High-tech Metals Research Articles

Carboxylic Acid-Assisted Leaching of Critical Elements from Coal Fly Ash: Experimental and Simulation Studies

<p>Critical elements are essential in a variety of high-tech applications. In the context of the circular economy, demand has arisen for technologies that are able to recover high-tech metals from wastes and byproducts. The aim of the present study is to investigate the leaching potential of critical elements from coal fly ash (CFA) using carboxylic acids as a milder yet efficient leaching agent. The leaching efficiency of citric acid and acetic acid was investigated in a simple single step process (pH 2.5-3.5 depending on the fly ash used) and the effect of acid type, acid concentration, temperature, and time on the process was studied with leaching experiments and the parameters were simulated using a non-linear equation and the uniform random distribution through MONTE CARLO simulations. Two coal fly ashes were studied. The major constituents of the fly ashes were analyzed by X-ray fluorescence spectroscopy (XRF) and their mineralogy was studied by X-ray powder diffraction (XRD). The content of fly ash samples in critical elements (Zn, Cr, Co, Mn, Ni, La, Ce, Li) as well as critical elements in the leachates, was determined by ICP–MS. The results revealed that citric acid appeared to be a better leaching agent, in most cases, with leaching efficiencies that reached 88%. The leaching efficiency for both acids in all cases was much higher for transition metals studied, compared to La, Ce, and Li. Experimental results adequately fitted to a non-linear equation in all cases with MARE < 11% and equations relating elements’ recovery to the three parameters investigated were successfully (MARE<16%) produced.</p>

Recycling potential and development strategies of high-tech metals for low-carbon energy technologies

Low-carbon technology has become the focus of addressing global climate challenges but is facing the supply restriction of critical high-tech metals. Recycling has become a powerful measure to solve this issue. In the paper, a comprehensive recycling potential index (RPI) is constructed to evaluate the recycling potential of high-tech metals for low-carbon energy technologies in China from 2020 to 2050, and development strategies are proposed based on the evaluation results. The results indicate that the future trends of recycling potential show four evolution modes – either reaching or rapidly rising to a high level, increasing to the middle and middle-high level, unsteadily staying at the low and middle-low level, or remaining at a low and continuously decreasing level. According to the evolution trend, different strategies, including key development, reserves, digestion, and transfer, should be adopted in different stages. Co, Li, Dy, Nd, Tb, and Eu should be the focus of technology, funds and policy from both the government and enterprises due to their high recycling potential in the long term. Moreover, measures should be taken to encourage recycling and mitigate the supply risk of high-tech metals for low-carbon energy technologies, including tracking the development of low-carbon energy technologies, adjusting the list of critical high-tech metals, promoting recycling technology, and exploring substitute resources.

Lithium in Greek Coal Fly Ashes: Contents and Characterization by Sequential Extraction

Lithium belongs to the critical elements and is used in a variety of high-tech applications. In the context of the circular economy, demand has arisen for technologies that are able to recover high-tech metals from wastes and byproducts. To achieve efficient recovery, apart from assessing metal enrichment, extensive knowledge of metal binding and leaching characteristics is required. The aim of the present study is to investigate the Li contents and mode of occurrence in Greek coal fly ashes. Eight coal fly ashes from different power plants in Greece were collected, and their major constituents were analyzed by X-ray fluorescence spectroscopy (XRF); their mineralogy was studied by X-ray powder diffraction (XRD), and their Li content was determined by ICP–MS. To identify Li binding and leaching characteristics, two sequential extraction methods (Tessier and BCR) were employed. The results showed that the Li content in the samples studied was between 95 and 256 μg/g and could be mainly attributed to the amorphous material encountered in the samples. The sequential extraction experiments revealed that 70–90% of Li is included in the residual fraction, indicating that it is strongly bound to the fly ash matrix.

Об актуальных вопросах развития минерально-сырьевой базы России

The article deals with topical issues of the development of the domestic mineral resource base (MRB). It is noted that the problem of providing Russia's industry with strategic mineral raw materials is becoming more acute every year due to the steady decline in rich and relatively technically and economically accessible deposits and the instability of its imports from producing countries due to political instability in the world. The share of Russian production of most strategic metals in the global structure of their output is small, despite the available reserves. Many large domestic deposits containing strategic metals are not being developed. At the same time, 17 strategic types of mineral raw materials necessary for the Russian high–tech industry are imported. Most of the mineral raw materials and products produced in the Russian Federation are exported, and exports significantly exceed domestic demand. To forecast the development of MRB, it is necessary to know the country's needs for the future, and it is very difficult to obtain such information in a market economy. The main problem hindering the development of high–tech metals (HTM) MRB in Russia is the lack of large domestic demand. Due to the fact that most of the HTM is mined along the way, the growth of their production depends on an increase in the production of base metals. The analysis performed, the results of which are discussed in the article, showed that Russia can completely replace the import of mineral raw materials at the expense of its own MRB. An innovative scenario for the development of MRB is proposed and discussed.

Phytoextraction Options.

Wastewaters often contain an array of economically valuable elements, including elements considered critical raw materials and elements for fertilizer production. Plant-based treatment approaches in constructed wetlands, open ponds, or hydroponic systems represent an eco-friendly and economical way to remove potentially toxic metal(loid)s from wastewater (phytoextraction). Concomitantly, the element-enriched biomass represents an important secondary raw material for bioenergy generation and the recovery of raw materials from the harvested plant biomass (phytomining). At present, phytoextraction in constructed wetlands is still considered a nascent technology that still requires more fundamental and applied research before it can be commercially applied. This chapter discusses the different roles of plants in constructed wetlands during the phytoextraction of economically valuable elements. It sheds light on the utilization of plant biomass in the recovery of raw materials from wastewater streams. Here, we consider phytoextraction of the commonly studied water pollutants (N, P, Zn, Cd, Pb, Cr) and expand this concept to a group of rather exotic metal(loid)s (Ge, REE, PGM) highlighting the role of phytoextraction in the face of climate change and finite resources of high-tech metals.

Microstratigraphic geochemical characteristics of ferromanganese crust from central pacific: Implication for the role of Fe and Mn in REY enrichment

Rare earth elements plus yttrium (REY), well-known critical metals for many new and emerging technologies and as proxies in geological events, are one type of the most important high-tech metals in ferromanganese (Fe-Mn) crusts. The REY(III) are accumulated in Fe-Mn crusts through adsorption by Fe-Mn (oxyhydr)oxides. However, negative correlations between Mn and REY in some Fe-Mn crusts reveal a controversial role of Mn oxides in REY enrichment, which remains equivocal. In this study, texture, structure, mineralogy, and microstratigraphic geochemistry with the growth of a Fe-Mn crust (MP2D32A) from the Line Islands archipelago were analyzed using multiple microanalysis methods. The Fe-Mn crust is characterized by laminar structures, stromatolite-like structures, and micronodules that are primarily composed of low-crystalline Fe-vernadite and ferrihydrite. Throughout the profiles of MP2D32A, the contents of elements are more or less interdependent. Analysis of elemental correlations from the MP2D32A samples and 847 collected data sets from non-phosphatized hydrogenetic Fe-Mn crusts shows Fe plays a positive role and Mn plays multiple roles in REY accumulation during Fe-Mn crust formation. The REY content increases initially and then decreases with increasing Mn content and Mn/Fe ratio and the turning points (i.e., highest REY contents) mainly occur at an Mn content of ∼18–26% and an Mn/Fe content ratio of ∼0.8. These fundamental results provide novel insights into understanding the influence of Fe and Mn in REY accumulation in the Fe-Mn crusts and are very significant in enhancing our understanding of the REY geochemical processes in the ocean.

Unveiling High-Tech Metals in Roasted Pyrite Wastes from the Iberian Pyrite Belt, SW Spain

The Iberian Pyrite Belt (IPB), in the southwestern Iberian Peninsula, is a large metallogenic province exploited since ancient times. As a result of historical and current mining activity, a vast volume of metallic mineral waste, mainly derived from the processing of pyrite, is still in situ and polluting the environment. A specific mine waste residuum locally known in the area as “morrongos”, which was produced during pyrite roasting mainly in the 19th century, is evaluated here in order to unravel untapped resources of high-tech metals commonly used in high-tech devices. Applying a combination of whole-rock geochemical (ICP-AES, ICPMS, FA-AAS) and single-grain mineralogical techniques (EPMA, LA-ICP-MS, FESEM, and FIB-HRTEM) on the “morrongos”, we unhide the still-present remarkable concentrations of Au, Ag, Pb, Zn, and Cu in them. The mineralogical expressions for these economic metals include oxides (hematite, magnetite, and hercynite), arsenates, sulfates of the jarosite group, native metals, and, to a lesser extent, relictic sulfides. This first-ever estimation of these economic metals in this type of residue allows their revalorization, highlighting them as suitable sources for the exploitation and recovery of metals necessary for the clean energy transition.

Influence of Phosphatization in REY Geochemistry in Ferromanganese Crusts in Line Islands, Central Pacific

Ferromanganese (Fe-Mn) crusts are potential marine deposits for many high-tech metals and are exciting proxies for recording the oceanic paleoenvironment. During their growth, phosphatization generally occurs, causing the remobilization and reorganization of the elements and minerals in Fe-Mn crusts. Rare earth elements plus yttrium (REY), well-known critical metals for many new and emerging technologies, as well as valuable geological proxies, are the important critical metals in Fe-Mn crusts. The REY occurrence is closely influenced by the phosphatization processes, which still remain discursive. In this study, the textures, structures, and REY geochemistry of the growth of an Fe-Mn crust sample (MP2D32A) from the Line Islands archipelago were analyzed using multiple microanalysis methods. The analyzed Fe-Mn crust is mainly characterized by the presence of laminated and concentric colloforms. Massive fine particles and some veins of carbonate-rich fluorapatite (CFA) were observed in the old part of MP2D32A, demonstrating that this sample underwent phosphatization. The phosphatized and non-phosphatized layers, as well as the CFA veins, display distinctly different PAAS-normalized REY patterns. Higher REY contents in the phosphatized layer than those in the non-phosphatized layer suggest the positive role of phosphatization in REY enrichment. Moreover, the phosphatized layer contains higher REY contents than the CFA, implying that the REY enrichment in the phosphatized layer is not only influenced by CFA and Fe-Mn (oxyhydr)oxides but also other factors, such as the probable PO43− complexation induced by Fe oxyhydroxides. The synergistical sorption of REY(III) and HPO42− ions on Fe oxyhydroxides should facilitate REY enrichment during the phosphatization processes. These fundamental results provide novel insights into the influence of phosphatization in REY geochemical behaviors in the Fe-Mn crust.

Новые подходы к прогнозированию крупных месторождений стратегических металлов

Synthesis of the obtained materials by sources of metals, agents of their transportation and areas of deposition or accumulation of ores makes it possible to zone the most promising territories to identify new large deposits of strategic metals. As a result of research the main ore-forming systems – sources of strategic metals are identified; a database of deposits and promising ore occurrences of strategic and high-tech metals of Russia has been created; geological and genetic models have been prepared, and on their basis predictive prospecting models of large deposits of strategic metals; new approaches to forecasting large deposits of strategic metals have been developed, including on the basis of data from the GOCE (Gravity Field and Steady-State Ocean Circulation Explorer) spacecraft, which allow using elements of the deep structure of the Earth's crust in predictive prospecting models; a series of predictive metallogenic maps of the territory of various regions of Russia has been compiled.

Fundamental Problems of Development of the Mineral-Resource Base of High-Tech Industry and Energy of Russia

The problem of provision of the Russian high-tech industry with critical minerals is becoming more drastic every year due to the steady reduction of rich and relatively accessible deposits in technical and economic terms and the instability of its import delivery from producer countries due to political instability in the world. Domestic and global trends in the development of the mineral-resource base of high-tech industry and energy are shown. Having applied spatial statistics of geoinformational analysis, the maps of the locations of the main deposits and promising ore occurrences of high-tech metals (HTMs) in Russia were compiled. The degree of criticality of strategic and high-tech mineral raw materials for Russia was assessed. It is noted that the share of Russian HTM production in the world structure of their output is extremely small, despite the available reserves. Many domestic complex HTM-bearing deposits are not developed. Most HTMs necessary for the Russian industry are imported. The analysis has shown that Russia can increase the production of two HTM groups critical for green technologies—“battery” metals (Ni, Co, Li, Pt, Pd, Ro, and REE) and components for “photovoltaics” (Cd, Se, Te, Ge, Ga, and In). In recent years, the mineral-resource base of HTMs in Russia has been showing positive growth, and the development of a number of deposits is planned.

Mineral and raw potential of high-tech metals and the level of study (category)

Mineral and raw potential of high-tech metals and the level of study (category)

Main tasks of geological exploration for high-tech metals

Main tasks of geological exploration for high-tech metals

Ore-forming systems of large deposits of high-tech metals in Russia: patterns of placement, conditions of formation, mineral resource potential

Ore-forming systems of large deposits of high-tech metals in Russia: patterns of placement, conditions of formation, mineral resource potential

Редкие и редкоземельные элементы руд Печенгского района

The article presents the investigations in the Pechenga ore region — one of the largest industrial regions in the Arctic zone of Russia, located on the territory of the Murmansk area. The researchers obtained new data on the chemical composition of the main ore minerals, the content of trace elements, including rare earths (REE), in the ores of the Pilguyarvi and Vostok deposits and late polymetallic veins of the Pechenga region. They found that the main textural types of ores (massive, veined and disseminated) differ significantly in chemical composition and content of rock and ore-forming components. They also revealed the enrichment of ores with a wide range of trace elements. In comparison with the upper crust, the Pechenga ores are clearly enriched with chalcophilic and siderophilic trace elements. The enrichment coefficients of ore elements reach mainly tens (Cr, Au, Cd) hundreds (Ag, Se, Re, Pt) and thousands (Ni, Cu, Ir) times. The distribution of trace elements in various types of Cu-Ni ores has a great similarity, which indicates their geochemical affinity and synchronous participation in ore formation. The geochemical features are in good agreement with the mineral composition of the ores. The concentration of rare earth elements in the main types of ores, with the exception of massive ores and late polymetallic veins, exceeds the level of the chondrite standard and the REE fractionation is weak. The composition of the REE in ores came by from the host rocks. The research has established the high enrichment of all types of Re, Bi and Cd ores, which are potentially industrially significant as high-tech metals and are of considerable interest for associated mining.

Resource Assessment of Renewable Energy Systems—A Review

The reduction of greenhouse gas emissions by the energy transition may lead to trade-offs with other impacts on the environment, society, and economy. One challenge is resource use impacts due to increasing demand for high-tech metals and minerals. A review of the current state of the art resource assessment of energy systems was conducted to identify gaps in research and application. Publications covering complete energy systems and supplying a detailed resource assessment were the focus of the evaluation. Overall, 92 publications were identified and categorized by the type of system covered and the applied abiotic resource assessment methods. A total of 78 out of 92 publications covered sub-systems of renewable energy systems, and nine considered complete energy systems and conducted a detailed resource use assessment. Most of the publications in the group “complete energy system and detailed resource assessment” were found in grey literature. Several different aspects were covered to assess resource use. Thirty publications focused on similar aspects including criticality and supply risks, but technology-specific aspects are rarely assessed in the resource assessment of renewable energy systems. Few publications included sector coupling technologies, and among the publications most relevant to the aim of this paper one third did not conduct an indicator-driven assessment.

Life cycle impact assessment methods for estimating the impacts of dissipative flows of metals

The dissipation of metals leads to potential environmental impacts, usually evaluated for product systems with life cycle assessment. Dissipative flows of metals become inaccessible for future users, going against the common goal of a more circular economy. Therefore, they should be addressed in life cycle impact assessment (LCIA) in the area of protection “Natural Resources.” However, life cycle inventory databases provide limited information on dissipation as they only track emissions to the environment as elementary flows. Therefore, we propose two LCIA methods capturing the expected dissipation patterns of metals after extraction, based on dynamic material flow analysis data. The methods are applied to resource elementary flows in life cycle inventories. The lost potential service time method provides precautionary indications on the lost service due to dissipation over different time horizons. The average dissipation rate method distinguishes between the conservation potentials of different metals. Metals that are relatively well conserved, including major metals such as iron and aluminum, have low characterization factors (CFs). Those with poor process yields, including many companion and high-tech metals such as gallium and tellurium, have high CFs. A comparative study between the developed CFs, along with those of the Abiotic Depletion Potential and Environmental Dissipation Potential methods, show that dissipation trends do not consistently match those of the depletion and environmental dissipation potentials. The proposed methods may thus be complementary to other methods when assessing the impacts of resource use on the area of protection Natural Resources when pursuing an increased material circularity. This article met the requirements for a gold-silver JIE data openness badge at http://jie.click/badges.

Relevance of FeoAB system in Rhodanobacter sp. B2A1Ga4 resistance to heavy metals, aluminium, gallium, and indium.

Aluminium (Al), gallium (Ga), and indium (In) are metals widely used in diverse applications in industry, which consequently result in a source of environmental contamination. In this study, strain Rhodanobacter sp. B2A1Ga4, highly resistant to Al, Ga, and In, was studied to reveal the main effects of these metals on the strain and the bacterial mechanisms linked to the ability to cope with them. An indium-sensitive mutant obtained by random transposon mutagenesis has the feoA gene interrupted. This gene together with the feoB gene is part of the feo operon which encodes a ferrous uptake system (FeoAB). The mutant strain exhibited higher oxidative stress supported by a high concentration of reactive oxygen species (ROS) and low levels of reduced glutathione (GSH) in the presence of metals. The iron supplementation of the growth medium reverted the growth inhibition of the mutant strain caused by Ga and In, significantly reduced the ROS amounts in mutant cells grown in all conditions, and increased its GSH/total glutathione ratio to values similar to those of the native strain. Moreover, the mutant strain when submitted to In increased the production of siderophores. The genome sequence analysis of strain B2A1Ga4 showed a large number of genes encoding putative proteins involved in iron uptake from the cell surface to the cytoplasm. Understanding the bacteria-metal interactions linked to resistance to high-tech metals is relevant to future application of microorganisms in bioremediation and/or biorecovery processes of these metals. KEY POINTS: • The disruption of FeoAB system compromises the bacterial resistance to Al, Ga, and In. • The iron acquisition in Rhodanobacter sp. B2A1Ga4 controls the oxidative stress. • Genome mining of strain B2A1Ga4 reveals several iron transport related genes.

Редкие и редкоземельные элементы в Cu-Ni рудах Норильского района

The deposits of the Norilsk region are confined to the marginal northwestern part of the Siberian platform and are associated with the manifestation of the Early Mesozoic trap volcanism. Sulfide mineralization is concentrated in the intrusive facies of the volcano-intrusive complex. Four main types of Cu-Ni ores are distinguished according to textural features: massive, vein-disseminated, brecciated, and disseminated. The main types of Cu-Ni ores differ significantly from each other in the chemical composition and content of rock- and ore-forming components. The enrichment ratios of ore trace elements in the Oktyabrskaya and Talnakhskaya vein-disseminated ore mainly reach hundreds (S, Pt, Au, Se,Te, Pb, As, Sn, Mo) and thousands (Ni, Cu, Ag, Pd) times. A rather high enrichment of all types of Bi, Re and Cd ores has been revealed, which are potentially industrially significant as high-tech metals, and can be promising for associated mining. The amount of rare-earth elements (REE) in ores is several times less than in the upper crust and more than in the primitive mantle. The concentration of rare earths in the main types of ores, with the exception of massive ones, exceeds the level of the chondrite standard, and REE fractionation is weak. The distribution spectra of chondrite-normalized REEs have a slight negative slope: the total content of light REEs is higher than that of heavy ones. The similarity of the geometry of the REE spectra of massive, vein-disseminated, brecciated and disseminated types of ores containing a significant admixture of host rocks indicates the inheritance of the REE composition in ores from the host rocks. In the disseminated ores of common taxite gabbro-dolerites, the Eu anomaly is present in the Kharaelakhsky (Oktyabrskoye Deposit) and Talnakhsky (Talnakhskoye Deposit) intrusions, it is positive, and in the Norilsk I Intrusive (in the same rocks), it is negative. Higher concentrations of REEs and significant fractionation of light and heavy rare elements are typical for host contact-metamorphic and metasomatic rocks with vein-disseminated (exocontact) ores. For olivine-free hornfels and skarns in brecciated ores, as well as for vein-disseminated ores, significant fractionation of light REEs with relatively heavy ones and a pronounced Eu minimum are characteristic. In massive ores, the distribution of REEs is determined by the composition of xenoliths.

Bond flotation with exotic commodity collateral

Exotic high tech metals such as rare earth oxides, titanium and nickel wire are increasingly important to semi-conductor, aerospace and high end defence technology R & D and production. As a result—while not market traded and therefore sporadic order dependent and highly volatile—prices of these commodities have been rising on average over the past decade. The metals trading subsidiary of an international group acquired over 6 M metres of nickel wire which at the current market price of about 300 EUR per metre is worth over 1.6 B EUR. The firm wished to raise from 300 M to 1B EUR in the capital markets in order to purchase a variety of these high tech metals to take advantage over the medium term (5–10 years) of generally rising prices. After a brief description of the current state of the exotic high tech metals markets, this paper treats the technical pricing and default risk analysis of an example 350 M EUR 7 year amortized corporate bond issue backed by a nickel wire inventory and subsequent high tech metal trading as collateral. Topics covered include security price modelling with high tech metal collateral, the design of 100% risk free securities with third party derivatives and security pricing and trading methodology. The complex stochastic and Monte Carlo simulation analyses presented are based in part on specially developed modelling of the nickel wire catalogue price and third party price projections for rare earth oxides and titanium. This analysis is based on 10 year (2008–2017) daily market data and supports an optimistic view in that after accounting for all ongoing costs we find a zero default probability for the bond issue—a situation seldom seen to accompany its stipulated 12% internal rate of return.

The Effect of Co-Crystallising Sulphides and Precipitation Mechanisms on Sphalerite Geochemistry: A Case Study from the Hilton Zn-Pb (Ag) Deposit, Australia

High-tech metals including Ge, Ga and In are often sourced as by-products from a range of ore minerals, including sphalerite from Zn-Pb deposits. The Hilton Zn-Pb (Ag) deposit in the Mount Isa Inlier, Queensland, contains six textural varieties of sphalerite that have formed through a diverse range of processes with variable co-crystallising sulphides. This textural complexity provides a unique opportunity to examine the effects of co-crystallising sulphides and chemical remobilisation on the trace element geochemistry of sphalerite. Early sphalerite (sph-1) is stratabound and coeval with pyrrhotite, pyrite and galena. Disseminated sphalerite (sph-2) occurs as isolated fine-grained laths rarely associated with co-crystallising sulphides and represents an alteration selvage accompanying the precipitation of early stratabound sphalerite (sph-1). Sphalerite (sph-3) occurs in early ferroan-dolomite veins and formed from the chemical remobilisation of stratabound sphalerite (sph-1) during brittle fracturing and interstitial fluid flow. This generation of veins terminate at the interface, and occurs within clasts of the paragenetically later sphalerite-dominated breccias (sph-4). Regions of high-grade Cu (>2%) mineralisation contain a late generation of sphalerite (sph-5), which formed from the recrystallisation of breccia-type sphalerite (sph-4) during the infiltration of a paragenetically late Cu- and Pb-rich fluid. Late ferroan-dolomite veins crosscut all previous stages of mineralisation and also contain chemically remobilised sphalerite (sph-6). Major and trace elements including Fe, Co, In, Sn, Sb, Ag and Tl are depleted in sphalerite associated with abundant co-crystallised neighbouring sulphides (e.g., pyrite, pyrrhotite, galena and chalcopyrite) relative to sphalerite associated with minor to no co-crystallising sulphides. This depletion is attributed to the incorporation of the trace elements into the competing sulphide minerals. Chemically remobilised sphalerite is enriched in Zn, Cd, Ge, Ga and Sn, and depleted in Fe, Tl, Co, Bi and occasionally Ag, Sb and Mn relative to the primary minerals. This is attributed to the higher mobility of Zn, Ge, Ga and Sn relative to Fe and Co during the chemical remobilisation process, coupled with the effect of co-crystallising with galena and ferroan-dolomite. Results from this study indicate that the consideration of co-crystallising sulphides and post-depositional processes are important in understanding the trace element composition of sphalerite on both a microscopic and deposit-scale, and has implications for a range of Zn-Pb deposits worldwide.