In the production process of low-cost electrolytic aluminum prebaked anodes, raw materials such as petroleum coke or powder coke are mainly used, so that the selected binder is prepared to form a block for combustion. In addition, waste rubber and smokeless fuel are used as substitutes, and the spare anode cheap material produced after high-temperature calcination is used as a raw material. Finally, the ash content of the smokeless fuel is reduced by using the relevant treatment basis to realize the effective preparation of the prebaked anode.
Methods for low-cost electrolytic aluminum prebaked anode
1. The effect of ash on the performance of prebaked anodes
During the development of aluminum, the demand for anodes is getting higher and higher, especially in terms of raw materials, and trace elements need to be strictly controlled. Among these elements, electrolysis can affect the quality of aluminum, which not only leads to an increase in resistivity, but also further reduces the mechanical strength of aluminum. In petroleum coke, the main impurities include oxides such as S, Fe, V, and Na. Once these impurity oxides are brought into the anode, it is difficult to remove them, which will affect the behavior of the anode and the quality of the molten aluminum in the electrolytic cell. Impurities such as Si and Fe will have a direct impact on the taste of the entire molten aluminum, and V, Na, etc. will increase the consumption of carbon, and even have a serious impact on the surrounding environment. Na has a strong catalytic oxidation effect on carbon dioxide reactivity and air reactivity in carbon anode, and S can inhibit this effect, but the oxide of S will increase the hot brittleness of the anode. If the content of impurities is high, the life and toughness of the whole product will be seriously affected. Only by reducing the ash content of the fuel to the specific requirements of the carbon raw material for aluminum, the effective manufacture of the prebaked anode product is finally completed.
2. Petroleum coke instead of raw materials
The use of petroleum coke to replace raw materials requires the completion of a complete set of technological development from the fuel to the anode electrolysis process. The smokeless fuel used as the raw material for carbon production should meet the following requirements in the manufacturing process. First of all, the ash content should be low, and the ash content of smokeless fuel under the production of various carbon blocks should be kept below 8%, and the ash content in the raw material of aluminum electrolysis prebaked anode is very low and less than 1%. Secondly, it is necessary to provide sufficient guarantee for the mechanical strength, and after a certain period of storage, it can also provide a high guarantee for the mechanical strength. Then the thermal stability is required to be high, and the overall sulfur content should also be kept relatively small.
3. Partial replacement of petroleum coke by waste rubber and smokeless fuel to prepare prebaked anode
There are a lot of discarded tires every year. If these materials are processed into coke, some petroleum coke can be used to produce anodes, which can turn waste into wealth without polluting the environment. In the specific waste rubber experiment, the total volatile content reached 60.40%, and the fixed carbon content was not high, reaching 6.7%. In order to improve the wear resistance of tires in the manufacturing process, a certain amount of carbon black can be added to the rubber and vulcanized to produce ash in the rubber.
4. Preparation of prebaked anodes from smokeless fuel ash reduction
The main elements in smokeless fuel are silicon, iron, sodium, etc., and the content is relatively large, and it is also the main substance that constitutes the ash content of smokeless fuel. In the specific implementation process, the anode production formula is adjusted to A, B, C grades and ball milled powder mainly in combination with the actual situation of the aluminum factory and the anode factory. Except that no smokeless fuel is added to the fraction, the other two fractions are respectively added with 15% of the calcined smokeless fuel of the same particle size to replace the raw materials for production. Raw materials can be obtained from the production workshop of the relevant factory.
