Оценка технико-экономической эффективности пирометаллургической технологии переработки пылей электросталеплавильного производства

Abstract

An evaluation of technical and economic efficiency parameters of a previously proposed technological solution for processing dust from electric steel production by the pyrometallurgical method is presented. The technological approach consists in the reduction of iron and zinc from their oxygen-containing forms (ZnFe 2 O 4 and ZnO) by active carbon-containing materials. Experiments were carried out on samples with a 26.02 and 37.7%wt. of ZnO and Fe 2 O 3 , respectively, to evaluate the processing of industrial dust of PJSC Magnitogorsk Iron and Steel Works in a laboratory facility based on the LHT 08/17 high-temperature furnace (Nabertherm, Germany). "Small long-flame nut" brand charcoal was applied as a carbon reducing agent, with lime and quartz sand serving as sources of slag-forming components. Commercial products were obtained in the form of granular cast iron (96.75 and 2.92%wt. of Fe and C, respectively) and a zinc oxide product (90.21%wt. of ZnO). The extraction of iron and zinc in cast iron comprised the values of 94.0 and 91.0%, respectively. As a result, an annular hearth furnace is recommended as the main technological unit for the industrial implementation of the process. The basic technological scheme is proposed including dosing raw materials, preparing charge briquettes, performing reduction smelting, separation of smelting products (cast iron and slag) and trapping zinc-containing sublimates. To assess the technical and economic efficiency of the developed technology on an industrial scale, the costs of building a dust processing plant involving one annular furnace with an average diameter of 12 m having a steel production capacity of 15 000 tonnes per year were taken into account. The proposed technology was shown to be capable of supporting commercial granular cast iron and zinc oxide products in the amount of 33264 and 4435 tonnes per year, respectively. Considering the investment period, the estimated payback period is determined to be 34 months with the expected net profit equal to 535.59 million rubles/year.