Aluminum recovery from water clarifier sludges by ion exchange - Comparison of strong and weak electrolyte cation resins performances

Technical feasibility of an ion exchange based process for removal and reco very of the coagulating principle (Al, Fe chemicals) from water clarifier s ludges is illustrated. The innovation is a typical example of 'conservative technology' applied to the solution of environmental problems, thus allowi ng for the minimization of the environmental impact related to the disposal of the solid wastes, through conditioning and detoxification of the sludge s for land application, and simultaneous recovery of valuable products from non-conventional sources. The paper illustrates laboratory scale comparati ve experiments between weak (carboxylate) and strong (sulphonic) cation res ins performances in reference to a typical acidic leachate from water clari fier sludges (pH 3.5). Together with mechanistic interpretation of the mult icomponent-polyvalent Al/Fe/Na ionic system involved, in this paper indicat ions for process optimization are also given. (C) 1998 Elsevier Science B.V . All rights reserved.