公开(公告)号：US3908072A

公开(公告)日：1975-09-23

申请号：US43488774

申请日：1974-01-21

Applicant: ASEA AB

Inventor： COLLIN PER HARALD

IPC: C22B5/10 ,  C21B11/00 ,  C21B11/10 ,  C21C5/52 ,  C21C7/00 ,  C22B4/00 ,  C22B5/02 ,  F27D11/06

CPC classification number: C22B4/00 ,  C21B11/10 ,  F27D11/06 ,  Y02P10/136 ,  Y02P10/253

Abstract: Metal oxide particles, such as particulated iron ore, are fed to the surface of a molten metal melt containing carbon which reduces the oxides and thus adds the metal to the melt. The latter''s carbon content, necessary for the reduction, is maintained by feeding carbonaceous material to its surface, the carbon with time, dissolving in the melt. The latter is heated by an electric induction coil designed to induce electric currents in the melt with a flux field pattern causing a bulge to form upwardly in the melt in the shape of a closed loop having inner and outer descending slopes of oppositely flowing molten metal, this loop of bulging metal being largely above the level of slag formed from gangue included by the oxides, and presenting metal surfaces which are free from slag or naked. The particulated oxides are fed to the inner slope so that metal is added to the melt while the slag collects in what is in effect a valley or basin formed in the melt within the upwardly bulging loop of metal. The melt is contained in an electric induction furnace hearth having an upstanding side wall surrounding the bulging loop at a distance forming an annular or peripheral valley of molten metal which free from slag because the oxides are not fed to the outer slope of the loop. The carbonaceous material required to maintain the carbon content of the melt, is fed to this outer slope and collects in this peripheral valley on naked metal free from slag, permitting the carbon to dissolve into the melt without interference by a slag barrier. A special induction furnace is provided wherein, among other features, the necessary induction coil is designed so that at one localized portion of the upwardly bulging loop of melt, the height or upward elevation of the bulge is lowered, the furnace having a tap hole in its side wall at this location for permitting the removal of slag collected in the basin or inner valley as well as the metal obtained by reduction of the oxides.