Sinter plants and coke ovens
The sinter plants and coke ovens were formed on May 1, 2014 following a global restructuring of PAO Severstal’s Russian Steel Division.
The sinter plants and coke ovens are made up of three large divisions of the Cherepovets Steel Mill, each with their own coke and by-product plants, sinter plants and blast furnaces, developed over the course of more than 50 years. In combination they deliver higher productivity and quality of cast iron, lower costs and a more efficient management structure.
The sinter plants and coke ovens currently consist of four blast furnaces with volumes ranging from 1,007 to 5,500 m3, including the largest blast furnace in Europe – BF No. 5, “Severyanka”.
Coke and by-product plants
Coke is manufactured by eight coke oven batteries. No. 3 coke battery of ПВР system and No. 4 coke battery of ПК-2К system, with an annual output of 460,000 tons of coke, were commissioned in 1958. Each battery comprises 61 ovens each with a volume of 21.6 m3.
Coal used in the coking process comes from the Pechorsky and Kuznetsky coal fields.
Coking coal grades are: 1Ж, 2Ж, ГЖО (Pechorsky field) and СС, КС, КСН, ГЖ, КЖ (Kuznetsky field).
Sinter is produced by sintering a blend of concentrates. Metallurgical coke fines are used to fuel the sintering process.
Limestone is used as a fluxing agent. The basicity of fluxed sinter is determined by the blast furnace process.
Burden is fed from the collecting conveyor for primary mixing and from the mixing drum it is forwarded via feed bins to a pelletizing drum to be humidified, pelletized and heated.
Sinter cake is produced by belt-type sintering machines with a sintering area of 84 m2 and 252 m2 and a sinter layer 355−375 mm high.
The average temperature of finished sinter cake is about 850 °С. After it is crushed in a tooth crusher, sinter cake is cooled by straight line coolers.
After screening, 0−5 mm sinter enters the burden preparation plant for sintering (reverse product). [sinter of] 5−12 mm size is used as a bed before the burden is loaded into the sintering machine, while sinter above 10−12 mm is fed by a conveyor system to blast furnaces.
Sinter produced by a sinter plant is used, along with pellets, as the basic iron ore raw material. Sinter is transported from the sinter plant via a conveyor system to the blast furnace automated stock house.
Lump ore is added in minor amounts, while metallurgical coke, produced by coke batteries, is used as fuel for the blast furnace process.
The process uses hot blast enriched with oxygen and natural gas.
The state of the art technology makes it possible top produce high-quality hot metal with 0.3 — 0.7% silicon; sulfur to 0.015 %; carbon to 4.9%, and manganese to 0.35 — 0.45%.
Hot metal is delivered to the electric arc furnace (EAF) shop and to piggers in 100−ton ladle cars and in 600−ton torpedoes to the basic oxygen furnace (BOF) plant.