Study On The Novel Depressant Of Copper-Molybdenum Flotation Separation And Its Mechanism

Chalcopyrite and molybdenite are the main raw materials for extracting copper and molybdenum.The two minerals are closely symbiotic in nature,and it is difficult to separate from each other.Flotation is the most common way to separate chalcopyrite and molybdenite,but due to similar floatability,depressants must be added to separate them effectively.Aiming at the poor selectivity and serious pollution of traditional copper-molybdenum separation depressants,a novel environmentally friendly and efficient molybdenite depressant and two chalcopyrite depressants were developed in this work.The influences of the three novel depressants on flotation behaviors of chalcopyrite and molybdenite were systematically studied by flotation tests.The interaction mechanism between the depressants and chalcopyrite or molybdenite was deeply explored through Zeta potential,X-ray photoelectron spectroscopy（XPS）,secondary time-of-flight ion mass spectrometry（To F-SIMS）and other analysis methods.The main conclusions were as follows:（1）Xanthan gum（XG）could selectively depress molybdenite,and realize efficient flotation separation of copper-molybdenum,which could expand the recovery gap of the two minerals to more than 70%.And XG has excellent applicability,which could effectively suppress molybdenite polluted by kerosene,and achieve copper-molybdenum flotation separation with high selectivity.The addition order of kerosene and XG would affect the molybdenite floatability,the depression effect on molybdenite was stronger when the addition of kerosene prior to XG.The results of mechanism analysis showed that the adsorption of XG on molybdenite surface was through hydrophobic interaction,which greatly enhanced the hydrophilicity of molybdenite,thereby depressing molybdenite floating chalcopyrite.（2）Dithiothreitol（DTT）could selectively depress chalcopyrite within p H=9～12,realize the separation of copper and molybdenum,and reduce the recovery of chalcopyrite to less than 20%,while the recovery of molybdenite remained above 80%.For chalcopyrite contaminated with xanthate,DTT could still achieve efficient separation of copper and molybdenum.DTT was adsorbed on the chalcopyrite surface through its sulfhydryl group and copper ion chelation,and the hydrophilic hydroxyl group was exposed to the solution to increase the hydrophilicity of chalcopyrite surface,thereby depressing chalcopyrite floating molybdenite.（3）Tiopronin（TPN）could selectively depress chalcopyrite float molybdenite,and achieve copper-molybdenum separation with high selectivity in a wide p H range of 6-12.In the presence of xanthate,TPN could still depress chalcopyrite with high selectivity without affecting the flotation of molybdenite,and realize the separation of copper and molybdenum.And TPN was more selective and environmentally friendly than the traditional depressant Na₂S.The C=O and-SH groups in the TPN molecule would complex with the copper ions on the chalcopyrite surface to form a five-membered chelate ring,while the hydrophilic-COOH was exposed to the solution to make the chalcopyrite surface hydrophilic.Thus depressing chalcopyrite floating molybdenite.