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Yan Jia
Yan Jia
Dr.Habil., Associate Professor
CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences
, Dr.Habil., Associate Professor
CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences

Articles

Metallurgy and concentration
  • Date submitted
    2020-06-10
  • Date accepted
    2020-11-19
  • Date published
    2021-04-21

Influence of jarosite precipitation on iron balance in heap bioleaching at Monywa copper mine

Article preview

Ferric iron is an important oxidant in sulfide ore bioleaching. However, recirculating leach liquors leads to excess iron accumulation, which interferes with leaching kinetics and downstream metal recovery. We developed a method for controlling iron precipitation as jarosite to reduce excess iron in heap bioleaching at Monywa copper mine. Jarosite precipitation was first simulated and then confirmed using batch column tests. From the simulations, the minimum pH values for precipitation of potassium jarosite, hydronium jarosite, and natrojarosite at 25 °C are 1.4, 1.6, and 2.7, respectively; the minimum concentrations of potassium, sulfate, ferric, and sodium ions are 1 mM, 0.54, 1.1, and 3.2 M, respectively, at 25 °C and pH 1.23. Column tests indicate that potassium jarosite precipitation is preferential over natrojarosite. Moreover, decreased acidity (from 12 to 8 g/L), increased temperature (from 30 to 60 °C), and increased potassium ion concentration (from 0 to 5 g/L) increase jarosite precipitation efficiency by 10, 5, and 6 times, respectively. Jarosite precipitation is optimized by increasing the irrigating solution pH to 1.6. This approach is expected to reduce the operating cost of heap bioleaching by minimizing the chemicals needed for neutralization, avoiding the need for tailing pond construction, and increasing copper recovery.

How to cite: Soe K.M., Ruan R., Jia Y., Tan Q., Wang Z., Shi J., Zhong C., Sun H. Influence of jarosite precipitation on iron balance in heap bioleaching at Monywa copper mine // Journal of Mining Institute. 2021. Vol. 247. p. 102-113. DOI: 10.31897/PMI.2020.1.11