At present, the quality level of aluminum foil products of the company is just the reflection of the quality level of cast rolling aluminum melt, which belongs to the second-class level compared with advanced manufacturers. In terms of Molten Metal Purification purification, it can basically meet the requirements for mass production of products.
However, there are some defects in the molten metal purification process, equipment and management in order to upgrade the products and produce high-quality aluminum foil. It is mainly reflected in the following aspects:
- Metal injection: there is a big difference between melting furnace and standing furnace, and slag forming and air suction are serious.
- Flow supply system: the insulation of degassing unit and launder is not ideal, the melt temperature control is too high or the melt temperature control is too low sometimes, which leads to the chute burning and heating, hydrogen absorption and metal oxidation increase.
- Either in furnace degassing (static furnace) or on-line degassing, single inert gas argon is used. Inert gas does not react with aluminum at general melting temperature. Due to large bubbles blown in and fast floating speed, hydrogen in bubbles can not reach equilibrium, that is, it rises to the surface, so the degassing effect is not ideal.
- Filtration: at present, ceramic foam filter is used in the filter, and the precision is between 30 ~ 50ppi. Because the inner dimension of filter box is difficult to maintain the original size after using for a period of time, in addition, there is slag falling from the filter plate. For the production of high-quality aluminum foil, the filtering accuracy is not easy to achieve and the stability is poor.
- Nonstandard operation and imperfect management: it mainly refers to the degassing operation of static furnace refining, including the size of gas volume, refining time, operation method, etc., and the refining effect cannot be stable and consistent between teams and personnel.
- The rotor speed and gas flow rate (bubble size) of degasser are not standardized and stable, and online degassing is not ideal.
In order to improve melt quality, it is necessary to understand the molten metal purification mechanism. The degassing processes in metal melt purification are complementary. The deslagging is also carried out in the degassing process, and the deslagging is beneficial to degassing. At present, the melt degassing of aluminum processing is basically carried out by floating method, and the slag is removed by filter screen or ceramic filter plate and tube filter.