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This publication presents the chemical compositions of carbon reducers used in the production of ferroalloys, with particular emphasis on the content of Al, Ca, Mg, Mn, Cr, Ti, P, or S in their mineral substances. A certain amount of these elements is transferred to the produced alloys, creating inclusions and precipitations in the metal structure. Most of them are undesirable and adversely affect the final effect of the production process. The work includes sample images of the microstructure of alloys, the chemical compositions of the samples at the test point, and diffragrams. On the basis of the obtained metallographic data, technological observations are made, especially of the crushing process and the amount of grain fractions obtained. [ABSTRACT FROM AUTHOR]

In the paper, the course of post-reaction gas afterburning generated during the metallurgical process where the reduction of metal and semi-metal oxides is performed with the use of carbon is presented. Process waste gases can be an alternative source of energy to be used in the same process or converted to another. The participation of chemical enthalpy in the total energy stream of the post-reaction gas is 93 %, the rest is physical enthalpy. In the study, particular attention was paid to the proper mixing of fuel and oxidizer and to maintaining an appropriate ratio of excess combustion air λa. The dynamics of the post-reaction gas combustion processes was calculated according to several popular models but the best results were obtained using the two-step mechanism with reaction constants according to Westbrook-Dryer.

In this paper, a system which uses hot furnace gases from a metallurgical process to heat compressed air necessary for another energy process is presented. The applied construction of the recuperator ensures high temperatures of the heated air needed for its utilisation in a separate process. Their levels depend on the processes in the reactor. A limitation to the construction of the installation is creep resistance of the materials used to assemble the recuperator modules which operate under high-temperature regimes. The well-prepared gas dynamic design of the recuperator ensured low pressure loss for the flowing air. Furnace gases leaving the recuperation system still have a high energy potential which can be utilised. As it is not possible to manage such large amounts of additional energy, the problem will be solved in the future when necessary.

The authors of the study focused on the problem of hydrogasifying coal extracted from a particular location. Since hydrogen is transparent to radiation, it can only be heated by convection. To achieve this, we developed a swirler and utilized Fluent software (version 19.0) to simulate the primary flow vectors and the temperature distribution of hydrogen in the hydrogasification reactor. The process was carried out under varying conditions, including temperatures ranging up to 1173 K, pressures of up to 8 MPa, and gas flow rates between 0.5 and 5 dmn3 min−1. The results showed that the carbon reactivity of the char was high up to a certain level of carbon conversion. In this study, the kinetic equations of the hydrogasification process were developed based on the theory of active centers. The researchers also evaluated the kinetic constants at the maximum reaction rate for the analyzed chars. The analysis was conducted for four extreme cases of process parameters, which included temperatures of 973 and 1173 K as well as pressures of 6 and 8 MPa. The results showed that the maximum hydrogasification reactivity of chars could be accurately described using equations for both the first- and second-order reactions toward hydrogen. This was likely due to the use of a narrow pressure range of 6–8 MPa during the experiments. The kinetic equations developed in the study could be used to model the process on a technical scale. [ABSTRACT FROM AUTHOR]

The mining industry is an industry branch with one of the highest rates of accidents at work in Poland and the presented analysis develops the knowledge about the safety in the mining sector. The work below presents a short-term prediction of the overall work accident number in a selected industrial facility, developed on the basis of statistical accident rate data and using 25 selected econometric models. In the summary assessment of a specific prediction, the scoring method was applied, taking the following weights into consideration: C1 and C2 criteria (C) - 10 % each, C3 and C4 criteria - 20% each, and C5 criterion - 40 %, where: C1 was the value of ex post prediction error - for the series including the empirical data covering the period between 2007 and 2016; C2 was the value of ex post prediction error - for the series including the empirical data covering the period between 2007 and 2018; C3 was the value of coefficient of random variation Ve for the ex post predictions from the period between 2007 and 2016 (for all predictions except the linear and linearized models, the RMSE* value was applied to estimate their value); C4 was the value of coefficient of random variation Ve for the ex post predictions from the period between 2007 and 2018 (for all predictions except the linear and linearized models, the RMSE* value was applied to estimate their value); C5 was the value of ex post prediction error - for the series including the empirical data covering the period between 2017 and 2018. Statistical work accident rate data covering the period between 2007 and 2018 were used in the analysis. [ABSTRACT FROM AUTHOR]

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The experimental facility for pressure hydrogasification research was adapted to the pressure of 10 MPa and temperature of 1300 K, which ensured repeatability of results and hydrogen heating to the process temperature. A hydrogasification reaction of chars produced from two rank coals was investigated at temperatures up to 1173 K, pressures up to 8 MPa, and the gas flow rates of 0.5-5 dm(n)(3)/min. Reactivity of the "Szczerców" lignite char was found to be slightly higher than that of the subbituminous "Janina" coal char produced under the same conditions. A high value of the char reactivity was observed to a certain carbon conversion degree, above which a sharp drop took place. It was shown that, to achieve proper carbon conversion, the hydrogasification reaction must proceed at a temperature above 1200 K.