Leaching of the residue from the dry off-gas de-dusting and desulphurization process of an iron ore sinter plant
C. Lanzerstorfer, Q. Xu, R. Neuhold - Leaching of the residue from the dry off-gas de-dusting and desulphurization process of an iron ore sinter plant - INTERNATIONAL JOURNAL OF MINERALS, METALLURGY AND MATERIALS, Vol. 22, No. 2, 2015, pp. 116-121
The residue from a second-stage dry sinter plant off-gas cleaning process contains both fine dust from the sinter plant and used sorbent. Recycling of the material which is usually disposed of in landfills to the sinter plant feed is not possible because of its chloride content. Leaching of the chlorides would allow recycling of the remaining solids. The saline leachate produced contains some heavy metals and has to be treated before discharge into the sea. In laboratory experiments leaching tests with subsequent treatment of the leachate were performed. After optimization of the process, all heavy metal concentrations were below the permissible values. The optimum treatment conditions for heavy metal precipitation were found to be a filtration of the suspended solids followed by a dosing of lime milk until the pH-value of the liquid is 10 and a subsequent precipitation using sodium sulphide.