The local structural changes of ZrW ₂ O ₈ after ammoniation treatment.

Orthorhombic Dy₂W₃O₁₂ shows NTE (−2.6 × 10⁻⁵ °C⁻¹) in the temperature range of 150–500 °C. So far, this value is the largest coefficient of negative thermal expansion in the A₂W₃O₁₂ family (A = rare earth element).

Steel slag, as industrial solid waste, is difficult to recycle owing to its complex components and poor mechanical properties. However, steel slag can be modified by adding Al₂O₃–SiO₂ through high temperature sintering, which would improve the mechanical properties and expand the scope of its application. The phase changing, morphology evolution and the mechanical properties of the modified steel slag were investigated. The results indicate that the main phase changes to gehlenite occur with increasing temperature. The compressive strength increases to 115 MPa at 1350 °C. The relationship of the quantity of gehlenite and the compressive strength were explored.

The electrochemical reduction mechanism of Mn in LiMn₂O₄ in molten salt was studied. The results show that in the NaCl-CaCl₂ molten salt, the process of reducing from Mn (IV) to manganese is: Mn (IV)→Mn (III)→Mn (II)→Mn. LiMn₂O₄ reacts with molten salt to form CaMn₂O₄ after being placed in molten salt for 1 h. The reaction of reducing CaMn₂O₄ to Mn is divided into two steps: Mn (III)→Mn (II)→Mn. The results of constant voltage deoxidation experiments under different conditions show that the intermediate products of LiMn₂O₄ reduction to Mn are CaMn₂O₄, MnO, and (MnO)_x(CaO)_(1−x). As the reaction progresses, x gradually decreases, and finally the Mn element is completely reduced under the conditions of 3 V for 9 h. The CaO in the product can be removed by washing the sample with deionized water at 0 °C.

CaCl ₂ molten salt, as a common electrolyte in the process of molten salt electrolysis, has a high decomposition potential and a strong ability to bind O ²⁻ . So the study of the structure and properties of CaCl ₂ is significant for the molten salt electrolysis. In this paper, molecular dynamics simulations (MD) method was used to investigate the variation rule of the local structure and physicochemical properties of CaCl ₂ molten salt with temperature. The results show that the temperature has less effect on the heterozygous ion pairs and more effect on the homozygous ion pair. With the increase of temperature, the interaction between ion pairs is weakened, the coordination number decreases, the local structure changes a little, and the structural configuration tends to be an irregular octahedral structure with vacancies. The calculated self-diffusion coefficients, viscosities, and ionic conductivities are consistent well with the reality, but there is a significant error in densities due to the strong polarization effect of Ca ²⁺ compared to the reality. The local structure directly determines the thermodynamic properties of the molten salts. This study promotes the basic theoretical research on alkaline earth metal-containing molten salts and is an important reference for the study of molten salt electrolysis process.