Industrial valorization of Quercus cerris bark: Pilot scale fractionation

Cork-rich Quercus cerris bark collected from Turkey was fractionated in a laboratory and in a pilot-scale equipment to obtain cork and phloem fractions. After a primary trituration as a field post-harvest operation, the cork-rich bark granules were mainly concentrated in the big granules (>12 mm) indicating different mechanical properties of cork and phloem. The smaller granules (<4 mm) could be fractionated using water flotation by separating a floating cork fraction. The pilot-scale fractionation consisted of a mechanical grinding of the whole bark fractions followed by a granulometric and a densimetric separation. The operation was quite efficient and as a result, pure cork (8.4% wt) and cork-rich (18.5% wt) fractions were obtained. The colour analysis and FTIR spectroscopy showed the separation efficiency of the cork fractions. The results show the potential of Q cerris bark for production of valuable cork fractions and the efficiency of combined granulation and fractionation. (C) 2016 Elsevier B.V. All rights reserved.