Ultrasonic Leaching Research Articles

Mechanism and Kinetic Study on Ultrasonically Enhanced Reduction Leaching of Zinc Suboxide.

The leaching process represents the primary bottleneck in achieving efficient utilization of zinc suboxide, thereby resulting in a squandering of germanium resources. In this Article, the kinetic mechanisms of conventional and ultrasonic enhanced reduction leaching of zinc suboxide were investigated while optimizing the leaching conditions. The optimized conditions for the ultrasonic enhanced reduction leaching process were found to be 358 K, FeS of 0.6% zinc suboxide mass, and 300 W of ultrasonic power. The leaching efficiency of germanium can reach 91.34% under these conditions, exhibiting an improvement of 8.51%, compared with conventional conditions. Moreover, the Fe3+ concentration in the leaching solution is consistently maintained at ∼15 mg/L, satisfying the requisite criteria for germanium precipitation. Moreover, both the conventional and ultrasonic leaching processes obey the Drozdov kinetic model and are governed by internal diffusion. The difference, however, is that, under ultrasonic conditions, the activation energy of the reaction is reduced by 2.05 kJ/mol, the self-resistance coefficient is smaller, the reaction rate is faster, and the germanium leaching efficiency is higher than under conventional conditions. Ultrasonically enhanced FeS reduction leaching disrupts the encapsulation of silica gel and lead sulfate, shattering large dust grains and reducing the surface tension and viscosity of the solution, thus reducing the energy barrier to the leaching of germanium-containing components and improving the kinetics. The present study elucidates the kinetic laws governing conventional and ultrasonic processes, thereby offering guidance and a theoretical foundation for enhancing the germanium leaching efficiency in zinc suboxide. These findings hold significant implications for maximizing the utilization of germanium resources and advancing the development of the germanium industry.

Greener and Sustainable Production: Production of Industrial Zinc (II) Acetate Solution and Recovery of Some Metals (Zn, Pb, Ag) from Zinc Plant Residue by Ultrasound-Assisted Leaching

Zinc plant residue (ZPR) contains significant amounts of valuable metal (Zn, Pb, Ag, etc.) compounds, as well as various heavy metals and harmful compounds that pollute the environment. Processing such residues allows for the recovery and reuse of valuable metals, which is crucial for sustainable resource management. This study investigated a two-stage leaching process of Zn, Pb, and Ag recovery from ZPR. The first stage of ultrasonic-assisted leaching of ZPR was applied to produce an industrial selective zinc acetate solution. Leaching experiments were carried out with an ultrasonic device in the presence of acetic acid, known as organic acid. Under optimum leaching conditions, the extraction of Zn and Fe metals was obtained as 76.13% and 1.32% Fe, respectively. According to the Brunauer–Emmett–Teller (BET) analysis results on the original sample and ultrasonic leaching residue (ULR), the BET surface area and micropore area increased. However, the mean adsorption pore width decreased. In the second stage, conventional sodium chloride leaching was applied to recover lead and silver from the remaining solid after the first stage. Under the optimum conditions in this stage, 80.12% of Pb and 96.2% of Ag were extracted. The presence of coordination between Zn2+/AcO− (acetate) and Pb2+/Cl− complexes in the leaching solution was revealed by Raman spectroscopy. Finally, according to the characterization analysis of the final leaching residue, it was determined that iron oxides and silicate species accumulated in the solid. In conclusion, a significant reduction in the rate of pollution and toxic metals in ZPR was noticed.Graphical

Innovative Recovery of Vanadium from Vanadium–Chromium-Reducing Residue by Ultrasonic-Assisted Alkaline Leaching

ABSTRACT Vanadium–chromium-reducing residue (VCRR) was generated using a sodium-roasting-leaching-precipitation process for vanadium recovery. The retained vanadium and chromium could be utilized for an important sources. Here, a novel process was developed that utilized ultrasonic to enhance the alkaline leaching process of vanadium from VCRR. The effect of various parameters was studied, and a corresponding kinetic model was established. It was found that the maximum vanadium leaching efficiency of 96.9% was obtained at optimum reaction conditions: reaction temperature of 90°C, reaction time of 60 min, dosage of NaOH at m(NaOH)/m(VCRR) = 0.5 g/g, liquid-to-solid ratio of 5 mL/g, stirring rate of 500 rpm, and ultrasonic frequency of 40 kHz. The leaching kinetics analysis showed that the leaching process was controlled by diffusion through a product layer both in normal leaching and ultrasonic leaching. The calculated Ea for vanadium leaching out was 20.56 kJ · mol−1 for ultrasonic leaching and 23.06 kJ · mol−1 for normal leaching. Ultrasonic-assisted leaching might be a potential industrial application technique for recovery of valuable metals from metal ores.

Ultrasound assisted sodium-chlorate leaching of selenium from copper anode slime

This study proposes an environmentally friendly process for recovering selenium from copper anode slime, a resourceful solid waste. Selenium is recovered during exposure to chlorine radicals and ultrasonic waves, which cooperate to stimulate advanced oxidation processes in the wet selenium extraction process. The influences of different experimental parameters on the selenium leaching efficiency were investigated. The ultrasonic selenium leaching efficiency reached 98.2% under the optimum conditions, whereas the deseleniumization efficiency of conventional leaching was only 57.5%. A series of mineral characterization tests proved that the ultrasonic leaching process improved the leaching efficiency by fully breaking the raw ores. The sodium chlorate process with ultrasound is a promising hydrometallurgical approach for the efficient and profitable extraction of a value-added product (selenium) from hazardous waste (copper anode slime).

Pulse ultrasonication leaching approach for selective Li leaching from spent LFP cathode material

ABSTRACT Lithium-iron-phosphate (LFP) batteries are a type of battery whose usage is increasingly expanding due to their features and low production costs. The recovery of precious metals from discarded LFP batteries, resulting from their growing utilization, holds significance from both environmental and economic perspectives. Hydrometallurgical recycling of LFP has gained attention due to its cost-effectiveness and environmental considerations. This study explores the application of ultrasound-assisted leaching as an alternative to conventional hydrometallurgical leaching processes, yielding promising results. The utilization of ultrasound facilitates efficient Li solubility within a short duration of 15 min, eliminating the need for prolonged leaching times. Moreover, selective Li solubility was achieved without the use of additional oxidizing agents through the calcination of the LFP cathode powders. In the ultrasonic leaching of uncalcined powders, a Li dissolution efficiency of 98.60% was obtained, while the Fe dissolution efficiency remained at 32.46%. However, in the ultrasonic leaching of calcined powders, the Li dissolution efficiency was 90.66% within 15 min, while the Fe leaching efficiency remained at 4.88%. Thermodynamic models were employed to elucidate all leaching processes, and the influential parameters were discussed. Furthermore, Al current collectors were successfully recycled, resulting in the production of amorphous Al2O3 powders.

Improved Palladium Extraction from Spent Catalyst Using Ultrasound-Assisted Leaching and Sulfuric Acid–Sodium Chloride System

This paper presents a process for efficiently recovering palladium (Pd) from spent Pd/Al2O3 catalysts used for hydrogenation reactions, using ultrasound-assisted leaching (UAL). A system composed of H2SO4 and NaCl was investigated under ultrasound-enhanced conditions and compared to regular leaching methods to demonstrate the superiority of UAL. Single-factor experiments were conducted to determine the optimal conditions for leaching, which included an ultrasound power of 200 W, a liquid–solid ratio of 5:1, a leaching time of 1 h, a leaching temperature of 60 °C, H2SO4 concentration of 60%, and 0.1 mol of NaCl. The leaching rate under these conditions was found to be 99%. Additionally, kinetic analysis of the UAL process showed that the apparent activation energy of the Pd leaching reaction was 28.7 kJ/mol, and it was found that Pd leaching from spent catalysts was controlled by diffusion. The tailings were analyzed by SEM, revealing that during ultrasonic leaching, the specific surface area of the spent catalyst increased, the mass transfer rate of the solution was accelerated, the passivation film on the surface of the spent catalyst was peeled off, and a new reaction interface was formed. This improved the leaching rate of Pd and provided a new approach to efficiently leach precious metals such as Pd from spent catalysts.

Effect of ultrasound power on HCl leaching kinetics of impurity removal of aphanitic graphite

This study aimed to investigate the effect of ultrasonic power and temperature on the impurity removal rate during conventional and ultrasonic-assisted leaching of aphanitic graphite. The results showed that the ash removal rate increased gradually (∼50 %) with the increase in ultrasonic power and temperature but deteriorated at high power and temperature. The unreacted shrinkage core model was found to fit the experimental results better than other models. The Arrhenius equation was used to calculate the finger front factor and activation energy under different ultrasonic power conditions. The ultrasonic leaching process was significantly influenced by temperature, and the enhancement of the leaching reaction rate constant by ultrasound was mainly reflected in the increase of the pre-exponential factor A. Ultrasound treatment improved the efficiency of impurity mineral removal by destroying the inert layer formed on the graphite surface, promoting particle fragmentation, and generating oxidation radicals. The poor reactivity of hydrochloric acid with quartz and some silicate minerals is a bottleneck limiting the further improvement of impurity removal efficiency in ultrasound-assisted aphanitic graphite. Finally, the study suggests that introducing fluoride salts may be a promising method for deep impurity removal in the ultrasound-assisted hydrochloric acid leaching process of aphanitic graphite.

Study on ultrasonic leaching and recovery of fluoride from spent cathode carbon of aluminum electrolysis.

Under the assistance of ultrasound, the fluoride in the spent cathode carbon of aluminum electrolysis was recovered by the process of washing first and then leaching. The effects of time, temperature, liquid-solid ratio, ultrasonic power, alkali amount and acid concentration on the leaching rate of fluoride were investigated. The useful components in the leaching solution were recovered by evaporation crystallization and cryolite regeneration. The tests of X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), and scanning electron microscopy combined with energy dispersive spectroscopy (SEM-EDS) showed that under the optimal experimental conditions (water washing: 50 s, 3 : 1, 420 W; alkaline leaching: alkali amount 1 g, 60 min, 70 °C, 7 : 1, 480 W; acid leaching: acid concentration 0.6 mol L-1, 60 min, 5 : 1, 70 °C, 480 W), the leaching rate of fluoride was 82.99%, and the fluoride contents recovered in the water washing and leaching processes are 94.67% and 95%, respectively. There is no solid waste and waste water in the whole experimental process.

Leaching of rubidium from biotite ore by chlorination roasting and ultrasonic enhancement

Aiming at the problems of the low grade of rubidium (Rb) in biotite, and long leaching time and low leaching efficiency of Rb in mica ore, the chlorination roasting-assisted ultrasonic enhanced water leaching method was employed to extract Rb from biotite ore in this study. During the chlorination roasting process, the optimal conditions were obtained, namely roasting temperature 900 °C, roasting time 40 min, and the mass ratio of ore to calcium chloride 1:1, the optimum leaching rate was 96.75 %. Compared with conventional leaching, the ultrasonic field could greatly shorten the leaching time and realize fast and efficient leaching of Rb. The optimal conditions for ultrasonic enhanced leaching were: ultrasonic power 100 W, leaching temperature 60 °C, leaching time 20 min, liquid–solid ratio 4:1, the Rb leaching rate was 98.73 %, which was 40 min shorter than conventional leaching. The particle size and SEM results indicated that the samples by ultrasonic leaching were smaller, no agglomeration phenomenon in a large area, and the surface of the samples was relatively smooth.

Study on Ultrasonically-Enhanced Deep Eutectic Solvents Leaching of Zinc from Zinc-Containing Metallurgical Dust Sludge

In this study, the zinc containing dust and sludge of iron and steel smelting was taken as the research object, and the new ionic liquid of choline-urea was prepared and synthesized as the leaching agent. The conventional and ultrasonic leaching of zinc were compared, and the influence of liquid-solid ratio, temperature, time, ultrasonic power and other conditions on the zinc leaching rate were analyzed. The leaching residue was characterized by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-ray diffraction (XRD), and the kinetic equations of ligand leaching based on ultrasonically enhanced metallurgical dust sludge were constructed. The results showed that the choline chloride-urea ionic liquid has a special solubilization ability for ZnO, and the leaching rate of Zn at temperature 60 °C, ultrasonic power 350 W, and leaching time 240 min reached more than 98%. Kinetic fitting of the ChCl-urea leaching process revealed that the ChCl-urea leaching process was in accordance with the nucleation contraction model under both conventional and ultrasonic conditions, and the leaching process was dominated by interfacial mass transfer and solid film layer diffusion control for the reactions, respectively. The activation energies were Ea1 = 44.56 kJ/mol and Ea2 = 23.06 kJ/mol.

Recovery of Rare Metals from Superalloy Scraps by an Ultrasonic Leaching Method with a Two-Stage Separation Process

Superalloy scraps are deemed as potential unconventional sources of rare metals. In this study, an ultrasonic leaching method with a two-stage separation process was proposed. A series of Eh-pH diagrams for rare metals was constructed, and the results indicated that the leaching and separation process could be realized by adjusting the potential and pH values of leaching solutions. In the ultrasonic leaching process, results showed that the economic leaching percentages of Re, Ni, Co, Al, and Cr were 92.3%, 95.2%, 98.5%, 98.7%, and 97.5%, respectively. Compared with conventional leaching, ultrasonic leaching can improve the leaching percentages of rare metals by approximately 20%. In the two-stage separation process, the optimal recovery efficiencies of Al and Cr were 94.6% and 82.1% at a pH of 4.5, and Ni and Co were 99.5% and 98.3% at a pH of 7.5. With a two-stage precipitate process, rare metals can be efficiently recovered without generating any waste acid.

One-stage ultrasonic-assisted calcium chloride leaching of lead from zinc leaching residue

To efficiently leach Pb from Zn leaching residue, an ultrasonic-assisted one-stage leaching process was developed and compared with a two-stage leaching process under conventional conditions. The results showed that Pb leaching efficiency reached up to 83.8% under the optimized one-stage ultrasonic leaching conditions (including 480 W of ultrasonic power, 100 min duration, 350 g/L of CaCl2, 5:1 of liquid-solid ratio, 35°C, and pH of 3), higher than that under conventional process with same conditions (65.7%). A diffusion model controlled the ultrasonic-assisted leaching process at 7.57 kJ/mol activation energy. X-ray diffraction and scanning electron microscopy showed that the mineral phase of Pb-containing anglesite disappeared during the leaching. By contrast, the Zn-containing franklinite minerals and Zn orthosilicate remained in the leached residue. The possible leaching mechanism of the ultrasonic-assisted effect was related to that the Pb released from Zn leaching residue by forming PbCl42− in the leachate, avoiding PbCl2 precipitation under the conventional method. Moreover, introducing could lower the leaching temperature and reduce the amount of leaching agent, which could potentially be a sustainable technique for increasing the leaching efficiency of Pb from Zn leaching residue.

The effect of ultrasound on the sulfuric acid leaching of uranium by use of MnO2 as a oxidant

ABSTRACT The paper reported sonochemical leaching of uranium from black shale in Fe2+-containing sulfuric acid solution of pH 2 using MnO2 as an oxidant. Ultrasound enhanced uranium leaching at the initial time but suppressed it over a prolonged time. In addition, the amount of MnO2-input was increased for ultrasonic leaching than conventional leaching at the same time. It was understood that ultrasonic leaching conditions should be optimized to achieve a positive effect. Faster leaching of uranium and reduced consumption of MnO2 could be found under the optimum condition of leaching up to ca. 85% at the sonication power of 25 W.

Study on Ultrasonically-Enhanced Sulfuric Acid Leaching of Nickel from Nickel-Containing Residue

In this paper, nickel-containing residue, a typical solid waste produced in the battery production process, was used to study the cavitation characteristics of ultrasonic waves in a liquid–solid reaction. The ultrasonically-enhanced leaching technology for multicomponent and complex nickel-containing residue was studied through systematic ultrasonic-conventional comparative experiments. An ultrasonic leaching kinetics model was established which provided reliable technological guidance and basic theory for the comprehensive utilization of nickel-containing residue. In the study, it was found that ultrasonically-enhanced leaching for 40 min obtained the same result as conventional leaching for 80 min, and the Ni extraction degree reached more than 95%. According to the kinetic fitting of the leaching process, it was found that the sulfuric acid leaching process belonged to the diffusion-controlled model of solid product layers under conventional and ultrasonic conditions, and the activation energy of the reaction was Ea1 = 17.74 kJ/mol and Ea2 = 5.04 kJ/mol, respectively.

Recovery of nickel from spent NiCd batteries by regular and ultrasonic leaching followed by electrodeposition

This study focuses on the hydrometallurgical route of separating Ni metal from spent nickel cadmium (NiCd) batteries. The comparison of separation of nickel metal with the assistance of ultrasonic leaching and regular leaching was performed. Sulphuric acid (solvent) was used as the lixiviant to leach out the nickel metal ions from the spent battery and the parameters affecting the leaching with and without ultrasonication were optimized. The major parameters affecting the leaching process are volume of solvent, concentration of lixiviant and leaching time. The electrodeposition of nickel metal ions from ultrasonically assisted and regular leaching was carried out at an optimized current density of 8 A dm-2, contact time of 4 hours and the concentration of lixiviant of 5 M. It was observed that the recovery efficiency for ultrasonically assisted leaching followed by electrodeposition is 98.5 %, while in regular leaching followed by electrodeposition is 90.8 %.

Microwave and Ultrasound Effect on Ammoniacal Leaching of Deep-Sea Nodules

The influence of ultrasound and microwaves on extraction of copper, nickel, and cobalt from manganese deep-sea nodules by reductive ammoniacal leaching in the presence of ammonium thiosulfate as a reducing agent was studied. The ultrasonic ammoniacal leaching provides higher metals extraction, while the effect of microwaves on the metals extraction under the studied leaching conditions is insignificant. In general, increasing leaching temperature increases significantly extraction of the metals of interest. At high temperatures, extraction efficiencies of copper, nickel, and cobalt decrease over longer leaching duration as a result of decomposition of the metals amino-complexes and reverse precipitation of metals. However, during the ultrasonic leaching at a temperature of 85 °C, the extraction of nickel remains almost unchanged over longer leaching durations and does not follow the decreasing course, observed in the extraction of copper and cobalt. The finding suggests that nickel can be selectively extracted from the nodules by the ultrasonic leaching. The maximal extraction efficiency of copper, nickel, and cobalt was 83%, 71%, and 32%, respectively, when the reductive ultrasonic ammoniacal leaching was carried out at 85 °C for 90 min. In the presence of microwaves, the maximal extraction efficiency of copper, nickel, and cobalt was 67%, 48%, and 8%, respectively, when the reductive ultrasonic ammoniacal leaching was carried out at the output power of 60 W for 210 min.

Ultrasonic-assisted cleaning of Indian low-grade coal for clean and sustainable energy

Abstract In this study, the ability of ultrasound was described in cleaning Indian low-grade coal in the presence of leaching reagent particularly emphasizing the role of ultrasound in demineralization. Moreover, the focus has been made on the development of a novel technique for coal cleaning and the possibilities of scaling-up of the proposed process. It was proved that there is the superiority of ultrasonic leaching over pressure leaching under the optimized conditions. This superiority was supported by employing studies on leached coals using different techniques such as X-ray Diffraction (XRD), Fourier Transform Infrared (FTIR) Spectroscopy, Raman Spectroscopy, Scanning Electron Microscopy (SEM), and Thermogravimetric Analysis (TGA). The fuel properties of coals were determined in term of fixed carbon content, ash composition, degree of demineralization, Carbon-Hydrogen-Nitrogen-Sulphur (CHNS) content, gross calorific value (GCV), and ash fusion temperature (AFT). Comments and discussions are also made on the feasibility of scaling-up of the process addressing various technological limitations and their possible solutions.

Ultrasound-assisted oil removal of γ-Al2O3-based spent hydrodesulfurization catalyst and microwave roasting recovery of metal Mo

Currently, roasting-leaching is the main treatment process of spent hydrodesulfurization (HDS) catalyst, but it will produce impurities, such as nickel molybdate and cobalt molybdate (NiMoO4 or CoMoO4), which is adverse to recover valuable metals. In this paper, a combined ultrasonic-microwave method was developed to remove oil and recover molybdenum (Mo) from the spent HDS catalyst. Firstly, ethanol was used to extract the surface oil of the spent MoNiCo/Al2O3 catalyst with ultrasonic assistance. Effects of temperature, ultrasonic time, liquid-solid ratio and ultrasonic power on the oil removal rate were investigated systematically and the process conditions were optimized using response surface methodology (RSM). The results showed that the oil removal rate was over 99% under the optimum conditions of temperature 55 °C, ultrasonic time 2 h, liquid to solid ratio 5:1, and ultrasonic power 600 W. After oil removal, the sample was roasted in microwave field at 500 °C for 15 min. The generation of toxic gas could be effectively avoided and no hardest-to-recycle impurity CoMoO4 was found. At last, the roasted sample was subjected to ultrasonic leaching with sodium carbonate (Na2CO3) solution for recovering Mo. Extraction of Mo of the deoiled sample after microwave roasting reached 94.3%, which is about 7% higher than that of oily sample. Moreover, microwave roasting method resulted in a much higher Mo extraction than traditional method for both the oily and deoiled spent catalyst. It was concluded that the ultrasonic-microwave assisted method could remarkably improve the recovery of Mo and greatly shorten the processing time.

Ultrasound augmented leaching of nickel sulfate in sulfuric acid and hydrogen peroxide media

A new method of preparation high purity nickel sulfate assisted by ultrasonic was studied. The process mechanism was analyzed by Inductively Coupled Plasma (ICP), X-ray diffraction (XRD), Scanning electron microscopy (SEM), and Energy dispersive X-ray spectrometry (EDS).The reaction mechanisms of oxidizing leaching and ultrasonic leaching were explored, respectively. Results showed that ultrasonic treatment peel off the oxide film on the surface of nickel. The leachate under strongly agitated, the yield rate of nickel sulfate was accelerate. And the reaction area was increased by the cavitation effect, the liquid-solid reaction was promoted, and the activation energy was reduced. The leaching rate of nickel reached 46.29% by conventional leaching, which takes about 5h. Under the same conditions, the ultrasonic leaching rate reached 40%, only half of the conventional leaching time. Concentration of leaching agent, reaction temperature, ultrasonic power, leaching time had significant effect on the enhancement of the leaching reaction with ultrasonic radiation. The leaching rate of 60.41% under the optimum experiment conditions as follows: sulfuric acid concentration 30%, hydrogen peroxide 10%, leaching temperature 333K, ultrasonic power 200W and leaching time 4h. The kinetic study of the system was investigated, and the reaction rates of conventional leaching and ultrasonic leaching were controlled by diffusion, and the apparent activation energies were 16.2kJ/mol and 11.83kJ/mol.

Comparison of Probe with Bath Ultrasonic Leaching Procedures for Preparation to Heavy Metal Analysis of Bio-Collectors Prior to Atomic Absorption Spectrometry

ABSTRACTBoth comparison and optimization of two sample preparation methods (probe and bath) based on leaching of lead (Pb), zinc (Zn), manganese (Mn) and nickel (Ni) from bio-collector sprouts (Pinus sylvertris L., Picea orientalis L., Thuja orientalis L.) under ultrasonic effect has been examined. The best analytical conditions influencing leaching such as sonication times, acid type, acid concentrations, ultrasound amplitude and sample position (wet, dry and grinding) were determined. Leachatants obtained upon sonication were directly nebulized into an air-acetylene flame for fast metal determination by atomic absorption spectrometry (AAS). Optimum conditions for ultrasonic metal leaching were as follows: a 15 min for probe or 30 min for bath sonication time, wet sample position, nitric acid (HNO3) solvent, 1% (w/v) for probe or 2% (w/v) for bath solvent concentration and 20% amplitude for probe. Comparable results for the ultrasonic leaching with probe (UL-P) and the ultrasonic leaching with bath (UL-B) for metals in certified reference material and bio-collectors have been obtained. Besides, UL-P reduces the time required for all treatments with UL-B approximately from 30 min to 15 min. The accuracy of methods was tested either by comparing obtained results with those of ashing method (AM) or by application on a certified reference material (CRM-7, Tea Leaves). The recoveries of metals using CRM-7 ranged from 94% to 104% for UL-P and 91% to 101% for the UL-B. The precision variance either between UL-P and UL-B or UL-P and AM was not significant at 0.05 probability for all metals. The relative standard deviation % was obtained between 3.4–7.6% (n = 3) and 4.7–9.5% (n = 3) for UL-P and UL-B, respectively, depending on the analyte.