The new recirculation system will enable exhaust gases to be re-used during the sintering process.
Severstal said the equipment upgrade, which includes the installation of a sinter gas recirculation system and replacement of current dust gas purification devices, will result in a 22.5% reduction in gross emissions.
"Following a review of Severstal's strategic investment programme for 2021-2025, we decided to install new equipment to reduce emissions at sintering machines No.10 and No.11 at CherMK," said Alexander Shevelev, chief executive of Severstal.
"Severstal is committed to constantly improving the environmental situation in the cities in which we operate, and this remains a key area of our focus in spite of the current difficulties presented by COVID-19."
The company added that the strategic investment programme also includes a future provision to replace the plant's battery cyclones, reducing dust emissions by more than 80%, from 170 mg/m3 to 30 mg/m3. This and the gas cleaning equipment will reduce emissions by 668,000 tonnes by 2025, said the firm.
Last July, the Church of England's pension board wrote to Severstal on behalf of almost 100 European investors seeking to know the impact of its operations on the environment. The church also included the firm in its April 30 survey of Mining & Tailings Safety Initiatives.