footpaths and other surfaces to prevent ice from forming, or to melt existing ice and snow