Metallurgical vessel and method of using the same

A method for improving the yield efficiency of a metallurgical vessel for holding a molten metal having a layer of slag thereon comprising:

• employing a metallurgical vessel comprising a shell having side walls and a bottom to form an interior of said metallurgical vessel for containing a molten metal;
• forming a refractory lining covering the interior of said side walls and bottom of said vessel wherein said refractory lining forms a sloping bottom surface exposed to the interior of said vessel, wherein said sloping bottom surface has a tapered upper surface terminating at a vertical surface, said vertical surface terminating at a lower tapered surface for forming a pocket block reservoir, said pocket block reservoir having a volume of less than or equal to about five percent of the total volume of said vessel, and said pocket block reservoir having a tap hole having an opening located at said lower tapered surface for providing drainage of said vessel, wherein said tap hole having a removable tap hole cover means in juxtaposition to said tap hole for opening and closing said tap hole opening;
• placing said removable tap hole cover means in the closed position under said tap hole opening;
• placing said molten metal into said vessel and allowing sufficient volume for a layer of slag on top of said molten metal within said vessel for the formation of a slag-molten metal interface;
• draining said vessel by moving said removable tap hole cover means in the open position for allowing said molten metal within said vessel to collect in said pocket block reservoir and then to pass through said tap hole opening;
• and
• moving said removable tap hole cover means in the closed position simultaneously with, before or after the entry of said slag into said pocket block reservoir for increasing the yield of said molten metal discharged from said vessel.