"mixed several powdered compounds containing lead, oxygen, sulphur and phosphorus"
But we do not know what those compounds were? Lead is diamagnetic, so magnatism associated with small internal currents within the resulting non magnetic substance cause levitation? Or does the unamed compound contain something that normally reacts magnetically?
Uses? ..Superconducting motor brushes if you can keep your motor at room temp? For EV cars in cold places, although the Batteries in cold places are the real problem. Cathode/anode battery material?? Propulsion engine or exterior coating for your personal magnetically propelled craft? (Do not lick the coating!)
(So...having some fun with this, the Secret Sauce compounds.....Powdered crushed refrigerator magnets!)
( My Current News Tin Foil Take!) Magnetically fixed on the refrigerator...note what looks like a child's picture of a fleet of UFOs (not pumice rocks!) fleeing their base in an erupting volcano! :O)