Ltv Steel Company, Inc.

Chung S Kim

Ken M Goodson

Kenneth M Goodson

A BOF process in which iron oxide units are added to the melt during the blow characterized in that the oxygen flow is reduced during pellet feeding and is replenished with inert gas so that the total gas flow remains the same as that designed to achieve optimum BOF performance.

Basic oxygen process with iron oxide pellet addition

A method of improving post-combustion heat recovery in a vessel containing a charge of molten ferrous metal and slag includes the use of a lance for the introduction of oxygen gas into the charge. The method includes blowing oxygen into the charge through at least one first nozzle of the lance for refining the molten metal into steel. Oxygen is blown through at least one second nozzle of the lance from at least one location spaced above the first nozzle at an oxygen flow rate effective to produce foamy slag in an amount for obtaining a post-combustion heat transfer efficiency of at least about 40% without appreciable overflow of the slag from the vessel. The oxygen flow rate from the second nozzle is at a minimum at about a starting point of a peak decarburization period of the charge. Iron oxide containing pellets may also be added to the charge. In this case, the oxygen flow rate from the first nozzle may be reduced while the iron oxide containing material is being added, and the reduced oxygen flow may be replenished with an inert gas.

Foamy slag process using multi-circuit lance

A self-cleaning lance includes a lance body elongated along a longitudinal axis and having an upper end portion and a lower end portion, the lower end portion being spaced apart from the upper end portion along the longitudinal axis. One or more main nozzles are located proximal to the lower end portion and are adapted to release an oxygen-containing gas. One or more deskulling nozzles are spaced upwardly from the lower end portion and are adapted to release a deskulling gas. The lance body has a first portion that extends axially from the deskulling nozzles to the main nozzles and a second portion above the deskulling nozzles. The first portion has a smaller outer perimeter than the outer perimeter of the second portion. Each of the deskulling nozzles extends by an angle of not greater than 25 degrees with respect to the longitudinal axis.

Preventing skull accumulation on a steelmaking lance

A method of improving the post-combustion heat recovery in a basic oxygen furnace by controllably forming a foamy slag. The foamy slag is generated by increasing the lance height and reducing the rate of lance height reduction during the oxygen blowing cycle. The foamy slag is controlled to prevent slopping by calculating the approximate starting point of the peak decarburization period for the charge and then adjusting the oxygen flow rate to be at a minimum at the commencement of the peak decarburization period.

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Hudson, OH, United States of America

Chung S Kim