Sodium Percarbonate for Eco-Efficient Cyanide Detoxification in Gold Mining Tailings
Berkinbayeva A. Saulebekkyzy S. Kenzhaliyev B. Smailov K. Yessengaziyev A. Nurtazina N. Karim D. Birlikzhan Y.
October 2025Multidisciplinary Digital Publishing Institute (MDPI)
Metals
2025#15Issue 10
Cyanide-containing effluents from hydrometallurgical gold extraction pose significant environmental risks due to their high toxicity. This study investigates the detoxification of cyanide-laden tailings from the Altyntau Kokshetau gold extraction facility (Kazakhstan) using sodium percarbonate in alkaline conditions. Employing response surface methodology (RSM) and central composite design (CCD), we optimized key parameters—pH (10–12), sodium percarbonate dosage (1.5–4.0 g), reaction time (10–40 min) and temperature (20–25 °C)—achieving 83.33% detoxification efficiency within 40 min and 99.99% after 8 h, reducing cyanide from 443.2 mg/L to 0.05 mg/L. The process follows biphasic pseudo-first-order kinetics ((k1 = 0.0517) min–1 initially, (k2 = 0.01665) min–1 subsequently), driven by HO• radical-mediated oxidation of (Formula presented.) to (Formula presented.), as described by (Formula presented.)). pH emerged as the dominant factor, optimizing radical stability and (Formula presented.) protonation (pKa ≈ 9.21) at pH 10. Infrared spectroscopy confirmed the presence of cyanide complexes ((Formula presented.), (Formula presented.)) in tailings, underscoring the need for effective treatment. The method ensures compliance with stringent environmental standards (e.g., ICMI limit of 0.2 mg/L), offering a scalable, eco-efficient solution for mitigating the environmental footprint of gold mining operations.
cyanide detoxification , eco-efficient , gold mining , hydrometallurgical tailings , kinetics , sodium percarbonate
Text of the article Перейти на текст статьи
The Institute of Metallurgy and Ore Beneficiation, Satbayev University, Almaty, 050013, Kazakhstan
The Institute of Combustion Problems, Bogenbay Batyr Str. 1721, Almaty, 050012, Kazakhstan
The Institute of Metallurgy and Ore Beneficiation
The Institute of Combustion Problems
10 лет помогаем публиковать статьи Международный издатель
Книга Публикация научной статьи Волощук 2026 Book Publication of a scientific article 2026