Japan is a major consumer of precious metals. Nevertheless, it imports most of its required amount of precious metals. In order to ensure a stable supply of precious metals as well as deal with the increasing global demand, it is important to develop cost effective and environmental-friendly technologies that are able to recover the precious metals from electronic waste, known as e-waste.

Generally speaking the conventional method for recovering gold (Au) from printed circuit boards (PCB) involves the incineration of scarp, followed by acid leaching. In an attempt to improve the Au extraction process, the authors are putting forward a new method. The sample was first subject to carbonization in N₂ atmosphere, followed by flotation in order to reduce the amount of sample subject to acid leaching as well as reduce the acid consumption. The sample recovered by flotation was then treated with aqua regia to dissolve Au. After investigating the effect of the carbonization temperature, a Cost-Benefit Analysis and a Life Cycle Assessment (LCA) were carried out in order to compare the efficiency of both conventional and suggested methods.