Extraction of zinc from metallurgical waste using non-conventional energy sources

Abstract

Laboratory studies were carried out on samples prepared from the waste of the Nizhny Tagil Iron and Steel Works (NTMK) for the sublimation of zinc from them using non-traditional energy sources in the form of microwave fields. The study of physical and chemical processes was carried out, and a kinetic analysis was performed during heating of pellets, pellets and non-lumped charge from the waste of the NTMK plant in microwave fields in a wide temperature range. Recommendations are offered to accelerate the processes considered and to increase temperatures in relation to real technological parameters. A method for processing waste without pelletizing is proposed for industrial implementation, which is associated with the lowest capital costs. Experiments were carried out on heating pellets in a tubular electric resistance furnace, which made it possible to determine the dependence of the degree of zinc removal from pellets on the maximum heating temperature. Recommendations are given to intensify the process of heating the materials under study and to increase the temperature to a value that allows complete sublimation of zinc. The scheme of a conveyor unit with the use of a metal heat-resistant belt, consisting of two technological zones and allowing to carry out zinc sublimation from the unburnt charge. Approximate calculations were carried out, which made it possible to determine the temperature range in which zinc is sublimated and iron is metallized, as well as the specific power con-sumption and the useful power of the microwave generator. The sequence of technological operations and equipment necessary for the organization of production for the processing of zinc-containing dusts using microwave energy is con-sidered. The results obtained in the work are of particular interest for technologists and specialists involved in the pro-cessing of secondary waste at ferrous metallurgy enterprises. They can also be used in the development of new technol-ogies and installations for waste disposal and substantiation of the optimal modes of their operation, providing a high degree of extraction of valuable components with minimal energy costs.