Magnitogorsk Iron and Steel Works (MMK) has restarted blast furnace No. 7 following a full-scale major overhaul. The furnace is now operating normally, enabling the blast furnace shop to meet its production targets.
The overhaul took around a year to complete, with total investment of RUB 4.8 billion. The furnace's production capacity has increased from 1.0 million to 1.1 million tonnes per year, while coke consumption has been reduced by 16 kg per tonne of pig iron.
A key element of the upgrade was the modernisation of the furnace's hot-blast stoves. Two new units were built before the overhaul began, while hot-blast stove No. 24 - a shaftless unit with a top combustion chamber - was completed during the project. The new equipment enables the Company to increase the hot-blast temperature to 1,250°C and reduce coke consumption, thus lowering pig iron production costs and improving the furnace's environmental performance. The plate conveyor in the sinter feed system was also replaced with a belt conveyor following the transition to cold sinter at sinter plant No. 5.
The previous overhaul on this scale at blast furnace No. 7 was carried out in 2002. During the most recent overhaul, the furnace was almost completely rebuilt: this process included dismantling old structures, repairing the foundation, replacing the hearth cooling pipes and iron receiver, and installing a new shell, cooling plates and throat armour. In addition, upgrades were carried out on the hot-blast valves and hot-blast stove shut-off valves, skip hoist, power supply and automation systems. At peak periods, up to 1,000 specialists per shift were working at the site.