Bone, charred temperature

Finally, it is essential that adsorbents proposed for sugar refinery use be capable of regeneration in existing equipment, and preferably at the same temperature as bone char in order that the proposed adsorbent can be added to the service char as make-up. To fulfil this latter requirement it is also necessary that the proposed adsorbent be of such a nature that it will not react chemically with bone char in filters or kilns, since such reaction would almost certainly be deleterious to both adsorbents. 

The reactivation of bone char in sugar factories is a long established practice.3 The spent char is washed in the column to recover sugar syrup ( sweetening off ) and then heated to a dull red temperature in the almost complete absence of air. 

Bone char. This is obtained by the destructive distillation of crushed, dried bones at temperatures in the range 600 to 900°C. It is used chiefly in the refining of sugar and can be reused after washing and burning. 

The uptake of fluoride onto the bone char surface is one of the major defluoridation methods. The process involves ion exchange in which carbonate radical of the apatite comprising bone char, and Ca(P0 g.CaC03, gets replaced by fluoride to form an insoluble fluorapatite. Bone char produced by carbonizing zone at temperature of 1100-1600° C had superior qualities than those of unprocessed bone as a defluoridation agent [8]. 

More recently, Michel and co-workers have studied charred modern bone by ESR, IR and x-ray diffraction, and have also studied Middle Pleistocene fossil bone from Lazaret Cave in France (25). They found that the IR feature that they took to be the signature of the organic component of the bone disappears from the spectra of bone that had been heated above about 400 °C. They also found that bone developed a characteristic ESR spectrum upon heating to temperatures between 200 °C and 600 °C, and that this spectrum was replaced by a different, much weaker, spectrum in samples that were heated above 600 °C. 

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