Application of Ultrasonic-Enhanced Leaching for the Recovery of Metal Elements from Mineral Raw Materials and Secondary Resources

Primary and secondary mineral resources are of strategic importance to the EU economy. Montenegro, as a country candidate for membership in the EU, is required to follow (and later to implement) European policies, strategies as well as initiatives, including those related to mineral resources and the mining sector. The importance of providing access to mineral raw materials in the future is recognized by the EU, as well as meeting the needs of European industry, maintaining employment and ensuring further development. Considering the overall economic situation in Montenegro, it is important to encourge the mining sector and other industries based on the use of mineral resources in making a greater contribution to the development and sustainability of society as a whole and also increase the share of national GDP. The potential for discovery and utilization of primary and secondary mineral resources in Montenegro is demonstrated. The most important metallic mineral resources are bauxite, lead and zinc, while conventional energy resources include coal (oil and gas potential has yet to be proven). In addition, there are abundant non-metallic mineral raw materials - industrial minerals and construction materials. Secondary mineral resources, especially aluminous red mud (bauxite residue), are also significant and have been the subject of research in recent years. Tailings from flotation processes at operating and abandoned lead and zinc mines might also be of interest for metal recovery. Bottom and flay ash from thermal power plants, slag from steel production, as well as marlstone and limestone from the hanging wall of coal deposits may also have potential. Waste rocks could be used particularly for secondary aggregate production. A database was developed and the most important deposits of primary and secondary mineral resources in Montenegro were mapped during the RESEERVE project. Mineral data were harmonised so as to be INSPIRE compliant. In addition, some novel geochemical exploration results of secondary mineral resources are presented.

The demand for precious and rare earth elements is gradually increasing mainly due to the advancement in their various industrial applications. However, the mining industry is facing challenges of natural resource depletion and it is predicted that in the near future there will be no natural sources of these metals. Therefore, several studies have been conducted to recover precious and rare earth elements from secondary resources such as spent industrial catalysts, jewellery, magnets, automobile parts, and electronic and industrial effluents. For this reason, solvent extraction using ionic liquids has attracted a lot of attention. This is because ionic liquids have improved properties such as non-volatility, non-flammability and low toxicity (when compared with tradition organic solvents used in the recovery of precious metals and rare earth elements). In addition, ionic liquids can be used to separate, extract and recover ionic species without the aid of a ligand, thus rendering them as the best ion-exchange extractants. In this chapter, the application of ionic liquids for the extraction, dissolution and recovery of precious metals and rare earth elements from waste (secondary resources) is reviewed. Special attention is given to solvent extraction which has proven to be one of the most widely used methodologies for metal recovery. This is due to the attractive features such as simplicity, flexibility and rapidity. Application of deep eutectic solvents (known to be greener than traditional ionic liquids) has been discussed to tackle existing challenges of ionic liquids.

Metals are essential in our daily lives and have a finite supply, being simultaneously contaminants of concern. The current carbon emissions and environmental impact of mining are untenable. We need to reclaim metals sustainably from secondary resources, like waste. Biotechnology can be applied in metal recovery from waste streams like fly ashes and bottom ashes of municipal solid waste incineration (MSWI). They represent substantial substance flows, with roughly 46 million tons of MSWI ashes produced annually globally, equivalent in elemental richness to low-grade ores for metal recovery. Next-generation methods for resource recovery, as in particular bioleaching, give the opportunity to recover critical materials and metals, appropriately purified for noble applications, in waste treatment chains inspired by circular economy thinking. In this critical review, we can identify three main lines of discussion: (1) MSWI material characterization and related environmental issues; (2) currently available processes for recycling and metal recovery; and (3) microbially assisted processes for potential recycling and metal recovery. Research trends are chiefly oriented to the potential exploitation of bioprocesses in the industry. Biotechnology for resource recovery shows increasing effectiveness especially downstream the production chains, i.e., in the waste management sector. Therefore, this critical discussion will help assessing the industrial potential of biotechnology for urban mining of municipal, post-combustion waste.

Advances in bio/chemical approaches for sustainable recycling and recovery of rare earth elements from secondary resources

Green recovery of rare earth elements under sustainability and low carbon: A review of current challenges and opportunities

Mining is one of the oldest human activities and industries and involves exploration and exploitation of mineral resources. In addition, there are many areas of geology with the basic goal of collecting information for understanding the Earth's structure, and planning and conducting various types of geological research of mineral resources and raw materials. Mining is the holder of the mineral raw materials management like a non-renewable natural resource. The utilization value of mineral raw materials increases but constantly changes, depending on the needs, so the task of the mining and geological professions is to continuously valorization of their value. Miners and geologists should be actively involved in spatial planning and solving of potential activation of a particular mine location in terms of increasing the number of inhabitants and reducing living space with adequate environmental protection. Mining activities are predetermined by the place of mineral resources and raw materials occurrence and are limited by the real conditions and possibilities of a certain community and society. It is necessary to determine the real possibilities of exploitation because the organization of mining production at any cost is humanistically, ecologically and economically speaking, unsustainable. The mineral resources of the Republic Srpska enable the exploitation and processing of mineral raw materials in the metal, metal processing, construction, chemical, cement, ceramics construction materials industry etc. The largest part (over 90% in terms of value) are reproductive materials for processing in other industries, a smaller part are products that go directly to the market. In the conditions of increased and faster technological development and the tendency of increasing exploitation of natural resources in the world with changes in previous conceptions of life, there was a need to analyze the sustainability of natural and raw mineral resources for further development of Republika Srpska. The issue of sustainable development, in terms of strengthening the economic structure and geopolitical position of RS and BiH in relation to the surrounding countries, becomes a matter of strategic approach to the organization and development of the mineral complex.

Recycling of a secondary lead smelting matte by selective citrate leaching of valuable metals and simultaneous recovery of hematite as a secondary resource

Mineral raw materials were for many years the missing link in the climate debate. It is now evident that climate goals can’t be met without them. Mineral-based lithium battery and neodymium magnets value chains are not in balance between upstream-downstream efforts e.g. electric vehicles boom when energy transition mineral resources are yet not secured, Considering the long period of time (from exploration to mining takes about 15 years) needed for the mineral value chains to be fully operational, the technologies addressing the implementation plan of climate change goals might not always readily available due to lack of the mineral resources needed. However, Europe’s opportunity to become self-sufficient in mineral raw materials supply from own sources and resources, is strongly favored by its geological setting and metallogenetic evolution. Critical and strategic mineral raw materials from European primary and secondary resources produced in Europe can be taken as a guarantee for high standards in social, environmental, and economic terms. Elements and practices related to circular economy, responsible sourcing and resource efficiency addressed by the new EU industrial strategy, should be particularly considered. Major European mineral belts, such as Fennoscandian, Iberian, Carpathian-Balkan, host highly potential exploration targets challenging the likelihood for discovery of new resources and feasible mining prospects. At this stage recycling is not significant resource provider for some of the critical and strategic mineral raw materials. For the EU and the rest of the world to develop mineral supply chains, less dependent on China, strengthening key technology value chains, including processing, refining and metallurgy facilities, seems to be a dominant target.

The increased consumption of rare earth elements (REEs) requires processing of new lowprofitable mineral raw materials such as ores with low REE con� tents and industrygenerated wastes of various origin (chemical plant wastes, spent nuclear fuel and so on). Eudialyte containing up to 2.5% lanthanide impurities is a highly promising "nontraditional" mineral for the recovery of lanthanides (1). The elemental composi� tion of lanthanides in eudialyte is characterized by high (up to 50% of the lanthanide sum) contents of heavy lanthanides, which makes eudialyte a valuable mineral raw material for the recovery of rare earth elements. This distinguishes eudialyte from other known minerals such as apatite or loparite, in which the content of most expensive yttrium group lan� thanides is much lower (2). Eudialyte is readily digested with acids without preliminary activation, which markedly facilitates the industrial processing of the mineral (3). Since eudialyte contains consider� able amounts of some other valuable components (zirconium, scandium), apart from lanthanides, a topical task is to develop an integrated processing technology for this mineral. The traditional ore processing flow charts include leaching with concentrated mineral acids and recovery of rare earth elements by multistep liquid extraction (3-6). In the processing of raw materials with low contents of valuable components (eudialyte, apatite, or fluoroapatite ores), it is especially important to choose an appropriate extractant, because the known neutral organophosphorus extractants (NOPCs) have rather low distribution ratios and separation levels for lanthanides and extract actinides at almost the same level. Therefore, the search for new effective, synthet� ically accessible, and commercially attractive extract� ants for the recovery and separation of rare earth ele� ments remains topical.

Recovery of lithium and cobalt from spent lithium ion batteries (LIBs) using organic acids as leaching reagents: A review

Platinum group metals (PGMs) play a key role in modern society as they find application in clean technologies and other high-tech equipment. Spent catalytic converters as a secondary resource contain higher PGM concentrations and the recovery of these metals via leaching is continuously being improved but efforts are also directed at the purification of individual metal ions. The study presents the recovery of PGMs, namely, rhodium (Rh), platinum (Pt) and palladium (Pd) as well as base metals, namely, zinc (Zn), nickel (Ni), iron (Fe), manganese (Mn) and chromium (Cr) using leachates from spent diesel and petrol catalytic converters. The largest amount of Pt was leached from the diesel catalytic converter while the petrol gave the highest amount of Pd when leached with aqua regia. Merrifield beads (M) were functionalized with triethylenetetramine (TETA), ethane-1,2-dithiol (SS) and bis((1H-benzimidazol-2-yl)methyl)sulfide (NSN) to form M-TETA, M-SS and M-NSN, respectively, for recovery of PGMs and base metals from the leach solutions. The adsorption and loading capacities of the PGMs and base metals were investigated using column studies at 1 M HCl concentration. The loading capacity was observed in the increasing order of Pd to be 64.93 mmol/g (M-SS), 177.07 mmol/g (M-NSN), and 192.0 mmol/g (M-TETA), respectively, from a petrol catalytic converter. The M-NSN beads also had a much higher loading capacity for Fe (489.55 mmol/g) compared to other base metals. The finding showed that functionalized Merrifield resins were effective for the simultaneous recovery of PGMs and base metals from spent catalytic converters.

The hydrometallurgical recovery of critical and valuable elements from WEEE shredding dust: Process effectiveness in a life cycle perspective

The article presents the history of collecting data on mineral raw materials export and import in Poland and balancing mineral raw materials resources. The methodology of gathering data was analyzed on the basis of the publication “The Balance of Mineral Resources Deposits in Poland”. This is the current title of the yearbook, the back issues of which are collected in the Polish Geological Institute-National Research Institute headquarters. During the last decades the institutions responsible for collecting and delivering data have changed and they were cited in the article along with the names of general editors of the publication and the authors of the chapter devoted to the exports and imports. As a result, data on mineral raw materials international trade have been presented every year. Moreover, the scope of data and the manner of their presentation were covered in the article. The information on Polish export and import of mineral raw materials has been compiled since the 1960s. Significant changes took place for more than 50 years not only within Polish but also in the world economy, and these economic conditions – the growing number of trade partners, changes in accounting for commodities or currency changes – were the main factors influencing the successive conversions of data presentations. The range of data grew significantly, the source of data altered several times and the methodology of data presentation changed a lot. Over time, there were data presented in longer hindsight and not only on exports and imports but also on the turnover balance. The balance is treated as a reflection of the domestic mineral raw materials sector and of a situation in world mineral economy. Thus, tendencies in the trade turnover have been presented for the last 30 years, for export, import and balance. Graphs were also included in the article showing such changes in relation to the value and magnitude of the trade turnover for all mineral resources and for particular groups – energy, metallic, chemical and rock raw materials. The most important raw materials – in terms of affecting the total balance in Poland – were also specified in the article.

One of the ways to solve the problems of rational and integrated use of mineral raw materials, including canned man-made facilities, is the development of critical technologies for their processing in order to extract strategic metals, which include gold. The object of research is a preserved gold-bearing mineral resource object (landfills) with a conservation period of 10 years. The purpose of the study is to identify the technological and environmental problems facing the Russian gold mining industry, hindering scientific and technological development and ensuring the independence and competitiveness of the state; to develop a critical technology for extracting gold from landfills (strategic mineral raw materials). Research objectives are as follows: to conduct a systematic analysis of the level of development of gold mining equipment and technology in Russia; to identify the technological and environmental problems facing the gold mining industry; to study the material composition of a preserved mineral resource facility (landfills); to develop a critical technology for extracting gold from landfills and conduct laboratory studies. Research methods are presented by the study of the material composition of the mineral raw materials samples, which has been carried out using modern tools: optical and electron microscopy, assay and atomic adsorption analysis methods. Based on a systematic analysis of the level of gold mining equipment and technology development in Russia, the main disadvantages of using non-stationary processing plants have been identified and technological and environmental problems arising during the operation of landfills for heap leaching of gold have been identified. The following flowcharts are presented: environmental assessment of the consequences of open-pit mining; the impact of methods, processes, elements, relationships, structures on environmental components during the processing of gold-containing mineral raw materials; the main components of the negative impact of gold-containing raw materials processing enterprises on the environment. A critical technology for deep processing of strategic mineral raw materials from landfills has been developed, and its technological scheme is given. Experimental studies have been conducted and the results are presented. This technology makes it possible to comprehensively use mineral raw materials, improve the environmental situation and increase the efficiency of gold extraction.

The aim of the study. Using the latest data of Geoinform of Ukraine, to carry out economic and geographical zoning of the territory of Podillya by mineral resources in order to identify spatial and temporal and dynamic patterns of concentration of mineral deposits, their place and role in the economic complex of the region, substantiation of proposals for optimization of its structure and optimization. Research results. Within the Podilskyi macrodistrict, six mineral-raw areas were distinguished: Vinnytsia, Khmelnytskyi, Tovtry, Chortkiv, Western and Podnistrovskyі. All districts (except Chortkiv and Podnistrovskyi) are of a complex type, that is, mineral resources are concentrated within their limits in the form of macrobunches, deposits, separate deposits. In particular, it is established that the main components of the component structure of mineral resources of Podillya are different types of construction materials. Agrochemical and technological raw materials are of subordinate importance. The isolated mineral resources are characterized by a well-defined set of major and specific (area-specific) mineral resources and a distinct genetic link between the latter and the individual stratigraphic and structural-geomorphological taxones of the territory. Most territorial structures of the region's mineral resources are complex and only a few are classified as grouped. Within the region, multicomponent concentrations of mineral deposits and deposits dominate, in which raw materials for the construction industry most often play a dominant role.On the basis of the explored deposits of solid mineral resources of the region, several mineral-oriented mining hubs were formed and are functioning: Shepetivka-Polonne, Glukhiv-Turbiv, Slavuta and Kamianets-Podilskyi - Chemerivtsi. The fields of medicinal and medical-table waters of Podillya are basic for the formation in the region of territorial and recreational complexes: Konopkiv, Sataniv-Makiv and Khmilnyk. Scientific novelty. Own interpretation of such territorial structural unit of mineral resources as an area is given, regionalization of Podillya territory by combinations of mineral resources is carried out for the first time, the set of basic and specific (peculiar to this area only) types of mineral raw materials and a distinct genetic link of the latter with separate stratigraphs are established - geomorphological taxons of the territory, which are separately formed on the basis of combinations of mineral resources, mining sites and their specificasy was outlined. Practical importance. Economic and geographical zoning of the Podillya area by mineral resources is conducted which will help to form a reliable, holistic view of the actual resource potential of the region and to plan and conduct on this basis by local administrative bodies aimed at optimizing the structure of the present mineral resources and raw materials.