Processing metallic materials, such as copper, from waste materials. The systems and methods employ a dynamic sensor, which measures the rate of change of current generated by metallic objects that pass by the sensor to identify metallic objects in a waste stream. The dynamic sensor may be coupled to a computer system that controls a material diverter unit, which diverts the detected metallic objects for collection and possible further processing. The systems or methods may employ stages of sensors for sequential recovery of materials.