In this work the results on the batch and column adsorption of copper and some associated ions by employing linden and poplar sawdust as a low-cost adsorbent are presented. The mine water from a local abandoned copper mine, as well as synthetic solutions of those ions which are the main constituents of the mine water were both used as a model-system in this study. The adsorption ability of the chosen sawdust to adsorb heavy metal ions is considered as a function of the initial pH of the solution and kind of metal ions. At lower pH of solutions the adsorption percentage (AD %) decreases leading to a zero AD % at pH < 1.1. Maximum AD % is achieved at 3.5 < pH < 5. It was found that poplar and linden sawdust have both almost equal adsorption capacities against copper ions. The highest AD % ( ?80%) was achieved for Cu2+, while for Fe2+ it was slightly above 10%. The other considered ions (Zn2+ and Mn2+) were within this interval. The results obtained in the batch mode were verified through the column test by using the real mine water originating from an acid mine drainage (AMD) of the copper mine 'Cerovo', RTB Bor. The breakthrough curves are presented as a function of the aqueous phase volume passed through the column allowing having an insight into the column adsorption features. Breakthrough points were determined for copper, manganese and zinc ions. A very high adsorption degree - higher than 99% was achieved in these experiments for all mentioned ions. After completing the adsorption, instead of desorption, the loaded sawdust was drained, dried and burned; the copper bearing ash was then leached with a controlled volume of sulphuric acid solution to concentrate copper therein. The obtained leach solution had the concentration of copper higher than 15 g dm-3 and the amount of H2SO4 high enough to serve as a supporting electrolyte suitable to be treated by the electrowinning for recovery of copper. The technology process based on the column adsorption is proposed and discussed.

Two Cu-Zn-Al alloys with variable content of Zn (25 and 30 wt%) and constant Al content (4 wt%) prepared by induction melting of pure metals and hot rolled into strips of 0.5 mm thickness were thermally processed by using three different heat treatments: direct quenching, step-quenching and up-quenching with boiling water and room temperature water as the quenchants. The effects of composition and different methods of heat treatment on the microstructure and transformation temperatures of the investigated Cu-Zn-Al alloys were investigated using SEM-EDS and DSC techniques.

Flotation waste, which was produced through seventy years of copper ore processing in RTB Bor, Serbia, is deposited in a flotation tailings pond. In total, almost 26.4 Mt could be considered as available for eventual reprocessing and reuse. Chemical analysis has shown that an average concentration of targeted metals in the tailings is: 0.183% Cu, 0.35 g/t Au and 2.17 g/t Ag. The tailings contain 60 to 70% of SiO2, 10 to 17% of Al2O3 and pyrite 5 to 8%. Flotation tailings reprocessing consisted of acid leaching followed by re-flotation of the leach residue. Leaching of the tailings resulted in leach liquors containing Cu2+ ions from 50 to 580 ppm. The average copper removal degree in the leaching stage was 70%. After re-flotation, the total copper removal degree reached 83 to 85%. Sulphur removal degree reached 77%. Sulphur concentration in the treated tailings was reduced almost 5 times compared to the inlet concentration. An equivalent amount of iron was also reduced through the flotation process. Concentration of total copper was reduced 3 times.