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.

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.

Fuel consumption in blast furnaces depends on many factors that are mainly conditioned by the technological level of a given blast furnace, the steel mill in which it operates, and the type and quality of ferrous feed, coke, and additional reducing agents. These are global factors which a furnace crew cannot control during operation. On the other hand, using their own experience and decision-making software, a crew can run a blast furnace with minimal fuel consumption under current batch and process conditions. The paper presents a model-based algorithm for optimizing the operation of blast furnaces to achieve the lowest fuel consumption. The algorithm allows the heat demands to be continuously calculated and highlights any wastage that could be reduced without affecting the stable operation of the blast furnace.

Sludge, due to its form and significant moisture and zinc content, is the most problematic metallurgical waste. Near the site of a disused steelworks plant in Krakow (Poland) there is an estimated 5 million tonnes of landfill sludge that consists of more than 90% iron and other metal oxides. There is a global tendency to switch steel production towards carbonless technologies, which is why the presented work investigates the possibility of simultaneous waste liquidation and recovery of valuable metals with the use of hydrogenous reduction. Direct reduced iron (DRI) production was selected as the targeted technology, so the sludge was lumped and bound with cement or CaO addition. The obtained lumps were reduced in a hydrogenous atmosphere with gradual heating to 950 °C, after which their phase structure was analyzed and elemental analysis was performed. It was found that zinc evaporated during the experiment, but mostly thanks to the carbon contained in the sludge. The increased addition of binder to the sludge resulted in the enhancement of the lumps, but also limited the reduction range. The products obtained were mostly wustite and less pure iron. Taking into account the degree of reduction and the lumps’ compression strength, the best binding was achieved by adding cement at a quantity of 5% mass.

The modern metallurgical industry produces approximately 90% of the volume of all produced steel; for this, integrated technology based on fossil materials such as coal, fluxes, and especially iron ore is used. This industry generates large amounts of waste and by-products at almost all stages of production. Alternative iron and steel production technologies based on iron ore, methane, or pure hydrogen are also not waste-free. To ensure sustainable waste management, efforts are made to seal processes as well as capture and recycle dusty waste. This work presents the results of research on the processing of sludge resulting from the dedusting of the basic oxygen furnace (BOF) process and landfilling in a lagoon. The work discusses the treatment of fine dusty sludge hydrated to 26–60% H₂O, to which various amounts of caking agents were added; also discussed are the rheological characteristics of the tested suspension systems, the possibility of forming these systems into larger fractions, and rapid drying using 100–600 W microwaves with a drying time of 1–9 min. The aim was to identify, describe, and characterize the parameters of the agglomeration process and obtain a product that was durable enough to transport and dose into slag baths in order to reduce iron oxides in liquid phases. During the research, completely dried briquettes with an appropriate strength were obtained. The study demonstrates that microwave drying at 300 W for 6 min achieved complete drying with a weight loss of 35%, whereas a higher-power treatment at 750 W for 2 min enhanced compressive strength by up to 95% and reached 15 N/psc, which was comparable with green iron ore pellets. This approach offers a sustainable alternative to traditional methods, but with a reduced drying time.