Concentration of gold in natural waters

McHugh, John B.

doi:10.1016/0375-6742(88)90051-9

Cited by 73 publications

(41 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…There are also several technical options available for gold extraction. However, the average gold concentration range from <0.001 to 0.005 ppb [50]. This means that one km 3 of sea water would give only 5.5 kg of gold.…”

Section: Lithium Brine Depositsmentioning

confidence: 99%

Lithium availability and future production outlooks

2013

View full text Add to dashboard Cite

Lithium is a highly interesting metal, in part due to the increasing interest in lithium-ion batteries. Several recent studies have used different methods to estimate whether the lithium production can meet an increasing demand, especially from the transport sector, where lithiumion batteries are the most likely technology for electric cars. The reserve and resource estimates of lithium vary greatly between different studies and the question whether the annual production rates of lithium can meet a growing demand is seldom adequately explained. This study presents a review and compilation of recent estimates of quantities of lithium available for exploitation and discusses the uncertainty and differences between these estimates. Also, mathematical curve fitting models are used to estimate possible future annual production rates. This estimation of possible production rates are compared to a potential increased demand of lithium if the International Energy Agency's Blue Map Scenarios are fulfilled regarding electrification of the car fleet. We find that the availability of lithium could in fact be a problem for fulfilling this scenario if lithium-ion batteries are to be used. This indicates that other battery technologies might have to be implemented for enabling an electrification of road transports. Highlights:• Review of reserves, resources and key properties of 112 lithium deposits • Discussions of widely diverging results from recent lithium supply estimates • Forecasting future lithium production by resource-constrained models • Exploring implications for future deployment of electric cars

show abstract

Section: Lithium Brine Depositsmentioning

confidence: 99%

Lithium availability and future production outlooks

2013

View full text Add to dashboard Cite

show abstract

“…Low-temperature aqueous transportation of gold in the Ashanti soils is indicated by: the presence of measurable quantities of gold in the supergene waters at Ashanti (up to 84.4 ~g/l; Bowell, 1991) 40000 times greater than the average gold concentration in natural waters (0.002 ~tg/l; McHugh, 1988); the gold-rich rims; and the composition and morphology of the secondary gold grains. However, the extent of the gold migration appears to be limited to a metre at the most with negligible lateral or vertical redistribution of gold in the soil profiles at Ashanti (Bowell etal., 1991).…”

Section: Supergene Mobilisation Of Gold In Tropical Weathering Profilesmentioning

confidence: 99%

Supergene gold mineralogy at Ashanti, Ghana: Implications for the supergene behaviour of gold

Bowell

1992

Mineral. mag.

View full text Add to dashboard Cite

At the Ashanti concession, Ghana, gold-bearing quartz veins and disseminated sulphide lodes occur in narrow (1-3 m) shear zones with altered argillites and metatholeiite host rocks. The mineralisation is concealed by up to 10 m of kaolinite-mica forest ochrosol soils, beneath which is a saprolitic zone of leached rock extending down 60-70 m to the hypogene ore zone. In the unweathered hypogene orebody, gold occurs as free grains in quartz, as sub-microscopic inclusions in the disseminated arsenopyrite, as gold tellurides and as aurostibite. The gold is released from the hypogene orebody by physical dissaggregation and chemical dissolution, the latter involving hydroxyl, thiosulphate, cyanide, and fulvate complexing. Dissolution and reprecipitation of the gold appears to have taken place largely in situ with little evidence of supergene enrichment. Consequently, the gold mineralogy of the soils is complex with residual and secondary gold grains exhibiting widely different textural and compositional characteristics. Residually enriched grains display pitted, rounded surfaces and have silver-depleted rims, while supergene gold grains are compositionally homogenous and have unpitted surfaces. The supergene grains display platelet, dendritic, irregular and octahedral habit. A fine grained spongy form of gold has also been observed from weathered telluride-bearing quartz veins. Much of the secondary gold is intergrown with iron oxides and hydroxides. The gold mineralogy of the Ashanti soils appears to be controlled by physico-chemical processes active during the lateritic pedogenesis producing residual and supergene enrichment of gold.

show abstract

“…Gold is one of the ten rarest elements in the Earth's crust with an average concentration of 5 ng g À1 (solid material), and a concentration range from 0.0197 to 0.197 mg l À1 in natural waters (Goldschmidt, 1954;McHugh, 1988). However, gold is not uniformly distributed and is often highly enriched in mineralized zones, where it may form economic primary deposits (for example, skarn type-, vein type-and disseminated deposits; Boyle, 1979).…”

Section: The Geochemical Characteristics Of Goldmentioning

confidence: 99%

The geomicrobiology of gold

et al. 2007

View full text Add to dashboard Cite

Microorganisms capable of actively solubilizing and precipitating gold appear to play a larger role in the biogeochemical cycling of gold than previously believed. Recent research suggests that bacteria and archaea are involved in every step of the biogeochemical cycle of gold, from the formation of primary mineralization in hydrothermal and deep subsurface systems to its solubilization, dispersion and re-concentration as secondary gold under surface conditions. Enzymatically catalysed precipitation of gold has been observed in thermophilic and hyperthermophilic bacteria and archaea (for example, Thermotoga maritime, Pyrobaculum islandicum), and their activity led to the formation of gold-and silver-bearing sinters in New Zealand's hot spring systems. Sulphatereducing bacteria (SRB), for example, Desulfovibrio sp., may be involved in the formation of goldbearing sulphide minerals in deep subsurface environments; over geological timescales this may contribute to the formation of economic deposits. Iron-and sulphur-oxidizing bacteria (for example, Acidothiobacillus ferrooxidans, A. thiooxidans) are known to breakdown gold-hosting sulphide minerals in zones of primary mineralization, and release associated gold in the process. These and other bacteria (for example, actinobacteria) produce thiosulphate, which is known to oxidize gold and form stable, transportable complexes. Other microbial processes, for example, excretion of amino acids and cyanide, may control gold solubilization in auriferous top-and rhizosphere soils. A number of bacteria and archaea are capable of actively catalysing the precipitation of toxic gold(I/ III) complexes. Reductive precipitation of these complexes may improve survival rates of bacterial populations that are capable of (1) detoxifying the immediate cell environment by detecting, excreting and reducing gold complexes, possibly using P-type ATPase efflux pumps as well as membrane vesicles (for example, Salmonella enterica, Cupriavidus (Ralstonia) metallidurans, Plectonema boryanum); (2) gaining metabolic energy by utilizing gold-complexing ligands (for example, thiosulphate by A. ferrooxidans) or (3) using gold as metal centre in enzymes (Micrococcus luteus). C. metallidurans containing biofilms were detected on gold grains from two Australian sites, indicating that gold bioaccumulation may lead to gold biomineralization by forming secondary 'bacterioform' gold. Formation of secondary octahedral gold crystals from gold(III) chloride solution, was promoted by a cyanobacterium (P. boryanum) via an amorphous gold(I) sulphide intermediate. 'Bacterioform' gold and secondary gold crystals are common in quartz pebble conglomerates (QPC), where they are often associated with bituminous organic matter possibly derived from cyanobacteria. This may suggest that cyanobacteria have played a role in the formation of the Witwatersrand QPC, the world's largest gold deposit.

show abstract

Concentration of gold in natural waters

Cited by 73 publications

References 13 publications

Lithium availability and future production outlooks

Lithium availability and future production outlooks

Supergene gold mineralogy at Ashanti, Ghana: Implications for the supergene behaviour of gold

The geomicrobiology of gold

Contact Info

Product

Resources

About