scholarly journals Bioreductive Dissolution as a Pretreatment for Recalcitrant Rare-Earth Phosphate Minerals Associated with Lateritic Ores

Minerals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 136 ◽  
Author(s):  
Ivan Nancucheo ◽  
Guilherme Oliveira ◽  
Manoel Lopes ◽  
David Johnson
Keyword(s):  
Rare Earth ◽  
Elemental Sulfur ◽  
Ferric Iron ◽  
Mineral Dissolution ◽  
Base Metals ◽  
Iron Minerals ◽  
Acidophilic Bacteria ◽  
Biotechnological Approach ◽  
Potential Resource ◽  
Rare Earth Phosphate

Recent research has demonstrated the applicability of a biotechnological approach for extracting base metals using acidophilic bacteria that catalyze the reductive dissolution of ferric iron oxides from oxidized ores, using elemental sulfur as an electron donor. In Brazil, lateritic deposits are frequently associated with phosphate minerals such as monazite, which is one of the most abundant rare-earth phosphate minerals. Given the fact that monazite is highly refractory, rare earth elements (REE) extraction is very difficult to achieve and conventionally involves digesting with concentrated sodium hydroxide and/or sulfuric acid at high temperatures; therefore, it has not been considered as a potential resource. This study aimed to determine the effect of the bioreductive dissolution of ferric iron minerals associated with monazite using Acidithiobacillus (A.) species in pH- and temperature-controlled stirred reactors. Under aerobic conditions, using A. thiooxidans at extremely low pH greatly enhanced the solubilization of iron from ferric iron minerals, as well that of phosphate (about 35%), which can be used as an indicator of the dissolution of monazite. The results from this study have demonstrated the potential of using bioreductive mineral dissolution, which can be applied as pretreatment to remove coverings of ferric iron minerals in a process analogous to the bio-oxidation of refractory golds and expand the range of minerals that could be processed using this approach.

Reduction and Complexation of Copper in a Novel Bioreduction System Developed to Recover Base Metals from Mine Process Waters

2013 ◽  
Vol 825 ◽  
pp. 483-486 ◽  
Author(s):  
Sabrina Hedrich ◽  
Chris du Plessis ◽  
Nelson Mora ◽  
D. Barrie Johnson
Keyword(s):  
Copper Sulfide ◽  
Iron Reduction ◽  
Elemental Sulfur ◽  
Ferric Iron ◽  
Sodium Sulfide ◽  
Base Metals ◽  
Processing Scheme ◽  
Step Process ◽  
Potential Alternative ◽  
Axenic Cultures

An integrated bio-processing scheme was devised and tested in the laboratory for recovering copper, or other base metals, from pregnant leach solutions (PLS) using a two-step process involving both iron-reduction, and sulfate-reduction for H2S generation and sulfide precipitation, as a potential alternative to conventional SX-EW. Reduction of ferric iron in the PLS was achieved using iron-reducingAcidithiobacillusspp. andSulfobacillus thermosulfidooxidansin column reactors containing elemental sulfur as electron donor. Analysis of the column reactor effluents showed not only that most of the ferric iron was reduced to ferrous, but also that all of the copper (II) had been reduced to copper (I), i.e. cuprous copper. This copper (I) appeared to be complexed as it was not oxidized when exposed to ferric iron nor precipitated as a copper-sulfide when exposed to either sodium sulfide or H2S. The data suggested that copper (II) was reduced and the resulting copper (I) complexed, with both reactions probably mediated by sulfur oxy-anions produced indirectly by the bacteria, in the anoxic sulfur column bioreactors. It was also noted that copper (I) produced chemically by reduction of copper (II) by hydroxylamine was more toxic to axenic cultures ofAcidithiobacillusspp. andSb. thermosulfidooxidansthan was the copper (I) in the column effluent liquors.

Diffraction studies of rare-earth phosphate glasses

2000 ◽  
Vol 270 (1-3) ◽  
pp. 234-246 ◽  
Author(s):  
A.G. Shikerkar ◽  
J.A.E. Desa ◽  
P.S.R. Krishna ◽  
R. Chitra
Keyword(s):  
Rare Earth ◽  
Phosphate Glasses ◽  
Rare Earth Phosphate

Catalysis by rare earth phosphate II: Selective o-methylation of phenols by methanol in vapor phase

1996 ◽  
pp. 48-61 ◽  
Author(s):  
Laurent Gilbert ◽  
Marcelle Janin ◽  
Anne-Marie Le Govic ◽  
Pascale Pommier ◽  
Alain Aubry
Keyword(s):  
Rare Earth ◽  
Vapor Phase ◽  
Rare Earth Phosphate

Vitusite — an apatite derivative structure

1992 ◽  
Vol 56 (383) ◽  
pp. 235-239 ◽  
Author(s):  
Adrian A. Finch ◽  
James G. Fletcher
Keyword(s):  
Rare Earth ◽  
Late Stage ◽  
Sensu Stricto ◽  
Hydrothermal Fluids ◽  
Stable Phase ◽  
Synthetic Analogue ◽  
Apatite Structure ◽  
Phosphate Mineral ◽  
Rare Earth Phosphate ◽  
Rare Earth Substitution

AbstractThe uncommon sodium rare-earth phosphate mineral vitusite-(Ce) (Na3RE(PO4)2) can be considered as the extreme product of sodium and rare-earth substitution in the apatite structure. Lesser amounts of substitution provide sodium and rare-earth-bearing apatites up to about 80 mol.% exchange; beyond this point vitusite is the stable phase. The structure of vitusite, determined previously from a synthetic analogue, can also be considered as a derivative from apatite, but with cations exchanged on sites normally occupied by anions. Vitusite can therefore be considered as a sodium- and rare-earthrich apatite end-member, with a distinct, but apatite-derived, structure, formed in highly persodic and high rare-earth environments. From an examination of the literature on diffusion in apatite, vitusite in principle could be formed from apatitesensu strictoby subsolidus diffusion in response to late-stage NaandRE-rich hydrothermal fluids.

scholarly journals An EXAFS study of rare-earth phosphate glasses in the vicinity of the metaphosphate composition

1998 ◽  
Vol 232-234 ◽  
pp. 286-292 ◽  
Author(s):  
R Anderson ◽  
T Brennan ◽  
G Mountjoy ◽  
R.J Newport ◽  
G.A Saunders
Keyword(s):  
Rare Earth ◽  
Phosphate Glasses ◽  
Exafs Study ◽  
Rare Earth Phosphate

Synthesis of Tributylphosphate Capped Luminescent Rare Earth Phosphate Nanocrystals in an Ionic Liquid Microemulsion

2009 ◽  
Vol 21 (15) ◽  
pp. 3570-3575 ◽  
Author(s):  
Chao Zhang ◽  
Ji Chen ◽  
Xingfu Zhu ◽  
Yunchun Zhou ◽  
Deqian Li
Keyword(s):  
Ionic Liquid ◽  
Rare Earth ◽  
Rare Earth Phosphate
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