Composite additive for water mist fire suppression and preparation method and application method thereof

The invention discloses a composite additive for water mist fire suppression. The composite additive comprises 1 wt% to 5 wt% of ferrous lactate, 2 wt% to 30 wt% of sylvite, 2 wt% to 30 wt% of phosphate and the balance water. The preparation method of the composite additive comprises the step that the ferrous lactate, the sylvite and the phosphate are sequentially dissolved into the water to obtain the composite additive. The application method of the composite additive comprises the steps that the composite additive and water are diluted according to the proportion of 1:2-1:30; and then a water mist generator is filled with the diluted solution which is sprayed to a fireground for fire extinction. The ferrous lactate, the sylvite and the phosphate in the composite additive have a good synergistic flame retardant effect, so that the fire extinction time is greatly shortened, and the fire extinction and inflaming retarding performance is more excellent.