TECHNOLOGICAL BASICS OF ADSORPTION DEHYDRATION AND THERMOCHEMICAL SINTERING OF BOF SLUDGE

The global volume of steel smelted in 2016 exceeded 1600 million tons, of which more than 1200 million tons of steel were smelted in the units of converter type. Depending on the number of technological factors, up to 25 kg of fi ne dust forms in the process of smelting of 1 ton of steel, which contains up to 65 % of iron in the form of oxides. The recycling organization of waste generated in metallurgical production makes it possible to reduce production costs by two to three times in comparison with the use of concentrates obtained from natural raw materials and minerals. In the context of solving the recycling problem of converter sludge, the method for conditioning high-moisture wastes was developed and improved, including their non-thermal adsorption dehydration and subsequent thermo-chemical agglomeration. The solid residue of brown coal pyrolysis is used as the adsorbent – a fi ne-grained brown coal semi-coke produced at the pilot plant of the open-pit mine Berezovsky-1. The obtained samples from brown coal char are of highly developed and porous structure and, accordingly, high adsorption capacity and energy properties. The granulo metric composition of the brown coal semi-coke is almost identical to the granulometric composition of the slurry. At the same time, the density of the brown coal semi-coke particles, even if the entire porous space is fi lled with adsorbed moisture, is more than 2.5 times lower than the density of the converter slurry particles. When mixing brown coal semi-coke and converter slurry, the former absorbs moisture, giving the mixture a high looseness, while at the same time the moisture adsorbed in the pores transforms into a bound state and becomes an active participant in oxidation-reduction processes. As a result of the experiments, the new material was obtained – “ferrocoke” containing up to 39 % of Fe_met and up to 49 % of C. The results obtained in the work made it possible to develop an effi cient technology for the utilization of converter sludge with production of a ferrocoke suitable for use in blast-furnaces and steelmaking plants as a coolant and reducing agent, without a complicated mechanical-thermal dehydration and briquetting with a binder.

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