Manganese diffusion coating of cast irons

Previous work on the diffusion coating on steels and cast iron has been followed by systematic experiments on five types of cast irons with flake or nodular graphite.Considerable diffusion depths were obtained at treatment temperatures somewhat lower than those previously used for steels. The treatment resulted in a very hard surface diffusion; primarily composed of manganese-replaced cementite

Heavy Metals Retention On Recycled Waste Glass. A Comparative Study Among Different Species

Heavy metals retention [Pb2+, Cd2+, Ni2+, and Cr(VI)] on recycled waste porous glass (RWPG) from solid wastes sorting operations was carried out. To the purpose metals containing solutions in the concentration range 24 mg/L, reproducing the average concentration present in, e.g., solid waste leachate from landfills or industrial effluents, were percolated onto columns loaded with RWPG beads with particle size in the range 0.351.0 mm and flow-rates between 0.23 and 0.75 L/h. Metals retention mechanism was associated with ion exchange with overall capacities in the following order: Pb2+ > Cd2+ > Ni2+ > Cr(VI) in consideration of the hydrated ion radius and free energy of hydration of the metal ions. The rate controlling step was identified with the ions interdiffusion in the Nernst liquid film around particles. The metals exhausted beads were embedded into cement conglomerates as inert materials thus minimizing metals release in the environment. The prepared mortar specimen showed improved thermal properties as compared to conventional (sand based) composites

Recycled porous glass from municipal/industrial solid waste sorting operations as a lead ion sorbent from wastewaters

Recycled waste porous glass (RWPG), from municipal solid wastes (MSW) sorting operations, may be used as a sorbent for lead ion removal from industrial wastewaters. To the purpose, dynamic (laboratory columns) operations were carried-out by the use of differently sized glass beads in the range 0.35\u2013 1.25 mm which were eluted with lead ion containing synthetic solutions (2\u20139.5 mg/L). Temperature was kept constant (298 K), whereas column flow-rates varied in the range 0.20\u20130.75 L/h. Lead ion retention mechanism was associated to the adsorption/ion exchange phenomena. Best column performance was obtained at 0.5\u20131 mm bead size range, influent concentration 2 mgPb2+/L and column flow-rate 0.20 L/h. In the reference conditions lead ion retention capacity exceeded 1.10 mg/g. Kinetic analysis of the experimental data was also carried-out and film interdiffusion of the involved ions in the Nernst stationary liquid around the particle was identified as the rate controlling step