Dry grinding of waste wood fiberboard: Theoretical and practical aspects affecting the resulting fiber quality

Abstract

This paper presents the results of research on the treatment of secondary wood fibre semi-finished materials using a dry-grinding-type rotary cutting mill and the possibility of their use in finished products for various purposes. The physical phenomena, processes, and regularities of the treatment of secondary wood fibre materials in dry processing conditions were determined and evaluated. The influence of grinding plant design parameters on wood fibre quality indices was evaluated. Mechanical effects on wood fibre waste of face-cross cutting (cutting, crumpling, collapsing, and breaking) and the dry grinding environment (breaking, collision, defibering, and fibrillation) was studied. These phenomena contribute to the formation of external and internal fibrillation of secondary wood fibre and an increase in the specific surface area. This is achieved in the absence of high temperatures and pressure, in the absence of chemical additives, and without the application of water and vapour. The effectiveness of secondary wood fibre semi-finished material treatment was demonstrated under dry processing conditions, thus confirming the environmental and economic feasibility of this method.

Assessment of the morphological properties of secondary semi-finished wood-fibre products obtained from production waste

“…The experimental results related to the influence of technological and design parameters of the MR-4 rotary cutting machine on the dimensional and qualitative parameters of wood fibres are presented in Matygulina et al (2021b).…”

“…The ratio characterizes the intensity of changes in the geometric dimensions of wood fibres in different directions and determines their specific surface area and flexibility. The method for determining the arithmetic mean values of fibre length L and diameter D is presented in earlier studies (Zyryanov 2012;Matygulina et al 2021b). The authors carried out a two-factor experiment according to the second-order Bplan with processing in the STATISTIСA-6 software package (Dell Technologies, version 6.1, Round Rock, TX, USA) using the Quasi-Newton method (Borovikov and Borovikov 1998;Pizhurin and Pizhurin 2005).…”

“…It is soaked, ground in high-speed disk or conical mills, and mixed with press pulp, thereby putting it back into main production. However, studies (Matygulina 2007;Сhistova 2010;Zyryanov 2012;Сhistova et al 2015) have shown that this leads to the quality of finished products deteriorating: the tensile strength and density of boards decrease, while moisture absorption and swelling in thickness increase. Lump waste is also processed into fuel for thermal power plants (ground to a size suitable for loading into boilers).…”

“…The authors (Morozov 2016;Matygulina et al 2021b) have demonstrated the effectiveness of processing secondary wood-fibre waste in an MR-4 grinding machine. The machine operates according to the dry grinding method, in which the fibres are subjected to cutter forces and aerodynamic phenomena occurring in the grinding chamber.…”