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Aiming at leaching solution of indium residue produced by zinc hydrometallurgy, rotating disk extraction tower was used to separate indium and iron from the solution. The extraction effects of indium and iron ions in the solution, the extraction sequence of metal ions, the separation effect and emulsification of light and heavy phases was studied. The influences of the rotating disk rotating speed, feed flow rate, concentration of P204, solution acidity, reaction temperature and the phase ratio on separation effects were examined. The results show that under the optimal conditions of reaction temperature of 25 °C, heavy phase volume flow rate of 7. 8 L/h, P204 concentration of 20%, rotating disk rotating speed of 360 r/min, initial acidity of 60 g/L, Vo/VA phase ratio of 1/1, the extraction rate of indium can reach 75%, the extraction rate of impurity element iron is less than 5%. The light and heavy phases are basically completely separated, and there is no emulsification. The result of extraction isotherms shows that complete extraction of indium can be achieved by three-stage countercurrent extraction under the condition of Vo/VA phase ratio of 1/1. The loaded organic phase is pre-washed with dilute sulfuric acid, and then stripping with 5 mol/L hydrochloric acid under the condition of Vo/VA = 1/1. And the extraction rate of indium is more than 98%. After the replacement treatment, the stripping solution can be directly returned to zinc hydrometallurgy, the organic phase can be recycled after scrubbing. [ABSTRACT FROM AUTHOR]

The main study object is the lead-zinc mixed concentrate(zinc sulfide concentrates) obtained by the secondary beneficiation of tailings, aiming at the characteristics of high lead content and low iron content. The effects of oxygen pressure leaching of different zinc sulfide concentrates were compared, and the oxygen pressure leaching behavior of high lead and low iron zinc sulfide concentrates was analyzed. The results show that the low iron zinc concentrate needs to add 5 g/L iron to transfer oxygen in the second stage, the leaching rate of zinc is more than 99%, and the leaching rate of copper is about 90%. Most of the iron enter into the leachate with zinc in the form of divalent iron, and a small part enter into the residue. It exists in the form of pyrite with a small amount of iron oxide. Lead, silver and silicon are basically precipitated into the residue and enriched in the result. The leaching residue can realize the recovery of valuable metals such as lead and silver, and the sulfur in the concentrate is mainly in the form of elemental sulfur. In the two-stage oxygen pressure countercurrent leaching, copper in the second stage leaching solution will precipitate into the first stage residue, which will accumulate in the system until equilibrium. The final residue contains 0.16% copper, and the first stage leaching solution contains 1.00 g/L copper, which has high recovery value. [ABSTRACT FROM AUTHOR]

In light of environmental issues, the lead-free ferroelectric single crystal K(Ta 1- x Nb x )O 3 (KTN) has attracted considerable interest due to its excellent piezoelectric properties. This research focus on improving the piezoelectric performance of KTN by engineering domains through polarization in the [011] c direction. The full-matrix parameters of KTN crystals after polarization along the [011] direction were determined. The finding reveal that KTN polarized in the nonspontaneous polarization direction [011] c exhibits higher piezoelectric constants ( d 33 = 156 pC/N, d 15 = 155 pC/N) and dielectric constants (ε 33 T ∼ 2337). Additionally, tensor matrix transformation techniques were utilized to analyze the directional dependence of the piezoelectric ( d 33 * ), dielectric (ε 33 T * ), elastic ( s 33 E * ) constants, and electromechanical coupling coefficient ( k 33 * ). The results indicate that these constants reach their maximum values along the polarized [011] c direction. A comparison of the experimental polarization values in the [011] c direction with those calculated for a single-domain state, demonstrates that ferroelectric domains in KTN crystals contribute significantly to the piezoelectric properties. Finally, polarized light microscopy was used to conduct a detailed analysis of the domain structure in KTN single crystals, revealing various orientations and sizes of domain walls. This research offers strategies for optimizing piezoelectric performance.