Refractory materials and carbon materials for aluminum electrolytic cells
Aluminum electrolytic cells are the main thermal equipment for aluminum electrolytic production. Electrolytic aluminum is the process of converting aluminum in alumina into metallic aluminum. The main principle of the conversion is to use cryolite and alumina melt as electrolytes, carbon materials as two poles, direct current is introduced into the electrolyte and aluminum liquid layer through the anode, and then discharged from the cathode.
During the construction of aluminum electrolytic cells, refractory materials and carbon materials are mainly used as masonry materials, and their varieties are as follows:
Refractory materials
01 Calcium silicate board
Calcium silicate board is a board made of loose short fibers such as inorganic mineral fibers or cellulose fibers as reinforcing materials, and siliceous-calcium materials as the main binder. It is made of pulping, molding, and accelerating the curing reaction in high-temperature and high-pressure saturated steam to form calcium silicate gel. Calcium silicate board can be divided into two types according to its use, namely calcium silicate board for building materials and calcium silicate board for high-temperature kilns. Calcium silicate board for high-temperature kilns requires high temperature resistance ≥1050℃. Calcium silicate board, in accordance with the national standard GB/T10699.
02 Clay Insulating Refractory Brick
Clay Insulating Refractory Brick refers to an insulating refractory product with an Al2O3 content of 30%~48% made of refractory clay as the main raw material. Using refractory clay, floating beads, refractory clay clinker as raw materials, adding binders and sawdust, after batching, mixing, molding, drying and firing, a product with a volume density of 0.3~1.5g/cm3 can be obtained, and the production volume accounts for more than half of the total production of insulating refractory bricks. Clay Insulating Refractory Brick, in accordance with the national standard GR/T3994.
03 Clay Refractory Brick
Clay Refractory Brick is a clay brick produced with refractory clay as raw material for masonry blast furnace lining. Its Al2O3 content is ≥45%. Clay bricks are weakly acidic refractory products that can resist the erosion of acidic slag and acidic gas, but have a slightly poor resistance to alkaline substances. Clay bricks have good thermal properties and are resistant to rapid cooling and heating. Clay refractory bricks comply with the standard YB/T5106-1993.
04 Dry anti-seepage material
Dry anti-seepage material is a special functional material for aluminum electrolytic cell furnace construction. It has a significant effect on improving the technical and economic indicators of the electrolytic cell and extending the service life of the electrolytic cell.
Carbon material
01 Ordinary cathode carbon block for electrolytic cell
Cathode carbon block refers to a carbon block made of high-quality anthracite, coke, graphite, etc. as raw materials. It is used as the cathode of the aluminum electrolytic cell. It is built at the bottom of the electrolytic cell and is also called the bottom carbon block. The cathode carbon block is an important component of the aluminum electrolytic cell, which is beneficial to energy saving and cell life improvement in aluminum electrolysis production. Ordinary cathode carbon block for electrolytic cell. Implement industry standard YS/T286-1999. The appearance should comply with the following regulations:
(1) The surface of the carbon block is flat, and the cross-sectional structure is not allowed to have holes, stratification and inclusions.
(2) The bonding filler on the surface of the carbon block must be cleaned.
(3) Carbon blocks are strictly prohibited from being damp or contaminated by oil.
02 Semi-graphite cathode carbon blocks for electrolytic cells
Semi-graphite cathode carbon blocks shall comply with the national standard GB8744-1988. The appearance shall comply with the following provisions: the product surface shall be flat, and the cross-sectional structure shall not have holes, stratification and inclusions.
03 Carbon paste
Carbon paste includes hot-rammed roughing paste and cold-rammed carbon paste.
(1) Hot-rammed roughing paste shall comply with the metallurgical industry standard YS65-1993. There are two formulas for roughing paste. Formula 1 is used for roughing paste connecting steel rods and cathode carbon blocks, and formula 2 is used for roughing paste used to tie the seams between carbon blocks.
(2) Cold-rammed carbon paste:
LTC-1 is suitable for electrolytic cell pads and filling the seams between carbon blocks or electrolytic cell linings.
LTC-2 is suitable for the joints between cathode carbon blocks and cathode steel rods in electrolytic cells.
04 Other materials
In addition to the above-mentioned refractory materials and carbon materials, materials such as water glass asbestos putty and silicon nitride combined with silicon carbide are also used in aluminum electrolytic cells.
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