Sulfuric acid pressure leaching of nickeliferous limonites

Chou, E. C.; Queneau, Paul B.; Rickard, R. S.

doi:10.1007/bf02658621

Cited by 8 publications

(9 citation statements)

References 5 publications

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“…[12] through [18]) in which the molalities of the following six aqueous species are unknown: H + , Al 3+ , Al(SO 4 ) + , , , and . [1] or [2] in terms of molalities and ion-interaction parameters. [1] or [2] in terms of molalities and ion-interaction parameters.…”

Section: Calculations and Discussionmentioning

confidence: 99%

“…In the Pitzer equations, m is the molality; I is the ionic strength (in mol 1/2 kg Ϫ1/2 ); ␣ 1 , ␣ 2 , and b are constants and are equal to 1.4, 12, and 1.2 kg 1/2 mol Ϫ1/2 , respectively (when ␤ (2) is zero, then ␣ 1 ϭ 2.0 kg 1/2 mol Ϫ1/2 ); Z i is the valence of ion i; and ␤ (0) , ␤ (1) , ␤ (2) , C are the Pitzer ioninteraction parameters, which have a unique value for a pair of M-X ions at any given temperature. The subscripts c, a, and i mean any cation, any anion, and any ion, respectively.…”

Section: B Ion-interaction: Pitzer Activity Coefficient Modelmentioning

confidence: 99%

“…In the Pitzer model, the activity coefficient of each ion is described by two terms. [2] for anion X. [10].…”

Section: B Ion-interaction: Pitzer Activity Coefficient Modelmentioning

confidence: 99%

“…To this end, the sulfuric acid pressure leaching process is employed, operating at temperatures between 240 ЊC to 270 ЊC using autoclaves. [1][2][3][4][5][6] The sulfuric acid consumption for pressure acid leaching of a limonitic ore is typically 18 to 26 wt pct of dry ore, whereas, for a saprolitic ore, 40 to 60 wt pct is required to achieve 97 pct Ni extraction. [4,5] The application of pressure acid leaching has also been extended to treat the entire ore body (limonite plus saprolite).…”

Section: Introductionmentioning

confidence: 99%

“…Laterite leach solutions at high temperatures [1,2] contain, in addition to Ni and Co, several metal sulfates including Al, Mg, Mn, Zn, Fe, Cu, and Cr, as well as H 2 SO 4 . The most abundant metals in the leach solution are Al, Mg, Ni, and Mn, due to both their high solubility and high content in the ore. [1,2,6] Mg and Al have a more pronounced impact on the process than the other two metal sulfates.…”

Section: Introductionmentioning

confidence: 99%

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The ion-association-interaction approach as applied to aqueous H2SO4-Al2(SO4)3-MgSO4 solutions at 250 °C

Baghalha

Papangelakis²

1998

Metall and Materi Trans B

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A hybrid ion-association-interaction approach is implemented to describe the chemistry and thermodynamics of aqueous H 2 SO 4 -Al 2 (SO 4 ) 3 -MgSO 4 solutions at 250 ЊC. These solutions are relevant to the sulfuric acid pressure leaching of nickeliferous laterites. Strong complexes in solution are handled via the ion-association approach. Nonidealities, including weak ion pair formations, are treated through the Pitzer ion-interaction theory. The existing complexes in solution and the Pitzer ion-interaction parameters were identified through processing solubility data in the binary (H 2 SO 4 -Al 2 (SO 4 ) 3 and H 2 SO 4 -MgSO 4 ) as well as the ternary (H 2 SO 4 -Al 2 (SO 4 ) 3 -MgSO 4 ) electrolyte solutions at or near 250 ЊC. The existing aqueous aluminum-bearing species identified were Al 3+ , Al(SO 4 ) + , and , with as the dominant species at moderate to high H 2 SO 4 concentrations. 0 0 Al (SO ) Al (SO ) 2 4 3 2 4 3The existing aqueous magnesium-bearing species found were Mg 2+ and , with Mg 2+ being 0 MgSO 4 dominant except at low concentrations of H 2 SO 4 . The dominant species identified for Al and Mg explain why a higher H 2 SO 4 concentration in solution is required during the processing of highmagnesium laterites.

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Section: Calculations and Discussionmentioning

confidence: 99%

Section: B Ion-interaction: Pitzer Activity Coefficient Modelmentioning

confidence: 99%

“…In the Pitzer model, the activity coefficient of each ion is described by two terms. [2] for anion X. [10].…”

Section: B Ion-interaction: Pitzer Activity Coefficient Modelmentioning

confidence: 99%