Method for removing heavy metals form waste water

摘要

Removing heavy metals from waste water involves: (a) taking a part vol. from the waste water, (b) producing suspended ferri- or ferromagnetic particles in it by dissolving an iron(II) salt in it, precipitating the dissolved iron(II) salt with an alkaline medium in such a way that the pH does not exceed 11.5, introducing air into the part stream or part vol. until the aq. soln. increases to -200 mV to -100 mV, combining the part stream or part vol. again with the waste water, (c) adding an alkaline medium in an amt. such that the pptn. pH value for the heavy metals is exceeded and a ppte. forms and (d) removing the ppte. in a magnetic filter.