Effect of Modification Methods of Wheat Straw Fibers on Water Absorbency and Mechanical Properties of Wheat Straw Fiber Cement-Based Composites

Five modification methods are adopted for wheat straw fibers (WSFs). The effects of modification methods on the water absorbency of wheat straw fiber/wheat straw fiber cement-based composite (WSFCC) and the mechanical properties of WSFCC are analyzed. The crystallinity, chemical structure, and micromorphology of WSFs and WSFCC 28-day specimens are characterized by XRD, FTIR, and SEM methods. The results show that the water absorption of WSFs modified with sodium silicate solution, pure acrylic acid emulsion, and silicone waterproof emulsion surface spraying is 10.67%, 5.18%, and 1.05% lower than that of unmodified WSFs, respectively. Alkali modification is the ideal method for improving the strength of WSFCC. Establishing a fitting formula of the relationship between water absorption of WSFs and strength of WSFCC specimens has important theoretical and practical guiding significance for development and application of WSFCC

Research on coal combustion catalysts for cement kiln via comprehensive evaluation method based on combustion characteristics

Thermogravimetric-differential thermal analysis (TG-DSC) has been used to obtain information on combustion characteristics of bituminous coal and anthracite incorporating Cu(NO3)2, KNO3, ZnO and MnO2, and the apparent kinetic parameters were determined by the first-order Coats & Redfern method based on the TG-DSC results. Experiments were conducted from the 303 K–1172 K at heating rate of 10 K min−1. The ignition index, burning intensity, burnout index and activation energy were used as evaluation indexes. The weight of evaluation indexes was given by relative comparison method, The catalyst activity was evaluated by linear weighted synthesis method. It was indicated that those of bituminous coal and anthracite, the relative active sequence of catalysts to the comprehensive combustion performance of bituminous coal could be described as follows: Cu(NO3)2>KNO3>ZnO > MnO2. The relative active sequence of catalysts to the comprehensive combustion performance of anthracite could be described as follows: Cu(NO3)2>ZnO > MnO2>KNO3