Separation of copper and indium from zinc hydrometallurgy solution

The separation and recovery of copper and indium from a solution arising from the reductive leaching of a zinc leaching residue was studied. Copper was enriched into a copper precipitate produced by iron powder precipitation; indium was hydrolyzed and enriched into a gypsum indium precipitate produced by limestone adjustment of pH. Separation and recovery of both copper and indium were achieved. The results showed that precipitation of copper(II) and arsenic(III) as Cu2O and Cu3As is thermodynamically feasible by adding iron powder to the reductive leach of a zinc leaching residue. Increasing the iron powder addition and reaction temperature promoted the formation of Cu2O and Cu3As. In the process of neutralizing and precipitating indium by adjusting the pH using limestone, indium was mainly concentrated in the precipitate by hydrolytic precipitation. The pH of the neutralization endpoint plays a decisive role in this hydrolytic enrichment. The extent of indium precipitation exceeded 98%, and the indium content of the precipitate reached 3.6 kg/t. Addition of limestone balances the acid across the entire production process. The main phase in the gypsum indium precipitate was CaSO4·2H2O, the stable properties of which create favorable conditions for the recovery of indium in subsequent steps.

PEDOT-PSS-Coated FeFe(CN)6 Composite Cathode for Lithium-Ion Batteries with the Improved Electrochemical Performances

Prussian-blue type FeFe(CN)6 nanocrystals with perfect nanocubic morphology were prepared by a facile hydrolytic precipitation method using Fe(CN)[Formula: see text] as a single iron-source. The resulting FeFe(CN)6 nanocrystals have subsequently been encapsulated within a mixed electronically and ionically conducting polystyrene sulfonic acid (PSS)-doped poly(3,4-ethylenedioxythiophene) (PEDOT) (PEDOT-PSS) with ethylene glycol (EG) as the polar solvent to obtain a high electrical conducting organic–inorganic nanohybrid. The FeFe(CN)6/PEDOT-PSS nanohybrid offers discharge capacity of [Formula: see text], which is improved compared to that of the naked FeFe(CN)[Formula: see text]. Also, it demonstrated the improved capacity retention and rate capability, which makes it a promising way for high performance Li-ion batteries for energy storage application.

Research and simulation of hydrated alumina homogeneous precipitation and its application to obtain a carrier for catalysts in the petrochemical industry

The results of studies of the process of hydrated alumina homogeneous precipitation were presented in this work. The variants of this process are considered. The most convenient embodiment of this process is the precipitation of hydrated alumina from its salts with the use of auxiliary substances, such as urea. Urea hydrolysis allows a homogeneous precipitation process under the most mild conditions. It is shown that the process of hydrolytic precipitation in the aluminum salt-urea system proceeds according to the dissociative mechanism SN1. This article analyzes the regularities of precipitation of solid colloidal particles of hydrated metal oxides on the surface of various substrates. Two models of this process are proposed. The proposed α-model is a process of continuous nucleation of interaction centers, at random points of a free surface throughout the process. The proposed β-model provides for the instantaneous nucleation of these centers when they are randomly distributed over the entire surface of the substrate. Based on the proposed models, the average values of the following values are calculated: the thickness of the gel film; its roughness and specific surface area. The calculations carried out in the article showed that these parameters are universal functions of the degree of filling of the surface and do not depend on the specific model of the mechanism of the process. Studies have been conducted on the use of homogeneously precipitated aluminum hydroxide as a binder in the preparation of porous materials. The resulting materials have a developed specific surface area and porosity.

BISMUTH TELLURID WASTE PROCESSING

The main stages of bismuth telluride processing comprising sintering with NaOH, leaching and precipitation were investigated. Bi2Te3 samples produced by "ADV Engineering" were used as starting compounds. The studies revealed regularities of tellurium behavior during the sintering of Bi2Te3 with NaOH and the resulting the solid residue leaching. It was noted that annealing at 350-450°C with NaOH transforms tellurium into Na2TeO3, which is an appropriate form for further dissolution and separation from bismuth. Increasing temperature results in Na2TeO3 oxidation and formation of the water-insoluble compound Na2TeO4. Thus, it decreases tellurium extraction degree during the leaching. It has been shown that increasing temperature from 8 to 25°C at the step of tellurium hydrolytic precipitation slightly affects the extraction degree, the value of which is 93.5-98.2%.