Cork: Sustainability and New Applications

Abstract

Cork is a strategic material used in multiple applications and its use has accompanied mankind since the days of Ancient Egypt. The cork oak forests are extremely well adapted to the semi-arid regions of south- ern Europe and northern Africa (west- ern Mediterranean). These forests help to prevent the advance of desertification, improve water penetration into the soil and hydrological regulation, promote soil conservation, and being the perfect habi- tat for many animal and vegetables species. Consequently, these forests promote biodi- versity (Pereira, 2007; Gil, 2011, 2014). the extraction. During the tree lifetime in operation, an average cork oak produces about four times more cork bark than the cork tree would produce if it were not sub- ject to stripping. The sum of the various layers of cork produced and harvested is greater than the single layer of cork pro- duced if there was no extraction during the life of a tree (Gil, 1998, 2011). Related to environmental aspects of the transformation of the cork raw mater- ial, it can be mentioned the production of expanded cork agglomerate. The man- ufacture of this cork product only uses superheated steam, using generators fueled with cork waste, not introducing any other products not exclusively cork, and giving up agglomeration based on resins of the cork itself. So, this is a completely nat- ural and ecological product. In addition, in the processing of this and other cork products an important residue is produced, cork powder. This powder is commonly burned to produce steam and/or power used in the factories themselves, given the high energy content of this material. Also, all other industrial cork wastes are reused or valorized in another way (Gil, 1998). So, there is really no wasted cork.