In recent years, environmental considerations and requirements about limiting of carbon dioxide emissions into the atmosphere again forced researchers to consider hydrogen as an alternative reducer at the ironmaking processes. In those studies, the reduction of iron oxides by a mixture of hydrogen and carbon monoxide mainly was considered, but reducing ability of solid carbon was taken into account rarely. The article presents an analysis of the impact of different content of hydrogen and carbon monoxide on the reduction processes equilibrium at the blast furnace conditions. Calculations were performed by using the FactSage thermochemical software and databases. The study presents influence of hydrogen content in the bosh gas on range of wustite stability at the blast furnace process conditions. The calculations revealed possible mechanisms of wustite reduction and role of water−gas shift reaction and hydrogen itself.

Metallurgical wastes landfills in Poland significantly grew during last four decades. Landfilled wastes are characterised by iron content at range 30-50% and zinc content about 2-3%. Therefore wastes are not interesting for the zinc smelter, on the other hand, even such low zinc content in ironmaking burden causes problem with a shaft furnace operation. So, the wastes are valuable for ironmaking due to the high iron content, provided that zinc will be removed from them. The article describes the general ways of dealing with zinc containing metallurgical wastes. In detail, the semi-industrial research conducted on sinter pot set of Stanislaw Staszic Institute for Ferrous Metallurgy is presented. The study determined the conditions under which obtained three benefits: landfilled sludge utilisation, raw materials substitution and zinc recovery.

The paper shows the use of novel modelling techniques adapted from ironmaking in the pyrometallurgical process of zinc production. Firstly, regarding the purpose to determine the boundary conditions of reduction processes taking part in the working volume of an Imperial Smelting Furnace (ISF), a deep thermochemical analysis was conducted. On this basis and using Ramm’s principles of direct and indirect reduction optimal share, the fuel rate minimization model was built. The model’s leading role is minimizing coke consumption in the ISF while maintaining the thermal state of the furnace at the correct level. In addition, the proposed presentation of the ISF thermal state shows in a unified way all the shortcomings in the correct process operation. Verification in real conditions on the ISF in Miasteczko Śląskie shows that model implementation can bring tangible benefits. Coke savings can reach over 30 kg per tonne of raw zinc.

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Coke is the only batch component that does not soften in blast furnace thermal conditions. It is especially important at the temperatures of the cohesive zone forming because coke layers are the only gas-permeable charge. The aim of the work described in this article is the identification of individual coke layers situation in the cohesive zone. Numerical calculations of the cohesive zone situation are based on the horizontal below burden probe measures, however, coke layers are calculated using analytical geometry. The results can be presented as a bitmap; the individual and total area of the coke layers passing gases through the cohesive zone is also calculated. This form of results allows for subjective but quick assessment of the blast furnace operation by its crew.