Proceedings of the International scientific and practical conference ―Advances in Science and Humanity‖ (March 29-31, 2026) / Publisher website: www.naukainfo.com. – Vienna, Austria, 2026. - 176 p.

36 Fig. 1. The radionuclide specific activities and effective specific activities for Zaporizhstal slag fractions Determination of acidity of slag particle surface layers . Acidity slightly varies in slag fractions. More basic is <0.63 mm fraction (рН=9.67), 2.5–5 (рН=9.11), >20 (рН=8.17) . Hydraulic activity of Zaporizhstal dump waste blast-furnace slag . The hydraulic activity of blast-furnace slags is an important factor determining the feasibility of their disposal in the production of slag Portland cement. Experimental results were obtained on determination of the hydraulic activity of the slag fraction >20 mm by the CaO absorption value (mg/g) at a certain time of blast furnace slag contact with Ca(OH)2: 1 day – 184; 7 days – 227; 14 days – 360. Zaporozhstal dump blast furnace slag shows high hydraulic activity, CaO absorption increases in time. The content of CaO in the slag, determined by dissolution in water, is 13.44 mg/g. Conclusions – Elemental slag composition that is determined by the electron probe microanalysis enables to characterise its fractions in terms of toxicity. The third hazard class of dump waste blast furnace slag is determined.