mineral fraction
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Geoderma ◽  
2022 ◽  
Vol 409 ◽  
pp. 115657
Tianyi Wu ◽  
Alexander D. Ost ◽  
Jean-Nicolas Audinot ◽  
Martin Wiesmeier ◽  
Tom Wirtz ◽  

2021 ◽  
pp. 315-322
Michael Steineder ◽  
Bernhard Hofko ◽  
Lukas Eberhardsteiner

2021 ◽  
Vol 18 (6) ◽  
pp. 1521-1536
Michele Freppaz ◽  
Mark W. Williams ◽  
Jacopo Gabrieli ◽  
Roberta Gorra ◽  
Ilaria Mania ◽  

AbstractIn the summer of 2003 and 2004, characterized by a rapid glacier retreat, a stony surface covered by well-structured organic-rich mineral debris was observed very close to the Indren glacier terminus (Monte Rosa Massif, NW Italy, 3100 m ASL), on an area covered by the glacier tongue till the year before. The origin and type of this organic-rich material were investigated, in order to detect their characteristics, potential sources and fate within the foreland system. The deposits were dated using Carbon-14 and analyzed for the chemical characteristics of the organic component, the elemental composition of the mineral fraction and presence of microbial markers. The material, granular and dark in color, had a total organic carbon (TOC) content ranging between 17.4 ± 0.39 and 28.1 ± 0.63 g kg−1 dry weight (dw), significantly higher than the surrounding glacial till (~ 1.4 g kg−1 dw), although only 0.33% of it was in water soluble form. Microbial carbon (C) and nitrogen (N) accounted for 10.6% and 3.13% of TOC and total N, respectively. Dissolved nitrogen (N), mainly present as ammonium, represented 2.40% of the total N. The low aromatic component and large presence of nitrogen (N)-derived compounds suggested that most of the organic carbon (OC) in these organic-rich mineral deposits was derived from microbial cells, although the high average radiocarbon age of about 2900 years may also point to the contribution of aeolian depositions of anthropogenic or natural origin. Elemental composition and the crustal enrichment factor of trace elements in the mineral fraction of the aggregates corroborated the hypothesis that most part of the accumulated material derived from ice meltwater. Some indicators of the colonization of these deposits by microbial communities were also reported, from the abundance of DNA and phylogenetic markers, to the presence of bacterial taxa commonly able to thrive in similar habitats. All these elements suggested that such kind of deposits may have a potential role as energy and nutrient sources in recently deglaciated areas, highlighting the necessity to better understand the processes underlying their formation and their evolution.

2021 ◽  
Keishi Okazaki ◽  
Katsuyoshi Michibayashi ◽  
Kohei Hatakeyama ◽  
Natsue Abe ◽  
Kevin TM Johnson ◽  

2021 ◽  
Françoise Bodénan ◽  
Yannick Ménard ◽  
Patrick d'Hugues

<p>Whereas there are growing needs for mineral resources (metals for the energy and digital transitions<br>and construction materials), the mining industry must produce them from poorer, more<br>heterogeneous and more complex deposits. Therefore, volumes of mine waste produced (including<br>tailings) are also increasing and add up to waste from mining legacy. For example in Europe (x27): 732<br>Mtons of extractive waste are generated per year and more than 1.2 Btons of legacy waste are stored<br>all over the European territory. The localisation (and potential hazards) are well known and covered<br>by the inventories carried out in EU countries under the Mining Waste Directive.<br>At the same time, Europe is implementing the circular economy approach and put a lot of emphasis<br>on the resource efficiency concept. In this context, reprocessing operation to recover both metals and<br>mineral fraction is studied with the objective of combing waste management (reducing final waste<br>storage and long-term impact) and material production from secondary resources.<br>Numerous industrial experiences of reprocessing of mine waste and tailings exist all over the world to<br>recover metals such as copper, gold or critical raw materials - CRM They concern mainly active mine<br>where both primary and secondary resources are considered in profitable operations; for example in<br>Chile, South Africa, Australia. Mineral fraction recovery is often not considered which still leaves the<br>industry with a high volume of residual minerals to store and manage.<br>In addition, legacy mining waste are potentially available for reprocessing. In this case, numerous<br>mining liabilities issues need to be managed. Some of the European legacy mining waste have residual<br>valuable metals that could be recovered but some of them have very low metal contents. In Europe,<br>classical rehabilitation operations – usually at the charge of member states and local authorities – is<br>the priority and concern the reduction of instabilities and impacts to the environment including heap<br>remodelling, covering and water management with long-term treatment. Completing this risk<br>management approach by a circular economy one is a very active R&D subject in EU27.<br>This presentation will give an overview of EU research projects which tackled the legacy mining waste<br>challenge from inventory to process development. Several process flowsheets to recover metals were<br>designed and tested on several case studies with CRM – REE, Co, W, Sb, etc. Initiatives to reuse mineral<br>fraction are also underway and should be ready for commercialisation in the coming years.<br>Resources efficiency concept and the circular economy implementation starts on mining sites. In order<br>to facilitate the implementation of this approach, the technical solutions will need to be included in<br>innovative global initiatives covering also legal (liability management), environmental (Life Cycle<br>Analysis approaches) and social (acceptance) questions.</p>

2021 ◽  
Jerzy Weber ◽  
Elżbieta Jamroz ◽  
Andrzej Kocowicz ◽  
Magdalena Debicka ◽  
Jakub Bekier ◽  

<p>Methods of isolation of the humin fraction can be divided into two main groups: (1) extraction of humic (HA) and fulvic (FA) acids followed by extraction of humin with different organic solvents, and (2) extraction of HA and FA followed by removal of soil mineral fraction. To isolate the large amounts of humin necessary to study the interactions of this fraction with pesticides, we examined some modifications of the latter method.</p><p>The first step was to separate HA and FA according to a modified IHSS method (Swift 1996). HA and FA were extracted with 0.1 M NaOH with a 5:1 ratio of extractant to soil. 20 hours shaking was found to be more effective, but 4 hours shaking provided the advantage of being able to extract twice a day,  which ultimately shortened the procedure time.</p><p>The HA and FA free residue was then digested to remove mineral components. We used several (up to 8 weeks) digestions with 10% HF/HCl as higher concentrations of HF can result in structural alteration of the organic compounds (Hayes et al. 2017). While HF/HCl treatment can lead to hydrolysis and loss of polysaccharide and protein materials (Stevenson 1994), the advantage of using HF is the removal of paramagnetic compounds (such as Fe), which facilitates the use of spectroscopic techniques to characterize humin. In contrast to the procedures for only increasing the concentration of organic matter (Schmidt et al. 1997), the sample was digested until the mineral fraction not complexed with humin was completely digested. We tested different modes of mineral fraction digestion in 10% HF/HCl using polyethylene centrifuge bottles. Occasional shaking once a day had the same effect as continuous shaking. It takes 6 weeks to digest 200 g of pure sand in a 1000 cm<sup>3</sup> bottle, when the HF/HCL was weekly replaced. After replacing HF/HCl every 2 weeks, the digestion time of the same material increased to 8 weeks.</p><p>After treatment with HF/HCl, the residue was rinsed with 10% HCl to remove secondary minerals. The residue was washed with distilled water until the neutral pH and then dialyzed to a negative Cl<sup>−</sup> test with AgNO<sub>3</sub>. Then the humin fraction was freeze dried. </p><p> </p><p>Literature</p><p>Hayes M.H.B., Mylotte R., Swift R.S. 2017. Humin: Its Composition and Importance in Soil Organic Matter. In: Sparks D.L. (ed) Advances in Agronomy, Vol. 143, Academic Press, Burlington, 47–138.</p><p>Schmidt, M.W.I., Knicker, H., Hatcher, P.G., Kögel-Knabner, I. 1997. Improvement of 13C and 15N CPMAS NMR spectra of bulk soils, particle size fractions and organic material by treatment with 10% hydrofluoric acid. European Journal of Soil Science, 48, 319-328.</p><p>Stevenson F.J. 1994. Humus Chemistry; Genesis, Composition, Reaction. 2nd ed. John Wiley & Sons., New York.</p><p>Swift R.S. 1996. Organic matter characterization. In: Sparks, D.L., et al. (Ed.), Methods of Soil Analysis. Part 3. Chemical Methods - Soil Science Society of America, Book Series no 5,  1011-1069.</p><p> </p><p>Acknowledgements</p><p>This work was supported by the National Science Center (NCN) Poland (project No 2018/31/B/ST10/00677 “Chemical and spectroscopic properties of soil humin fraction in relation to their mutual interaction with pesticides").</p>

2021 ◽  
Karin Kauer ◽  
Sandra Pärnpuu

<p>The aim of this research was to study the effect of different plants on soil organic matter (SOM) composition. The composition of SOM was studied in a field experiment established in 1964 on a carbonaceous glacial till soil with very low initial SOC concentration (1.28 g kg<sup>-1</sup>). The effects on SOM composition of bare fallow, barley, grasses, and clover-grasses mixture, were studied using 13C nuclear magnetic resonance (NMR) spectroscopy which is a common tool to characterize SOM. In 2014 the soil samples were collected from 0-5 cm soil layer, air-dried samples sieved through a 2-mm sieve and pretreated with 10% HF solution before NMR spectroscopy analysis. Samples of bulk soil and density fractionated mineral fraction (John et al., 2005) were analyzed. Also, a sample from barley treatment collected in 1966 was analyzed.</p><p>O/N-alkyl C was the most abundant C type at the start of the experiment and also in all treatments after 50 years. During 50 years the proportions of O/N-alkyl C and alkyl C increased but contributions of carboxyl C and aromatic C decreased. The ratio of alkyl C/O-alkyl C, which describes the degree of soil organic matter decomposition, decreased from 0.47 (in 1966) to 0.40-0.44 in treatments with plants. In bare fallow treatment, the SOM decomposition stage did not change a lot during the time. In soil mineral fraction the differences between treatments appeared more clearly and the degree of decomposition decreased in line: bare fallow>barley>clover-grasses>grasses (0.49>0.40>0.36>0.34) and this was due to higher O/N-alkyl-C content in treatments with plants. The higher O/N-alkyl C contribution in soil heavy fraction can be attributed to microbially synthesized carbohydrates (Yeasmin et al., 2020) and depended on the amount and properties of C input into the soil in different treatments.</p><p>In conclusion, the SOM composition was influenced by plant composition and the effect was more pronounced in soil mineral fraction. The SOM degree of decomposition was higher in treatment with annual crop (barley during 50 years). Under perennial grasses and clover-grasses mixture, the soil organic matter decomposition degree was lower.</p><p>This work was supported by the Estonian Research Council grant PSG147.</p><p>References</p><p>John, B., Yamashita, T., Ludwig, B., & Flessa, H. (2005). Storage of organic carbon in aggregate and density fractions of silty soils under different types of land use. Geoderma, 128(1–2), 63–79. https://doi.org/10.1016/j.geoderma.2004.12.013</p><p>Yeasmin, S., Singh, B., Smernik, R. J., & Johnston, C. T. (2020). Effect of land use on organic matter composition in density fractions of contrasting soils: A comparative study using 13C NMR and DRIFT spectroscopy. Science of the Total Environment, 726, 138395. https://doi.org/10.1016/j.scitotenv.2020.138395</p>

2021 ◽  
Luana Dalacorte ◽  
Edson Campanhola Bortoluzzi

Abstract Aims Silicon (Si) dynamic in system controls mineral evolution. We expected that the Si exported from soil due to soybean cultivation would affect Si forms and clay minerals. The objective of this study was to evaluate Si forms in the soil-plant system in areas with different soybean cultivation times in order to respond how Si exportation affects soil mineralogy. Methods Oxisols under soybean cultivation for 2, 8 and 40 years were evaluated and an adjacent area with native vegetation was used as the control treatment. The total and available Si in the soil and in the roots, aerial part of the plants and in the soybeans were evaluated, as well as the physical, chemical and mineralogical attributes of the soil. Results We estimated that 12 to 15 kg/ha of Si were exported by soybean grains per cultivation. The Si exportation for 40 years decreased the available Si contents in the soil by 9%, compared to the native field. The total Si contents in the clay fraction after 40 years of cultivation were 29% lower when compared to the native field. As a consequence of the soil cultivation for 40 years, we observed a decrease in the clay content and a clay dissolution, changing the clay mineral fraction. Conclusions The Si exportation by soybean grain promotes changes in particle size contents and mineral fraction of cultivated soils. Our results highlighted that Si, should be taken into account in a suitable fertilization process in agricultural lands submitted to intensive use.

Foods ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1646
José M. Roncero ◽  
Manuel Álvarez-Ortí ◽  
Arturo Pardo-Giménez ◽  
Adrián Rabadán ◽  
José E. Pardo

This work presents a bibliographic review about almond kernel non-lipid components, in particular about the protein fraction, the carbohydrates and the mineral fraction. In addition, other fat-soluble phytochemicals which are present in minor concentrations but show important antioxidant activities are reviewed. Almond kernel is a rich protein food (8.4–35.1%), in which the globulin–albumin fraction dominates, followed by glutelins and prolamins. Within the almond kernel protein profile, amandine dominates. Free amino acids represent a small amount of the total nitrogen quantity, highlighting the presence of glutamic acid and aspartic acid, followed by arginine. Carbohydrates that appear in almond kernels (14–28%) are soluble sugars (mainly sucrose), starch and other polysaccharides such as cellulose and non-digestible hemicelluloses. Regarding the mineral elements, potassium is the most common, followed by phosphorus; both macronutrients represent more than 70% of the total mineral fraction, without taking into account nitrogen. Microminerals include sodium, iron, copper, manganese and zinc. Within the phytochemical compounds, tocopherols, squalene, phytosterols, stanols, sphingolipids, phospholipids, chlorophylls, carotenoids, phenols and volatile compounds can be found.

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