Positive synergistic effect of the reuse and the treatment of hazardous waste on pyrometallurgical process of lead recovery from waste lead-acid batteries

Modification and optimization of the pyrometallurgical process of lead recovering from the waste lead-acid batteries have been studied in this paper. The aim of this research is to develop a cleaner production in the field of the secondary lead metallurgy. Lead smelting process with the addition of flux (sodium(I)-carbonate) and reducing agents (coke, iron) has been followed. The modified smelting process with the addition of hazardous waste (activated carbon) as alternative reducing agents has shown positive results on the quality of the secondary lead, the generated slag and the process gases. Filtration efficiency of the gases, the return of baghouse dust to the process and use of oxygen burners have positive effect on the environment protection and energy efficiency. Optimization of the recycling process has been based on the properties of the slag. Stabilization of slag is proposed in the furnace with addition of waste dust from the recycling of cathode ray tube (CRT) monitors. Phosphorus compounds from dust reduce leachability of toxic elements from the generated slag. Reduction the slag amount and its hazardous character through the elimination of migratory heavy metals and valorization of useful components have been proposed in the patented innovative device - cylindrical rotating washer/separator.  http://dx.doi.org/10.5937/metmateng1403171

Influence of reducing agents and surfactants on size and shape of silver fine powder particles

Silver fine powder with different shapes and sizes were prepared by chemical reduction and characterized by scanning electron microscope. In this paper was presented the method for the preparation of the fine Ag powder with particles size smaller than 2.5 µm with suitability for the mass-production scale. Reduction was performed from nitrate solution directly by vigorous stirring at room temperature by three different reduction agents, with and without presence of two dispersants. Scanning electron microscopy revealed the preferred size of the particles obtained in all experiments with aim of the protecting agent. Larger particles and wider size distribution were obtained without surfactants although with average size of about 1 µm and small quantity of larger clusters of primary particles that is out of the fine powder classification. High purity, 99.999%, of silver was obtained in every experiment.  http://dx.doi.org/10.5937/metmateng1402073

Ni-Pd-Al2O3 catalyst supported on reticulated ceramic foam for dry methane reforming

In the present study, Ni-Pd/Al2O3 catalyst supported on α-Al2O3 based foam was prepared and evaluated in the dry methane reforming process. Corresponding metal chlorides were deposited to the foam surface by impregnation of the foam with ultrasonically aerosolized salt solutions at 473 K and drying at that temperature. Calcination step was excluded and the catalyst was reduced at very low temperature - 533 K. The reforming experiment lasted for 3 h, with standing time of 1 h at the following temperatures: 873, 973 and 1023 K. Conclusions on selectivity, catalytic activity and stability were reached on the basis of CO and H2 yields

Exploitation Properties of Ni-Pd/Al2O3 Catalyst Supported on Ceramic Foam

The goal of this research was to examine exploitation properties of Ni-Pd/Al2O3 catalyst supported on α-Al2O3 based foam in the dry methane reforming. The catalyst was prepared by using aerosol method. Chloride precursors for Ni and Pd were reduced by hydrogen at low temperature of 533 K, without previous calcination. The reforming experiment was performed for 3 h, with standing time of 1 h for each of the following temperatures: 873, 973 and 1023 K. Conclusions on selectivity, catalytic activity and stability were made on the basis of CO and H2 yields

Nickel production in Serbia-technological and environmental aspects

Demand for nickel is constantly growing due to the versatility of its application, at the first place for stainless steel production. Ore reserves and possibility of nickel production of today’s Serbia and in neighboring countries were thoroughly investigated, and presented work is part of a wider project of sublimation of scientific and professional experience in the field of nickel extractive metallurgy on domestic raw materials. Presented research explores the possibility of high pressure sulfuric acid leaching of Serbian lateritic ores from localities Rudjinci, Ba and Lipovac. All three investigated ore deposits behaved differently both during preparation and during hydrometallurgical treatment. As optimal method for ore preparation proved to be crushing-milling-sieving route, but without possibility of concentrate production. Only for Rudjinci ore deposit achieved leaching efficiency reached satisfactory level of 95%. Within presented paper flow-sheet is proposed for processing high-magnesium laterite ores, with iron and magnesium oxide Both could be recirculated and used again in technological process; MgO for iron precipitation and SO2 for production of leaching agent, sulfuric acid. Final decision on the sustainability of the process will be made according to techno-economic and environmental evaluation. Estimated overall impact of the project implementation on the environment is negative.  http://dx.doi.org/10.5937/metmateng1404275