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<p>The present study investigates the efficiency of hydrochloric acid (HCl) leaching of low–grade limonitic laterites from Evia island (Greece). The effect of the main parameters affecting the process efficiency, i.e. acid molarity (4 and 8&#xa0;mol/L, M), temperature (40 and 80&#xa0;°C), leaching time (2, 4 and 6&#xa0;h), and solid-to-liquid ratio (S/L) (0.30 and 0.45) is explored. The chemical analysis of laterite and the concentrations of Ni, Co, Fe, Al, Cr, Mn, Ca, and Mg in the pregnant leach solution (PLS) are determined by Atomic Absorption Spectroscopy (AAS), while the HCl consumption is calculated using the titrimetric method. The experimental results show that the extraction of all elements increased with the increase of acid molarity, leaching time and leaching temperature. The maximum extractions obtained in the optimum conditions (8&#xa0;mol/L HCl, temperature 80&#xa0;°C, leaching time 6&#xa0;h and S/L ratio 0.30) are 95% for Ni, 98% for Co, 37% for Fe, 82% for Al, 53% for Cr, 90% for Mg, 76% for Ca, and 62% for Mn, while the respective acid consumption was 154&#xa0;kg HCl/t laterite ore. Finally, the alkali activation of laterite residues after calcination at 750 or 900 °C and mixing with ferroonickel slag or metakaolin was also investigated. The alkaline solution used consisted of a mixture of 8 mol/L (M) NaOH and Na<sub>2</sub>SiO<sub>3</sub> solutions (mass ratio 1:1), while the produced specimens were obtained after pre-curing and curing periods of 24 h, curing temperature 80 °C and ageing for 7 or 28 days.</p>

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Hydrochloric Acid Leaching of Low–grade Limonitic Laterite

  • 期刊论文

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  • 发表日期：

    2026年3月18日

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  • K. Komnitsas,
  • V. Karmali,
  • G. Bartzas,
  • A. Kritikaki

摘要

The present study investigates the efficiency of hydrochloric acid (HCl) leaching of low–grade limonitic laterites from Evia island (Greece). The effect of the main parameters affecting the process efficiency, i.e. acid molarity (4 and 8 mol/L, M), temperature (40 and 80 °C), leaching time (2, 4 and 6 h), and solid-to-liquid ratio (S/L) (0.30 and 0.45) is explored. The chemical analysis of laterite and the concentrations of Ni, Co, Fe, Al, Cr, Mn, Ca, and Mg in the pregnant leach solution (PLS) are determined by Atomic Absorption Spectroscopy (AAS), while the HCl consumption is calculated using the titrimetric method. The experimental results show that the extraction of all elements increased with the increase of acid molarity, leaching time and leaching temperature. The maximum extractions obtained in the optimum conditions (8 mol/L HCl, temperature 80 °C, leaching time 6 h and S/L ratio 0.30) are 95% for Ni, 98% for Co, 37% for Fe, 82% for Al, 53% for Cr, 90% for Mg, 76% for Ca, and 62% for Mn, while the respective acid consumption was 154 kg HCl/t laterite ore. Finally, the alkali activation of laterite residues after calcination at 750 or 900 °C and mixing with ferroonickel slag or metakaolin was also investigated. The alkaline solution used consisted of a mixture of 8 mol/L (M) NaOH and Na2SiO3 solutions (mass ratio 1:1), while the produced specimens were obtained after pre-curing and curing periods of 24 h, curing temperature 80 °C and ageing for 7 or 28 days.