I have a rough knowledge of the operation, a machine traverses the drop area and separates most of the earth from the shot. The shot is then melted down where all impurities are separated. During the last very high lead price time (70's) I had friends that screened the reclaimed shot after tumbling it in a cement mixer. They them returned it to the mixer, adder graphite and sold it in milk jugs. It was good enough for 16 yard trap and skeet. No one shot in high quality guns. At that time it was for 1100,s or something you could replace the barrel with ease and low cost. The problem was sand grains the size of 9's.
bill
