Process for waste confinement by vitrification in metal cans

Process for confining a waste containing at least one chemical species to be confined, by vitrification in a heated metal can composed of either an iron-based alloy or a nickel-based alloy, wherein the process consists of adding only the waste, a vitrification additive and at least one oxidizing agent into the iron-based alloy or nickel-based alloy metal can, such that the waste and the vitrification additive melt in reactive contact with said metal can during the vitrification process for producing a glass melt and the glass melt is cooled, characterized in that the vitrification additive is an oxide or mixture of oxides selected from the group consisting of:

• SiO2, B2O3, Al2O3, Na2O, Fe2O3, CaO, Li2O, ZnO, ZrO2, and Nd2O3 and wherein the at least one oxidizing agent is selected from the group consisting of multivalent oxidizing species of iron, chromium, vanadium, antimony, titanium, arsenic, cerium, manganese, chromium, ruthenium and mixtures thereof, and wherein the at least one oxidizing agent is provided separately from the vitrification additive, wherein the at least one oxidizing agent is not part of the waste wherein either the at least one oxidizing agent is mixed with the waste before the waste is fed into the metal can, or the at least one oxidizing agent is mixed with the vitrification additive before either the vitrification additive is fed into the metal can, or the oxidizing agent is fed directly into the metal can, separately from the waste and the vitrification additive, and wherein the concentration of said at least one oxidizing agent expressed as an oxide or oxides in the glass melt is in a range of from 0.1 to 20% by mass of the mass of the glass melt for allowing minimal reduction of the glass melt by the metal can to occur while minimizing degassing and foaming from occurring during the vitrification process thereby improving the glass melt properties.