Value-added utilization of coal fly ash and recycled polyvinyl chloride in door or window sub-frame composites

Abstract Comprehensive utilization of coal fly ashes (CFA) solid waste is a worldwide urgent issue. In China, tens of millions of tons of CFA are un-utilized and stored or discarded in landfills per year, causing a significant waste of resources and a serious environmental hazard. Herein, we developed a new process to reuse CFA and recycled polyvinyl chloride (r-PVC) to produce door or window sub-frame (DWSF) composite materials, realized CFA and r-PVC trash to treasure. In this process, aluminate-modified CFA mixing with r-PVC and other additives obtain a mixture, subsequently extruding into pellets, re-extrusion, cooling, shaping, hauling, and cutting to DWSF materials. The mechanical properties of these are excellent and meet the National Standards, with static bending and tensile strengths of 33 and 13.6 MPa, respectively, and a hardness of 89.2 HRR. Compared with the traditional CaCO3-based DWSF, our CFA-based DWSFs have higher competitive both from the perspective of “carbon neutrality” and production costs. More strikingly, this process is simple, robust, and easy to industrialize, which allows large-scale, value-added utilization of CFA.