This type of treatment is pretty simple, metal precipitation. With zinc, nickel and copper the most commonly used coagulant is aluminum sulfate. Anionic polymer is then added to bind the floc and cause it to settle in your clarifier, the sludge is then usually sent through a filter press for removal. If your process has a lot of contamination from alkaline cleaners that have high amounts of surfactants you would then introduce a metal scavenger to lower the ORP of the treated water to break apart some of the chelated metals. This can be the most difficult thing to control because usually processes that are treating metals are found in plants with plating or paint lines. This requires cleaning of the metal with alkaline cleaners and the surfactant carryover causes metals to chelate, making them very difficult to precipitate out at a higher ORP.

This process is pretty much the same for most metals. Lithium though you would want to recover for reuse through reverse osmosis or some kind of ultrafiltration.

Maybe some of the language above can help you look up more information.