In recent years, the recycling of scrap aluminum has attracted the attention of many metallurgical and foundry workers at home and abroad, and the recycling technology of scrap aluminum is also constantly improving. Scrap aluminum smelting is a key part of the recycling technology of scrap aluminum, and the quality of the smelting technology is largely determined by the flux used in the smelting process and its corresponding treatment technology.
KCl and NaCl are the most common basic components in aluminum alloy fluxes. They mainly act as covering agents. Therefore, KCl and NaCl are selected as their main components, and a small amount of fluoride salt is added to the chloride salt mixture, which mainly plays the role of slag removal. . At the same time, the chloride salt can enhance the ability of the slag cleaning agent to adsorb oxidation inclusions.
Aluminum Chip Pretreatment
In order to obtain better quality recycled aluminum scraps, it is necessary to pre-treat the aluminum scraps before melting. The main purpose is to remove iron scraps, sand and oil stains mixed in the aluminum scraps. Therefore, a permanent magnet is used to suck out the iron filings in the waste aluminum filings, a sieve is used to sieve out the sand in the waste aluminum filings, and the waste aluminum filings are cleaned with detergent to remove oil stains. Finally, the waste aluminum scraps are dried in a drying furnace. Due to the large specific surface area of aluminum scraps, if the loose aluminum scraps are directly added to the crucible to melt during melting, the aluminum scraps will be seriously oxidized, which will greatly reduce the aluminum recovery rate.
Scrap Aluminum Smelting Process
The crucible furnace, pouring spoon, slag skimmer spoon, bell jar, and the mold for pouring the sample are cleaned and then preheated. After preheating to about 200, apply the paint and then dry. Add 1kg of alloy aluminum ingots when smelting. Heat it to above the liquidus temperature and melt completely. Then gradually add scrap aluminum cake. After adding the waste aluminum cake, add the prepared flux when the molten aluminum temperature reaches the smelting temperature of the experimental design, and continue to stir. When the particle size of the slag is observed to change from large to small, it can be stripped off when it reaches a fine powder. Slag. After the slag is removed, the auxiliary refining agent is added when the temperature of the molten aluminum is controlled to about 720, and the slag inclusions are quickly removed when there are no bubbles and the slag inclusions float up. After removing the slag, the sample and aluminum ingot were poured immediately.
Because the amount of aluminum casting flux added is one of the most important factors affecting the recovery rate of scrap aluminum, the amount of flux added is first tested. Considering the cost in actual production, the flux should not be added too much, generally not more than 5%. Through observation, it is found that when the amount of flux added is 0.5%-4%, the recovery rate of scrap aluminum will increase with the increase of the amount of flux added.
As the consumption of aluminum alloys increases year by year, the amount of aluminum scrap generated therewith also increases. Melting these scrap aluminum materials for reuse and improving their recycling rate is conducive to saving resources and energy, and has significant economic and social benefits.