In Part II of this series of review papers, the reaction mechanisms, thermodynamics, slag chemistry and process flowsheets are analyzed concerning cases where the TSL bath smelter has found its application. These include the primary and secondary production routes of five non-ferrous metals (tin, copper, lead, nickel, zinc), ironmaking and two waste-processing applications (spent pot lining and municipal solid waste/related ash treatment). Thereby, chemistry and processing aspects of these processes are concisely reviewed here, allowing for clear and in-depth overview of related aspects. In contrast to Part I, the focus lies on a holistic analysis of the metallurgical processes themselves, especially the particularities induced by carrying them out in a TSL reactor rather than on the respective equipment and auxiliaries. The methodology employed per metal/application is presented briefly. Firstly, the feed type and associated statistical information are introduced, along with relevant process goals, e.g., the secondary metallurgy of copper involves the recovery of platinum group metals (PGMs) from waste from electrical and electronic equipment (WEEE). Subsequently, associated chemistry is discussed, including respective chemical equations, analysis of the reaction mechanisms and phase diagrams (especially of associated slag systems); these are redrawn using FactSage 8.1 (databases used: FactPS, FToxid, FTmisc, FTsalt and FTOxCN) and validated by comparing them with the literature. Then, based on the above understanding of chemistry and thermodynamics, the flowsheets of several industrial TSL plants are introduced and discussed while providing key figures associated with process conditions and input/output streams. Finally, this article culminates by providing a concise overview of the simulation and digitization efforts on TSL technology. In light of the foregoing discourse, this paper encapsulates basic principles and operational details, specifically those pertaining to TSL bath smelting operations within the non-ferrous industry, thereby offering valuable insights intended to benefit both scholarly researchers and industry professionals.

Part I of this series of papers focuses on plant and reactor engineering aspects of the TSL reactor technology. A general flowsheet is presented, while emphasis is given to the definition of different reactor zones in terms of fluid dynamics and occurring reactions. Then, the technical advantages of TSL processing, such as feed flexibility and high conversion rates (due to induced turbulence), low dust generation, and low fugitive emissions, are explained. In addition, the reactor is analyzed part by part, also taking into account patent literature, focusing on furnace design, settling furnaces for molten phase disengagement, feeding systems regarding input material streams such as concentrates and fuels, vessel cooling arrangements, off-gas system, and aspects associated with the refractory lining. Furthermore, specific focus is given to the centerpiece of the TSL reactor, i.e., the reactor lance. Associated developments have focused on establishing a slag coating to hinder lance wear, i.e., the development of cooling mechanisms (e.g., use of fluid-cooled lance and shroud arrangements), the increment of O₂ enrichment within the incoming air stream, and influencing of fluid dynamics (e.g., O₂ conversion at the lance tip, bubble formation, and bath splashing). Finally, comprehensive tables concerning process developments and commissioned TSL plants are provided thus concluding Part I of the review.

The state-of-the-art technology of raw silver refining in a silver nitrate-based electrorefining process (Moebius-electrolysis) is accompanied by several disadvantages, both from a technological and from an ecological point of view. In addition, increasing concentrations of critical impurities from secondary sources, like palladium, in raw silver are a further challenge for the future of silver refining. Thus, there is strong motivation for the development of an adequate, alternative process of raw silver refining to substitute the existing Moebius-electrolysis. Due to its less environmentally toxic character and the high aqueous solubility of its silver salt, methanesulfonic acid (MSA) is a possible base chemical for the design of an efficient refining method based on leaching of raw silver followed by electrowinning, with less ecological and technological complications. In this paper the results of some fundamental investigations on the leaching of raw silver granules, containing approx. 94% silver, with methanesulfonic acid and hydrogen peroxide as an oxidation agent are presented. Agitation leaching experiments were conducted on a laboratory scale and the effects of the solid concentration, the hydrogen peroxide dosage and the temperature as leaching parameters were studied. The obtained results indicate that silver leaching yields of more than 90% are achievable with leaching at elevated temperatures of 65 °C or 80 °C, solid concentrations of 500 g/L and at a stoichiometric H₂O₂:Ag-ratio of 3:1. Increased solid concentrations greater than 500 g/L and elevated temperatures of 65 °C or 80 °C additionally improved the selectivity of the process regarding the leaching of Pd.

The recycling of material containing precious metals can lead to the entry of ruthenium into the copper electrowinning process, by so far unknown effects. There, ruthenium is oxidized to highly volatile ruthenium tetroxide. In order to avoid ruthenium losses during electrolysis, the oxidation behavior of ruthenium in copper electrowinning was investigated by testing different oxygen overvoltages using lead alloy and diamond anodes. Furthermore, the temperature and the current density were varied to investigate a possible chemical or electrochemical reaction. The results of the study show that ruthenium is not directly electrochemically oxidized to ruthenium tetroxide at the anode. Especially at anodes with high oxygen overvoltage, the formation of other oxidants occurs parallel to the oxygen evolution in the electrolyte. These oxidants oxidize ruthenium compounds to highly volatile ruthenium tetroxide by chemical reactions. These reactions depend mainly on temperature; the formation of the active oxidants depends on the anodic potential. To avoid ruthenium losses in the copper electrowinning process, anodes with a low anodic potential should be used at low electrolyte temperatures.

Top Submerged Lance (TSL) technology is widely used in non-ferrous smelting, yet in-situ bath dynamics remain challenging to quantify because the process operates in a closed, high-temperature, highly turbulent and optically inaccessible environment. The absence of direct diagnostics limits the ability to relate operating conditions to bubble dynamics, gas penetration and bath agitation and constrains validation of multiphase CFD models under realistic conditions. This study introduces a multimodal sensing framework that combines spectral acoustic analysis with lance-mounted inertial motion sensing to characterize dynamic bath behavior across cold-model, laboratory-scale and pilot-scale systems. Water-glycerin experiments establish repeatable acoustic signatures of individual bubble-collapse events, with dominant emission bands in the 300–900 Hz range and higher-frequency components extending into the kilohertz domain. High-temperature laboratory trials using fayalitic slag reproduce these frequency regions while exhibiting depth-dependent attenuation and clear spectral separation between submerged and non-submerged lance operation. Power Spectral Density (PSD) and cumulative spectral power analyses resolve the influence of gas flow rate and lance submersion depth on acoustic spectral power distribution, while inertial measurements capture corresponding increases in vertical lance acceleration associated with back-pressure fluctuations. Pilot-scale trials at 120 Nm³/h air and 13 L/h diesel confirm that shallow lance submersion substantially increases measured acoustic spectral power below 3 kHz, whereas deeper penetration enhances periodic vertical acceleration response measured by the inertial sensor. The combined acoustic-inertial methodology provides a physically interpretable and cross-scale framework for assessing bubble collapse activity, plume interaction and bath agitation under high-temperature TSL conditions. The approach enables frequency-based diagnostics that can be systematically compared with CFD predictions of plume oscillation and collapse-related dynamics. Once baseline frequency ranges are established for a given slag system, the method can support process monitoring and may provide indirect indicators related to changes in surface agitation or foaming tendency, enabling structured data-driven analysis. The framework thus provides a practical bridge between cold-model experiments, high-temperature measurements, multiphase modeling and industrial TSL operation.