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Anna Pajdak and Arkadiusz Szymanek

Abstract

This article presents the results of research into calcareous waste from the production process of oxide propylene. The obtained results show a considerable chemical diversity of calcareous waste with a predominant percentage share of Ca, C and Cl, which are the products of the process. It was shown that the share of calcium bonded in CaCO3was over 20%, which is indicative of the secondary carbonisation process taking place in the waste. The morphological and structural analyses revealed that the grains had a surface area above 12% and a percentage porosity in the range of 25-35%. The reactivity test made it possible to classify calcareous waste as a material for sorbents of 'satisfactory' sorption properties, insufficient to be effectively used in the power sector. For the stored waste to be reused, it is necessary to improve its sorption abilities through the application of a properly selected activation method.

Open access

Anna Pajdak and Mateusz Kudasik

Abstract

The characteristics of copper-bearing rocks that include the structural and textural parameters are an important factor determining a possible gas accumulation in those rocks. In September 2009, in the Rudna copper mine in Poland, an outburst of gases and dolomite occurred. The analysis of the outburst mass showed that one of the main causes of the outburst was the different structural properties such as high porosity and presence of gas in the pores. This paper presents data from the structural analysis of dolomite from the Polkowice-Sieroszowice copper mine and the Rudna copper mine. Seven rock samples from various areas of the mines were tested by the following methods: mercury porosimetry (MIP), low pressure gas adsorption (LPNA), scanning electron microscopy (SEM), computed microtomography (micro-CT). The SEM analyses of the rock samples allowed pores of various sizes and shapes to the observed. The porosity (MIP) of the dolomite changed in the range of 3-15%. The total micro and mesopore volume (LPNA) was from 0.002 cm3/g to 0.005 cm3/g. The macropore volume (MIP) was from 0.01 cm3/g to 0.06 cm3/g and the mean macropore diameter was from 0.09 μm to 0.18 μm. The dolomite samples varied in the surface area (LPNA) (0.7-1.5 m2/g) and the pore distribution. The structure of dolomite determines the possibility of the occurrence of gasogeodynamic phenomena and hence it is urgent that research be conducted into its changeability. To better understand the gasogeodynamic processes in copper-bearing rocks, it is necessary to constantly monitor and analyse in detail those areas that have different structural properties.

Open access

Barbara Walawska, Arkadiusz Szymanek, Anna Pajdak and Marzena Nowak

Abstract

This paper presents the results of study on structural parameters (particle size, surface area, pore volume) and the sorption ability of mechanically and thermally activated sodium bicarbonate. The sorption ability of the modified sorbent was evaluated by: partial and overall SO2 removal efficiency, conversion rate, normalized stoichiometric ratio (NSR). Sodium bicarbonate was mechanically activated by various grinding techniques, using three types of mills: fluid bed opposed jet mill, fine impact mill and electromagnetic mill, differing in grinding technology. Grounded sorbent was thermally activated, what caused a significant development of surface area. During the studies of SO2 sorption, a model gas with a temperature of 300°C, of composition: sulfur dioxide at a concentration of 6292 mg/mn 3, oxygen, carbon dioxide and nitrogen as a carrier gas, was used. The best development of surface area and the highest SO2 removal efficiency was obtained for the sorbent treated by electromagnetic grinding, with simultaneous high conversion rate.