Crystallochemical classifications of phyllosilicates based on the unified system of projection of chemical composition: I. The mica group

Clay Minerals ◽  
1990 ◽  
Vol 25 (1) ◽  
pp. 73-81 ◽  
Author(s):  
A. Wiewióra
Keyword(s):  
Chemical Composition ◽  
Divalent Cations ◽  
Layer Charge ◽  
Vector Representation ◽  
Similar Formula ◽  
Crystallochemical Formula ◽  
Trivalent Cations ◽  
Image Position ◽  
Composition I ◽  
Unit Vectors

AbstractA unified system of vector representation of chemical composition is proposed for the phyllosilicates based on projection of the composition, as given by crystallochemical formula, onto a field with orthogonal axes chosen for octahedral divalent cations, R2+, and Si (X, Y, respectively), and oblique axes for octahedral trivalent cations, R3+, and vacancies, □, (V, Z, respectively). Point coordinates for each set of axes were used to define the direction and length of the unit vectors for phyllosilicates belonging to different groups. Parallel to these fundamental directions the composition isolines were drawn in the projection fields. Applied to micas, this system enables control of the chemical composition by the general crystallochemical formula covering all varieties of Li-free dioctahedral and trioctahedral micas:where z (number of vacancies) = (y-x+ m)/2; m (layer charge) =1; u+y+z = 3. There is a similar formula for vacancy-free lithian micas:where w = m — x+y;m=1; u+y+w = 3, and for Li-free brittle micas:where z = (y — x+m)/2; m = 2; u+y+z = 3. Projection fields were used to classify micas.

scholarly journals Influencing Factors of the Mineral Carbonation Process of Iron Ore Mining Waste in Sequestering Atmospheric Carbon Dioxide

2021 ◽  
Vol 13 (4) ◽  
pp. 1866
Author(s):  
Noor Allesya Alis Ramli ◽  
Faradiella Mohd Kusin ◽  
Verma Loretta M. Molahid
Keyword(s):  
Carbon Dioxide ◽  
Particle Size ◽  
Chemical Composition ◽  
Iron Ore ◽  
Divalent Cations ◽  
Mining Industry ◽  
Mining Waste ◽  
Aluminum Silicate ◽  
Mineral Carbonation ◽  
Carbonation Process

Mining waste may contain potential minerals that can act as essential feedstock for long-term carbon sequestration through a mineral carbonation process. This study attempts to identify the mineralogical and chemical composition of iron ore mining waste alongside the effects of particle size, temperature, and pH on carbonation efficiency. The samples were found to be alkaline in nature (pH of 6.9–7.5) and contained small-sized particles of clay and silt, thus indicating their suitability for mineral carbonation reactions. Samples were composed of important silicate minerals needed for the formation of carbonates such as wollastonite, anorthite, diopside, perovskite, johannsenite, and magnesium aluminum silicate, and the Fe-bearing mineral magnetite. The presence of Fe2O3 (39.6–62.9%) and CaO (7.2–15.2%) indicated the potential of the waste to sequester carbon dioxide because these oxides are important divalent cations for mineral carbonation. The use of small-sized mine-waste particles enables the enhancement of carbonation efficiency, i.e., particles of <38 µm showed a greater extent of Fe and Ca carbonation efficiency (between 1.6–6.7%) compared to particles of <63 µm (0.9–5.7%) and 75 µm (0.7–6.0%). Increasing the reaction temperature from 80 °C to 150–200 °C resulted in a higher Fe and Ca carbonation efficiency of some samples between 0.9–5.8% and 0.8–4.0%, respectively. The effect of increasing the pH from 8–12 was notably observed in Fe carbonation efficiency of between 0.7–5.9% (pH 12) compared to 0.6–3.3% (pH 8). Ca carbonation efficiency was moderately observed (0.7–5.5%) as with the increasing pH between 8–10. Therefore, it has been evidenced that mineralogical and chemical composition were of great importance for the mineral carbonation process, and that the effects of particle size, pH, and temperature of iron mining waste were influential in determining carbonation efficiency. Findings would be beneficial for sustaining the mining industry while taking into account the issue of waste production in tackling the global carbon emission concerns.

scholarly journals An elementary renewal theorem for random compact convex sets

1995 ◽  
Vol 27 (4) ◽  
pp. 931-942 ◽  
Author(s):  
Ilya S. Molchanov ◽  
Edward Omey ◽  
Eugene Kozarovitzky
Keyword(s):  
Support Function ◽  
Convex Sets ◽  
Compact Convex ◽  
Renewal Function ◽  
Renewal Theorem ◽  
Closed Sets ◽  
Random Closed Sets ◽  
Minkowski Sums ◽  
Image Position ◽  
Unit Vectors

A set-valued analog of the elementary renewal theorem for Minkowski sums of random closed sets is considered. The corresponding renewal function is defined as where are Minkowski (element-wise) sums of i.i.d. random compact convex sets. In this paper we determine the limit of H(tK)/t as t tends to infinity. For K containing the origin as an interior point, where hK(u) is the support function of K and is the set of all unit vectors u with EhA(u) > 0. Other set-valued generalizations of the renewal function are also suggested.

Significance of compositional zoning in cumulate chromites of the Kabanga chonoliths, Tanzania

2018 ◽  
Vol 82 (3) ◽  
pp. 675-696 ◽  
Author(s):  
David M. Evans
Keyword(s):  
Divalent Cations ◽  
Chrome Spinel ◽  
Compositional Zoning ◽  
Sulfide Deposits ◽  
Nickel Copper ◽  
History Of ◽  
Trivalent Cations ◽  
Indicator Mineral ◽  
Normal Zoning ◽  
North Western

ABSTRACTCompositional zoning is observed rarely in chrome-spinel grains from slowly-cooled layered intrusions because diffusion of cations continues within the spinel to low temperatures. However, in certain circumstances, such gradational zoning of both divalent and trivalent cations is observed and may be useful in deciphering the thermal history of the host intrusions. The accessory chrome-spinels of the Kabanga mafic-ultramafic chonolith intrusions of the Kibaran igneous event in north western Tanzania are notable because they have preserved gradational compositional zoning. This zoning is demonstrated to predate and be independent of later hydrous alteration of the silicate assemblage. At Kabanga, most chrome-spinel grains within olivine-rich cumulate rocks are gradationally and cryptically zoned from Fe2+-Cr3+ rich cores to more Mg2+-Al3+ rich rims (normal zoning). A few grains are zoned from Mg2+-Al3+ rich cores to more Fe2+-Cr3+ rich rims (reverse zoned). The zoning of divalent cations is proportional to that of trivalent cations with Mg2+ following Al3+ and Fe2+ following Cr3+ from core to rim. The zoning of trivalent and tetravalent cations is interpreted to be caused by either new growth from an evolving melt or peritectic reactions between evolved or contaminated melt and adjacent Al-Cr-bearing ferromagnesian minerals, which is preserved by relatively rapid initial cooling in the small chonolith intrusions. Divalent cation zoning is controlled by sub-solidus exchange of Fe2+ and Mg with adjacent ferromagnesian minerals and continues to lower temperatures, indicated to be 580 to 630°C by the spinel-olivine geothermometer. Preservation of such zoning is more likely in the smaller chonolith intrusions that typically host magmatic nickel-copper sulfide deposits and can be used as an exploration indicator when interpreting chromite compositions in regional heavy indicator mineral surveys.

Adsorption of EDCs On Reclaimed Water-Irrigated Soils: A Comparative Analysis of A Branched Nonylphenol, Nonylphenol and Bisphenol A

2020 ◽  
Author(s):  
Shiyu Wang ◽  
Wentao Jiao ◽  
Xiaoou Li ◽  
Cunzhen Liang ◽  
Wenyong Wu
Keyword(s):  
Bisphenol A ◽  
Divalent Cations ◽  
Human Health Risk ◽  
Reclaimed Water ◽  
Van Der Waals Interactions ◽  
Freundlich Model ◽  
Alkyl Chains ◽  
Infrared Spectrometer ◽  
Trivalent Cations ◽  
Irrigated Soils

Abstract Nonylphenol (NP) and bisphenol A (BPA) are two typical endocrine disrupter chemicals (EDCs) in the reclaimed water. The adsorptions of NP, a branched NP (NP7) and BPA on reclaimed water-irrigated soils were studied by isothermal experiments, and the different environmental factors on their adsorptions were investigated. The results showed that the adsorptions of NP and NP7 on soils conformed to Linear model, and the adsorption of BPA conformed to Freundlich model. The adsorptions of NP, NP7 and BPA on soils decreased with the increasing temperatures and pHs, while increased with the cation valence. Adsorption equilibrium constant (Kd or Kf) were maximum at pH=3, temperature 25℃ and As (Ⅲ)-soil, respectively; The adsorption capacity of NP, NP7, and BPA to soils increased in accordance with cation valence: trivalent cations > divalent cations > mono- cations. Kd of NP7 on soil was less than that of NP under the different pH and temperatures; while under different cations concentrations, it was inverse. Fourier Transform Infrared Spectrometer (FTIR) analysis showed alkyl chains of NP and BPA seemed to form van der Waals interactions with the cavity of soil. Results of this study will provide further comprehensive fundamental data for human health risk assessment of nonylphenol in the soil.

Modifying chemical composition of the fine Ni4Nb2O9 powders using chloride melts as reaction medium

2019 ◽  
Vol 9 (4) ◽  
pp. 1300-1305
Author(s):  
V. Khokhlov ◽  
I. Zakir'yanova ◽  
V. Dokutovich ◽  
G. Shekhtman ◽  
B. Antonov ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Reaction Medium ◽  
Chloride Melts ◽  
Image Position

Abstract

Smectite, chlorite and a regular interlayered chlorite-vermiculite in soils developed on a small serpentinite body Massif Central, France

Clay Minerals ◽  
1976 ◽  
Vol 11 (2) ◽  
pp. 121-135 ◽  
Author(s):  
J. Ducloux ◽  
A. Meunier ◽  
B. Velde
Keyword(s):  
Chemical Composition ◽  
Clay Minerals ◽  
Closed System ◽  
Soil Profile ◽  
Crystalline Rocks ◽  
Soil Profiles ◽  
Massif Central ◽  
Three Stages ◽  
Image Position ◽  
Chemical Migration

AbstractThree soil profiles developed on a serpentinite body (La Rochel'Abeille, near Limoges) show three stages of weathering. All soils contain iron-rich smectites and secondary chlorites. The latter are very silica-rich, more so than 14 Å chlorites from crystalline rocks. In the (B)1g horizon of the hydromorphic profile, these minerals seem to give a reaction of the type:This reaction, typical of a closed system, appears to be operative in a soil profile which is certainly, in part, open to chemical migration. The chemistry of the weathered serpentinite and the chemical composition of newly formed minerals as well as those of the serpentinite are used to indicate the chemiographic relations of clay minerals formed in the weathering profiles.

Ion behaviour in plant cell walls. IV. Selective cation binding by Sphagnum russowii cell walls

1990 ◽  
Vol 68 (4) ◽  
pp. 773-781 ◽  
Author(s):  
Conrad Richter ◽  
Jack Dainty
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Divalent Cations ◽  
Selectivity Coefficient ◽  
Weak Acid ◽  
Small Population ◽  
Cation Binding ◽  
Trivalent Cations ◽  
Using Data ◽  
A Site

Selective cation binding by Sphagnum russowii cell walls was investigated using data from bicationic potentiometric titrations of isolated cell walls. Selectivity measurements were interpreted in the context of Manning condensation. In titrations with cations of different valency, selectivity favoured the higher valency cation, as expected in Manning condensation. This selectivity generally increased with bathing pH until the wall-bound polyuronic acids became fully ionized (pH > 5). The selectivity coefficient order at full ionization was Na+–Ca2+ > Na+–La3+ > Ca2+–La3+, as predicted by the weak acid Donnan–Manning (WADM) model. Other phenomena also appear to influence binding selectivity. A small population of isolated binding sites are more effectively neutralized by univalent (or divalent) than divalent (or trivalent) cations. High selectivity for cations of lower valency at low pH also suggests a site isolation effect. In bicationic titrations involving divalent cations only, Sr24+ and Ca2+ were bound by the cell wall with approximately equal effectiveness, as predicted by the WADM model. However, cation or binding site specificities probably account for the favoured binding of Ca2+ over Mg2+ by the cell wall. Key words: ion exchange, cell wall, selectivity.

scholarly journals Evaluation of metal removal performance of rod-type biosorbent prepared from sewage-sludge

2019 ◽  
Vol 25 (5) ◽  
pp. 700-706
Author(s):  
Ji Hae Seo ◽  
Namgyu Kim ◽  
Munsik Park ◽  
Sunkyung Lee ◽  
Seungjae Yeon ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Metal Removal ◽  
Divalent Cations ◽  
Batch Experiments ◽  
Equilibrium Studies ◽  
Adsorption Performance ◽  
Trivalent Cations ◽  
Solid Liquid ◽  
Solid Liquid Separation ◽  
Potential Use

The aim of this work was to evaluate the potential use of recycled sewage-sludge as a biosorbent for removing various metals from aqueous solution. To improve adsorption capacity and accomplish easy solid-liquid separation, the sludge was immobilized into the rod type with Ca-alginate. The removal performance was analyzed through kinetic and equilibrium studies. We conducted batch experiments examining the removal of cationic metals and anionic metals/metalloid by the rod-type biosorbent (cations: Cd(II), Cu(II), Cr(III), Fe(II), Ni(II), Pb(II), Zn(II), Mn(II), Al(III), As(III), and Fe(III); anions: As(V), Cr(VI) and Mn(VII)).The rod-type biosorbent, which was manufactured using sludge and alginate, showed higher adsorption capability for the removal of cationic metal than anionic metal. In evaluations of cation adsorption, divalent cations adsorbed more and faster than trivalent cations. The maximum uptake of Cd(II) was determined to be 67.29 mg/g, which was higher than those of other sludge adsorbents reported in the literature. In evaluations of anions, As(V), Cr(VI) and Mn(VII) were removed by different mechanisms. In this study, we simultaneously evaluated the adsorption performance of a new biosorbent for cationic and anionic metals. Our findings are expected to contribute to the commercialization of sludge-based biosorbents.

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