Separation of Bone, Charcoal, and Seeds by Chemical Flotation

Abstract

Gravel, bone, carbonized seeds, and charcoal recovered from a 2,000 year old cereal pit were successfully separated by chemical flotation. Specific gravities of each material were determined experimentally, and then for each pair of materials to be separated (e.g., bone from gravel, seeds from charcoal), a solution with a specific gravity intermediate between those of the two materials was used for flotation. Optimal sample sizes and possible sources of error are discussed, as are criteria for selection of solutions. A procedure for evaluating the effect of solutions and flotation practices on test seeds is also presented.