Dowa Mining Co., Ltd.

Makoto Watanabe

Tatsumi Inamura

Yoshio Moteki

At least one basic precipitant selected from the group consisting of NaOH, KOH, NHOH, NH, NHHCOand (NH)COis added to an indium salt solution, which contains 0.1 to 3 M of indium, in an adding time of not longer than 24 hours, while the solution is maintained at a temperature of 5 to 95&#xb0; C. until the equivalent of the basic precipitant reaches an equivalent of 0.5 to 3. Then, a precipitate obtained from the solution by a solid-liquid separation is dried and calcined at a temperature of 570 to 780&#xb0; C. in an non-oxidizing atmosphere which contains ammonia gas and water vapor.

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Honjo, Japan

Makoto Watanabe