According to Baidu map query, Tangshan has purchased sulfuric acid residue. Sulfuric acid residue, also known as pyrite cinder or pyrite cinder, is the residue produced in the process of sulfuric acid production from pyrite. It is a kind of chemical waste residue, and the recovery of reduced iron powder, ferric chloride, iron red and other non-ferrous metals from sulfuric acid residue by high and medium temperature chlorination is under experimental study. In Tangshan, some companies or individuals will buy sulfuric acid residue for reprocessing or resource recovery.