Composite collecting agent, flotation reagent and method for low-grade lithium ore

The invention belongs to the field of mineral flotation, and particularly discloses a composite collecting agent for ultralow-grade spodumene, lepidolite and amblygonite lithium ores, the composite collecting agent comprises saponified industrial oleic acid, kerosene, alcohol and a compound A. The invention further discloses a flotation method for composite lithium ores by adopting the collecting agent and a water-soluble copper salt activating agent. According to the flotation method, the water-soluble copper salt is adopted for activation in a strong alkaline system, the composite collecting agent which is resistant to low temperature, good in selectivity and high in collecting capacity is added, the best effect is achieved, the separation technology becomes the basis for factory building and production of the type of lithium ore, the factory building requirement that the Li2O recovery rate is larger than 70% is met, the production cost can be remarkably reduced, and the method is suitable for industrial pr