Producing particulate bark products for use as fillers or insulation materials involves granulation under specified conditions with soft lignite as granulation aid

摘要

Production of particulate bark products for use as fillers or insulation materials and having good pouring and dosage characteristics, high pressure resistance, low hygroscopicity, low swelling in water and high water-resistance involves granulation with soft lignite while observing a number of processing conditions. Production of particulate bark products for use as fillers or insulation materials and having good pouring and dosage characteristics, high pressure resistance, low hygroscopicity, low swelling in water and high water-resistance involves observing the following conditions : (a) granulation of the pre-comminuted bark with activated soft lignite which acts not only in the unrolling and particle classification processes but also functions as a binder and hydrophobicizer; (b) pre-comminution of both the bark and the lignite to particles below 5 (especially below 2)mm; (c) moisture saturation or surface moisturization to give a stable adhesion between the surfaces of the bark and the lignite; (d) activation of the lignite by intensive mechanical working, swelling and colloidal or macromolecular dissolution so as to develop its binding effect and hydrophobicizing properties and also to convert the mixture into a moist composition with good rolling and particle classification properties under high mechanical energy input, this being accompanied by controlled addition of diluting water and heating; (f) controlled addition of at least part of the lignite during the granulation process; (g) production of a moist crude granulate of particle size below 6mm; and (h) drying of the granulate to moisture content below 20 (especially 3-12)%.