Demulsification Behavior of Alkali and Organic Acid in Zinc Extraction

Alkali agents could be used to enhance the extraction of zinc from solution of high concentration, but excess alkali can sensitively lead to emulsification of the solution. In this paper, the emulsification in the extraction process, demulsification, and extraction with different additives and its action mechanism were studied. The results indicate that the associated addition of alkali and organic acid could eliminate emulsification and improve zinc extraction. The extraction ratio of zinc reached 99.61% under the conditions of 104 mL/L organic acid, 80 g/L alkali, and 40% extractant concentration. Zinc hydroxide formed from hydroxyl and zinc ion at sensitively increased pH was the cause of emulsification during extraction. Associated addition of alkali and organic acid could contribute to the control solution pH in the range of 3.0–4.0, which is lower than that of the formation of zinc hydroxide, and therefore, improve zinc extraction.

Recycling and Extraction of Zinc Ions in Disc-Donut Column Considering Forward Mixing Mass Transfer, Chemical Reaction and Effects of Pulsed and non-Pulsed Condition

The current study focuses on the recovery of zinc ions by solvent extraction in the pulsed contactor. The Zn(II) ions from chloride solution were extracted into the organic phase containing D2EHPA extractant. The resulting data were characterized for the relative amount of (a) pulsed and no-pulsed condition; and (b) flow rate of both phases. Based on the mass balance equations for the column performance description, numerical computations of mass transfer in a disc-donut column were conducted and validated the experimental data for zinc extraction. Four different models, such as plug flow, backflow, axial dispersion, and forward mixing were evaluated in this study. The results showed that the intensification of the process with the pulsed condition increased and achieved higher mass transfer rates. The forward mixing model findings based on the curve fitting approach validated well with the experimental data. The results showed that an increase in pulsation intensity, as well as the phase flow rates, have a positive impact on the performance of the extractor, whereas the enhancement of flow rate led to the reduction of the described model parameters for adverse phase.

Reactive Zinc Extraction in MRDC Column; Case Study by Mathematical Modelling and Applying the Droplet Size Distribution with Forward Mixing Approach

In this survey, the reactive mass transfer data are determined for zinc extraction from chloride solution using D2EHPA in the MRDC extraction column. The numerical analysis for evaluating the column performance is applied to describe mass balance equations. Four mathematical models (backflow, forward mixing, plug flow, and axial dispersion) are investigated to compute the mass transfer coefficients of the dispersed phase. The solvent extraction experiments showed that the optimum zinc transport efficiency in rotor speed of 410 rpm in this column is equal to 98.85% and 99.85 for extraction and stripping stages, respectively. The model's achievement is compared with the solvent extraction data and a significant validity is obtained by coupling the forward mixing approach. The mathematical modeling expresses that the coefficients of axial dispersion and backflow based on the continuous phase increase by an increase in the rotor speed and inlet continuous phase rate. While these coefficients reduce at a higher inlet dispersed phase rate. The FMM method is preferred to predict the reactive mass transfer rate in the MRDC column due to the lowest relative deviation. The experimental study and mathematical modeling in this report provide beneficial information about the metallurgical industry to design solvent extraction equipment.

Investigation of the processes of dust processing gas cleaning of steelmaking industries

The article deals with the issues of processing of dust from electric steelmaking production by the method of thermodynamic extraction of iron, zinc and lead in order to reduce the environmental impact and increase the resource base of the industry. The paper presents various methods of zinc extraction from dust and gas purification, thermodynamic calculation of the decomposition and reclaiming of zinc ferrite.

Characterization and leaching of mechanically activated zinc residue

Zinc extraction from zinc-containing residual (ZCR) was examined with the leach of sulfuric acid of original materials and the materials milled in two different mill systems. For this purpose, vibrating ball mill (VBM) and ring mill (RM) were used. In chemical analysis of ZCR, it was determined that it contains a significant amount of zinc, lead, iron and silver and consisted of mostly CaSO4.2H2O, PbO, SiO2, Fe2O3, ZnFe2O4, Al2FeO4 and PbSO4 mineral phases. It was determined in XRD analysis of samples milled at both mills that peak intensity dramatically decreased when compared to original sample.According to comparative characterization analyses of the milled samples, it was determined that through the increasing grinding time, the particles became agglomerated and an increase in grain size occurred. This situation was also supported by N2-BET and SEM analyses.While zinc extraction value of the sample milled for 1 min, which was obtained at 0.5 M H2SO4 at leach temperature of 25 °C, at the solid–liquid rate of 100:1 and during the leach time of 30 min, was 90% and 60% for, respectively, VBM and RM, zinc of 54% was determined to be extracted in the leach of the original sample, under the same conditions.