Study of Lime-Slurry Injection into Blast Furnace

Abstract

The effects of injection of lime-oil slurry through the tuyeres were studied with the use of modelling instruments, and full scale tests of injection into blast furnace were carried out at Muroran Works, Nippon Steel Corp., Japan.
Following results were obtained.
(1) Degree of sulphur distribution coefficient between pig iron and slag under the condition of an operating blast furnace was only 20-40% compared with the equilibrium to be obtained.
(2) Sulphur content of pig iron drops was reduced rapidly in fluidized lime fines. Lime fines reacted mostly in melted zone of materials so that those slag basicity was increased. The dropping temperature of melted materials, however, did not rise in proportion to injection rate of lime, when the parts of the amount of lime in the burden materials charged into the furnace top were replaced beforehand by the equivalent amount of injected lime fines.
(3) Lime-oil slurry injection tests through all the tuyeres of Muroran No. 1 blast furnace showed that 25% of sulphur content of pig iron was reduced at the lime injection rate of 20 kg/t-p, and permeability of the melting zone was improved without producing the viscous slag.