Studies on the applicability of chelating agents as universal collectors for copper minerals

The efficacy of copper chelating agents as collectors for both copper oxide and sulfide minerals has been assessed through contact angle measurements. Because of the insoluble nature of many of these organic reagents, the use of a suitable solvent was necessary for preparing aqueous solutions. Finit e contact angle results are presented as average values for the pH range wh ere only finite contact was observed. The chelating reagents tested were cl assified according to the type of atoms that bond the metal cation and part icipate in the closure of the chelate ring. Five different types of bidenta te chelating reagents were identified: N-O, O-O, S-N, S-S, and N-N. The mos t refractory copper mineral was found to be chrysocolla, which exhibited co ntact angles only with 1-phenylthiosemicarbazide and with potassium octyl h ydroxamate. This last reagent proved to have excellent collecting propertie s for copper oxide minerals and native copper, primarily because of its alk yl chain length. (C) 2000 Elsevier Science B.V. All rights reserved.