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Gossan ore of sulfide zinc deposit contains abundant zinc, iron, and other metal elements, which is a significant resource with complex components and can be utilized. In this study, a new technology of preparing zinc ferrite from zinc sulfide deposit gossan was proposed. The effects of Al2O3, CaO, and SiO2 in gossan on the formation of zinc ferrite were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and specific surface area and pore size analysis (BET). The results show that the presence of Al2O3 and CaO could hinder the formation of zinc ferrite, while silica had no effect on the formation of zinc ferrite. Under the conditions of the molar ratio of ZnO and Fe2O3 to Al2O3, CaO, and SiO2 of 1:1:1, an activation time of 60 min, and a roasting temperature of 750 °C for 120 min, the products, which had good crystallinity, smooth particle surface, and uniform particle size could be obtained. In addition, compared to the roasted products with Al2O3 and CaO, the specific surface area, pore volume, and pore size of the products with SiO2 were the largest. [ABSTRACT FROM AUTHOR]

The phase evolution mechanism and purification of titanium oxycarbide (TiCxOy) synthesized via the carbothermal reduction of ilmenite are investigated. The reaction process and products of the performed carbothermal reduction are analyzed by means of X-ray diffraction (XRD), scanning electron microscopy-energy disperse spectroscopy (SEM-EDS), X-ray photoelectric spectroscopy (XPS) and enthalpy, entropy and heat capacity (HSC) thermodynamic software. According to the shapes of Ti 2p3/2 and Ti 2p1/2 peaks in XPS spectra, together with the XRD analyses, the reduction products of TiO, TiCxOy or TiC can be judged. The phase evolution mechanism involves FeTi2O5, Ti2O3, Fe, TiO, TiCxOy and TiC under enhancing the content of carbon. The phase evolution law can be written as FeTiO3 → FeTi2O5 → Ti2O3 + Fe → TiO + Fe → TiCxOy + Fe. Due to the incomplete reduction state of TiCxOy, the ΔGθ of TiCxOy is detected between TiC and TiO. TiCxOy could be attained under reduction conditions of Ti:C, 1:3–1:4 in argon atmosphere at 1550 °C after 2 h. Grinding, flotation and magnetic separation processes displayed that C, TiCxOy and Fe are not dissociated until the particle size of −38 μm. TiCxOy and Fe can be separated by an iron-bath in a high temperature. 95.56% TiCxOy can be obtained, and resistance of TiCxOy is less than 0.05 Ω. [ABSTRACT FROM AUTHOR]

Single- or dual-cation organomontmorillonites (OMt) modified by one or two cationic surfactants, respectively and/or cysteamine hydrochloride (CSH) were used to remove Zn 2 + and/or phenol from aqueous solutions. The OMt were characterized by XRD, FTIR spectroscopy and N 2 adsorption-desorption isotherm analyses. The adsorption results of Zn 2 + and phenol showed that OMt had much larger adsorption capacities of phenol than that of Na + -Mt or CSH-Mt in the presence of Zn 2 + . Experiments with the simultaneous presence of both the contaminants showed that one did not affect the adsorption of the other with all the adsorbents. The uptakes of Zn 2 + and phenol onto dual-cation OMt increased with increasing solution pH, contact time, temperature and initial concentration of Zn 2 + and phenol. The adsorption equilibrium time was 10 min for both contaminants and the maximum adsorption capacities of Zn 2 + and phenol were found under alkaline environment. The adsorption of both Zn 2 + and phenol can be better described by Freundlich model than Langmuir isotherm. Phenol adsorption onto OMt was caused primarily by partitioning into an organic phase in the interlayers, and the uptakes of phenol increased with increasing alkyl chain length and loading amount of surfactant in single-cation OMt. Zn 2 + adsorption onto dual-cation OMt was due to ion exchange, formation of complexes and/or precipitation mechanism depending on the solution pH. [ABSTRACT FROM AUTHOR]

Three types of alkyl-ammonium with different branching chains and three complexants with different functional groups were used to prepare alkyl-ammonium or complexant intercalated montmorillonite nanocomposite (A-Mt or C-Mt). In addition, synergistic intercalated montmorillonite nanocomposites (A/C-Mt) with alkyl-ammonium along with complexant were also prepared. The adsorption performance of the various nanocomposites toward Zn 2+ and p-nitrophenol (PNP) from simulated binary wastewater containing both Zn 2+ and PNP were systematically investigated. Characterization of Mt nanocomposites showed that both alkyl-ammoniums and complexants were successfully intercalated into the interlayers of Mt. The surfactant loading amounts of the various nanocomposites were also determined and correlated with the resulting expansion of the interlayer spacing. It was found that intercalation of alkane (OTAC) and -SH (CSH) were conducive to the adsorption of Zn 2+ while -C 2 H 4 NH (TETA) and all alkyl-ammoniums were beneficial for PNP adsorption. The extent of adsorption was found to be controlled primarily by pH, i.e., the higher pH had a good effect on the adsorption of both Zn 2+ and PNP. The adsorption process of Zn 2+ onto Mt nanocomposites was more in line with the Freundlich model (R 2  = 0.99), while the Langmuir model described the adsorption of PNP well (R 2  = 0.99). The adsorption kinetics could be well described by the Elovich equation (R 2  = 0.98) and the double-constant model (R 2  = 0.89). Chemical adsorption was determined to be the dominant process between the contaminant and Mt nanocomposite surfaces., (Copyright © 2021 Elsevier Inc. All rights reserved.)