Acid leaching of metals from deep-sea manganese nodules – A critical review of fundamentals and applications

Senanayake, Gamini

doi:10.1016/j.mineng.2011.06.003

Cited by 87 publications

(52 citation statements)

References 50 publications

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“…15. This supports the view that the diffusion of H + through a thickening porous product layer is the rate controlling step, as in the case of limonite and manganese nodules proposed previously (Senanayake and Das, 2004;Senanayake, 2011). The concentrations of acid used in the case of different smectite ores reported in Table 6 are also comparable.…”

Section: Accepted M Manuscriptsupporting

confidence: 88%

“…The first order dependence of k ap on c has been confirmed using a plot of log{k ap } as a function of log{c} which showed a linear relationship of slope close to unity: log{k ap } = 1.04 log{c} -8.17 for the leaching of iron and nickel from manganese nodules and limonitic laterite ores during AAL or RAAL processes (Senanayake, 2011). The values of k ap for nickel leaching from smectite ores A-D during AAL and RAAL processes (Table 8) are also included in the logarithmic plot in Fig.…”

Section: Accepted M Manuscriptmentioning

confidence: 75%

“…In contrast the values of LE (Mn) and LE (Co) are lower than LE (Fe) under non-reducing conditions. However, under reducing conditions the values of LE (Mn) and LE (Co) and Mn 3 O 4 can be involved in reductive leaching of high-valent Co-Mn oxides (Zhang et al, 2002;Senanayake, 2011;Senanayake et al, 2011). A certain fraction of iron associated with the smectite structure and mineralogical formulae of silicates noted in Fig.…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

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Reductive atmospheric acid leaching of lateritic smectite/nontronite ores in H2SO4/Cu(II)/SO2 solutions

et al. 2015

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Despite the success of reductive atmospheric acid leaching (RAAL) of limonitic nickel laterite ores in recent studies limited attempt has been made to apply this method to smectite/nontronite ores of different mineralogy. A comparative study of four smectite/nontronite ores in this study showed that the use of 700 kg H 2 SO 4 /ton dry ore leaches only 74-86% Ni, 37-76% Co, 47-58% Fe and 24-66% Mn at 90 o C from slurries of 20-35% (w/w) pulp density even after 10 h, depending upon the mineralogy. These values increased to 90-97% Ni, 94-97% Co, 92-98% Mn and 72-85% Fe in the presence of Cu(II)/SO 2 . The first order dependence of initial fraction of iron, aluminium and nickel leached from a typical smectite ore in the first 0.5 h on the initial acid concentration provide evidence for the involvement of hydrogen ions in the surface reaction. Low activation energy of 10 kJ/mol based on the fraction of nickel leached in the first 0.5 h indicates a diffusion controlled reaction. This is supported by the applicability of a shrinking core kinetic model for metal dissolution over the first 2 h, with different apparent rate constants (k ap ) depending upon the iron oxide content, mineralogy and porosity. A log-log plot of k ap for ores with high iron content as a function of acid concentration agrees reasonably well with the correlation already established for the leaching of nickel from limonitic laterite and manganese nodules. Thus, initial fast leaching can be related to the higher porosity and a rate controlling step which involves the diffusion of H + through a thickening solid layer. The slow leaching at latter stages is a result of low remnant acid, thickening solid layer and changes in mineral composition.

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Section: Accepted M Manuscriptsupporting

confidence: 88%

Section: Accepted M Manuscriptmentioning

confidence: 75%

Section: Accepted M Manuscriptmentioning

confidence: 99%

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Reductive atmospheric acid leaching of lateritic smectite/nontronite ores in H2SO4/Cu(II)/SO2 solutions

et al. 2015

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“…The measured solubility of metal ions in sea water (pH~8) can be rationalised on the basis of the solubility products (K SP ) of carbonate sediments of divalent or monovalent metal ions. The values of pK SP (= -log K SP ) of carbonates increase with the increasing softness of cations, causing a lower solubility of metal ions in the ocean (Senanayake, 2011). In this review, the softness and the Lewis acidity/basicity of ions are used to rationalise the relative stability of various Au(I) complexes and the effect of background reagents on the reactions between copper(II), thiosulphate and host minerals.…”

Section: Hard/soft and Lewis Acid/base Properties Of Ionsmentioning

confidence: 99%

Gold leaching by copper(II) in ammoniacal thiosulphate solutions in the presence of additives. Part I: A review of the effect of hard–soft and Lewis acid-base properties and interactions of ions

Senanayake

2012

Hydrometallurgy

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Gold leaching in thiosulphate media has attracted renewed interest of many researchers over the last three decades due to fast kinetics in the presence of some oxidants/ligands and adaptability to gold ores which are unsuitable for direct cyanidation.The acidity (pH) and concentration of copper(II), ammonia, thiosulphate and polythionates, produced by the reaction between copper(II) and thiosulphate and other added background reagents including chloride, carbonate, sulphite, sulphide, phosphate and cations such as silver(I), lead(II) and counter ions of thiosulphate salts affect the rate per unit area and extent (%) of gold dissolution. The literature data on beneficial and detrimental effects of background reagents on gold dissolution from rotating discs, suspended foils and particles of gold ores/concentrates are reviewed. Reaction mechanism(s) with applications to leach systems are also reviewed and discussed on the basis of the Lewis acid-base and hard-soft properties and interactions of metal ions and anions. These interactions determine the ability of background reagents to affect the residual copper(II) concentration and E H , surface reaction with gold by catalytic action and/or by avoiding/removing passivating layers on gold.

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“…Despite the apparent large size of the resources, the economically viable resources are likely to be much smaller (Glasby 2002). Techniques for recovery of the nodules from the ocean floor and subsequent mineral processing strategies have been the intensely studied and have been the subject of a numerous articles (Senanayake 2011;Kumari and Natarajan 2001a, b;Mehta et al 2003;Vu et al 2005;Mehta et al 2010;Kanungo and Jena 1988) and a conference series facilitated by the International Seabed Authority.…”

Section: On Mn Nodulesmentioning

confidence: 99%

Environmental Microbial Biotechnology

Sukla¹,

Pradhan²,

Panda³

et al. 2015

Soil Biology

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Acid leaching of metals from deep-sea manganese nodules – A critical review of fundamentals and applications

Cited by 87 publications

References 50 publications

Reductive atmospheric acid leaching of lateritic smectite/nontronite ores in H2SO4/Cu(II)/SO2 solutions

Reductive atmospheric acid leaching of lateritic smectite/nontronite ores in H2SO4/Cu(II)/SO2 solutions

Gold leaching by copper(II) in ammoniacal thiosulphate solutions in the presence of additives. Part I: A review of the effect of hard–soft and Lewis acid-base properties and interactions of ions

Environmental Microbial Biotechnology

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