This study investigates the ultrasound-assisted leaching of Li and Co from spent batteries using a deep eutectic solvent (DES) composed of polyethylene glycol and thiourea. The synergistic effect of ultrasound and DESs was explored to enhance the efficiency of Li and Co recovery. The experimental results demonstrated that ultrasound significantly accelerates the leaching process, achieving up to four times higher recovery rates compared to traditional methods. Optimal leaching conditions were identified at a solid-to-liquid ratio of 0.02 g/g, a temperature of 160 °C, and periodic ultrasound exposure. Under these conditions, the leaching efficiency reached 74% for Li and 71% for Co within 24 h. A kinetic analysis revealed that the ultrasound application shifts the rate-limiting step from a mixed control of mass transfer and chemical reactions to predominantly chemical reaction control, reducing the activation energy by approximately 27%.

The potential for barium sulphate nanoparticles to be used in a variety of important fields has sparked a lot of attention. Methods for obtaining this material by milling (top-down approach) are not very popular due to the difficulty of controlling the size and shape of particles, as well as changes in their physicochemical properties during milling. More promising is the bottom-up approach, which is the interaction of Ba²⁺ and SO₄²⁻ ions in a liquid environment. Direct precipitation is the simplest method; however, it does not allow control of the particle size. Microemulsions, microreactors membrane dispersion, as well as spinning disc reactors are used to overcome drawbacks of direct precipitation and allow control of particle size and shape. This is ensured mainly by intensive controlled micromixing of the precursors with concentrations close to saturated ones. The present review focuses on recent advances in the production of barium sulfate nanoparticles using various approaches, as well as their advantages and limitations. The issues of scaling up the techniques are also considered, and promising methods for obtaining BaSO₄ nanoparticles are also discussed.

The study investigates the application of high-voltage electrical pulses (HVEP) as a pretreatment to enhance the leaching efficiency of rare earth elements (REE) from coal ash (CA) produced from the combustion of Ekibastuz Basin coal in Almaty, Kazakhstan. HVEP treatment was applied to the finest (<40 µm) non-magnetic fraction of CA under controlled conditions, optimizing discharge current, voltage, and treatment duration. Leaching experiments with 1 M citric acid at various solid-to-liquid ratios, temperatures, and durations were conducted on both treated and untreated samples. Results indicated that HVEP-treated CA significantly improved REE recovery rates compared to untreated samples, with optimal conditions achieving 74% cerium, 79% yttrium, and 77% lanthanum recovery. The leaching of untreated CA under the specified conditions allowed no more than 28% REE to be extracted into the solution. The leaching process was found to follow first-order kinetics, with the chemical reaction of metal dissolution being the rate-limiting step.

Copper smelting flue dust (CFD) is a byproduct of pyrometallurgical copper production, containing valuable metals like lead, zinc, and copper, but also hazardous arsenic, which complicates its handling and recycling. Traditional methods for arsenic removal from CFD, such as pyrometallurgical and hydrometallurgical processes, are often inefficient or result in the loss of valuable metals. This study explores the efficacy of ultrasound-assisted leaching for selective arsenic extraction from CFD, offering a potentially more efficient and environmentally friendly alternative. We employed a combination of sodium hydroxide and sodium sulfide in an aqueous solution, enhanced by ultrasonic waves, to selectively recover arsenic into solution. The optimal leaching conditions were determined to be 0.4 M NaOH, 0.2 M Na₂S, a liquid-to-solid ratio of 50 mL/g, a temperature of 80 °C, an ultrasound power of 150 W, and an ultrasound frequency of 100 kHz, under which up to 99% of arsenic was extracted within 45 min. The kinetic analysis conducted suggests that the leaching process is controlled by the chemical reactions occurring at the surface of the particles.

This paper introduces a novel method for synthesizing a cationic adhesion additive for road bitumen. The method involves condensing higher carboxylic acids and triglycerides of non-edible rapeseed oil with diethanolamine. The details of this innovative synthesis, the properties of the additive, and its action mechanism are shown in the results of this investigation. The surfactants in the synthesized products were identified by IR spectroscopy. They have significant practical implications. Different methods were used to investigate bitumen adhesion of acidic rock materials without and with additives. The results of the wetting angle study on the surface of rock materials changed from 19.81° to 80.33°, indicating a significant and remarkable improvement in its surface hydrophobicity. Moreover, the unique feature of the additive does not require dilution in organic solvents before use, which makes it highly practical for direct use.

Ammonium nitrate (AN) is of considerable interest to researchers in developing new types of energetic mixtures due to the release of environmentally benign gaseous products during burning and thermal decomposition. However, poor ignition and a low burning rate require special additives to speed up this process. The advantage of this research is the use of high-energy aluminum-based alloys as fuel to compensate for the disadvantages of AN. In addition, the effect of copper oxide (CuO) on the burning kinetics and thermodynamics of the energetic mixture based on ammonium nitrate–magnesium–aluminum alloys (AN/MgAl) is investigated. Alloys based on aluminum were created through a process of high-temperature diffusion welding, conducted in an environment of argon gas. The structure and thermal characteristics of alloys are determined by X-ray diffraction, scanning electron microscopy, and DTA-TG analyses. It has been found that CuO has significant effects on the thermal decomposition of an AN/MgAl-based energetic mixture by shifting the decomposition temperature from 269.33 °C to 261.34 °C and decreasing the activation energy from 91.41 kJ mol⁻¹ to 89.26 kJ mol⁻¹. Adding CuO reduced the pressure deflagration limit from 2 MPa to 1 MPa, and the linear burning rate of the AN/MgAl energetic mixture increased approximately twice (r_b = 6.17 mm/s vs. r_b = 15.44 mm/s, at a chamber pressure of P₀ = 5 MPa).