Abstract: A tundish has an entry location for receiving a molten alloy, such as steel, and bottom outlet openings for withdrawing the molten alloy. The tundish bottom comprises a sump located downstream of the inlet location and upstream of the outlet openings. Undissolved, molten alloying ingredient, denser than the molten alloy as whole, (e.g. lead or bismuth in the case of molten steel) accumulates in the sump. The sump has a floor and passageways which extend downwardly from the sump floor to a drain in the steel tundish shell underlying the sump. The passageways are permeable to undissolved, molten alloying ingredient but impermeable to the molten alloy. There are expedients for maintaining the passageways at a temperature which prevents undissolved alloying ingredient descending through the passageways from cooling to a temperature at which the undissolved alloying ingredient blocks the passageways against further passage by undissolved, molten alloying ingredient.

Abstract: A tundish and associated assembly are employed for the continuous casting of molten steel containing lead. Undissolved lead can accumulate at the bottom of the tundish, work its way through the refractory material lining the tundish interior bottom and weep through the metal tundish shell bottom into a casting mold located below the tundish, which is undesirable. Expedients are provided to minimize such lead weeping.

Abstract: Molten steel containing an undissolved alloying ingredient denser than molten steel (e.g. Pb and/or Bi) flows from a tundish to a continuous casting mold. Various expedients are employed to prevent large globules of undissolved alloying ingredient from flowing out of the tundish into the mold. Another expedient prevents large quantities of undissolved alloying ingredient from accumulating on the bottom of the tundish.

Abstract: A descending stream of molten metal is directed from a ladle into a bath of molten metal in a tundish. Molten alloying ingredient is added to the molten metal, either directly to the descending stream within a shroud, or it is injected into the bath, through a sidewall of the tundish, at a region of turbulence. The molten alloying ingredient is protected from the atmosphere outside the tundish.

Abstract: A descending stream of molten metal is directed from a ladle into a bath of molten metal in a tundish. Molten alloying ingredient is added to the molten metal, either directly to the descending stream within a shroud, or it is injected into the bath, through a sidewall of the tundish, at a region of turbulence. The molten alloying ingredient is protected from the atmosphere outside the tundish.

Abstract: A tundish and associated assembly are employed for the continuous casting of molten steel containing lead. Undissolved lead can accumulate at the bottom of the tundish, work its way through the refractory material lining the tundish interior bottom and weep through the metal tundish shell bottom into a casting mold located below the tundish, which is undesirable. Expedients are provided to minimize such lead weeping.

Abstract: Molten steel containing an undissolved alloying ingredient denser than molten steel (e.g. Pb and/or Bi) flows from a tundish to a continuous casting mold. Various expedients are employed to prevent large globules of undissolved alloying ingredient from flowing out of the tundish into the mold. Another expedient prevents large quantities of undissolved alloying ingredient from accumulating on the bottom of the tundish.

Abstract: An alloying ingredient is added to molten steel entering the tundish in a continuous casting process. The concentration of the alloying ingredient is maintained substantially uniform throughout the cast by exercising certain controls. Small scale, short term variations in the mass flow rates of the alloying ingredient and molten steel and in the recovery of the alloying ingredient are attenuated by employing a system having certain characteristics.

Abstract: A method of pyrometallurgical refining of crude silver to remove base metal impurities, particularly bismuth, by treatment with sulfer hexafluoride gas. The crude silver is melted and maintained at about 1000.degree. C. while it is treated concurrently with sulfur hexafluoride and an oxidizing gas, such as air. Base metal fluorides are formed and are removed from the silver, after which the molten bath is treated with a reducing agent, such as hydrogen gas.