GB968046A - Process for the production of steel from tin plate scrap - Google Patents

Abstract

A process for the production of steel from tin plate scrap comprises adding to the molten scrap a metal oxide or sulphide, preferably iron oxide or sulphide, capable of reacting with the tin therein, and subjecting the melt to vacuum treatment whereby the tin is substantially wholly removed for recovery, while the residual metal is utilized for the production of steel. For the reaction FeS+Sn-->Fe+SnS, in one example scrap was melted under 1 mm.Hg. vacuum; the temperature was held at 1570 DEG C. for 10 minutes; the calculated quantity of FeS was added and the pressure held at 2 mm. at the same temperature for 17 minutes; and the pressure was reduced to 1 micron and held for 15 minutes. In a second example, scrap was melted; argon was admitted and FeS added, the pressure being then reduced to about 2 mm. and the temperature held at 1570 DEG C. for 15 minutes; the pressure was reduced to about 1 micron for 15 minutes and then for a further 15 minutes. Excess sulphur is preferably removed by reagents, Pb and Cu and other metals having slightly volatile sulphides will be removed or reduced at the expense of FeS if they occur in the scrap. The tin may be recovered in the form of SnS or SnO from filters or fume catchers.ALSO:A process for the production of steel from tin plate scrap comprises adding to the molten scrap a metal oxide or sulphide, preferably iron oxide or sulphide, capable of reacting with the tin therein, and subjecting the melt to vacuum treatment whereby the tin is substantially wholly removed for recovery, while the residual metal is utilized for the production of steel. For the reaction FeS+Sn-->Fe+SnS, in one example scrap was melted under 1 mm.Hg. vacuum; the temperature was held at 1570 DEG C. for 10 minutes; the calculated quantity of FeS was added and the pressure held at 2 mm. at the same temperature for 17 minutes; and the pressure was reduced to 1 micron and held for 15 minutes. In a second example scrap was melted; argon was admitted and FeS added, the pressure being then reduced to about 2 mm. and the temperature held at 1570 DEG C. for 15 minutes; the pressure was reduced to about 1 micron for 15 minutes and then for a further 15 minutes. Excess sulphur is preferably removed by reagents, Pb and Cu and other metals having slightly volatile sulphides will be removed or reduced at the expense of FeS if they occur in the scrap. The tin may be recovered in the form of SnS or SnO from filters or fume catchers.