Metallurgical furnace vacuum slag removal

A process for slag separation and removal from a metallurgical process furnace containing a liquid metal bath and a slag layer floating on the surface of said bath, comprising the combination of the following steps:

• withdrawing liquid metal from said liquid metal bath by way of a liquid metal siphon-tube inserted through a furnace discharge opening penetrating through said slag with the siphon-tube inlet opening submerged within said metal bath and the outlet discharging into a pool of molten metal confined within an enclosed, evacuated metal withdrawal chamber outside the furnace;
• withdrawing liquid slag from said slag layer by way of a slag suction-tube inserted into the furnace through said furnace discharge opening with slag-entering the inlet said tube immersed in said slag layer but above said metal bath surface and the outlet connected and discharging into a slag cooling chamber positioned outside of the furnace;
• evacuating said slag cooling chamber maintaining a controlled vacuum pressure sufficient to cause a stream of slag to flow from said suction tube inlet exiting said outlet;
• introducing liquid coolant into said slag cooling chamber to intercept and solidify said stream to form granulated slag;
• collecting and removing said granulated slag and coolant from said chamber;
• and
• separating and recovering said granulated slag from said coolant.

A process for slag separation and removal from a metallurgical process furnace containing a liquid metal bath and a slag layer floating on the surface of said bath, comprising the combination of the following steps:

• withdrawing liquid slag from said slag layer by way of a slag suction-tube inserted into the furnace through said furnace discharge opening with slag entering the inlet said tube immersed in said slag layer but above said metal bath surface and the outlet connected and discharging into a slag cooling chamber positioned outside of the furnace;
• evacuating said chamber maintaining a controlled vacuum pressure sufficient to cause a stream of slag to flow from said tube inlet exiting said outlet;
• introducing liquid coolant into said chamber to intercept and solidify said stream to form granulated slag;
• allowing said granulated slag and coolant to flow by gravity into a descending laterally enclosed coolant column extension from the bottom said chamber, said granulated slag descending through and exiting said column into an atmosphere-exposed collection pool, said coolant column height substantially corresponding to said coolant height vacuum pressure equivalent;
• and collecting cooled and granulated slag from said pool.

An apparatus for slag separation and removal from a metallurgical process furnace containing a liquid metal bath and a slag layer floating on the surface of said bath comprising, in combination:

• slag cooling chamber means positioned outside a furnace discharge opening;
• slag suction-tube means with the outlet opening connected into said cooling chamber means and adapted to project into the furnace through said discharge opening with the tube inlet opening penetrating into a layer of slag floating on the surface of the metal;
• a controlled-pressure-vacuum gas outlet adapted to adjust and maintain a controlled vacuum pressure within said cooling chamber and draw a stream of hot liquid slag through said suction-tube into said chamber;
• coolant injection means adapted to introduce liquid coolant into said chamber directed to intercept the slag from said stream following entry into said chamber and solidify said slag into granulated form;
• and
• granulated slag collection and removal means from within said chamber.