Aluminum electrolytic cell having cathode carbon block with columnar protrusions embedded on its upper surface

Abstract

An aluminum electrolytic cell having cathode carbon block with columnar protrusions embedded on its upper surface is disclosed. The columnar protrusions are arranged into two rows or three rows in the length direction of the upper surface of the carbon block. Two adjacent rows of columnar protrusions are crisscross arranged, and the columnar protrusions of the cathode carbon block are immersed in the aluminum liquid. The pot holes in the positions of the cathode carbon block substrate and the upper surface of the cathode carbon block substrate where columnar protrusions are embedded can be one-step molded by vibration molding or compression molding, and can be made by machining as well.

What is claimed is: 
     
         1 . An aluminum electrolytic cell having cathode carbon block with columnar protrusions embedded on its upper surface, comprising:
 cathode carbon blocks,   wherein each cathode carbon block comprising a cathode carbon block substrate and a plurality of columnar protrusions on a surface of the cathode carbon block; the cathode carbon block substrate is cuboid, the upper surface of the cathode carbon block substrate is provided with grooves, the columnar protrusions are embedded on the upper surface of the cathode carbon block substrate by the grooves, and a graphite paste is filled between the columnar protrusions and the cathode carbon block substrate; the columnar protrusions are cuboid or cylindrical and are arranged into two rows or three rows in a length direction of the upper surface of the cathode carbon block substrate, two adjacent rows of columnar protrusions are crisscross arranged, all the columnar protrusions of the cathode carbon block are immersed into an aluminum liquid, and the aluminum liquid level is higher than the upper surface of the columnar protrusions.   
     
     
         2 . A preparation method of an aluminum electrolytic cell having cathode carbon block with columnar protrusions embedded on its upper surface as claimed in  claim 1 , comprising:
 (1) preparing a cathode carbon block substrate by using machining and vibration molding or compression molding, wherein
 1) machining: circular pot holes of 5-10 cm in depth are machined in positions where the columnar protrusions are embedded of an upper surface of an anthracite or graphite cathode carbon block substrate prepared at 1100° C.-1300° C. or the upper surface of an semi-graphitized or graphitized cathode carbon block substrate which is graphitized at 2300° C.-2500° C. after being roasted at 1100° C.-1300° C., a side wall of each pot hole is machined with internal threads, and the internal threads are matched with external threads of cylindrical columnar protrusions; 
 2) vibration molding or compression molding: when using vibration molding or compression molding to prepare a green compact of the cathode carbon block substrate, a bottom surface of a heavy object on a material in the vibration molding mold is changed from a traditional plane into a structure with protrusions, or the bottom surface of a compression mold on the material in a mold is changed from a traditional plane into a structure having protrusions on its surface during compression molding; thus, after the cathode carbon block substrate is prepared by vibration molding or compression molding, the upper surface of the green compact of the cathode carbon block substrate which is prepared by vibration molding or compression molding has pot holes used for arranging the columnar protrusions; wherein distribution locations of the protrusions on the bottom surface of the heavy object on the material in the mold or the mold bottom surface of the material in the mold correspond to the locations of the columnar protrusions embedded on the upper surface of the cathode carbon block substrate; a shape of the protrusions is consistent with that of the pot holes for arranging the columnar protrusions embedded on the upper surface produced by vibration molding or compression molding; the depth of the pot holes is 5-10 cm; when the cathode carbon block substrate is an anthracite cathode carbon block substrate, the graphite cathode carbon block substrate or the semi-graphite cathode carbon block substrate, the green compact of the above cathode carbon block is roasted at 1100° C.-1300° C. to be prepared into a cathode carbon block substrate with pot holes; when the cathode carbon block substrate is the graphitized or semi-graphitized cathode carbon block substrate, the roasting method and the method for making the pot holes are the same as those used in method 1), the cathode carbon block substrate is treated at high temperature of 2300° C.-3000° C. in a graphitizing furnace after being roasted to be prepared into the semi-graphitized or a fully-graphitized cathode carbon block substrate; the pot holes in the upper surface of the cathode carbon block substrate are divided into circular pot holes and square pot holes; when the pot holes are circular pot holes, an inner wall of each pot hole is machined with internal threads, and the internal threads are matched with the external threads of the cylindrical columnar protrusions; when the pot holes are square pot holes, the inner wall of each pot hole is provided with at least four circular pits with a diameter of not less than 5 mm and a depth of not less than 10 mm; 
   (2) embedding columnar protrusions: a thermosetting resin is mixed with a graphite powder to prepare a graphite paste, and a mix proportion is required to be capable of a mixing paste; the graphite paste is filled into the pot holes; the columnar protrusions are arranged into the pot holes, wherein when the columnar protrusions are cuboid, the pot holes are square pot holes, a length and a width of the pot holes are 1-10 mm more than a length and a width of the columnar protrusions, and the cuboid columnar protrusions are vertically compressed into the pot holes; when the columnar protrusions are cylindrical, the pot holes are circular, and the side wall of the pot hole is machined with the internal threads; the external threads of the columnar protrusions are matched with the internal threads of the pot holes, the columnar protrusions are screwed in the pot holes, and the graphite paste is filled in a gap between the internal threads and the external threads; after the columnar protrusions are arranged into the pot holes, a part of the graphite paste in the pot holes is extruded from the gap between the protrusions and the pot holes, and then is accumulated at a junction of the upper surface of the cathode carbon block substrate and the columnar protrusions.