Abstract: A method for removing at least one of chromate and other oxy-metal ions from liquid solutions includes contacting the liquid solution with solid barium compounds as adsorbents so that the at least one of chromate and other oxy-metal ions in liquid solution are subject to an exchange reaction with the anion of solid barium compounds to produce products including at least one of solid barium chromate and oxy-metal barium compounds and are removed from the liquid solution by a liquid-solid separation operation. A method for stabilizing at least one of chromate and other oxy-metal ions that are present in liquid or sludge wastes includes mixing the liquid or sludge wastes with barium compounds in solid form, so that the at least one of chromate and oxy-metal ions are immobilized in a solidified body after curing of the mixture.

Abstract: This invention discloses a method for the co-solidification of low-level radioactive wet wastes of BWR nuclear power plants, including concentrate waste, spent ion exchange resins and sludge wastes etc., with very high volume efficiency. In this invention, for promoting the stability of the solidified waste, sodium sulfate in the concentrate solution is converted to sodium hydroxide and barium sulfate by reacting with barium hydroxide. The conversion product barium sulfate possessing high density and stability is insoluble and used as a fine aggregate material in the solidified waste. Sodium hydroxide is used to stabilize ion exchange resins and to form a highly water-durable solidified waste form with silicates and phosphates in the solidification agent mixture. The solidification agent used in this invention is a formulated powder mixture completely made from inorganic materials. Therefore, there is no aging problem of the solidified waste.

Abstract: This invention discloses a method for removing and stabilizing liquid chromate ion and other oxy-metal ions with barium compounds.