Synergist of iron ore reverse flotation collecting agent and use method of synergist

The invention aims to improve the collecting effect of fatty acid collecting agents in an iron ore reverse flotation process, and provides a synergist of an iron ore reverse flotation collecting agent and a use method of the synergist. According to the technical scheme, the synergist of the iron ore reverse flotation collecting agent is prepared from the following raw materials in percentage by mass: 70% of octylphenol polyoxyethylene ether, 20% of fatty alcohol-polyoxyethylene ether and 10%-60% of polyoxyethylene sorbitan monooleate, wherein the mass ratio of the octylphenol polyoxyethylene ether to the fatty alcohol-polyoxyethylene ether to the polyoxyethylene sorbitan monooleate is 70%: 20%: 10%-60%: 10%: 30%. The synergist disclosed by the invention can form hydrogen-bond interaction with molecules of the fatty acid collecting agent, so that the activity of the collecting agent is improved, the selectivity of the fatty acid collecting agent on gangue minerals such as quartz is enhanced, and the recovery r