Properties and Kinetics of Selective Zinc Leaching with Choline Chloride and Urea

Abstract Multiple purification of zinc sulfate solution is an important process for zinc hydrometallurgy, and large quantities of copper-cadmium residues are generated as byproducts in this process. Copper-cadmium residues contain a large number of valuable metals that must be recovered. A comprehensive extraction process has been proposed using sulfuric acid as the leaching reagent and hydrogen peroxide as the oxidizing reagent. The effects of acid concentration, leaching temperature, leaching time, liquid-to-solid ratio, hydrogen peroxide dosage and stirring speed on the leaching efficiency were investigated. The optimum conditions were determined as an acid concentration of 150 g/L, liquid-to-solid ratio of 4:1, hydrogen peroxide amount of 20 mL, time of 60 min, temperature of 30 °C, particle size of −d75 μm, and agitation rate of 300 r/min. It was concluded that the leaching efficiency of copper and cadmium reached 97%, but because of the existence of zinc sulfide in the residues, a lower leaching efficiency of zinc was obtained. Furthermore, the leaching kinetics of copper was also studied based on the shrinking core model. The activation energy for copper leaching was 5.06 kJ/mol, and the leaching process was controlled by the diffusion through the product layer.

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Deep eutectic solvents aqueous two-phase system based ultrasonically assisted extraction of ursolic acid (UA) from Cynomorium songaricum Rupr.

10.7287/peerj.preprints.3495 ◽

2017 ◽

Author(s):

Xifeng Zhang ◽

Ji Zhang

Keyword(s):

Ursolic Acid ◽

Choline Chloride ◽

Deep Eutectic Solvent ◽

Deep Eutectic Solvents ◽

Selective Extraction ◽

Phase System ◽

Green Solvents ◽

Active Components ◽

Two Phase ◽

Solid Ratio

Deep eutectic solvents (DESs) are new green solvents that have attracted the attention of the scientific community mainly due to their unique properties and special characteristics, which are different from those of traditional solvents.A method based on ultrasonically assisted deep eutectic solvent aqueous two-phase systems( UAE-DES-ATPS) was developed for extracting ursolic acid (UA) from Cynomorium songaricum Rupr. Four different types of choline chloride-based DESs were prepared.Choline chloride-glucose (ChCl-Glu) exhibited good selective extraction ability. An optimum DES-ATPS of 36% (w/w) ChCl-Glu and 25% (w/w) K2HPO4 was considered to be a satisfactory system for extracting UA. Response surface methodology (RSM) method was used to optimize the extraction of UA using UAE-DES-ATPS. The optimum ultrasound-assisted conditions were as follows: solvent to solid ratio of 15:1 (g/g), ultrasound power of 470 W, and extraction time of 54 min. Compared with the conventional UAE method, the yields were basically the same, but the presented method had higher purity. The structure of UA did not change between pure UA and UA in the upper phase by UV–vis and FT-IR. This approach using ChCl-based DES-ATPS as a novel extraction system and ultrasound as a source of energy provided better choice for the separation of active components from other natural products.

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Dissolution Kinetics of Ilmenite Ore in A Binary Solution

European Journal of Engineering Research and Science ◽

10.24018/ejers.2019.4.7.1425 ◽

2019 ◽

Vol 4 (7) ◽

pp. 51-57

Author(s):

Chukwunonso Chukwuzuloke Okoye ◽

Okechukwu Dominic Onukwuli ◽

Chinenye Faith Okey-Onyesolu

Keyword(s):

Particle Size ◽

Acid Concentration ◽

Reaction Temperature ◽

Binary Solution ◽

Product Layer ◽

Solution Temperature ◽

X Ray ◽

Solid Ratio ◽

Oxidant Concentration ◽

Kinetics Of

Leaching of iron from ilmenite ore using a binary solution (HCl-NaNO3) was investigated. The raw ilmenite ore sample was characterized using Scanning Electron Microscopy (SEM), X-ray diffraction spectroscopy (XRD) and X-ray Flourescence (XRF) techniques. The influence of acid concentration, oxidant concentration, particle size, solution temperature, stirring speed and liquid-to-solid ratios on the extent of dissolution was examined. The experimental data obtained at various process parameter conditions were tested in six kinetics models: shrinking core model’s diffusion through liquid film model(DTLF), diffusion through product layer model (DTPL), surface chemical reaction model (SCR)); mixed kinetics model (MKM), Jander (three dimensional) model and Kröger and Ziegler model. The crystalline morphology of the sample was displayed by the SEM micrograph. XRF result revealed the dominance of titanium and iron in ilmenite while XRD confirmed that ilmenite exist mainly as FeTiO2. The results of the leaching studies showed that ilmenite dissolution in the binary solution increases with increasing acid concentration, oxidant concentration, reaction temperature, stirring speed and liquid-to-solid ratio; while it decreases with particle size. The study showed that 94.77% iron was dissolved by 1MHCl-0.6M NaNO3 at 75μm particle size, 75˚C reaction temperature, 300rpm stirring speed and 30L/g liquid-to-solid ratio. The kinetics of the leaching process was best described by Kröger and Ziegler model with diffusion through the product layer as rate controlling step. The activation energy, Ea, was calculated to be 6.42kJ/mol. The results indicate that HCl-NaNO3 binary solution can be used as an effective lixiviant for extracting iron from ilmenite ores.

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The Contrast Study of Microwave Heating and Traditional Heating Leaching Vanadium from Stone Coal with Sulfuric Acid Solution

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.774-776.660 ◽

2013 ◽

Vol 774-776 ◽

pp. 660-663

Author(s):

Hong Zhou Ma ◽

Yao Ning Wang ◽

Xin Zhe Lan

Keyword(s):

Sulfuric Acid ◽

Acid Solution ◽

Microwave Heating ◽

Sulfuric Acid Solution ◽

Product Layer ◽

Contrast Study ◽

Leaching Rate ◽

Solid Product ◽

Stone Coal ◽

Kinetics Of

The aim of this paper is to contrast the effect of the microwave heating and traditional heating leaching vanadium from stone coal with sulfuric acid solution, contrast the leaching rate of vanadium, kinetics of leaching vanadium and the phase change s of slag. The experiment results show that the leaching rate and leaching velocity of vanadium with microwave heating was higher greatly than traditional heating, the kinetics of leaching vanadium with two heating methods was similar and accords with unreacted core contraction model with have solid product layer model, the illite in the stone coal was decomposed with microwave heating, but the traditional heating could not decomposed.

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Leaching Kinetics of Rare Earth Elements in Phosphoric Acid from Phosphate Rock

Metals ◽

10.3390/met11020239 ◽

2021 ◽

Vol 11 (2) ◽

pp. 239

Author(s):

Zhili Li ◽

Zhihao Xie ◽

Jie Deng ◽

Dongsheng He ◽

Hengqin Zhao ◽

...

Keyword(s):

Rare Earth ◽

Phosphate Rock ◽

Empirical Equation ◽

Product Layer ◽

Fast Reaction ◽

Solid Product ◽

Reaction Stage ◽

Shrinking Core ◽

Semi Empirical ◽

Kinetics Of

Phosphate rock has been considered as one of the most significant secondary rare-earth resource, and the utilization of rare earth elements (REEs) in phosphate rock has attracted increasing attention. In this study, the leaching kinetics of REEs from a phosphate ore from China was studied with the variation of temperature and phosphoric acid concentration under the conditions: ratio of liquid to solid of 12 mL/g, stirring speed of 120 r/min, and phosphate particle size of −0.074 mm amounts 61.1%. The results suggest that there were two distinct stages in leaching process and kinetics of both stages followed shrinking core model. At fast reaction stage, the semi-empirical equation describing the kinetics was 1 − 3(1 − α)2/3 + 2(1 − α) = 1.885CH3PO40.89exp(−11220/8.31T)t. The semi-empirical equation for slow reaction stage was 1 − 3(1 − α)2/3 + 2(1 − α) = 0.299CH3PO42.50exp(−18720/8.31T)t. Using shrinking core model and time-to-a-given-fraction method, we found that leaching rate of fast reaction stage was controlled by solid product layer diffusion, and both solid product layer diffusion and chemical reaction determined slow reaction stage.

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Leaching Kinetics of Secondary Zinc Oxide in a NH3–NH4HCO3–H2O System

Crystals ◽

10.3390/cryst11050496 ◽

2021 ◽

Vol 11 (5) ◽

pp. 496

Author(s):

Hui Li ◽

Linfei Zhao ◽

Le Wang ◽

Jinglong Liang ◽

Hongyan Yan ◽

...

Keyword(s):

Zinc Oxide ◽

Recovery Process ◽

Ammonia Concentration ◽

Product Layer ◽

Ammonium Bicarbonate ◽

Zinc Recovery ◽

Solid Ratio ◽

Total Ammonia ◽

Hydrometallurgical Method ◽

Kinetics Of

Secondary zinc oxide (SZO), which comes from the zinc industry, is an important secondary resource of zinc and other valuable metals. In this study, the production feasibility and rationality of a cleaner zinc recovery process using SZO and a hydrometallurgical method were described. Zinc extraction is promoted by the addition of ammonium bicarbonate to a NH3–H2O system, and the maximum recovery of zinc could be close to 80% at the optimum leaching conditions of a stirring rate of 400 rpm, an ammonia/ammonium ratio of 7:3, a total ammonia concentration of 4 mol/L, and a liquid/solid ratio of 7 mL/g for 30 min at 35 °C. The kinetics of leaching were modeled using the shrinking core model of constant-size particles, and the rate-controlling step was determined to be the diffusion through the product layer. The apparent activation energy of the reaction was estimated to be 11.04 KJ·mol−1, while the order of reaction with respect to total ammonia concentration was 1.53 and the liquid/solid ratio was 2.26. The analysis results of the initial residue and the leached residue indicated that lead was transferred from PbCl2 to PbCO3 and that ZnFe2O4 was not leached in the NH3-NH4HCO3-H2O system.

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Deep eutectic solvents aqueous two-phase system based ultrasonically assisted extraction of ursolic acid (UA) from Cynomorium songaricum Rupr.

10.7287/peerj.preprints.3495v1 ◽

2017 ◽

Author(s):

Xifeng Zhang ◽

Ji Zhang

Keyword(s):

Ursolic Acid ◽

Choline Chloride ◽

Deep Eutectic Solvent ◽

Deep Eutectic Solvents ◽

Selective Extraction ◽

Phase System ◽

Green Solvents ◽

Active Components ◽

Two Phase ◽

Solid Ratio

Deep eutectic solvents (DESs) are new green solvents that have attracted the attention of the scientific community mainly due to their unique properties and special characteristics, which are different from those of traditional solvents.A method based on ultrasonically assisted deep eutectic solvent aqueous two-phase systems( UAE-DES-ATPS) was developed for extracting ursolic acid (UA) from Cynomorium songaricum Rupr. Four different types of choline chloride-based DESs were prepared.Choline chloride-glucose (ChCl-Glu) exhibited good selective extraction ability. An optimum DES-ATPS of 36% (w/w) ChCl-Glu and 25% (w/w) K2HPO4 was considered to be a satisfactory system for extracting UA. Response surface methodology (RSM) method was used to optimize the extraction of UA using UAE-DES-ATPS. The optimum ultrasound-assisted conditions were as follows: solvent to solid ratio of 15:1 (g/g), ultrasound power of 470 W, and extraction time of 54 min. Compared with the conventional UAE method, the yields were basically the same, but the presented method had higher purity. The structure of UA did not change between pure UA and UA in the upper phase by UV–vis and FT-IR. This approach using ChCl-based DES-ATPS as a novel extraction system and ultrasound as a source of energy provided better choice for the separation of active components from other natural products.

Download Full-text