Wood ash is the residue powder left after the combustion of wood. Main producers of wood ash are wood industries and power plants.
Wood ash is the residue powder left after the combustion of wood. Main producers of wood ash are wood industries and power plants.
Typically 0.43 and 1.82 percent of the mass of burned wood (dry basis) results in ash [1]. Many types of ash are found near campsites.[2] The composition of wood ash is influenced by the type of wood that has been burned. Also the conditions of the combustion affect the composition and amount of the residue ash, thus higher temperature will reduce ash yield.[3][1]
Wood ash contains calcium carbonate as its major component, representing 25[4] or even 45 percent.[5] Less than 10 percent is potash, and less than 1 percent phosphate; there are trace elements of iron, manganese, zinc, copper and some heavy metals.[4] However these numbers vary as combustion temperature is an important variable in determining wood ash composition.[1]
Wood ash is commonly disposed of in landfills, but with rising disposal costs ecologically friendly alternatives are becoming more attractive.[6]
For a long time wood ash has been used in agricultural soil applications as it recycles nutrients back to the land. Wood ash has some value as a fertilizer, but does not contain nitrogen. Because of the presence of calcium carbonate it acts as a liming agent and will deacidify the soil increasing its pH.[4] Potassium hydroxide can be made from wood ash,[7] which in turn can be used to make soap.