Method and apparatus for removing a molten slag with a vacuum from a chamber

A method for removing from a furnace molten slag floating on molten metal comprising the steps of:

• providing a vacuum chamber which is sealed from its surroundings;
• positioning the vacuum chamber within the furnace;
• establishing flow communication between the molten slag and the vacuum chamber;
• generating a vacuum in the vacuum chamber so that the slag is drawn into the vacuum chamber;
• thereafter discontinuing the step of establishing flow communication;
• and
• retaining in the vacuum chamber the slag previously drawn into the vacuum chamber.

A method of withdrawing molten slag from a plasma arc centrifugal furnace having an upwardly open rotor including a base, a wall extending upwardly from the base, molten metal and molten slag which float on the metal, and a housing enclosing the rotor, the method comprising the steps of positioning a slag container within the housing having a first opening at a lower end of the container and a second opening at an upper end of the container;

• placing the first opening inside the molten slag pool;
• applying a sufficient vacuum to the second opening so that a pressure differential between an interior of the housing and an interior of the slag container causes molten slag to flow into the container until the molten slag reaches the second opening;
• freezing a portion of the molten slag in a vicinity of the second opening while the vacuum is applied so as to close the second opening and prevent fluid communication via the second opening between the interior of the slag container and an exterior thereof;
• and thereafter removing the container from the interior of the housing;
• whereby molten slag in the container is withdrawn from the interior of the housing without flowing out of the housing through the first opening.

A metal treatment furnace comprising a base;

• a furnace wall extending upwardly from the base;
• a heating device for heating metal and slag placed in the furnace;
• a slag container positioned within the furnace having a lower opening extending into the slag pool and an upper opening located above the slag pool;
• a vacuum source;
• and a vacuum conduit communicating the upper opening of the slag container with the vacuum source so that the insertion of the lower opening of the slag container into the molten slag and the application of the vacuum to the conduit causes molten slag to flow from the furnace into the container such that the molten slag may be removed within the container from the furnace.

A method for removing molten slag comprising the steps of:

• providing a vacuum chamber which is sealed from its surroundings, wherein the vacuum chamber has a first opening at a lower end and a second opening at the upper end;
• establishing flow communication between the molten slag and the vacuum chamber;
• generating a vacuum in the vacuum chamber so that the slag is drawn into the vacuum chamber;
• freezing a portion of the molten slag in a vicinity of the second opening while the vacuum is applied so as to close the second opening and prevent fluid communication via the second opening between the interior of the vacuum chamber and exterior thereof;
• thereafter discontinuing the step of establishing flow communication;
• and
• retaining in the vacuum chamber the molten slag previously drawn into the chamber.