A comparative study on the chemical composition of humic acids from forest soil, agricultural soil and lignite deposit

Allard, Bruno

doi:10.1016/j.geoderma.2005.01.010

Cited by 102 publications

(44 citation statements)

References 81 publications

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“…Humic acid (HA) is a mixture of macromolecular organics and can be easily extracted from peat, lignite and decomposed coal, whose molecules have abundant negatively-charged functional groups like carboxyl and hydroxyl groups [53]. The gold extraction from a refractory gold concentrate calcine was improved from 72.6% to 81.4% and thiosulfate consumption was reduced from 42.7% to 13.2% by the use of HA [54].…”

Section: Inorganic Additivesmentioning

confidence: 99%

A Review of Thiosulfate Leaching of Gold: Focus on Thiosulfate Consumption and Gold Recovery from Pregnant Solution

Kong

et al. 2017

Metals

136

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Thiosulfate leaching is a promising alternative to cyanidation, and the main hindrances for its wide commercial application are the high thiosulfate consumption and the difficult recovery of dissolved gold. In this review, the four solutions to reduce the consumption of thiosulfate, including the control of reaction conditions, the use of additives, the generation of thiosulfate in situ, and the replacement of traditional cupric-ammonia catalysis, are introduced and evaluated after the presentation of background knowledge about thiosulfate consumption. The replacement of cupric-ammonia catalysis with other metals, such as nickel-and cobalt-based catalysts, is proposed. The reason is that it not only reduces thiosulfate consumption observably via decreasing the redox potential of leach solution significantly but also is beneficial to gold recovery mainly owing to eliminating the interference of cuprous thiosulfate [Cu(S 2 O 3 ) 3 ] 5− . Based on the comparative analysis for five common recovery techniques of rare-noble metals from pregnant leach solution, ion-exchange resin adsorption is considered to be the most appropriate to recover aurothiosulfate [Au(S 2 O 3 ) 2 ] 3− because the resin can be employed in the form of resin-in-leach/pulp and, furthermore, is able to be eluted and regenerated simultaneously at ambient temperature. At last, how to reduce the process cost of the resin adsorption technique is discussed. In order to simplify the complex two-stage elution process for loaded resins, the traditional catalysis is suggested to be replaced.

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Section: Inorganic Additivesmentioning

confidence: 99%

A Review of Thiosulfate Leaching of Gold: Focus on Thiosulfate Consumption and Gold Recovery from Pregnant Solution

Kong

et al. 2017

Metals

136

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“…Additional lipidic moieties occur either within macromolecules like cutin and suberin (Kolattukudy 1980) or bound to other mineral or organic soil constituents (e.g. Amblès et al 1989a;Allard 2006). However, the release of bound lipids in the laboratory requires soil pretreatment and only free lipids will be considered in the present study.…”

Section: Introductionmentioning

confidence: 99%

Evolution of lipid abundance and molecular composition during the podzolisation of laterites in the upper Amazon basin

Bardy¹,

Derenne²,

Fritsch³

2008

Biogeochemistry

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In the upper Amazon basin, podzolisation involves the remobilization of large amounts of organic matter and chemical elements (Fe, Al, Si) previously accumulated in lateritic formations. In order to better understand the fate of organic matter in podzolic environments in this area, the evolution of lipid abundance and molecular composition were studied along a representative soil sequence showing the transition between a latosol and a well-developed podzol. Total solvent extracts were obtained from eight key soil samples from three profiles and their overlying litters, and enable us to follow both lateral and vertical evolutions. Lipid composition was determined by gas chromatography-mass spectrometry (GC-MS). Major compound classes include alkanes, alkanones, alkanols, alkanoic acids, x-hydroxyacids, as well as aromatics, steroids and triterpenoids. Free lipids do not accumulate in the early stages of podzolisation but are abundant in well-developed podzolic horizons, possibly due to (i) combined acidity and waterlogging, (ii) limited amounts of complexing elements, (iii) a decreased microbial activity. The evolution of lipid composition is consistent with podzolisation mechanisms previously highlighted in the sequence. This paper provides further evidence for the occurrence of anoxic conditions in deep waterlogged podzolic horizons. It also shows that aromatic, phytotoxic compounds are stabilized in the welldeveloped podzol. This may play a role in the vegetation changes associated with podzolisation in the area.

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“…Actually hydroxyl FAs are the second in abundance. Allard (2006) published a comparative study on the chemical compositions of humic acids extracted from soil, agricultural soil and lignite deposits based on the data for bound lipids, carbohydrates and amino acids compositions. ωΟΗ-FAs were determined only in soil humic acids being completely absent in lignite HAs.…”

Section: Acidic Fractionmentioning

confidence: 99%

Organic Geochemistry of Humic Acids From a Neogene Lignite Sample, Bulgaria

Stefanova¹,

Маринов²

2017

geosociety

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A comparative study on the chemical composition of humic acids from forest soil, agricultural soil and lignite deposit

Cited by 102 publications

References 81 publications

A Review of Thiosulfate Leaching of Gold: Focus on Thiosulfate Consumption and Gold Recovery from Pregnant Solution

A Review of Thiosulfate Leaching of Gold: Focus on Thiosulfate Consumption and Gold Recovery from Pregnant Solution

Evolution of lipid abundance and molecular composition during the podzolisation of laterites in the upper Amazon basin

Organic Geochemistry of Humic Acids From a Neogene Lignite Sample, Bulgaria

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