During a study aiming to recover strategic elements and minerals from coal fly ash and bottom ash (RAREASH and CHARPHITE projects funded, respectively, by the 2nd ERA-MIN and 3rd ERA-MIN Programs of the European Union Commission), it was found that in coal fly ash and bottom ash from Romania and Poland, several morphotypes did not fit into the general fly ash classifications, unless grouped together as “undifferentiated inorganics”. However, the combination of reflected light optical microscopy under oil immersion, scanning electron microscopy, and X-ray microanalysis (SEM/EDS) showed that many of these morphotypes not only have distinctive petrographic patterns but are also characterized by a chemical assemblage dominated by Ca, Mg, and P. In this paper, a survey of the literature is presented together with several detailed studies of samples from the RAREASH and CHARPHITE projects from which the following nomenclature are proposed: “calcispheres” for spongy Ca-rich morphotypes, “calcimagnesiaspheres” for (Ca + Mg)-rich morphotypes with visible MgO nodules and/or periclase (MgO) exsolved from Ca aluminate-silicate glass, and “magnesiaspheres” divided into “magnesiaferrospheres” for (Mg + Fe)-rich morphotypes with magnesioferrite, and “magnesiaoxyspheres” for magnesiaspheres mainly composed of (Mg + Fe)-rich amorphous material with visible MgO nodules and/or periclase.

Streszczenie: Pierwiastki ziem rzadkich nazywane powszechnie REE (Rare Earth Elements) to grupa 15 lantanowców od lantanu do lutenu, a także skand i itr, które charakteryzują się podobnymi właściwościami chemicznymi. Stanowią surowce uznane przez Unię Europejską za jedne z listy 14 surowców krytycznych, o znaczeniu strategicznym dla rozwoju nowoczesnych wysoko zawansowanych technologii. Światowe wydobycie REE kształtuje się aktualnie na poziomie 139 tys. Mg, a głównym producentem są Chiny, które dostarczają około 93% światowego zapo­trzebowania na surowce ziem rzadkich W związku z sytuacją na światowym rynku metali ziem rzadkich (REE), w ostatnich latach rozpoczęto wiele projektów w celu poszukiwania nowych źródeł REE. W artykule omówiono znaczenie ziem rzadkich w gospodarce światowej. Głównym celem pracy było określenie potencjału i form występowania pierwiastków ziem rzadkich w węglach kamiennych i odpadach z energetycznego wykorzystania węgla, jako alternatywnego źródła ich pozyskania. Na podstawie analizy literatury oraz przeprowadzonych badań własnych wytypowanych próbek polskich węgli kamiennych i popiołów z elektrowni, przedstawiono zawartości pierwiastków ziem rzadkich REE w wybranych węglach i popiołach lotnych z elektrowni na świecie i w Polsce. Średnia zawartość £ REE w węglach na świecie wynosi 60 ppm natomiast w badanych węglach polskich z KWK Jankowice £ REE wynosiła 77 ppm, dla pozostałych węgli uzyskano niższe zawartości od 8 do 40 ppm. Ponadto praca przedstawia perspektywiczne światowe zasoby tych pierwiastków, które mogą stać się ich cennym, alternatywnym źródłem w ciągu najbliższych lat.

The paper presents the characteristics of products annealing at the temperatures of 2400 and 3000 °C of unburned carbon from coal fly ash in terms of its possible use as a starting material in the graphitization process. An amorphous substance (organic substance) with an admixture of some minerals has been found in samples subjected to graphitization. However, the graphite phase is dominant in products subjected to graphitization. Studies have also shown a diverse grain morphology in individual samples. The presence of plate-shaped and tube-shaped grains was found. As the graphitization temperature of the starting material increases (2400 and 3000 °C), the specific surface area in the graphitization products decreases. The total pore volume in the samples after the graphitization process was significantly lower than the pore volume of active carbons produced from other unburned carbon. Average pore diameter is similar to the pore diameter in active carbons. The reflectance value of the matrix for the sample graphitized at 3000 °C is characteristic for graphite. Unburned carbon from Polish fly ash can be used as the starting material for graphitization.

This article presents the results of slag property studies, for characterization of unburned carbon separated. Size composition and loss-on-ignition distribution as a function of particle size were studied. The density analyses were performed for the selected size fractions. The successful tests on carbon particle separation using: the magnetic separation, separation in heavy liquids with magnetic separation of light ends and separation in a rising water stream with magnetic separation of the overflow methods, were performed. At laboratory scale and with using similarly rising water stream with magnetic separation methods, concentrates with 71–85% loss-on-ignition were obtained. Using gravitational separation method and magnetic separation, concentrates with 57–86.5% loss-on-ignition were obtained.

There are a lot of dangers associated with closing mine shafts which may emerge during its liquidation works, and after liquidation of a shaft. The most important of them are: methane hazard, water hazard, and public safety hazard, which are commonly connected with occurrence of sinkholes. In the process of shaft liquidation it is extremely important to choose the right backfill materials, which determine stability of the backfill column and proper drainage of the backfill, which will match or exceed potential flow of water into a shaft. When the water flows into a liquidated shaft the main problem is a change in permeability coefficient of the used backfill materials due to grain degradation resulting from the fall into a shaft and the pressure within the backfill column. The article presents results of laboratory tests on the influence of vertical pressure on filtration coefficient and compressibility of the most commonly used backfill materials. During the tests, samples of the materials were loaded in a hydraulic press, simulating in this way the increase in vertical pressure within the backfill column. Compressibility of a given material and the change in filtration coefficient were assessed.