Aluminum nanocrystalline powder production from aluminum alloy scrap by solid state recycling method

 The purpose of this research is solid state recycling of 3000 and 5000 series aluminum alloy scrap to produce aluminum nano-crystalline powder by mechanical milling without using process controlling agent. In this regard, aluminum used beverage cans (UBCs) which consist of lid (alloy 5182) and the monolith part (alloy 3004) of the body (thin) and bottom (thicker).

To achieve disintegration mechanism, lid part, body and bottom of monolith part are separated each other because of diverse constituent of Al series and different thickness. The three parts individually were decoated then cut into the small chips (app. 8 mm). The chips were mechanically ball milled at different times up to 104 hours under argon atmosphere. The ratio of ball to powder was 10 to 1.   

The lid part chips are crushed faster than the monolith part chips, and, resulting in a finer powder. According to the PSA results, the D90 of the lid powder is less than 150 micrometers; while D90 of the body and bottom powders are more than 150 micrometers. This result can be used on an industrial scale to separate the constituent elements of crushed UBCs from each other. The smallest D90 values of lid, body and bottom powders, which obtained after 72, 80 and 80 h as optimum milling time, are 109, 258 and 391, respectively. Also, their flowability were 57.8, 59.3 and 61.1 s/50 g, as well as the apparent density were 1.38, 1.43 and 1.46 g/cm3, respectively.