Nitric Acid Leaching for Magnesium Extraction from Asbestos Ore Waste: From DoE to Predictive Modeling and Cost-Efficient Optimization

Ivanov N.S. Kholkin O.S. Abilmagzhanov A.Z. Adelbayev I.E. Oparin S.K. Ivanova N. Kudryashov V.
November 2025 Multidisciplinary Digital Publishing Institute (MDPI)

Molecules
2025 #30 Issue 22

Kazakhstan’s asbestos industry produces over 3 million tons of waste annually. The primary component of asbestos ore waste (AOW) is magnesium rich minerals. In this study, the extraction of magnesium from AOW with nitric acid (HNO₃) was for the first time systematically studied. A series of experiments were conducted to optimize acid concentration (300–600 g/L), leaching temperature (55–95 °C), leaching time (60–180 min), solid-to-liquid ratio (1:3–1:7), and particle size, with the overall goal of maximizing magnesium extraction and cost efficiency. Our results provide dependence of magnesium extraction in the order of acid concentration > temperature > time > solid-to-liquid ratio, while particle size was found to be negligible. The cost-efficiency optimization demonstrated the positive impact of the relatively low acid concentrations (< 450 g/L) and temperatures between 65 and 85 °C, while the Protodyakonov model validated a linear dependence of the extraction rate on temperature and acid concentration. Our model demonstrates that extraction efficiencies of up to 90% can be achieved while reducing reagent use and lowering the overall cost of magnesium production. Leaching of magnesium by HNO₃ also opens a pathway to a closed-cycle process, due to the formation of magnesium nitrate. The thermal decomposition of Mg(NO₃)₂ provides valuable products such as MgO and NO₂ reused in HNO₃ regeneration for subsequent cycles. The proposed model predicts magnesium extraction from asbestos ore depending on leaching parameters with reasonable accuracy.

asbestos , cost-efficiency optimization , ecology , leaching , magnesium oxide , mathematical planning , modeling

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Laboratory of Applied Research, D.V. Sokolskiy Institute of Fuel, Catalysis and Electrochemistry JSC, Almaty, 050010, Kazakhstan
Renewable Energy Lab, National Laboratory Astana, Nazarbayev University, Astana, 010000, Kazakhstan

Laboratory of Applied Research
Renewable Energy Lab

10 лет помогаем публиковать статьи Международный издатель

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