Vaso Manojlović

Combustion of Metallurgical Wastes Using Secondary Aluminum Foils

ABSTRACT Simulating the reactions in a complex system can lead to self-sustaining and energy efficient treatment of wastes in recycling promoting manner. In this contribution, the synergic combination of electric arc furnace dust (EAFD), mill scale, and secondary aluminum, in a form of waste foil, was researched aiming to use exothermal energy of reactions and to obtain environmentally favorable products. The secondary aluminum in the form of foil was prepared in different ways in order to develop aluminum surface and to be suitable for aluminothermic reactions. The commercial aluminum powder was used to determine optimal conditions using full factorial experiment design. After that, research was performed on aluminothermic reactions with the aluminum powder obtained from secondary aluminum foils. Results show that the secondary aluminum can be successfully used for a treatment of oxides bearing hazardous wastes in an energy efficient and environmentally friendly manner. The comparative life-cycle assessment revealed several advantages of using the secondary aluminum foil as a reduction agent compared to the conventional recycling of the secondary aluminum foil.

Kinetics of barite reduction from refractory barite-sulphide ore

Refractory sulphide–barite ore was reduced with carbon in order to release lead, zinc, and copper sulphide from barite-pyrite base. Mineralogical investigations showed that due to the complex structural-textural relationships of lead, copper and zinc minerals with gangue minerals, it is not possible to enrich the ore using the conventional methods of mineral processing. The influence of temperature and time was studied to optimize the conditions, and to determine the kinetics of the barite reduction. The maximum removal of barite from ore was 96.7% at 900oC after 180 min. Chemically controlled kinetic model showed the best compliance with the experimental data. An activation energy of 142 kJ/mol was found.

Investigation of copper(I) sulphide leaching in oxidative hydrochloric acid solution

Present work is focused on the copper (I) sulphide leaching with sodium chloride in hydrochloric acid solution and with introduction of gaseous oxygen. Chemical reactions of leaching and their thermodynamic probabilities are predicted based on the literature data and products which were formed during the process and the overall leaching reaction was defined. The influence of temperature and time on the leaching degree of copper was experimentally determined. The quantity of dissolved copper increases with the increase of both investigated parameters. Elemental sulphur was formed as the main leaching product, precipitated at the particle surfaces and chloride ions have a role to disrupt the creation of this passive layer.

Complex sulphide-barite ore leaching in ferric chloride solution

The results of research on the leaching process of complex sulphide-barite ore were presented in this paper. The leaching process was carried out in a laboratory autoclave by ferric chloride solution. Considering that those minerals are represented in complex structural-textural relationships, it is not possible to extract lead, zinc and copper minerals from ore by flotation methods. The obtained results confirmed possibility of the ore processing directly, by chemical methods. The effect of temperature, time and oxygen partial pressure on the lead, zinc and copper dissolution was studied. The maximal leaching degree was achieved at 100 °C and amount of 91.5 % for Pb, 96.1 % for Zn and 60.7 % for Cu). Leaching at temperatures above 100 °C is impractical.