Research of metallurgical slags chemical composition, originating both from current production as well as gathered in dumping grounds formany years, show that they are very diversified. Slags contain substantial amounts of metals, including heavy metals, apart from elements from groups of non-metals and lanthanoids. In the article occurrence forms and relations with phase components of selected metals (iron, manganese, zinc, lead and others) on the basis of mineralogical and chemical research on slags after steel and ore Zn-Pb production were characterized. It was stated that metals may occur in metallurgical slags as fine drops not separated from slag during a metallurgical process, may form polymetallic aggregates, their own phases (especially oxide ones) and hide in structures of silicate phases. A considerable amount of metals is dissipated in glaze and amorphous substance. The conducted research delivers information on the occurrence of metals in metallurgical slags, which is extremely important during work connected with economic exploitation of slags. It especially refers to increasing attempts of acquiring elements from metallurgical slags. These activities determine the necessity of analyzing chemical and phase composition of slags because they may be an important indication, for instance while working on a proper technology of elements recovery.

Metallurgical slag is often treated as a material which could be used in the waste management, especially for production different kinds of aggregate. So it is necessary to know that material not only considering technical properties, but also its mineral and chemical composition. Such researches could deliver many valuable information during the waste utilization. Researches were made for samples of the metallurgical slag after steel and Zn-Pb production. Samples were taken from chosen dumps localized in the Upper Silesian District. Beside metallic aggregates, silicate and oxide phases, glaze is one of the main component of the metallurgical slag. The following stages of the glaze devitrification were presented; from not transformed and isotropic glaze pieces to the strong weathered glaze. Transformed glaze is red or brown with the cracks on the surface. Cracks are often filled by the metals oxides, which can be liberated during the glaze devitrification. On the base of researches executed using the electron microprobe the chemical glaze composition was presented. The chemical composition of the glaze is variable what is connected with the kind of the metallurgical slag. The following main elements were distinguished in the metallurgical slag: Si, Al, Fe, Ca and Mg. Slag after steel production contains also Mn, P, S and the slag after Zn-Pb production contains: As, Cd, Cu, Mn, Ni, Pb, Ti, Zn, Na, K, P and S.

Among the elements that compose steel slags and blast furnace slags, metallic precipitates occur alongside the dominant glass and crystalline phases. Their main component is metallic iron, the content of which varies from about 90% to 99% in steel slags, while in blast furnace slags the presence of precipitates was identified with the proportion of metallic iron amounting to 100%. During observations using scanning electron microscopy and X-ray spectral microanalysis it has been found that the form of occurrence of metallic precipitates is varied. There were fine drops of metal among them, surrounded by glass, larger, single precipitates in a regular, spherical shape, and metallic aggregates filling the open spaces between the crystalline phases. Tests carried out for: slags resulting from the open-hearth process, slags that are a by-product of smelting in electric arc furnaces, blast furnace slags and waste resulting from the production of ductile cast iron showed that depending on the type of slag, the proportion and form of metallic precipitates is variable and the amount of Fe in the precipitates is also varied. Research shows that in terms of quality, steel and blast furnace slag can be a potential source of iron recovery. However, further quantitative analyses are required regarding the percentage of precipitates in the composition of slags in order to determine the viability of iron recovery. This paper is the first part of a series of publications aimed at understanding the functional properties of steel and blast furnace slags in the aspect of their destructive impact on the components of devices involved in the process of their processing, which is a significant operational problem.

This paper presents results of mineralogical and chemical research connected with the polymorphic transformations of dicalcium silicates in aggregate based on open-hearth slag and also slags from the current production of EAF (electric arc furnaces), and LF (ladle furnaces). Particular attention was paid to the transformation of the polymorph β-Ca2[SiO4] into the variant γ-Ca2[SiO4], which is undesirable from the perspective of using steel slags in road construction. A full mineralogical characterization of the tested metallurgical slags enabled the verification of the effectiveness of detecting the decomposition of dicalcium silicate in observations in UV light in line with the PN-EN 1744- 1+A1:2013-05 standard. On the basis of the conducted research, it was found that in the aggregate based on open-hearth slags and in the EAF furnace slag, dicalcium silicates are mainly represented by the β-Ca2[SiO4] polymorph, accompanied by α’-Ca2[SiO4]. The slag from the LF furnace was characterized by a different composition, with a strong advantage (57%) of the α’-Ca2[SiO4] variety, with a 1% share of the β-Ca2[SiO4] and 15% of the γ-Ca2[SiO4].
It was found that the transformation of β-Ca2[SiO4] into γ-Ca2[SiO4] can take place only under certain conditions in the metallurgical process, but the process is not influenced by hyperergenic factors, as evidenced by the fact that after more than 100 years of storage of open-hearth slag, on the basis of which the aggregate was produced, it was primarily marked with all the variants of β-Ca2[SiO4], without the polymorph γ-Ca2[SiO4].
The comprehensive characterization of the slag phase composition requires use of an appropriately selected research methodology; this is of key importance prior to the secondary use of this material, especially in the presence of the γ-Ca2[SiO4] polymorph. It has been determined that the most accurate test results are obtained using the XRD technique. The method of determining the decomposition of dicalcium silicate according to the PN-EN 1744-1+A1:2013-05 standard proved to be unreliable. It seems that in the situation of using LF slag as an artificial aggregate, taking the test results according to the method described in the PN-EN 1744-1+A1:2013-05 standard as being decisive is very risky, especially on a large scale (e.g. in communication construction).

This paper presents the results of tests of selected physical and mechanical properties as well as the chemical composition of two types of natural aggregates: porphyry and diabase, as well as artificial aggregate based on steel slags. Based on the conducted tests, it was established that the physical and mechanical properties of the artificial aggregate exhibit slightly lower parameters as compared to the results obtained for porphyry and diabase aggregates. However, this does not limit the possibility of using the aggregate based on steel slags, as according to the applicable WT-4 and WT-5 standards, it can be used in mixtures unbound to the improved subsoil and layers of the road foundation as well as road mixtures with hydraulic binders for each category of traffic load. The chemical composition of the aggregate based on steel slags differs from the chemical composition of the tested natural aggregates. The slags contain lower amounts of SiO2 and Al2O3, while the concentration of CaO and Fe2O3 is greater. Additionally, heavy metals have also been exhibited in the slags. However, it was established that the alkaline nature of the slags, which is affected by low sulphur content and a significant proportion of CaO, as well as the way the metals occur limit the possibility of heavy metals release and migration from slags. The tested steel slags may constitute a prospective material used in road construction.

This paper deals with issues related to tribological processes occurring as a result of excessive wear of the surface of scraper conveyor components caused by the impact of the mined material created during drilling of development or exploitation galleries. One of the most common types of tribological wear is abrasive wear. W ear tests were carried out for hard coal – based abrasive using dry carbon abrasive and a hydrated mixture with 76 and 58% hard coal. Based on the conducted research, it was established that the effects of wear processes are associated with damage typical of wear mechanisms: micro-scratching and micro-fatigue. For the wear variant in the presence of dry coal abrasive, individual scratches caused by the abrasive grains were observed on the surface of the samples. The main reason for this type of damage was the aggregation of quartz, which is one of the basic components of the mineral substance present in the tested hard coal. When hydrated carbon mixtures were used as an abrasive, the surface of the samples also displayed scratches characteristic of the aggregate quartz. A small part of the carbon abrasive was pressed into the scratches. Under the influence of the wear caused by friction, small depressions were also formed, where coal penetrated. The effect of coal pressing into micro-scratches is related to its plastic properties. T ests of the abrasive conducted after the conclusion of wear tests have shown that under the influence of the local increase in temperature and pressure, the hard coal contained in the abrasive can undergo transformations. In the abrasive transformed under friction, small, but measurable changes in the content of the C element in relation to the initial hard coal sample were exhibited.

This article presents the results of studies into the phase and chemical composition of blast furnace slag in the context of its reuse. In practice, blast furnace slags are widely used in the construction industry and road building as a basis for the production of, for example, cements, road binders and slag bricks. T hey are also used in the production of concrete floors, mortars, and plasters. Blast furnace slag is mainly used as a valuable material in the production of hydraulic binders, especially cement that improves the mechanical properties of concretes.
The favorable physical and mechanical properties of slags, apart from economic aspects, are undoubtedly an asset when deciding to use them instead of natural raw materials. In addition to the above, there is also the ecological aspect, since by using waste materials, the environmental interference that occurs during the opencast mining of natural aggregates is reduced. S pecifically, this means waste utilization through secondary management.
However, it should be kept in mind that it is a material which quite easily and quickly responds to environmental changes triggered by external factors; therefore, along with the determination of its physical and mechanical properties, its phase and chemical composition must be also checked.
The studies showed that the predominant component of the blast furnace slag is glass which can amount up to 80%. In its vicinity, metallic precipitate as well as crystallites of periclase, dicalcium silicates and quartz can be found. With regard to the chemical composition of the slag, it was concluded that it meets the environmental and technical requirements regarding unbound and hydraulically bound mixtures. In case of the latter, in terms of its chemical composition, the slag meets the hydraulic activity category CA3. It also meets the chemical requirements for using it as a valuable addition to mortars and concretes, and it is useful in the production of CEM II Portland-composite cement, CEM III blast-furnace cement and CEM V composite cements. The blast furnace slag is a valuable raw material for cement production. Cement CEM III/C contains 81–95% of blast furnace slag in accordance with E N 197-1:2012. In 2019, the Polish cement industry used 1,939,387.7 tons of slag.