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Number of results: 8
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Abstract

This paper presents the idea of increasing the effectiveness of slag decopperisation in an electric furnace in the "Głogów II" Copper Smelter by replacing the currently added CaCO3with a less energy-intensive technological additive. As a result of this conversion, one may expect improved parameters of the process, including process time or power consumption per cycle. The incentives to optimize the process are the benefits of increasing copper production in the company and the growing global demand for this metal. The paper also describes other factors that may have a significant impact on the optimization of the copper production process. Based on the literature analysis, a solution has been developed that improves the copper production process. The benefits of using a new technology additive primarily include increased share of copper in the alloy, reduced production costs, reduced amount of power consumed per cycle and reduced time it takes to melt. At the conclusion of the paper, the issues raised are highlighted, stressing that mastering the slag slurry process in electric furnaces requires continuous improvement.
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Abstract

The paper concerns simulation of fully developed and axially-symmetrical turbulent flow of coarse-dispersive slurry if all solid particles have similar size and shape with particles diameter from 1 mm to 5 mm, solid density from 1045 kg/m^3 to 3000 kg/m^3, and solid concentration by volume from 20% to 40%. The author examines the influence of particle diameter on additional shear stress due to the ‘particles-wall’ interactions for moderate and high solid concentration. The mathematical model was developed using Bagnold's concept, [26] and assumes that the total wall shear stresses are equal to the sum of ‘liquid-wall’ and ‘particles-wall’ shear stresses. The mathematical model was successfully verified with own measurements of frictional head loss in vertical coarse - dispersive slurry flow, named: ‘sand-water’, ‘polystyrene-water’ and ‘pvc-water’, [10], [26]. The mathematical model can predict ‘particles-wall’ shear stress, pressure drop and friction factor for coarse-dispersive turbulent slurry flow in a pipe, [10]. The aim of the paper is to present qualitative and quantitative dependence of solid particle diameter, solid particle density, solid concentration, and Reynolds number for carrier liquid phase on the ‘particles-wall’ shear stress. It is demonstrated that the solid particle diameter plays crucial role in its dependence on the ‘particles-wall’ shear stress. It was proved that in particular flow conditions the ‘particles-wall’ shear stress is much higher compared to the carrier liquid wall shear stress.
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Abstract

The objective of the study was to compare the impact of three systems of multiannual fertilization applied in two long-term field experiments on the content of phenolic compounds in the soil. In the study, both natural (manure, slurry) and mineral (NPK) fertilizers were used, along with combined, organic-and-mineral fertilization. Experiment I was established in 1972 on grey brown podzolic soil; experiment II, in 1973 on brown soil. In both experiments crops were cultivated in a 7-year rotation, with a 75% share of cereals. The experimental samples were taken from the top layer of soil after 36 (experiment I) and 35 (experiment II) years following the establishment of the experiments. It was demonstrated that the presence of phenolic compounds in the soils was significantly dependent on the contents of organic C and total N, type of soil and the type and dose of used fertilizers. In grey brown podzolic soil, the content of total phenolic compounds was at a lower level than the content found in brown soil. Multiannual fertilization contributed to an increase in the content of total phenolic compounds in relation to the values obtained in control objects, which was particularly reflected in the soil originating from objects fertilized with slurry applied at a dose being equivalent to manure in terms of the amount of introduced organic carbon. The percentage of water-soluble phenols in the total content of these compounds in grey brown podzolic soil was at the level of 18.4%, while in brown soil it amounted to 29.1%.
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Abstract

This article presents test results for hydraulic conductivity and porosity structure of hardening slurries prepared of Portland cement, betonite, water and fluidal ashes from the combustion of hard and brown coal. The slurries were exposed to persistent filtering action (180 days) of liquids chemically aggressive to cement binders, i.e. distilled water, 0.5% solution of nitric acid, 1% solution of sodium sulphate, 1% solution of magnesium nitrate and 1% solution of ammonium nitrate. Samples exposed to filtration of tap water constituted the reference base. The research was into relations between hydraulic conductivity and pore structure parameters in slurries, as well as into the influence of the type of aggressive medium on leak tightness of slurries (their porosity and hydraulic conductivity).
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Abstract

This article presents ways of possible utilization and application of fl uidal combustion wastes as active additives to hardening slurries which are used to seal environment protection structures, i.e. cut-off walls in waste dumps and wastewater treatment plants. Cut-off walls are often exposed to fi ltrating action of eluates - polluted (aggressive) waters. Results of hydraulic conductivity tests of slurries after their long-term (210 days) fi ltration with eluates from a municipal waste dump and with tap water are presented. Porosity tests were also conducted to show the porosity structure of the fi ltered slurries. Additionally, compressive strength of slurries maturing in tap water and waste dump eluates was tested in parallel.
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Abstract

The results of the modification of austenitic matrix in cast high-manganese steel containing 11÷19% Mn with additions of Cr, Ni and Ti were discussed. The introduction of carbide-forming alloying elements to this cast steel leads to the formation in matrix of stable complex carbide phases, which effectively increase the abrasive wear resistance in a mixture of SiC and water. The starting material used in tests was a cast Hadfield steel containing 11% Mn and 1.34% C. The results presented in the article show significant improvement in abrasive wear resistance and hardness owing to the structure modification with additions of Cr and Ti.
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Abstract

Cast stainless steel of the Cr-Ni duplex type is used, among others, for the cast parts of pumps and valves handling various chemically aggressive media. Therefore, the main problem discussed in this article is the problem of abrasion wear resistance in a mixture of SiC and water and resistance to electrochemical corrosion in a 3% NaCl- H2O solution of selected cast steel grades, i.e. typical duplex cast steel, high silicon and manganese duplex cast steel, and Cr-Ni austenitic cast steel (type AISI 316L). The study shows that the best abrasion wear resistance comparable to Ni-Hart cast iron was obtained in the cast duplex steel, where Ni was partially replaced with Mn and N. This cast steel was also characterized by the highest hardness and matrix microhardness among all the tested cast steel grades. The best resistance to electrochemical corrosion in 3% NaCl- H2O solution showed the cast duplex steel with high content of Cr, Mo and N. The addition of Ni plays rather insignificant role in the improvement of corrosion resistance of the materials tested.
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Abstract

Along with the increase in popularity of the sewage sludge thermal treatment methods in Poland resulting from the implementation of European Union law, a management problem with ash, which is produced as a result of this process, appeared. The paper analyses the chemical composition and physical properties of fl y ash from thermal treatment of municipal sewage sludge in terms of its use in concrete technologies in relation to EN 450-1 Fly ash for concrete. Defi nition, specifi cations and conformity criteria (2012) and EN 197-1 Cement. Composition, specifi cations and conformity criteria for common cements (2011) standards. The tested material did not meet the requirements related to use of fl y ash for concrete production (chemical composition, low activity index, high water demand and fi neness), and as main and minor components for cement production. On the basis of the carried out research and analyses, it was found that the hardening slurry technology creates the greatest possibilities related to the management of fl y ash from thermal treatment of municipal sewage sludge.
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