Sludge Removal Devices, Systems, and Methods

Abstract

Methods for removing sludge and/or impurities from a molten metal are disclosed herein, as well as sludge removal devices and systems for use in the methods. Sludge removal devices that can reduce the downstream deposition of sludge in certain process components through upstream deposition and subsequent removal from the molten metal are also disclosed.

What is claimed is: 
     
         1 . A sludge removal device comprising:
 a body configured for contact with a molten metal; and   a plurality of channels extending through a width of the body;   
       wherein:
 the device comprises an upstream face and a downstream face; 
 each of the plurality of channels comprises an upstream opening on the upstream face of the device, and a downstream opening on the downstream face of the device; and 
 each of the plurality of channels independently has an average cross-sectional area from about 0.01 to about 10 square inches. 
 
     
     
         2 . The device of  claim 1 , wherein the body comprises a marinite, a fused silica, a sialon, a silicon carbide, a boron carbide, a boron nitride, a silicon nitride, an aluminum nitride, an aluminum oxide, or a zirconia. 
     
     
         3 . The device of  claim 2 , wherein the body comprises marinite A. 
     
     
         4 . The device of  claim 1 , wherein:
 the width of the body is in a range from about 0.5 to about 8 inches; and   the body is shaped to fit securely against the sides of a molten metal launder.   
     
     
         5 . The device of  claim 1 , wherein:
 a total cross-sectional area of upstream openings is in a range from about 10% to about 90% of the total surface area of the upstream face; and   a total cross-sectional area of downstream openings is in a range from about 10% to about 90% of the total surface area of the downstream face.   
     
     
         6 . The device of  claim 1 , wherein a cross-sectional shape of each of the plurality of channels is independently selected from a circle, oval, rectangle, square, triangle, hexagon, octagon, honeycomb, regular or irregular polygon, or any combination thereof. 
     
     
         7 . The device of  claim 6 , wherein each of the plurality of channels is cylindrical, and has a radius in a range from about 1/16 to about ¾ inches. 
     
     
         8 . The device of  claim 1 , wherein a flow axis of at least one of the plurality of channels is configured to be substantially parallel to a molten metal flow direction. 
     
     
         9 . The device of  claim 1 , wherein a flow axis of at least one of the plurality of channels is configured to be at an angle relative to a molten metal flow direction. 
     
     
         10 . The device of  claim 9 , wherein the angle is in a range from about 10° to about 80°. 
     
     
         11 . The device of  claim 9 , wherein the angle is in a range from about 30° to about 60°. 
     
     
         12 . A sludge removal system comprising:
 a molten metal launder configured to generate a molten metal flow between a launder inlet and a launder outlet; and   a first sludge removal device positioned within the molten metal launder and between the launder inlet and the launder outlet;   
       wherein the sludge removal device comprises:
 a body configured for contact with a molten metal; and 
 a plurality of channels extending through a width of the body. 
 
     
     
         13 . The system of  claim 12 , further comprising:
 a molten metal degassing device in fluid connection with the launder inlet; and   a metal casting machine in fluid communication with the launder outlet.   
     
     
         14 . The system of  claim 12 , further comprising a second sludge removal device arranged serially in the molten metal launder, downstream of the first sludge removal device;
 wherein a total cross-sectional area of the plurality of channels on the first sludge removal device is greater than that of the second sludge removal device.   
     
     
         15 . The system of  claim 12 , wherein:
 a cross-sectional area of the launder is in a range from about 1 to about 50 ft 2      a flow capacity of the molten metal launder is in a range from about 1 L/min to about 50 L/min.   
     
     
         16 . A method for removing impurities from a molten metal, the method comprising:
 flowing a molten metal comprising impurities through a sludge removal device, the sludge removal device comprising:
 a body configured for contact with a molten metal; and 
 a plurality of channels extending through a width of the body; and 
   depositing at least a portion of the impurities on the sludge removal device to form a purified molten metal;   wherein the molten metal comprises aluminum, copper, zinc, steel, or a combination thereof.   
     
     
         17 . The method of  claim 16 , further comprising:
 removing the sludge removal device from the molten metal after a saturation period; and   regenerating the sludge removal device by mechanically removing the deposited impurities from a surface of the sludge removal device.   
     
     
         18 . The method of  claim 16 , wherein:
 the molten metal comprises impurities in a range from about 1 ppm to about 100 ppm;   at least 80 wt. % of the impurities are removed from the molten metal; and   the impurities comprise a metal and/or metal oxide.   
     
     
         19 . The method of  claim 16 , further comprising:
 degassing the molten metal prior to flowing the molten metal through the sludge removal device; and   casting the purified molten metal.   
     
     
         20 . The purified molten metal produced by the method of  claim 16 . 
     
     
         21 . A cast metal article comprising the purified molten metal of  claim 20 .