Authors: J.N. Badalov, K.I. Kholov, Sh.R. Samikhzoda

Title of the article: Mathematical modeling of the nitric acid leaching process of lead-zinc concentrate from the Zarnisor deposit

Year: 2026, Issue: 4, Pages: 190-203

Branch of knowledge: 2.8.9. Mineral processing

Index UDK: 66.011:66.061.34

DOI: 10.26730/1999-4125-2026-4-190-203

Abstract: The article considers mathematical modeling of the nitric acid leaching process of lead-zinc concentrate from the Zarnisor deposit. The relevance of the study is determined by the need to develop an effective hydrometallurgical technology for processing polymetallic raw materials of Tajikistan, ensuring a high degree of valuable component recovery and reducing environmental impact compared with traditional pyrometallurgical methods. The main process factors studied were temperature, leaching duration, nitric acid concentration, and the solid-to-liquid ratio. Based on experimental data, factor coding was performed, partial dependences of lead and zinc recovery on individual technological parameters were constructed, and second-order approximation equations were selected. It was found that increasing the temperature, contact time, HNO₃ concentration, and changing the solid-to-liquid ratio positively affect the transfer of Pb and Zn into solution. To generalize the obtained results, linear regression models were developed, allowing assessment of the combined influence of the factors and prediction of metal recovery within the studied range. The coefficients of determination were 0.899 for lead and 0.901 for zinc, confirming satisfactory agreement between calculated and experimental values. The additionally calculated RMSE and MAE indicators demonstrate acceptable model accuracy for engineering interpretation of the process. Rational leaching conditions were established as follows: temperature of 80 °C, duration of 120 min, HNO₃ concentration of 400 g/dm3, and S:L ratio of 1:5. Under these conditions, lead recovery reaches 94.4–95.0%, while zinc recovery reaches 89.5–90.0%, which makes it possible to recommend the selected regime for further technological studies.

Key words: nitric acid leaching lead zinc Zarnisor concentrate modeling regression optimization hydrometallurgy recovery

Receiving date: 30.04.2026

Approval date: 01.09.2026

Publication date: 10.09.2026

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