| abstract |
A novel leaching process for separating extractable material from a particulate solid material that comprises extractable and non-extractable portions includes the steps of introducing the particulate solid material and a liquid solvent to an extraction zone; agitating the liquid solvent to a degree sufficient to suspend the particulate solid material and effect segregation of particles thereof in relation to their propensity to settle; maintaining contact between the liquid solvent and the particulate solid material for a time sufficient to leach extractable material therefrom; and selectively withdrawing particles of the solid material from the extraction zone. In a preferred embodiment, the leaching process is a multi-stage process in which the selectively withdrawn particles from each stage are introduced to the next successive stage of the series. A particularly important use for the novel leaching process is in the recovery of gelatin from bone, and specifically in that step of the gelatin manufacturing process in which granulated bone is demineralized by contact with a dilute acid solution which converts bone particles to particles of ossein by extracting the minerals from the bone. |