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Abstract: Effect of oleic acid on precipitation ratio, agglomeration and morphology of gibbsite was investigated at selected conditions. The results of titrimetric analysis suggest that oleic acid inhibit gibbsite precipitation from seeded sodium aluminate liquors, and the inhibitory effect is stronger at 65 °C than that at 75 °C. The variations of particle size distribution (PSD) indicate that the agglomeration of gibbsite is significantly enhanced when the concentrations of oleic acid are in a low range (0.01 g/L–0.05 g/L). However, relatively higher concentrations of oleic acid (>0.1 g/L) suppress agglomeration. The morphology of gibbsite was examined with scanning electron microscope (SEM). It shows that low concentrations of oleic acid in the sodium aluminate liquors lead to the formation of compact gibbsite particles, while high concentrations of oleic acid favor the growth of smooth texture of gibbsite surfaces, that is, the growth habit of gibbsite crystal changes under the influence of oleic acid. [Copyright &y& Elsevier]

Density is the most important parameter determining the performance of indium-tin oxide (ITO) targets. However, the full densification of ITO ceramics is extremely difficult. Previously reported strategies are based on the addition of components such as sintering aids or significant process adjustments. In this study, we aimed to realise the full densification of an ITO target by the fine regulation of parameters involved in the conventional pressure-less sintering process. The phase transitions, BET surface area, and particle size changes of indium-tin co-precipitated nanoprecursors sintered at different temperatures were studied. Moreover, the effects of the ITO powder state and sintering temperature on the density, resistivity, and microstructural uniformity of the ITO target were investigated. The results showed that the existence of rhombohedral In 2 O 3 in the ITO powder and ceramic sintering temperature are vital to the full densification of the ITO target. Density was found to dominate ITO-target resistivity when the sintering temperature was <1585 °C. In this study, an extraordinary high-density (99.81 %), low-resistivity (1.707 × 10−4 Ω cm), and uniform-microstructured ITO target is prepared under optimised operation conditions. [ABSTRACT FROM AUTHOR]

Recycling Sn from waste liquid crystal display (LCD) is crucial to alleviate resource shortage and prevent environmental pollution. However, the disposal of waste LCD is a complex coupling process affected by multi-factors. The lack of mature harmless and resource-based treatment process restricts the development of industrialization. Therefore, an environmentally sound process focusing on resource recovery was proposed to recover Sn efficiently and remove toxic substances from waste LCD in this study. The reaction mechanism and leaching kinetics were discussed assisted by mechanical activation, and the statistical and mathematical method (Box-Behnken Design (BBD) model) was adopted to optimize the leaching process. The results showed that the mechanical activation could improve the physical and chemical properties of ITO glass. The essence of the leaching reaction mechanism was that the H+ in H 2 SO 4 combined with O2− in the lattice of In 2 O 3 to form OH−, resulting in Sn–O bond broking and Sn4+ entering the aqueous solution. Furthermore, the Zeta potential results showed that the Zeta potential of SiO 2 particles less than 0.035 mm was close to zero near pH 2, resulting in agglomeration between SiO 2 particles under the action of Coulomb force. The leaching kinetics was well expressed by the shrinking core model. The BBD model showed satisfactory correlation between the predicted and actual results, and the particle size was the most critical factor affecting the leaching efficiency. The maximum leaching efficiency was 87.6% which was obtained under the following optimal condition: 6 mol/L H 2 SO 4 , 108 min, 88 °C, and 0.035 mm ITO glass powder. Our findings demonstrated that the developed recovery process was both efficient and environmentally sound, which had the potential in the industrialization of waste LCD recycling system. [Display omitted] • An eco-friendly process with experimental analysis and prediction model was proposed. • The process maximally recovered tin while treating hazardous liquid crystal display. • The shrinking core model was applied for the assessment of leaching kinetics. • Prediction model clarified the interaction and optimization of experiment parameters. • Besides the high efficiency the process proved to sustainability and practicality. [ABSTRACT FROM AUTHOR]

The treatment of hazardous LCD is a complicated coupled process, which contains a large number of impurity metals, especially Fe(III), increased the difficulty of In(III) recovery. Moreover, the defects of the traditional extraction process, such as extractant ageing quickly, difficulty to back-extraction, and easy emulsification, seriously restricted the efficient and environmentally friendly recovery of In. Therefore, a novel adsorbent (D2EHPA/SiO 2 –P) was synthesized for the separation and recovery of In(III), and a new recovery process was developed to eliminate the defects of traditional In recovery process in this study. D2EHPA/SiO 2 –P exhibited excellent adsorption selectivity and kinetics for In(III), and the adsorption equilibrium was obtained within 3 min. The adsorption process of In(III) conformed to the pseudo-second-order and Langmuir model. In(III) on D2EHPA/SiO 2 –P was desorbed by 3 M HCl solution, and D2EHPA/SiO 2 –P still had high adsorption and desorption efficiency for In(III) after 5 times of adsorption-desorption cycle experiments. The adsorption mechanism study found that the O–H bond on the D2EHPA participated in the substitution reaction and bonded with In(III) as the adsorption site during the adsorption process. The bond order value of In–O bond was the lowest in the D2EHPA adsorbed In(III) during the desorption process, indicating that In–O bond was easy to break and desorption form D2EHPA. Finally, in the 0.1M H 2 SO 4 system, a new process of using H 2 C 2 O 4 to reduce Fe(III) in advance, and then using D2EHPA/SiO 2 –P to adsorb In(III) was designed to recover In(III) without producing toxic gas, which realized the separation of In(III) and Fe(III). Our findings showed that the developed recovery process was both efficient and environmentally friendly, which had the potential for industrial application of In recovery from hazardous LCD. [Display omitted] • A silica-based adsorbent was successfully synthesized to separate and recover In(III). • A new process was designed to recover In(III) without producing toxic gas. • D2EHPA/SiO 2 –P showed excellent adsorption selectivity and kinetics towards In(III). • Adsorbent had good desorption and reusability proved by 5 adsorption-desorption cycles. • O–H bond in D2EHPA was involved in the binding and substitution reaction of In(III). [ABSTRACT FROM AUTHOR]