Silver Isotopes in Silver Suggest Phoenician Innovation in Metal Production

The current study presents Ag isotopic values of 45 silver artifacts with known Pb isotopic composition from the Southern Levant. These items originate from seven pre-coinage silver hoards, dating from the Middle Bronze Age IIC to the end of the Iron Age (~1650–600 BCE). These are the earliest silver artifacts analyzed for Ag isotopes; all former studies were performed on coins. All the sampled silver in this study contains relatively unfractionated Ag (−2 ≤ ε109Ag ≤ 1.5) that was more likely produced from hypogene, primary Ag-bearing minerals (e.g., galena and jarosite) and not from native, supergene silver. Four of the sampled hoards containing silver from Anatolia and the West Mediterranean (Iberia and Sardinia) are associated with the Phoenician quest for silver (~950–700 BCE). A significant amount of this Phoenician silver (12/28 items) plots within a narrower range of −0.5 ≤ ε109Ag ≤ 0.5. This is in contrast to non-Phoenician silver, which mostly underwent some degree of fractionation (16/17 items ε109Ag ≥ I0.5I). The results suggest that while all silver was exploited from primary ore sources, the Phoenicians dug deeper into the deposits, reaching ore minerals that did not undergo any weathering-associated fractionation. The results also call for further investigation regarding the influence of sealing and bundling in silver hoards on post-depositional fractionation of Ag isotopes.

Wear-Model-Based Analysis of the State of Blast Furnace Hearth

The condition and state of the hearth of the blast furnace is of considerable importance since the life length of the refractories governs the campaign length of the furnace, but it is also of significance as it affects the drainage of iron and slag and the hot metal temperature and composition. The paper analyses the hearth of a blast furnace using a model of the lining wear based on the solution of an inverse heat conduction problem, studying the changes in the lining state throughout the campaign. Different operation states are detected, characterized by smooth and efficient hot metal production and by erratic behavior with large disturbances in the hearth state. During the periods of poor performance, the hearth exhibits a cycling state with stages of excessive skull growth on the unworn refractory, followed by periods of dissolution of the skull and lining erosion. An explanation of the transitions is sought by a stating and solving a force balance for the deadman with the aim to clarify whether it is floating or sitting. A connection between the thermal cycles in the hearth and the hot metal sulfur content is finally demonstrated.

Special Issue “Advanced Techniques and Efficiency Assessment of Mechanical Processing”—Editorial Note and Critical Review of the Problems

The value chain of metal production consists of a number of processing steps that result in obtaining the final metal product from the given raw material [...]

Titanium: An Overview of Resources and Production Methods

For several decades, the metallurgical industry and the research community worldwide have been challenged to develop energy-efficient and low-cost titanium production processes. The expensive and energy-consuming Kroll process produces titanium metal commercially, which is highly matured and optimized. Titanium’s strong affinity for oxygen implies that conventional Ti metal production processes are energy-intensive. Over the past several decades, research and development have been focusing on new processes to replace the Kroll process. Two fundamental groups are categorized for these methods: thermochemical and electrochemical. This literature review gives an insight into the titanium industry, including the titanium resources and processes of production. It focuses on ilmenite as a major source of titanium and some effective methods for producing titanium through extractive metallurgy processes and presents a critical view of the opportunities and challenges.

Medieval Mining Centre of Buchberg in the Bohemian-Moravian Highlands. Metal Production in the Kingdom of Bohemia (13th–14th Centuries)

The study presents the results of a wide range of research approaches and surveys of the defunct mining centre at Buchberg in the region of Havlíčkův Brod, which was involved in silver production in the 13th and 14th centuries. Burchberg is exceptional in its size and well-advanced community infrastructure. Its significance is also reflected in written sources. Surveys and trial diggings focused on the residential area, and especially on the adjoining metallurgical facilities providing unique spatial information, as well as a wealth of valuable data obtained by analysing archaeometallurgical materials, representing the links in the operational chain, staring with the raw ore extraction and ending with the final production of the desired metals. The current deforestation of mining field relics enabled their three-dimensional survey, and, thus, providing a hitherto unknown view of the spatial structure of historical mining activities.

Simulation of Slag–Matte/Metal Equilibria for Complex and Low-Grade Raw Materials

The depleting and increasingly complex mineral resources bring challenges into the area of metal production, bringing new boundary conditions to the smelting and refining processes. Thermodynamics of phases and equilibria are the key to the analysis of pyrometallurgical processes, enabling descriptions of their limiting boundary conditions. The raw material basis of non-ferrous metals needs an effective control of iron oxide fluxing due to the challenging fact that the targeted metal values of, e.g., copper, nickel, lead, and tin will exist as minority components in the smelter feeds compared to iron sulphides, gangue, and many harmful elements. This means more complex slag compositions and the amount of produced slag being several times that of the metal production. This feature severely impacts the heat balance of the smelting vessels where autogenous operation without external fuels becomes more and more difficult to maintain.

Cadmium Recovery from Spent Ni-Cd Batteries: A Brief Review

The significant increase in the demand for efficient electric energy storage during the past decade has promoted an increase in the production and use of Cd-containing batteries. On the one hand, the amount of toxic Cd-containing used batteries is growing, while on the other hand, Cd is on a list of critical raw materials (for Europe). Both of these factors call for the development of effective technology for Cd recovery from spent batteries. The present paper is aimed at providing a short review of the recent progress in Cd recovery from spent batteries. Statistical data from the past decade on the source of Cd, its global production, and Ni-Cd battery recycling are given in the introduction. A short overview of the pyro-and hydro-metallurgical methods of metal production is provided. Recent progress in Cd recovery by commercial methods during the past decade is reviewed.

Rare Earth Electrolysis: key issues for measurement of greenhouse gases from oxide-fluoride systems

Over the past decade, the reduction of greenhouse gases (GHG) has been recognized as one of the key factors for sustainable primary metal production, in which the rare earth (RE) industry can be affected both in terms of price and use by GHG reduction policies and non-tariff technical barriers. From environmental and economic standpoint, the perfluorocarbons (PFC) emissions generated in RE electrolysis during events known as anode effects (AE) are strong infrared-absorbing GHG and play an important role for RE metals process improvements. However, there is no standard methodology to account these GHG emissions from RE metal production industry and the assessment of the contribution of PFC emissions from different technologies to the global warming is urgently needed. This paper focuses on the analysis of PFC measurements from RE metal production in terms of GHG inventory and sustainable production. The state of art of RE fused oxide-fluoride electrolysis, particularly of neodymium electrolysis, provides the technical fundamentals for the evaluation of PFC emissions factors reported in scientific articles. Based on International Panel on Climate Change (IPCC) standard methods and US Environmental Protection Agency (EPA) and International Aluminium Institute (IAI) protocol applied to analogous industrial process, the analysis of key issues for estimate CF4 and C2F6 emission factors from electrolytic RE production indicates the additional refinements are necessary to optimize the accuracy of total PFC emission amount from each currently RE technology. Additionally, the selection of emission estimation technique (EET) or mix EET should be considered on case-by-case basis as to their purposes and suitability for a particular process and facility. Finally, this paper highlights the technological implications related to the PFC emissions measurements and trends towards to set goals and develop strategies for GHG mitigation.

Rare Earth Electrolysis: key issues for measurement of greenhouse gases from oxide-fluoride systems

Over the past decade, the reduction of greenhouse gases (GHG) has been recognized as one of the key factors for sustainable primary metal production, in which the rare earth (RE) industry can be affected both in terms of price and use by GHG reduction policies and nontariff technical barriers. From environmental and economic standpoint, the perfluorocarbons (PFC) emissions generated in RE electrolysis during events known as anode effects (AE) are strong infrared-absorbing GHG and play an important role for RE metals process improvements. However, there is no standard methodology to account these GHG emissions from RE metal production industry and the assessment of the contribution of PFC emissions from different technologies to the global warming is urgently needed. This paper focuses on the analysis of PFC measurements from RE metal production in terms of GHG inventory and sustainable production. The state of art of RE fused oxide-fluoride electrolysis, particularly of neodymium electrolysis, provides the technical fundamentals for the evaluation of PFC emissions factors reported in scientific articles. Based on International Panel on Climate Change (IPCC) standard methods and US Environmental Protection Agency (EPA) and International Aluminium Institute (IAI) protocol applied to analogous industrial process, the analysis of key issues for estimate CF4 and C2F6 emission factors from electrolytic RE production indicates the additional refinements are necessary to optimize the accuracy of total PFC emission amount from each currently RE technology. Additionally, the selection of emission estimation technique (EET) or mix EET should be considered on case-by-case basis as to their purposes and suitability for a particular process and facility. Finally, this paper highlights the technological implications related to the PFC emissions measurements and trends towards to set goals and develop strategies for GHG mitigation.