Development of a new magnesium oxychloride cement board by recycling of waste wood, rice husk ash and flue gas desulfurization gypsum

Recycling construction waste wood to produce magnesium oxychloride cement board (MOCB) is an eco-friendly and high-value strategy. The effects of extrusion force, admixtures, wood fiber content and size on the physical and mechanical properties of MOCB were systematically investigated in this study. The results show that an appropriate increase in the wood fiber content in MOCB can not only reduce the density but also increase its flexural strength, but the pulling force decreases due to the reduction of compactness. Meanwhile, the small-sized wood fiber is beneficial to the increase of density and pulling force of MOCB, and the appropriate increase of wood fiber size can improve its flexural strength and water resistance. Increasing the extrusion force can also enhance the flexural strength and pulling force by increasing the compactness of the sample, but it is detrimental to the development of water resistance. Appropriate amount of rice husk ash (RHA) can improve the mechanical properties and water resistance of MOCB. The incorporation of flue gas desulfurization gypsum (FG) reduces the strength of MOCB, but its water resistance is improved. In addition, RHA and FG-modified MOCBs indicate better environmental benefits and performance indicators (Thickness swelling and water absorption) compared to conventional resin-based particleboard and Portland cement-based particleboard. This study provides not only strategies for recycling waste wood, but also technical parameters for producing eco-friendly cement composite boards.