Premium
Contribution to phosphorus behaviour in steelmaking with sponge iron
Author(s) -
Meraikib Mohammed
Publication year - 1988
Publication title -
steel research
Language(s) - English
Resource type - Journals
eISSN - 1869-344X
pISSN - 0177-4832
DOI - 10.1002/srin.198801539
Subject(s) - lime , steelmaking , slag (welding) , phosphorus , chemistry , phosphate , direct reduced iron , metal , electric arc furnace , metallurgy , kinetics , inorganic chemistry , analytical chemistry (journal) , materials science , environmental chemistry , organic chemistry , physics , quantum mechanics
Experiments were conducted in a 70 t UHP electric arc furnace to study the phosphorus behaviour in steelmaking with sponge iron. The proportion of sponge iron in the metallic feed was varied from 52 to 95.4 wt.%. The results are used to show the effect of the sponge iron proportion in the charge on the phosphorus content of the bath. They are also utilized to illustrate the effects of the composition, temperature and theoretical optical basicity of the slag on the phosphate capacity and to investigate the kinetics of dephosphorization. It is found that both initial and final phosphorus contents of the bath decrease almost linearly with increasing sponge iron proportion in the charge. Using regression analysis, linear equations were obtained which show the change of the phosphate capacity of a slag, at a given temperature, with the total lime content as well as with the theoretical optical basicity. Based on these equations, a functional relationship was derived which shows the effect of simultaneous variation of total lime content and temperature of a slag on its phosphate capacity. A similar equation is given for the influence of simultaneous change of theoretical optical basicity and temperature on the phosphate capacity of a slag. The effect of the compositions of the slag and metal on the phosphorus distribution ratio is expressed by an equation. The kinetics of dephosphorization are investigated, assuming that the mass transfer of phosphorus in the metal is the rate controlling step. In the present investigation the activation energy of dephosphorization is equal to 38 kJ/mol and the mass transfer coefficient of phosphorus at 1600°C is 0.0135 cm/s.