PROBLEM TO BE SOLVED: To provide a steel making slag product which is suitable for marine environment applications and can prevent pH rise and white turbidness of sea water.SOLUTION: A method of producing a slag powder molded body comprises mixing steel making slag powder with lignin sulfonic acid or a metal salt of the acid in a container and granulating, charging a mixed powder of a glassy material and a material containing one or more of Fe, Si and P compounds into the container and mixing, and heating to form a coating of the glassy material on the surface of a slag powder molded body.【課題】海水のｐＨ上昇や白濁を防止できる海洋環境用途に適した製鋼スラグ製品を提供【解決手段】製鋼スラグ粉末とリグニンスルホン酸またはその金属塩を容器内で混合および造粒し、ガラス質物質とＦｅ、Ｓｉ、Ｐの化合物のうち１種以上を含有する材料の混合粉末を容器内に装入し、混合後加熱することによってスラグ粉末成型体表面にガラス質物質の被覆を得る【選択図】 図１
