Method of recycling heat

A method of recycling heat during operation of a plant in which equipment for processing at least two different materials is co-located, the method comprising:

• (a) a first process which processes a first material having a first melting point, wherein, during the first process, the first material is subjected to a first melting process and then subjected to a first cooling process that includes solidification of the first material;
• (b) a second process which processes a second material having a second melting point, wherein the second melting point is less than the first melting point and, during the second process, the second material is subjected to a second melting process and then subjected to a second cooling process that includes solidification of the second material;
• and,
• (c) recovering heat from the first cooling process and using at least some of the heat as a heat source for the second melting process
• wherein recovering heat from the first cooling process comprises using a first heat exchange fluid to recover heat from the first cooling process and the first heat exchange fluid conveys the heat recovered from the first cooling process to a reactor containing a second heat exchange fluid, using at least some of the heat as a heat source for the second melting process comprises using the second heat exchange fluid to convey at least some of the heat, which was recovered from the first cooling process, to the second melting process.