METHOD FOR PRODUCTION OF SPONGE IRON AND SHAFT FURNACE THEREFOR Russian patent published in 2016 - IPC C21B13/02 

FIELD: metallurgy.

SUBSTANCE: in upper zone shaft furnace (SF) is preliminary reduction in counterflow with products of incomplete combustion of natural gas with air or its mixture with oxygen to degree of restoration of 40-70 %, in area of metallization is produced sponged iron with degree of recovery φ = 94-97 % with carbon content C = 2-3 % and then it is cooled. Final carbonisation of obtained in area of metallization sponged iron and cementing till content C = 3.0-4.0 %, including iron carbide Fe₃C, is carried out in intermediate zone located below metal coating. Reduction in area of metallization is performed in counterflow of gas-reducing agent, formed in layer of sponged iron by pyrolysis and conversion of hydrocarbons of natural gas supplied to furnace in mixture with return circulating gas purified from oxides and heated to 900-1,000 °C outside furnace, and overflow in zone of preliminary reduction to 20 % of total consumption of gas at outlet from metal coating.

EFFECT: method of obtaining sponged iron of high quality of lumps or pellets in shaft furnace SF using natural gas and recycling of recirculation gas.

3 cl, 1 dwg