Since the 12th century in the Silesian-Cracovian area, lead, litharge, and silver have been produced by the pyrometallurgical processing of Pb-Ag-Zn ore. Slags and soils contaminated with heavy metals (Zn, Pb, Cd, Fe, Mn, As) were the subject of this research. Samples were collected during archaeological works in the area of early medieval metallurgical settlement. The main goals of the analyses (Scanning Electron Miscroscopy-Energy Dispersive Spectroscopy (SEM-EDS), Electron Probe Microanalyzer (EPMA), X-ray diffraction (XRD), Atomic Absorption Spectroscopy (AAS)) were the determination of the mineralogical composition of furnace batches and smelting temperatures and conditions. In soils, the anthropogenic phases enriched in Pb, Zn, Fe, Mn, P, and primary minerals like goethite, ferrihydrite, sphalerite, galena, smithsonite, minrecordite, cerussite, gypsum, anglesite, jarosite, and hemimorphite were identified. The soil from former metallurgical settlements contained up to 1106 mg·kg⁻¹ Pb, 782 mg·kg⁻¹ Zn, 4.7 mg·kg⁻¹ Cd in the fine fraction. Much higher heavy metal concentrations were observed in the waste products of ore rinsing, up to 49,282 mg·kg⁻¹ Pb, 64,408 mg·kg⁻¹ Zn, and 287 mg·kg⁻¹ Cd. The medieval smelting industry and Pb-Ag-Zn ore processing are marked by highly anomalous geochemical pollution (Pb, Zn, Cd, Fe, Mn, Ba) in the topsoil. The methods of mineralogical investigation, such as SEM-EDS or EMPA, can be used to identify mineralogical phases formed during metallurgical processes or ore processing. Based on these methods, the characteristic primary assemblage and synthetic phases were identified in the area polluted by medieval metallurgy and mining of Pb-Ag-Zn ores, including MVT (Mississippi Valley Type) deposits. The minerals distinguished in slags and the structural features of metal-bearing aggregates allow us to conclude that batches have included mostly oxidised minerals (PbCO₃, ZnCO₃, CaZn(CO₃)₂, FeOOH), sulfides (PbS and ZnS) and quartz (SiO₂). The laboratory experiment of high-temperature heating of the examined slags showed that smelting temperatures used in the second half of 13th century were very high and could have reached up to 1550 °C. The results indicate, that geochemical and mineralogical methods can be used to obtain important information from archaeological sites, even after archaeological work has long ceased.

The study focuses on the reconstruction of the technological process in the 16th–17th century lead smelter in Sławków based on chemical and petrographic analyzes of slags. There are three main types of material at the landfill: glassy, crystalline, and weathered. Glassy slags are made of amorphous phase in which crystals of pyroxene, willemite, olivine, wüstite, and lead oxide appear. Crystalline slags are composed of wollastonite, rankinite, melilite, anorthite, quartz, and Fe oxides. Weathered slags have a composition similar to glassy slags, but they also contain secondary phases: anglesite and cerussite. Chemical analyzes confirmed that the smelter used sulphide ores, which were roasted, and the main addition to the charge was quartz sand. The smelting process took place in a brick-built furnace, under reducing conditions, with varied oxygen fugacity ranging from WM to MH buffer. The slag characteristics show a knowledge of the workers in the field of smelting methods. The addition of SiO₂ allowed for the binding of elements that could contaminate the obtained lead, and at the same time, the low melting point of the material (1150 °C) and the melt viscosity (logη = 1.34 for 1150 °C) was maintained, enabling the effective separation of liquid lead.

Slags from the historic metallurgy of Zn-Pb ores are known for unique chemical and phase compositions. The oxides, silicates, aluminosilicates, and amorphous phases present therein often contain in the structure elements that are rare in natural conditions, such as Zn, Pb, As. The study focuses on processes occurring on the contact of the melted batch and the refractory materials that build the furnace, which lead to the formation of these phases. To describe them, chemical (X-ray fluorescence (XRF), inductively coupled plasma mass spectrometry (ICP-MS)) and petrological ((X-ray diffraction (XRD), electron probe micro-analyses (EPMA), Raman spectroscopy) analyses were performed on refractory material, slag, and contact of both. Two main types of reactions have been distinguished: gas/fluid- refractories and liquid- refractories. The first of them enrich the refractories with elements that migrate with the gas (Pb, K, Na, As, Zn) and transport the components building it (Fe, Mg, Ca) inward. Reactions between melted batch and refractory materials through gravitational differentiation and the melting of refractories lead to the formation of an aluminosilicate liquid with a high content of heavy elements. Cooling of this melt causes crystallization of minerals characteristic for slag, but with a modified composition, such as Fe-rich pyroxenes, Pb-rich K-feldspar, or PbO-As₂O₃-SiO₂ glass.

This study presents the first reconstruction of the smelting conditions in 16th‐ to 18th‐century smelters from Miedziana Góra (Holy Cross Mountains, Poland). Based on geochemical (inductively coupled plasma mass spectrometry/emission spectrometry, X‐ray fluorescence) and mineralogical analysis (X‐ray diffractometry, scanning electron microscopy, electron probe micro‐analysis) of historical slags, their chemical/phase composition and the basic smelting parameters (temperature, melt viscosity, and oxygen fugacity) were determined. Due to the differences in chemical and phase composition, slags from different smelting stages have been distinguished: hypocrystalline slags (MG6) from speiss/matte production and glassy (MG1–MG5) from matte conversion. In glassy slags, pyroxenes, quartz/cristobalite grains, and aggregates composed of metallic Cu and PbO are dispersed in the glass. Hypocrystalline slags are composed of wollastonites, anorthites, and metallic Cu. The temperature range at which the slags were formed was from ~1100°C (solidus temperature) to 1150–1200°C (liquidus temperature). The silicate melt's viscosity was from log η = 1.19 to 4.42 Pa s (at 1100–1200°C). The higher viscosity of MG1–MG5 slags indicates that, unlike MG6 slags, they were not formed during gravity separation. Information about the phase composition made it possible to determine the oxygen fugacity in the range of log fO₂ = −4 to −12 atm. High oxygen fugacity indicates the oxidizing nature of the smelting process.