Cathode carbon block is a carbon block made of high-quality anthracite, coke, graphite, etc. as raw materials. Used as a cathode for aluminum electrolysis cells. Including the bottom carbon block, the side carbon block, the tamping carbon paste or carbon glue connecting the carbon block, and the cathode steel rod, etc.
1. Bottom carbon block. It plays a dual role of conducting electricity and forming the lining of the electrolytic cell. It is built at the bottom of the electrolytic cell, and the exterior is built with refractory materials and reinforced with steel shells. It can be divided into ordinary cathode carbon block, semi-graphite cathode carbon block and graphite cathode carbon block.
*Ordinary cathode carbon block is made directly from ordinary calcined anthracite without graphitization;
*Semi-graphite cathode carbon block, one is made of electro-calcined anthracite or more graphite fragments or even all graphite fragments as raw materials. Carbon block; another kind is made of easily graphitized coke as raw material, and the green body is roasted and then subjected to graphitization (1800~2000 ℃) heat treatment, also known as semi-graphitized (chemical) cathode carbon block;
*Graphite cathode carbon block is made of easily graphitized coke as raw material, and its graphitization temperature should reach about 2500 ℃, also known as graphite cathode carbon block.
*The new type of bottom carbon block includes titanium boride coated carbon block, which is to coat the surface of the cathode carbon block with a coating made of titanium boride, or directly press a layer of carbon paste containing titanium boride on the surface of the carbon block layer, and then subjected to firing heat treatment. The bottom carbon block accounts for 60% to 70% of the cathode material of the aluminum electrolytic cell.
2. Side carbon block. It is used to build the side part of the aluminum electrolytic cell to form the main body of the side lining of the electrolytic cell. It can be divided into ordinary side carbon block and semi-graphite side carbon block, and the production method is similar to the bottom carbon block. With the promotion and application of silicon nitride combined with carbonized silicon blocks on the side of aluminum electrolytic cells, the amount of carbon blocks on the side has been reduced.
3. Cathode steel rod. The product that connects the cathode carbon block and the cathode busbar in the aluminum electrolytic cell to form the cathode circuit of the aluminum electrolytic cell. It is divided into single rod assembly (that is, a cathode carbon block is assembled with one cathode steel rod) and double rod assembly (that is, two cathode steel rods are assembled at the end of a cathode carbon block).
The raw materials of the cathode carbon block are mainly anthracite, pitch coke, natural and artificial graphite and coal tar, etc. The raw materials are calcined, crushed and sieved into a certain particle size. After measuring according to the formula, a binder is added for kneading, and the finished product is obtained after kneading. Cathode paste. The kneaded paste is produced into a cathode carbon block by forming, roasting, even graphitization, machining and other processes.
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