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Combined decrease of sulphur, nitrogen, hydrogen and total oxygen in only one secondary steelmaking operation
Author(s) -
Bannenberg Norbert,
Bergmann Bernd,
Gaye Henri
Publication year - 1992
Publication title -
steel research
Language(s) - English
Resource type - Journals
eISSN - 1869-344X
pISSN - 0177-4832
DOI - 10.1002/srin.199201737
Subject(s) - lime , steelmaking , nitrogen , hydrogen , slag (welding) , ladle , sulfur , chemistry , metallurgy , oxygen , flue gas desulfurization , materials science , organic chemistry
The development of a matured metallurgical process allows the reduction of the sulphur, nitrogen, hydrogen and total oxygen content to the lowest values in only one secondary metallurgical step during treatment in a ladle tank degassing unit. By careful adjustment of a lime‐saturated ladle top slag at the beginning of the vacuum treatment, it is possible to obtain a desulphurization degree of more than 95%. The process of nitrogen removal by a stirring gas can be described with a dynamic model in excellent agreement with plant trials. The nitrogen content after vacuum treatment depends mainly on the nitrogen content before vacuum, the stirring gas quantity and the sulphur content. The achievable hydrogen contents mainly depend on the stirring gas quantity and dehydrogenisation can be described by the same model used for denitrogenisation. By a cleanliness stirring after the vacuum treatment under a nearly SiO 2 ‐free‐, lime‐alumina slag, saturated with lime, the total‐oxygen content can be lowered to less than 20 ppm.