Microstructure Transformation In Palm-Fiber Cell Wall And Its Influence On the Fiber's Mechanical Properties During Alkali Treatment

In this study, we examined the microstructure transformation of palm fiber and the influence of this transformation on the fiber mechanical properties during alkali treatment. The fibers were treated with different concentrations of NaOH to study the change rules of the microstructure and the tensile properties. FT-IR microspectroscopic imaging and confocal laser scanning microscopy were adopted to observe microstructure transformation during alkali treatment. Research results showed that the hemicellulose and lignin in the fiber cell wall were removed by alkali treatment, leading to a rearrangement of cellulose chains. The tensile properties palm fibers were significantly improved because of crystallinity alterations in the cell walls after alkali treatment. This study might provide a basis for palm fiber’s high-value utilization in the field of materials.

Carbothermic Reduction and Nitridation Mechanism of Vanadium-Bearing Titanomagnetite Concentrate

In this study, the carbothermic reduction and nitridation mechanism of vanadium-bearing titanomagnetite concentrate are investigated in terms of phase transformation, microstructure transformation, and thermodynamic analyses. The differences in the reaction behavior of titanomagnetite and ilmenite in vanadium-bearing titanomagnetite concentrate, as well as the distribution characteristic of V in the roasted products, are emphatically studied. It is observed that the reaction sequences of titanomagnetite and ilmenite transformations into nitride are as follows: Fe3−xTixO4→Fe2TiO4→FeTiO3→M3O5→(Ti, V)(N, C); FeTiO3→M3O5→Ti(N, C). The reduction of M3O5 to TiN is the rate-limiting step of the entire reaction, and metal iron is an important medium for transferring C for the reduction of M3O5. Titanomagnetite is faster to convert into nitride than ilmenite is, and the reasons for this are discussed in detail. During the entire roasting process, V mainly coexists with Ti and seems to facilitate the conversion of titanium oxides into (Ti, V)(N, C).