Ba0.4Sr0.6TiO3 ceramics by adding mental Fe powders have been fabricated via the solid-state reaction method. The microstructures and optical properties of samples are systematically studied in order to establish the effects of Fe powder additives on microwave dielectric properties of Ba0.4Sr0.6TiO3 ceramics by x-ray diffraction, x-ray photoelectron spectroscopy, and optical reflective spectrum. The results show the coexistence of Fe2+ and Fe3+ in Ba0.4Sr0.6TiO3 ceramics, the decrease of O vacancy concentrations, and their incorporation into the B-site (Ti) of the Ba0.4Sr0.6TiO3 host lattice give rise to excellent microwave dielectric properties. All samples have a higher Q value above 290 while maintaining relatively high tunability above 16.6%. In particular, the sample with the composition of x = 0.035 mol has the dielectric constant of 889, Q × f value of 826 (at 1.370 GHz), and tunability of 24%, which are very promising for high power tunable devices. In comparison, Fe2O3 oxide doped Ba0.4Sr0.6TiO3 ceramics with the same molar ratios of Fe exhibit inferior microwave properties. It indicates that additives of the metal Fe powders can more effectively improve dielectric properties of BaxSr1-xTiO3 system than Fe2O3 oxide.

xMgO–yMnCO3–0.70(1 − x − y)Ba0.4Sr0.6TiO3–0.30(1 − x − y)MgAl2O4 (where x, y = 0.0 wt% and x = 1.0 wt%, y = 0.5, 1.0, 2.0, 5.0, 10.0 wt%) composite ceramics synthesized by the solid-state reaction show two crystalline phases, corresponding to the Ba0.4Sr0.6TiO3 and MgAl2O4 phases. At a low MnCO3 content (y ⩽ 2.0 wt%), weak diffuseness is visible, while strong diffuseness is observed for a higher MnCO3 content. For x = 0.01 and 0.01 ⩽ y ⩽ 0.02, high tunability is attributed to the small cooperative displacements of Ti4+ ions in the close packed oxygen octahedra of the BST system. The Q value gradually increases with y, potentially due to the microstructural evolution of the BST lattice structure characterized by Raman spectra. Interestingly, the high Q value of the composition with x = 0.01 and y ⩾ 0.05 is in a wide frequency range, which may play an important role in the engineering of the electric-field tunable microwave elements.

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Cyanide tailings have become one kind of the most hazardous solid waste. In order to recycle iron in the cyanide tailings, we present a technique using roasting- water leaching- magnetic separation. After analysis of the different parameters on recovery efficiency of iron, the optimum reaction parameters were proposed as the following: in reduction roasting process, weight ratios of cyanide tailings / activated carbon at 100:10, roasting at 750 °C; the liquid to solid ratio is 15:1 (ml /g), leaching at 60 °C for 5 min at water leaching. The grade of magnetic concentrate 53.8231％Fe and recovery rate of 76.5458％ were obtained. Mineralography of roasted product, water-leached sample were studied by X-ray powder diffraction technique (XRD).

Al-Ni Alloys were obtained from NiCl2-AlCl3-1-ethyl-3-methylimidazolium bromide ([EMIM]Br) ionic liquid at room temperature. The analysis of Al-Ni alloys that co-deposited at different potentials for 2h were performed using Scanning Electron Microscopy (SEM) and X-ray diffraction analysis (XRD). It appears that Ni has been rapidly solidified in the alloys and homogeneous Al-Ni alloys can be obtained at room temperature. As increasing the overpotential, the amount of Ni in the alloys was decreased whereas the amount of Al was increased. The chloride pitting potentials of alloys with the molar ratio of NiCl2/AlCl3/[EMIM]Br 0.03:2:1 was approximately 0.3 V more than pure Al.