# Rudomain Iron Ore Treatment by High-Temperature Reduction
## 4 Conclusions  
The contribution of the present manuscript is in the comparison of the physico-chemical and metallurgical properties of three commercial iron ores, in the explanation of the mechanism of reduction of poorer ores, and in the prediction of obtaining higher-quality metallised products based on the results of laboratory experiments. Due to the fact that DRI and HBI are currently produced, at a global level, from iron-bearing materials of the highest quality (Fe\({}_{\text{TOTAL}}\) above 65%), the investigation into the research task specified in the present article was limited by the current quality of the Rudomain iron ore (an average content of Fe\({}_{\text{TOTAL}}\) = 59%). The purpose of this study was to conduct experiments focused on the high-temperature metallisation of iron ore fines and lumps and aimed at increasing their use value. High-temperature experiments in thermal stability and carbothermic reduction have elucidated knowledge that is also beneficial for the treatment of lower-grade ores with higher SiO\({}_{2}\) contents. Based on the evaluation of a complex chemical composition of Rudomain iron ore, it is possible to conclude that this iron ore exhibits an average richness and low contents of P, S, alkalis, and non-ferrous metals. Based on the identification of a mineralogical composition of Rudomain ore, it was observed that it contains two major and separated phases: hematite and silica. Self-hardened pellets exhibited higher resistance to thermal shock, which corresponds to the general knowledge of the effects of moisture and hardening on strength characteristics. A comparison of high-temperature reduction indicated that richer samples, namely that of Carajas and Krivbas, were subjected to greater changes in their Fe\({}_{\text{TOTAL}}\) contents and mass losses than those of Rudomain samples; this indicates that Carajas and Krivbas ores achieve higher degrees of reduction and degrees of metallisation. However, the differences between the individual iron ores were not significant; hence, Rudomain also has a good potential for effective metallisation. A comparison of various samples of the Rudomain ore with different degrees of richness clearly showed that with an increasing Fe\({}_{\text{TOTAL}}\) content in the input Rudomain ore, Fe\({}_{\text{TOTAL}}\) contents in the products of metallisation of those samples proportionally increased, too. The identification of a chemical composition of the produced DRI pellets clearly showed that the best-reduced DRI sample achieved a reduction degree of 95.6%. An X-ray phase analysis of the metallised DRI product confirmed reduction processes by identifying the iron-based phases (metallic Fe, ferrosilicon, and iron carbide) that correspond to the chemical composition of the samples. Important results of the experiments (physical properties of ores and products after reduction) were compared with world studies. The agreement is shown in the parameters that affect the reduction process (for example, temperature and reaction time), and the differences are in the properties of the metallized product since Fe ores with different chemical and mineralogical compositions were used in the studies. The reduction conditions were predicted by applying unconventional methods for scanning a high-temperature process using real-time thermal imaging and a software-assisted thermodynamic analysis, the results of which correlated very closely to the results of the laboratory experiments. Conceptualization and writing--original draft preparation, J.L., R.F. and D.B. ; funding acquisition and project administration, J.L. and K.K. ; data curation, validation, and formal analysis, K.K. ; writing--review and editing, B.B. and P.D. ; visualization, data curation, and investigation, S.H. All authors have read and agreed to the published version of the manuscript. This research was funded by the Slovak Research and Development Agency (APVV), Slovak Republic, No. APVV-21-0142.