Bone as a fuel: studying the properties based on the results of experimental observations

Purpose. Burnt animal bones are regularly found at archaeological sites of different eras and territories. One of the popular hypotheses suggests that they were used as fuel. The purpose of this work, based on experimental observations, is to determine the combustion temperature regime of bones different types in comparison with wood.Results. A series of nine experimental bonfires revealed the following advantages of bone as fuel: 1) increase in the maximum combustion temperature to 800-900 °C versus 600-700 °C in a fire with wood fuel only; 2) increase in the average range of combustion temperature by more than 100 °C; 3) minimization of temperature fluctuations; 4) ensuring a stable high temperature. We also found that the bones condition (fresh / dry; unbroken / fragmented) and its structure (the predominance of compact / spongy bone tissue) affects its combustible properties. Fresh bones with spongy tissue predominance (the spine, limbs bones) have the best qualities. Dry fragmented bones burn much worse and have no advantages over other fuels.Conclusion. Thus, animal bones are not universal independent fuel. Some of its properties could be used for operations requiring a stable high temperature. It could be simple activities (cooking, heating, hearth maintenance, drying) and the specialized ones.