Increase of Converter Life by Own Slag Coating
Abstract
This paper presents a method for the improvement of the lining life of the BOF
converter by slag coating, under nitrogen pressure. Own slag coating of converter
lining is put in practice after steel tapping. Dolomite blocks are used like standard
wear converter lining. Nitrogen blowing for own slag coating is carried out by
oxygen lance. After steel tapping without slag, the converter is tilt in blowing
position and the oxygen lance is let down in the lowest position. The nitrogen is
blown under 10-12 barr pressure and 450-500 Nm3/min rate, for 3 minutes. By this
slag coating technology the performance of refractories has been improved from
about 370 heats per campaign in reference year to about 800 heats per campaign at
the end of two years of experiments, and therefore refractory consumption
decreased from 5.25 kg/t under 3.00 kg/t and the cost of converter refractories
decreased by 0.24 $/t. Another variant for improvement of the BOF converter lining
life was the use of magnesia bricks for selective lining areas (trunion rings area and
charging mouth). The own slag coating technology has been used also. In the case
of this variant, the lining life of converter has been improved to about 800 heats per
campaign at the end of two years of experiments and so the refractories
consumption decreased under 2.45 kg/t. Because of the higher price of magnesia
bricks and of the lower price of dolomite blocks, the cost for converter refractories
has decreased only by 0.02$/t.
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- 2012 fascicula9 nr3 [13]