The present application relates to the technical field of resource
processing of waste residue, and particularly relates to a method for removing impurities based on coarse
salt water prepared from
molten salt chlorination residue. The method comprises the following steps: S1, adding
lime milk into the
molten salt chlorination residue to obtain saturated coarse
salt water with pH of 5.8-6.2, and after the saturated coarse
salt water is fully mixed and reacted, qualified coarse salt water is obtained; S2, adding waste lye into the qualified coarse salt water, wherein the waste lye is added in an amount according to the
molar ratio of effective
chlorine to
ferrous ions of 0.18-0.24, after the addition is completed, reaction and standing are performed, and then
filtration treatment is performed to obtain mixed salt water and iron-containing
sludge; S3, under the action of stirring, adding
calcium removal agent into the mixed salt water, adjusting pH to 8.0-8.5, and then standing and filtering to separate to obtain
magnesium removal salt water and Ca-containing residue; S4, heating the
magnesium removal salt water to 90-95 DEG C, adding
sodium carbonate solution, fully reacting, standing and filtering to separate to obtain qualified salt water after purification and basic
magnesium carbonate; and S5, configuring the qualified salt water and
hydrochloric acid into qualified NaCl salt water with pH of 4.6-4.9 in a volume ratio of 1:1.