1. Secondary deposits as a potential REEs source in South-Eastern EuropeRobert Šajn, Jasminka Alijagić, Ivica Ristović, 2024, original scientific article Abstract: The main objective of this manuscript is to collect, classify, and compile all available data about secondary mineral sources of REEs in the South-Eastern Europe (SEE). The material is generated from the extracting and processing sector, that might be possibly transformed in the business process becoming an important raw material for another industry. The management inventory guide will strengthen communication and dissemination efforts and simultaneously contribute to Europe’s self-sufficiency and support transitioning to green and digital technology. Identification of the knowledge gaps associated with secondary sources of REEs in SEE will contribute to connections between all partners being involved at the beginning, during the lifetime of products and at the end of the life cycle, represented with deposit owners, technology developers and potential processors, producers, and potential users. At the investigated area it was found 1835 individual landfills, most of them belonging to waste rocks. The total quantity of all material in SRM is about 3.2 billion tons on an area of about 100 km2. The largest 95 individual landfills were selected as potential prospective landfills, containing about 1600 million tons of material. The estimated total potential of REEs (ΣREE) is more than 200 Kt. The largest quantities are found in landfills for coal fly ash and Cu flotation, which correspond to more than 80% of the ΣREE. Most of the promising sites are located in Serbia and North Macedonia. It has been calculated that the valorisation potential and perspectivity of REE2O3 is about 32.5 billion USD (prices from December 2022). According to the average concentrations of REEs, the most prospective are the red mud dams but their total volume is limited compared to massive amounts of coal fly ash landfills. The REEs content in all type of investigated materials, especially in coal fly ash in North Macedonia is twice as high as in other countries.
Keywords: secondary raw materials, ESEE, rare elements, economic prospective
Published in DiRROS: 06.02.2024; Views: 154; Downloads: 41
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2. The importance of educating younger generations about raw materials and their uses in our daily lifeKim Mezga, Petra Vrhovnik, Janja Žmavc, Lidia Gullon, 2021, original scientific article Abstract: Raw materials are of great importance for humankind as they enable the development of technology, drive industry and economy, and overall the lifestyle we know today. The paper is addressing the topic of interactive learning about the mineral raw materials, i.e. metals and non-metals. Due to population growth and consequently in-creased global demand for raw materials, there is a need to educate younger generations about the raw materials and their properties and origin, so they would know from an early age where the mineral products they use come from and how purchase decisions affect the social environments of people who live in countries with resources exploitation.Todayʼs trends in mining are oriented towards more sustainable exploitation and management, taking into account the economic, social and environmental aspects. An example of such is exploitation of secondary raw materials from tail-ings and heaps. But in some countries, mining is stuck in the past, using obsolete technologies causing increased pol-lution and strongly present linear economy approaches of take-use-dispose attitudes or even unethical approaches, such as children being exploited as a cheap workforce, people being abducted, tortured and even killed over minerals (min-erals being exploited in such way are called blood or conflict minerals). Further, due to the potential negative impacts on health and safety, due to the emissions in air, water and surface disturbance, the public perception of mining is still perceived as negative in most cases. School curriculums most often lack description of current situations in the global mining. Therefore, within the EIT RawMaterials BRIEFCASE and 3D BRIEFCASE projects the project partners provide the comprehensive view of the issues of todayʼs mining and use of raw materials. The paper presents the description of both projects and the non-conventional teaching methods - the hands-on and digital tools for pupils and teachers, i.e. the briefcases, the "Briefcase of mineral applications" game, workshops and the supporting materials. The main objective of projects is to raise the pupils awareness about the utility and indispensability of minerals and mining and the consequences of their uses and production systems, which would increasein the long term the awareness about the social and environmental consequences of raw material production.
Keywords: raw materials, mining, pupils and students, non-conventional teaching tools, BRIEFCASE, 3D BRIEFCASE, curricular planning, EIT RawMaterials
Published in DiRROS: 04.12.2023; Views: 226; Downloads: 104
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3. Recovery of phosphorus and metals from the ash of sewage sludge, municipal solid waste, or wood biomass : a review and proposals for further useSara Tominc, Vilma Ducman, Wolfgang Wisniewski, Terttu Luukkonen, Kirkelund Gunvor M., Ottosen Lisbeth M., 2023, original scientific article Abstract: This review provides an overview of methods to extract valuable resources from the ash fractions of sewage sludge, municipal solid waste, and wood biomass combustion. The resources addressed here include critical raw materials, such as phosphorus, base and precious metals, and rare earth elements for which it is increasingly important to tap into secondary sources in addition to the mining of primary raw materials. The extraction technologies prioritized in this review are based on recycled acids or excess renewable energy to achieve an optimum environmental profile for the extracted resources and provide benefits in the form of local industrial symbioses. The extraction methods cover all scarce and valuable chemical elements contained in the ashes above certain concentration limits. Another important part of this review is defining potential applications for the mineral residues remaining after extraction. Therefore, the aim of this review is to combine the knowledge of resource extraction technology from ashes with possible applications of mineral residues in construction and related sectors to fully close material cycle loops.
Keywords: critical raw materials, extraction, sewage sludge ash, municipal solid waste incineration ash, wood biomass ash
Published in DiRROS: 03.11.2023; Views: 354; Downloads: 128
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4. Microstructural characteristics of belite–sulfoaluminate cement clinkers with bottom ashLea Žibret, Andrej Ipavec, Sabina Dolenec, 2022, original scientific article Abstract: The incorporation mechanism of impurities derived from raw materials into a belite-sulfoaluminate cement clinker with bottom ash was investigated in two raw mixtures. Alkalis lowered the sintering temperature by 50 °C. Ti stabilized β belite and prevented the formation of γ-belite. Sodalite solid solution showed an incomplete substitution of Si by Al. At a higher Ti content ferrite solid solution trended towards perovskite composition. Although calcium sulfoaluminate only fully developted at 1300 °C, the clinkers sintered at 1200 °C were the most reactive, as the presence of anhydrite at 1200 °C accelerated early hydration. Clinker reactivity decreased with an increase in sintering temperature.
Keywords: BSCA clinker, belite, calcium sulfoaluminate, secondary raw materials, microstructure, reactivity
Published in DiRROS: 03.07.2023; Views: 399; Downloads: 188
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5. Bioleaching process for copper extraction from waste in alkaline and acid mediumIvica Ristović, Darina Štyriaková, Iveta Štyriakova, Jaroslav Šuba, Emilija Širadović, 2022, original scientific article Abstract: Flotation wastes are becoming a valuable secondary raw material and source of many metals and semimetals worldwide with the possibilities of industrial recycling. The flotation tailings contain oxide and sulfide minerals that have not been sufficiently stabilized and form acidic mine waters, which in turn contaminate groundwater, rivers, and reservoi6sediments. An effective way to recycle these mine wastes is to recover the metals through leaching. While the focus is on acid bioleaching by iron- and sulfur-oxidizing bacteria, alkaline leaching, and the removal of iron- containing surface coatings on sulfide minerals contribute significantly to the overall environmental efficiency of leaching. For this study, static and percolate bioleaching of copper from flotation waste at the Bor copper mine in Serbia was investigated in alkaline and then acidic environments. The aim of the study was to verify the effect of alkaline pH and nutrient stimulation on the bioleaching process and element extraction. A sample was taken from a mine waste site, which was characterized by XRF analyses. The concentration of leached copper was increased when copper oxide minerals dissolved during alkaline bioleaching. The highest copper yield during alkaline bioleaching was achieved after 9 days and reached 67%. The addition of nutrients in acidic medium enhanced the degradation of sulfide minerals and increased Cu recovery to 74%, while Fe and Ag recoveries were not significantly affected. Combined bioleaching with alkaline media and iron- and sulfur-oxidizing bacteria in acidic media should be a good reference for ecological Cu recovery from copper oxide and sulfide wastes.
Keywords: copper, alkaline, acidic bioleaching, secondary raw materials, open access
Published in DiRROS: 05.05.2023; Views: 304; Downloads: 154
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