Wood ash

The solid remainder of completely burnt wood or charcoal. Usually between 0.5-1.9% of the dry mass of the wood burnt.

Uses

Primary

• Source of sodium and potassium carbonate via potash

Character

Ash is generally composed of a larger insoluble fraction and a smaller soluble fraction. The residual components are heavily dependent on the temperature of the fire. A plain wood fire may burn at 600°C, while a forced-air charcoal fire may burn at 1300°C. For instance, this means essentially all the potassium is volatilized in the hotter fires. If you want to make potash, ash from a regular fire will perform better.

Insoluble

• Calcium carbonate
• Magnesium carbonate

Soluble

• Potassium carbonate
• Sodium carbonate
• various chlorides and sulfates

Production

1. make fire
2. wait
3. collect ash

Disposal

Wood ash can be disposed of into the soil. Do not dispose of it in waterways.

See Also

• Misra MK, Ragland KW, Baker AJ (1993). "Wood Ash Composition as a Function of Furnace Temperature". Biomass and Bioenergy 4 (2): 103. doi:10.1016/0961-9534(93)90032-Y.
• J.O. Babayemi, K.T. Dauda, D.O. Nwude and A.A.A. Kayode (2010) "Evaluation of the Composition and Chemistry of Ash and Potash from Various Plant Materials" Journal of Applied Sciences, 10: 1820-1824. doi:10.3923/jas.2010.1820.1824