Lead was recovered through a direct smelting reduction route from a lead concentrate by using mixtures of Na₂CO₃ and SiC to 1000 °C. The lead concentrate was obtained from the mining State of Zacatecas, México by traditional mineral processing and froth flotation. The experimental trials showed that 86 wt.% of lead with a purity up to 97% can be recovered from the lead concentrate by a single step reduction process when 40 wt.% Na₂CO₃ and 0.4 g SiC were used in the initial charge. The process was modeled in the thermodynamic software FactSage 7.3 to evaluate the effect of adding different amounts of Na₂CO₃ on the lead recovery rates while holding constant the SiC amount and temperature. The stability phase diagram obtained showed that an addition of 34 wt.% Na₂CO₃ was enough to reach the highest lead recovery. It was observed that the interaction of Na₂CO₃ and SiC at a high temperature promotes the formation of C and Na₂O, and SiO₂, respectively, where the Na₂O partially bonds with silica and sulfur forming Na₂S and sodium silicates which may decrease the SO₂ emissions and increase the weather degradation of the slag. The PbS was mainly reduced by the produced C and CO formed by the interaction between Na₂CO₃ and SiC at 1000 °C. The predicted results reasonably match with those obtained experimentally in the lead recovery rates and compounds formation.

In the present work, the effect of low aluminum additions and the hot forging process on the microstructure and non-metallic inclusions of high manganese steels is analyzed. Four high-manganese steels (HMnS) were prepared by adding low aluminum contents of 1.1 and 1.5 wt. % to four carbon austenitic steels with medium carbon content (0.3 - 0.4 wt% C) and manganese contents of 17 and 22 wt. Samples of the as-cast steels were hot forged to 1100?C to obtain an overall reduction of 70 %. Microstructural evolution was studied using microscopy techniques (OM, and SEM-EDS) and X-ray diffraction measurements for the as-cast and hot forged steels. A typical grain columnar zone formed during solidification of a cast ingot was obtained in the as-cast condition, where the microstructure consisted of nonmetallic inclusions in a fully austenitic matrix. The non-metallic inclusions were identified as Al2O3 and MnS particles. Thermomechanical treatment allows the formation of an austenitic microstructure characterized by twins in steels with high manganese content, while an austenitic-martensitic duplex microstructure was obtained in HMnS, which contained the lowest manganese contents. The highest tensile strength values were obtained for 17Mn-1Al steel, which had the smallest grain size and higher content of non-metallic inclusions. The hardness values were similar to those obtained in the as-cast condition.

A silver-rich lead alloy was obtained through the recycling of two metallurgical wastes: these are lead paste obtained from spent lead–acid batteries and a jarosite residue obtained from the hydrometallurgical production of zinc. Mixtures of both wastes were pyrometallurgically treated with sodium carbonate in a silicon carbide crucible at 1200 °C. The alloy and slag produced were analyzed by atomic absorption spectrometry, X-ray diffraction, and scanning electron microscopy with energy-dispersive spectra. High silver recovery was obtained in a Pb-Ag alloy for a mixture ratio of 30% Na₂CO₃–40% lead paste–30% jarosite, reaching a silver grade of 126 ppm. The slags produced for the highest jarosite content allow the compound formation of Na₂(SO₄) and Na₂Fe(SO₄)₂, which have high sulfur-fixing, avoiding SO₂ release and contributing to the minimization of atmospheric pollution. The novel pyrometallurgical route addresses not only the valorization of precious metals such as silver and lead but also the reduction in accumulated industrial waste.

A barium-rich Celestine (Sr,Ba)SO₄ concentrate from the primary Mexican ore production was used as a thickening agent to produce closed-cell Zn-22Al-2Cu alloy foams, while calcium carbonate was used as a foaming agent. The microstructure and mechanical properties of the foams were analyzed by optical microscopy, scanning electron microscopy, and compression tests, respectively. The Zn-22Al-2Cu alloy foams showed a typical lamellar eutectic microstructure, constituted by a zinc-rich phase (η) and a (α) solid solution that was richer in aluminum, while a copper-rich (ε) phase was formed in the interdendritic regions. The SEM micrographs show the presence of small particles and aggregates that are randomly scattered in the cell walls and correspond to unreacted calcite and Celestine–Barian particles, especially for the higher barite addition. The compressive curves showed smooth behavior, wherein the particles at the cell walls did not affect the foam’s compressive behavior. The trial containing 1.5 wt. % of BaSO₄ and 1.0 wt. % of CaCO₃ showed a higher energy absorption capacity of 5.64 MJ m⁻³ because of its highest relative density and lowest porosity values. The Celestine–Barian concentrate could be used as a foaming agent for high melt-point metals or alloys based on the TGA results.

Powder addition onto a molten-lead surface followed by stirring is widely used for desilvering during lead bullion refining operations. We model submerged zinc particle injection by coupling (i) a transient particle–metal reaction following Ohguchi with a time-dependent reaction efficiency E, (ii) a Stefan-type estimate of the zinc melting time Tf, and (iii) hydrodynamic descriptors of residence (τ_res) and mixing (τ_mix) times. The model is validated against experiments under a benchmark condition (gas velocity U = 3.32 m/s, 70% submergence), achieving a mean absolute percentage error of 1.13% for the experimental desilvering curve. A parametric study over lance submergence (30–90% of bath depth), injection velocity (3.32–9.79 m/s), and geometric scalings of lance and kettle identifies conditions where the hydrodynamic residence time τres approaches the Stefan melting time, maximizing liquid-Zn contact with molten Pb. Specifically, the proposed optimum balances the competing effects of plume buoyancy at high velocities—which tends to reduce residence time—against the deeper injection depth, ensuring that particles remain submerged long enough to fully melt and react. Within 16 simulated scenarios, the pair “90% submergence + U = 9.79 m/s” provides the best multi-criteria performance (desilvering fraction, E, and residence time) under realistic constraints. A parametric sensitivity analysis ranks injection velocity and submergence as the dominant levers, with geometry playing a secondary role over the tested ranges. The coupled hydrodynamic–kinetic framework provides quantitative guidance for optimizing industrial desilvering by particle injection and is extensible to other powder-injection refining operations.

Aluminum metallic foams are lightweight porous materials characterized by low density, high stiffness, and remarkable energy absorption capacity. The mechanical performance of these materials strongly depends on the microstructure of the metallic matrix and the porous structure. In this study, closed-cell A356 aluminum foams were produced by the Alporas melt-foaming method using barite (BaSO₄) as a thickening agent and calcium carbonate (CaCO₃) as a foaming agent. The effect of grain refinement on the microstructure and energy absorption behavior under quasi-static compression was investigated. Grain refinement was evaluated by adding four concentrations of Al-5Ti-1B master alloy (0.02, 0.05, 0.08, and 0.10 wt.%) to the unrefined foam. The addition of Al-5Ti-1B reduced the secondary dendrite arm spacing (SDAS) from 41.85 µm to a minimum of 32.96 µm at 0.05 wt.%, producing stronger and more homogeneous cell walls that increased the plateau stress from 0.525 to 1.549 MPa and the energy absorption capacity from 0.299 to 0.735 MJ/m³—improvements of 195% and 145%, respectively. The energy absorption efficiency analysis confirmed that any refiner concentration improved the compressive performance compared to the unrefined foam. In addition, the energy absorption efficiency (E) and the ideality energy absorption efficiency (I) confirm that the refinement of the dendritic structure through Al-5Ti-1B addition strengthens the foam cell walls, improving their mechanical behavior and performance as an energy-absorbing material under quasi-static compression.