Study on separation of low-grade zinc oxide ore with sulfurization-amination flotation

With the continuous depletion of a large number of zinc sulphide ores that are easy to treat, the finely disseminated and refractory low-grade zinc oxide ores has become an important source for the production of zinc minerals. In this paper, a sulfurization-amination flotation process has been proposed for concentrating large amounts of low-grade zinc oxide ore in Lanping, Yunnan Province. Spectrum analysis, chemical analysis and element analysis was performed to provide research basis for process design and operational control. The main influencing factors during the process, including grinding fineness, reagent types and dosage, etc., have been studied through flotation tests. The results showed that the optimum grinding fineness was -0.074 mm accounting for 89.78% for the target run-of mine ore. Moreover, optimum dosages of sodium carbonate, sodium silicate, sodium hexametaphosphate, sodium sulphide and octadecylamine were determined as 1500 g/t, 500 g/t, 200g/t, 8000 g/t and 500 g/t, respectively. Under these conditions, an open circuit test and a closed circuit test with one stage rougher, two stage scavenger and three stage cleaner flotation were carried out with the run-of-mine ore with a zinc grade of 6.52% and the oxidation ratio of 94.62%. The zinc concentrate can be obtained with zinc grade of 44.09% at a zinc recovery of 66.35% with a 9.70% yield of zinc concentrate yield. The results confirmed the validity and practicability of the proposed process design and experimental operation. This study is of special value as it provides referencing significance for economically exploiting low-grade zinc oxide ore.