# Rudomain Iron Ore Treatment by High-Temperature Reduction
## 2 Materials and Experimental Works  
The tested iron ore is mined in the \"Yuzhny\" open pit located in the southern part of the Saksagan region (Kryvyi Rih, Ukraine) [25]. The total recovery level is 4 Mt/year, with a minimum Fe content of 38%. The product portfolio consists of several types of iron ores and lump ores, which are characterised and limited by standard quality indicators describing the contents of selected components and granulometry. The richest products contain a minimum of 60% of Fe and a maximum of 14% of SiO\({}_{2}\), whereas the lower-grade ones contain a minimum of 38% of Fe and a maximum of 38% of SiO\({}_{2}\). The moisture of the products reaches a maximum of 8%, while the maximum contents of sulphur and phosphorus represent 0.01%. The study of the processing (pre-treatment) of the tested Rudomain ore was carried out with selected samples, while the R7 sample represents a long-term average of this commodity. Parallel tests were carried out with two other ores that represented the reference samples (Table 1). In Section 3.1, the physico-chemical and metallurgical properties of iron ores are described in detailed specifications of the properties of those iron ores. Experiments in the reduction of three types of iron ores (KB, Krivbas; R7, Rudomain 7; CAR, Carajas) mixed with a solid reducing agent (charcoal, Table 2) at the ratio of ore to reducing agent of 4:1 (in a dry state) were carried out at various temperatures and various holding times. The experiments were conducted in a muffle furnace (MP-62, type MARK ESA, Electro, Prague, Czech Republic) and in an electric induction furnace (HFR 15, RAJMONT, Prague, Czech Republic). Raw pellets sized -10-15 mm were inserted into the MP-62 furnace (Electro, Prague, Czech Republic), pre-heated to 600 \({}^{\circ}\)C, and then heated up to 1200 \({}^{\circ}\)C with a gradient of 40 \({}^{\circ}\)C/min. Holding time at the maximum temperature was 10-300 min, followed by gradual cooling in the furnace and in the air. During the experiments, the gaseous phase was monitored in order to control reduction conditions. Measurements were carried out using a Testo 350 (Testo SE & Co., KGaA, Titisee-Neustadt, Germany) exhaust gas analyser with respective O\({}_{2}\) and CO modules. The CO\({}_{2}\) content was subsequently calculated. Due to the predicted and expected high concentration of CO in the system, the equipment was used in the mode of automatic dilution of exhaust gas (five times) for the purpose of protecting the modules. A gas probe was attached to the outlet of the heated ceramic tube in which a boat containing pellets was placed. During the measurements, it was observed that even the 5-fold dilution did not bring a sufficient dilution effect required for safe continuous measurements, and the equipment exhibited short interruptions (outages) in recording CO, which may be seen in the curves presented in Table 3. Regardless, it may be stated that the conditions of the reducing atmosphere \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Sample**} & **Fe Total** & **SiO\({}_{2}\)** & **Bulk Density** & **True Density** \\  & **(\%)** & **(\%)** & **(kg/m\({}^{3}\))** & **(kg/m\({}^{3}\))** \\ \hline
**Rudomain 1 (R1)** & 52.46 & 20.02 & 2435.60 & 3991.80 \\
**Rudomain 7 (R7)** & 58.20 & 13.40 & 2609.60 & 4412.66 \\
**Rudomain 8 (R8)** & 61.71 & 8.28 & 2678.80 & 4580.56 \\
**Krivbas (KB)** & 62.25 & 7.80 & 2810.20 & 4460.81 \\
**Carajas (C)** & 65.23 & 2.21 & 2606.40 & 4707.56 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Selected parameters of tested iron ores. were confirmed while the CO concentrations reached their peaks before achieving the temperature of holding that ranged in an interval of 900-1100 \({}^{\circ}\)C with a period of \(\sim\)5 min. The recordings also clearly showed that the conditions for the Boudouard reaction between CO\({}_{2}\) and solid carbon to form CO were successfully created.