Russian steel and mining heavyweight, Severstal, has recently successfully completed a record-length basic oxygen furnace (BOF) campaign relined by Calderys. This complex project was the first of its kind for our teams, and it has demonstrated Calderys has the skills and technology to be a major player in these types of applications.
BOFs convert liquid iron into steel. They are lined with special high magnesia-carbon bricks and magnesia repair gunning materials, aimed to sustain a targeted number of charges. The more complex furnaces also include “blowing elements”, allowing inert gas to be blown into the furnace through the bottom of the furnace lining. This bottom blowing generates a large contact surface among all reactants, improving the process control.
Providing a better solution for the client
Severstal began using bottom blowing in its BOFs towards the end of 2019 to improve the quality of its steel. Each furnace has a lining campaign life of five to six months, meaning it requires two refractory re-linings per year.
Vladislav Mischenko, General Director CIS, Russia, says: “Severstal uses one of the biggest BOFs in the world. The company set Calderys the task of fitting a BOF lining that could handle 6,000 charges in one campaign, to fit the steel plant’s overall plan for scheduled maintenance.
“As the BOF is a core process in steel making, any mistake in design, material selection, installation or initial lining heating could lead to a number of negative consequences such as production of lower-grade steels – so getting it right was paramount.”
The challenge was huge, but through dedicated efforts and teamwork, Calderys successfully provided an easy-to-install lining, with 24/7 support from installation to completion with technical support, and proposed improvements for the project. The relined BOF was able to handle 6,141 loads, marking a record for the company.
“The performance shown by all those involved, from our engineers and designers, to our plant operators and managers, was what enabled us to achieve what we did,” says Vladislav.
“BOF projects like this represent the higher technology demands within the steelmaking process, so companies that can deliver them are regarded as premium suppliers. Calderys has plenty of experience in refractories, but this was the first project of this kind for us, and we now have a really strong reference point in this specific field.”