Improvements in and relating to the treatment of decortication wastes

摘要

Sisal cuticle, containing wax, is recovered from a mixture of the cuticle and pulp resulting from the decortication of sisal by subjecting the mixture to aerobic fermentation under a spray of water containing dissolved oxygen, in a vat having a spray and a perforated base through which liquid is removed, the cuticle being separated from the retted mixture by washing with water. Water and plant juices are preferably first removed from the mixture. The spraying water is preferably re-circulated or sprayed through fresh material, oxygen being desirably added thereto. The sticky layer which forms at a small depth below the sprayed surface is preferably removed or water is injected at different, e.g. at successively lower levels or is supplied upwardly or downwardly. The vat may be emptied after 5 to 10 days before fermentation is completed and the partly retted mixture allowed to ferment further without further spraying. Oxygen-carrying chemicals, such as nitrates, may be added to the spraying water. The cuticle is finally recovered from the retted mixture by floating it in a washing cage partly immersed in water and agitating the cage or revolving the cage under a water spray. The cage may be mounted on a central axis and may be formed by a frame of square section to which is fixed a metallic fabric. The pulp is washed out, leaving the cuticle in the cage. The dried cuticle may then be extracted with solvents.