title: Kinetic study of the immobilization of galvanic sludge in clay-based matrix.
abstract: The viability of inertization of galvanic wastes through their incorporation in clay-based materials, such as common formulations for tiles and bricks, is here studied by determining the leaching kinetics in different media. Metals immobilization is assured by firing at reasonably high temperatures, since intimately contact and/or reaction between residue and clay particles is promoted but also due to formation of insoluble metal oxides that rest unreactive towards clay grains. For most metals, leaching rate follows a zero-order kinetic law, with values between 0.001 to 0.1 mg/(g day cm2). Leaching velocity tends to increase with rising atomic numbers: Zn < Cu < Ni < Cr. These values depend exponentially on the relative sludge content.
authors.affiliation: Department of Mechanical Engineering, University of Minho, 4800 Guimarães, Portugal.
authors.forename: Jorge M
authors.initials: JM
authors.lastname: Magalhães
authors.forename: João E
authors.initials: JE
authors.lastname: Silva
authors.forename: Fernando P
authors.initials: FP
authors.lastname: Castro
authors.forename: João A
authors.initials: JA
authors.lastname: Labrincha
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry*; D000077215:Clay; D004055:Differential Thermal Analysis; D007700:Kinetics; D012037:Refuse Disposal / Q000295:instrumentation* / Q000379:methods*; D012722:Sewage / Q000737:chemistry*; D013696:Temperature
chemical_list: D000538:Aluminum Silicates; D012722:Sewage; D000077215:Clay