Cost-Effective and Sustainable Preparation of Porous Mullite-Based Ceramics Combining MoO<sub>3</sub> Recovery from Industrial Calcine
Guanghui Li, Qunzhen Bu, Hu Sun, Dapeng Shi, Jun Luo, Mingjun Rao, Zhiwei Peng, Tao Jiang
Abstract
The preparation of porous mullite-based ceramics (PMCs) suffers from the pollution of fluorinated catalysts and high cost and large consumption of additives. The volatilization method for MoO3 recovery from industrial Mo calcine has demerits of low recovery efficiency and high requirements for equipment and waste treatments. Herein, this work presents a new strategy to co-produce pure MoO3 and PMCs by single-step roasting of green bodies composed of industrial Mo calcine, kaolin clay, and alumina. Ribbon-like MoO3 is recovered with a high recovery efficiency of 95.71%, while simultaneously acting as the pore-forming agent and crystallization catalyst to construct PMCs. The properties of PMCs, such as linear shrinkage, open porosity, bulk density, compressive strength, and thermal conductivity, are reported. The PMC sintered at a low temperature of 1100 °C with the addition of 200 wt % industrial Mo calcine shows great potential to serve as a thermal insulating material. The recovery of MoO3 is better than the traditional method because the PMC can absorb the melted calcine, intensify MoO3 volatilization, and incorporate the volatilizing slag. Generally, this work provides a cost-effective and sustainable method to co-produce pure MoO3 and PMCs with mutual promotion and zero waste.