Abstract: The invention provides an indium adsorbent that can cause indium to be adsorbed, and a simple and inexpensive indium fractioning method for isolating and recovering high-purity indium from an acid solution whose primary component is hydrochloric acid and that contains indium. A primary component of the indium adsorbent is an anion-exchange resin that has a crosslinked structure produced by the copolymerization of styrene or acrylamide and divinylbenzene, and at least one of a quaternary ammonium group and a tertiary ammonium group, and that is provided with an acid-adsorbing ability. An acid solution whose primary component is hydrochloric acid and that includes indium is brought into contact with the anion-exchange resin to cause indium to be adsorbed to the anion-exchange resin.

Abstract: The invention provides an indium adsorbent that can cause indium to be adsorbed, and a simple and inexpensive indium fractioning method for isolating and recovering high-purity indium from an acid solution whose primary component is hydrochloric acid and that contains indium. A primary component of the indium adsorbent is an anion-exchange resin that has a crosslinked structure produced by the copolymerization of styrene or acrylamide and divinylbenzene, and at least one of a quaternary ammonium group and a tertiary ammonium group, and that is provided with an acid-adsorbing ability. An acid solution whose primary component is hydrochloric acid and that includes indium is brought into contact with the anion-exchange resin to cause indium to be adsorbed to the anion-exchange resin.

Abstract: A method and apparatus for treating heavy-metal-containing wastewater using a sulfidizing agent. Sulfidizing treatment is carried out by adding a sulfidizing agent to heavy-metal-containing wastewater, while detecting hydrogen sulfide gas generated from the wastewater, such as to maintain a state in which hydrogen sulfide gas is just starting to be generated from the wastewater. When separately recovering each of a plurality of metals from wastewater in which are mixed ions of the plurality of metals, there is repeated for each of the metals a process in which the acidity of the wastewater is adjusted to within a range suitable for the metal to be separated out and recovered, a sulfidizing reaction is carried out on that metal, and the metal sulfide produced is precipitated and filtered off.