Stability analysis of copper slag by degree of leaching of calcium and magnesium in model experiment

Copper slag leaching by model rain water is analyzed with a view to assessing potential environmental risks. The aim of the research is to estimate leachability of calcium and magnesium from granulated copper slags by simulation of acid precipitation occurrent under conditions of high anthropogenic load. The subject of research is granulated copper slag of different degree of dispersion. The lab-scale testing of slag involved percolation of simulated acid precipitation containing sulfuric acid of various concentration. The eluates were used to measure pH, as well as calcium and magnesium contents. Samples of slag were subjected to powder X-ray diffraction, electronic probing and energy-dispersive microanalysis. Mineralogically, the test slag contains silicate minerals, vitreous and spinel-like phases, as well as secondary sulfide minerals. The leaching tests at different values of solution pH shows that slag experiences two main processes: diffusion and dissolution. At the stage of diffusion, no noticeable changes in pH are observed in the eluates; at the stage of dissolution, reaction shifts on the average by 2.5 pH units toward the neutral reaction. With increase in time, the total concentration of calcium grows in the eluates and elevates from 871.9 to 2573.9 mg/l by the end of the testing. Magnesium leachability from the slag is much weaker because of the presence of spinel-like phases in it. Initially, with increasing pH in acid precipitation, magnesium leachability increases in the first 70 days of the testing and drops by 3.5 times by the time of the test completion. After 70 days of the experimentation, the amount of leached magnesium increases in neither scenario. The implemented research proves high activity of copper slags towards the environment, especially in the regions of intense technogenesis and frequent acid precipitation. The practical relevance of the research findings consists in fostering of technological adjustment of production, processing and storage of manmade minerals. The obtained knowledge and obtained evaluations with the identification of the environmental risks can facilitate development of new concepts of industrial waste management and land utilization. 

Shabanov M. V., Marichev M. S. Stability analysis of copper slag by degree of leaching of calcium and magnesium in model experiment. MIAB. Mining Inf. Anal. Bull. 2026;(10):101-113. [In Russ]. DOI: 10.25018/0236_1493_2026_10_0_101.

The study was supported by the Russian Science Foundation, Grant No. 25-77-00021, https://rscf.ru/project/25-77-00021/, and was carried out at the Saint-Petersburg State Agrarian University. 

M.V. Shabanov¹, Cand. Sci. (Agr.), Assistant Professor, Assistant Professor, e-mail: geohim.spb@gmail.com, Scopus 35171489500, ORCID ID: 0000-0003-4725-3673,
M.S. Marichev¹, Cand. Sci. (Biol.), Head of Laboratory, e-mail: m.s.marichev@yandex.ru, Scopus 57216298057, ORCID ID: 0000-0003-0429-2234,
¹ Saint-Petersburg State Agrarian University, Pushkin, Russia.

M.S. Marichev, e-mail: m.s.marichev@yandex.ru.

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