Synthesis of 2-ethyl-2-hexenal oxime and its flotation performance for copper ore

A novel collector 2-ethyl-2-hexenal oxime was synthesized from 2-ethyl-2-hexenal and hydroxylamine hydrochloride. The yield of oxime was 78.05% under the optimum experimental conditions. The oxime was characterized by elemental analysis, infrared spectrum, mass spectrum, 1H NMR and 13C NMR spectroscopy. The results of ultraviolet spectrum showed that the oxime exhibited stronger reaction affinity with Cu2+ than with Ni2+ or Fe3+, etc. Infrared spectroscopic analysis implicated that the oxime bound to Cu2+ through both the CC and CN groups. Microflotation tests of pure malachite mineral and chalcopyrite mineral indicated that the recovery of chalcopyrite was 91.16% under the flotation condition of rougher pH 10 and collector concentration of 200 mg/L, and the recovery of malachite reached 90.56% under the flotation condition of rougher pH 11.5 and collector concentration of 250 mg/L. The results of flotation tests of sulfide–oxide copper from Dexing copper mine showed that 2-ethyl-2-hexenal oxime achieved an excellent mean concentration containing 4.52% Cu with 79.54% Cu recovery, and the Cu average recovery increased by 2.35% compared to that of butyl xanthate.