Primary aluminum and aluminum alloy are two basic classifications of aluminum materials. In the past aluminum products were very precious because relative process technology was too backward to produce large amount of aluminum in a short period of time. Many household aluminum basins or pots were made of primary aluminum, rather than aluminum alloy. Nowadays the latter has replaced the former in almost all industries.
What’s the difference between the two? First, they are of different elements. Primary aluminum, as the name hints, is mineral aluminum without delicate processing. It has been processed roughly to meet requirement of product making. However, it’s not pure aluminum as some people might think. It contains many impurities of other elements except aluminum. Aluminum alloy, on the other hand, has gone through complex processing steps. Although it contains other elements as well, the composition of the elements have been controlled by strict ratios to help an alloy obtain certain properties. Second, primary aluminum is of small hardness. It cracks easily by a hard knock of stone. Aluminum alloy, combined with Mg, Mn, Cu or other elements, gets much stronger and more corrosion resistant. After being anodized, aluminum alloy shows even better performance of mentioned properties. Further more, it can be coated with various colors and designs without safety problems as food containers, but containers made of primary aluminum are likely to lead to poisoning after being used for a long time.