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The prospects of processing blast furnace and steelmaking sludge using the Waelz process in a laboratory rotary kiln, is shown. The influence of different processing temperatures, furnace atmosphere and the type of reducing agents on the level of zinc reduction from sludges was analyzed. In general, the blast furnace sludge contains a high portion of iron (approx. 48 wt.%) and can be reused as a charge after satisfactory zinc reduction. It was found that N- atmosphere and a high content of the graphite or coke oven reducing agent in combination with high temperature can reduce the content of Zn in the sludge to 0.08 wt.% at 1200 °C for a mixture of steelmaking and blast furnace sludge. A significant reduction in the Zn content to 0.66 wt.% occurs at 1100 °C. The content and type of reducing agent plays an important role; graphite has shown a better reducing ability compared to coke oven dust. When nitrogen is used, zinc is reduced even without an additional reducing agent, since the carbon contained in the sludge is made use of for the reduction. In an air atmosphere, without the use of a reducing agent, there was no reduction in the Zn content.

The prospects of processing blast furnace and steelmaking sludge using Waelz process in a laboratory rotary kiln is shown. The influence of varying thermal treatment modes, furnace atmosphere and type of reducing agents on the level of zinc reduction from sludges was analyzed. In general, the blast furnace sludge contains a high portion of iron (approx.48 wt. %) and can be reused as a charge after satisfactory zinc reduction. It was found that N- atmosphere and high content of the graphite or coke oven reducing agent in combination with high temperature can reduce the content of Zn in the sludge to 0.08 wt. % at 1200 °C for mixture of steelmaking and blast furnace sludge. A significant reduction in the Zn content to 0.66 wt. % occurs at 1100 °C. The content and type of reducing agent play an important role; graphite has shown a better reducing ability compared to coke oven dust. When nitrogen is used, zinc is reduced even without an additional reducing agent, since the carbon contained in the sludge is made use of for the reduction. In an air atmosphere, without the use of a reducing agent, there was no reduction in the Zn content.

The article summarises the modelling of the technological process of Mannesmann piercing in the configuration of the GreatMannesmann rolling mill in the Tube Mill of Třinecké Železárny using the approach of both mathematical modelling and numerical simulation. In accordance with the mathematical model of the given process, the formation of the cavity during the rolling in the numerical range is replaced by pre-drilling a billet of a specific size given by the mathematical model. The numerical simulations have shown an absolutely fundamental effect of the distribution of the initial temperature field of the billet on the actual piercing process. The billet with the initial inhomogeneous temperature field was subject to very strong transverse oscillations and significant spiral structures appeared in the distribution of all physical quantities. When simulating the piercing process on the Mannesmann piercer in the Tube Mill of Třinecké Železárny, parameterised by a mathematical model so as to take into account in the best possible approximation the influence of the cavity initiation sequence during the actual piercing, the simulation results were completely consistent with the predictions of the mathematical model of the submitted process calibration.

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