Melting Point

Melting Point of pure substances

Temperature at which a product changes phase from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. When considered as the temperature of the reverse change from liquid to solid, it is referred to as the freezing point. Unlike the boiling point, the melting point is relatively insensitive to pressure because the solid/liquid transition represents only a small change in volume. Melting points are often used to characterize organic and inorganic compounds and to ascertain their purity. The melting point of a pure substance is always higher and has a smaller range than the melting point of an impure substance. The more impurity is present, the lower the melting point and the broader the range.

Melting point issues during tank cleaning

• Washing at 20 – 25°C above the MP
• No cold adjacent cargoes, no ballast
• Watch freezing in cold pipeline systems
• If high MP wash a.s.a.p.
• Watch IBC chapter 17 column o (specific and operational requirements) for 16.2.9