scholarly journals An Introduction to Montmorillonite Purification

2021 ◽  
Author(s):  
Hakan Ciftci
Keyword(s):  
Particle Size ◽  
Clay Minerals ◽  
Advanced Materials ◽  
Size Difference ◽  
Centrifugal Separation ◽  
Purification Process ◽  
Chemical Purification ◽  
Material Quality ◽  
Food Industries ◽  
Physical And Chemical

Purification of montmorillonite is a process to remove non clay minerals (gangue) such as calcite, feldspar, quartz, opal (C-T), and mica from montmorillonite ore. This is performed to make montmorillonite suitable for use in sensitive applications such as pharmaceutical, cosmetic, food, and advanced materials for nanotechnology. Gangue minerals in raw montmorillonite ores can cause serious health problems when used in pharmaceutics, cosmetic, and food industries and reduce material quality in advanced materials production. Montmorillonite purification can be divided into two main classes as physical and chemical purification. Physical purification processes are based on particle size difference between the gangue and montmorillonite minerals. Purification processes based on gravity separation are ineffective since the specific weights of gangue and montmorillonite minerals are very close to each other. Physical purification process includes sedimentation, centrifugal separation, aero separation, and sieving techniques. Chemical purification of montmorillonite is based on dissolution and so extraction of carbonates, metal hydroxides, organic materials, and silica, respectively, using different leaching techniques.

Particle Size Effects on Concentration of Metals in Lake Erie Bottom Sediments

1984 ◽  
Vol 19 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Alena Mudroch
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Clay Minerals ◽  
Surface Sediment ◽  
Size Effects ◽  
Lake Erie ◽  
Size Fraction ◽  
Mineralogical Composition ◽  
Major Elements ◽  
Sediment Samples

Abstract Surface sediment samples obtained at the offshore and nearshore area of Lake Erie were separated into eight different size fractions ranging from <2 µm to 250 µm. The concentration of major elements (Si, Al, Ca, Mg, K, Na, Fe, Mn and P), metals (Zn, Cu, Cr, Ni, V, Co and Pb) and organic matter was determined together with the mineralogical composition and morphology of the particles in each size fraction. The distribution of the metals in the offshore sediment was bimodal with the majority of the metals divided between the 63 to 250 um size fraction which also contained the highest concentration of organic matter (about 20%) and the <4 µm fraction containing up to 60% of clay minerals. However, the metals in the nearshore sediment were associated mainly with the clay minerals.

scholarly journals Investigation of Microbial Contamination and Physicochemical Properties of Compounded Medications in Pharmacies

2020 ◽  
Vol 26 (1) ◽  
pp. 82-93
Author(s):  
Reihaneh Radmanesh ◽  
◽  
Mohsen Nabi Meybodi ◽  
Vahid Ramezani ◽  
Maryam Akrami ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Microbial Contamination ◽  
Raw Materials ◽  
Chemical Properties ◽  
Pharmaceutical Product ◽  
Physical And Chemical ◽  
Made In ◽  
And Chemical Properties

Aims: Any pharmaceutical product made in pharmacy, hospital or factory may be contaminated with microbes. This contamination can originate from raw materials or during production. Hence, it is important to study the physical and chemical properties and stability of compounded drugs. Methods & Materials: In this study, first a specific sample of prescribed medication was ordered from 63 pharmacies in Yazd, Iran. After collecting the samples, the amount of microbial contamination, viscosity and particle size distribution and their stability were investigated and their results were compared to the standard levels. Findings: Based on the results, 31.7% of the samples had discoloration and 23.8% showed creaming phenomenon. In terms of particle size distribution, 57.1% of the samples had a 20-40 μm particle size and 49.2% had a viscosity equal to 2500-3000 centipoise. Regarding stability, 12.6% of the samples underwnet phase change at 30-40°C. About of the amount of hydroquinone in samples, 35% had acceptable amount. In 23.8% of the samples, fungal infection was observed. Conclusion: Contrary to a popular belief that the compounded medicines produced in pharmacies have microbial contamination, the results of this study showed that the microbial contamination of these compounded medications is low.

scholarly journals Determination of amorphous matter in industrial minerals with X-ray diffraction using Rietveld refinement.

2020 ◽  
Vol 56 (1) ◽  
pp. 1
Author(s):  
George Christidis ◽  
Katerina Paipoutlidi ◽  
Ioannis Marantos ◽  
Vasileios Perdikatsis
Keyword(s):  
Particle Size ◽  
Rietveld Refinement ◽  
Raw Materials ◽  
Internal Standard ◽  
Absolute Error ◽  
Matter Content ◽  
Size Difference ◽  
X Ray Diffraction ◽  
X Ray ◽  
Amorphous Matter

A great variety of fine grained industrial rocks, which are valued by the industry contain variable amounts of amorphous or poorly crystalline matter, which is not easily detectable by the conventional mineralogical analysis methods based on X-ray diffraction (XRD). The quantification of amorphous matter in industrial rocks is a major task because it provides a thorough characterization of the raw materials and assists to interpret their reactivity. Among the most reliable methods used for quantification of amorphous matter, are those which are based on Rietveld refinement. In this study we prepared 1:1 mixtures of synthetic or natural calcite and quartz with 5-80% glass flour and added corundum (α-Al2O3) internal standard and applied the Autoquan2.80 © software based on the BGMN computer code to quantify the amorphous matter content. The mixtures with synthetic minerals yielded results with minimum absolute error due to the similar particle size of the minerals, the internal standard and the glass. By contrast, the mixtures with natural minerals displayed greater relative error due to the particle size difference between the minerals on the one hand and the internal standard and the glass on the other, due to the microabsorption effect. Moreover, preferred orientation was important in the case of natural calcite, due to perfect  cleavage plane. Mixtures containing up to 25% amorphous matter did not display the characteristic hump at 20-30 °2θ, suggesting that the lack of the hump is not a safe criterion for the recognition of amorphous matter.

scholarly journals The hidden ecological resource of andic soils in mountain ecosystems: evidences from Italy

2017 ◽  
Author(s):  
Fabio Terribile ◽  
Michela Iamarino ◽  
Giuliano Langella ◽  
Piero Manna ◽  
Florindo Antonio Mileti ◽  
...  
Keyword(s):  
Clay Minerals ◽  
Chemical Properties ◽  
Organic C ◽  
Mountain Ecosystems ◽  
C Storage ◽  
Mountain Landscapes ◽  
Ecological Importance ◽  
Mineral Soils ◽  
Physical And Chemical ◽  
And Chemical Properties

Abstract. Andic soils have unique morphological, physical and chemical properties that induce both considerable soil fertility and great vulnerability to land degradation. Moreover they are the most striking mineral soils in terms of large organic C storage and long C residence time; this is especially related to the presence of poorly crystalline clay minerals and metal-humus complexes. Recognition of these soils is then very important. Here we attempt to show, through the combined analysis of 35 sampling points chosen, throughout the Italian non volcanic mountain landscapes, in accordance to specific physical and vegetation rules, that soils rich in poorly crystalline clay minerals have an utmost ecological importance. More specifically, in various non-volcanic mountain ecosystems (> 700 m) and in low slope gradient locations (

Physical and chemical characteristics of cryoconites, sampled from glaciers of the Central Caucasus (Russia).

2021 ◽  
Author(s):  
Ivan Kushnov ◽  
Evgeny Abakumov ◽  
Rustam Tembotov ◽  
Viacheslav Polyakov
Keyword(s):  
Particle Size ◽  
Organic Carbon ◽  
Particle Size Distribution ◽  
Solid Phase ◽  
Basal Respiration ◽  
Chemical Characteristics ◽  
Significant Similarity ◽  
Physical And Chemical Characteristics ◽  
Central Caucasus ◽  
Physical And Chemical

<p>Cryoconites are a dark-colored granular sediments found in glacial landscapes. Cryoconites are known as a dark colored accumulation of various origin material in superficial holed of the glaciers which formed in polar and mountain regions of the Earth. They can significantly accelerate glacier retreating by reducing the albedo of the glacier and play a significant role in the colonization of the territory after its retreat, being an "oasis" for development of microorganisms on an uninhabited glacier surface. The understanding of key cryoconites properties is necessary to understand their impact on the mountain glaciers of the Central Caucasus, especially taking into account their recent rapid retreat.</p><p>The aim of this research is to study the physical and chemical characteristics of various cryoconites and cryoconite derived periglacial soils of the Central Caucasus. Eight cryoconite samples and eight soil samples from three soil sections were selected. The following characteristics of the samples were determined in laboratory conditions: total organic carbon (TOC), basal respiration level, pH H<sub>2</sub>O and exchangeable soil acidity, solid phase density and particle size distribution.</p><p>The results of the analyses showed both differences and some similarities in the physical and chemical characteristics of the cryoconites and soils of periglacial zone which were studied. Cryoconites, on average, are characterized by lower values of basal respiration than more developed soils from this region. The total organic carbon content in most samples was relatively low, but its values increase significantly soils investigated due to accumulation of carbon in fine earth under the influence of primary vegetation. The water extractable acidity values showed a significant similarity between the studied cryoconites and soils, they vary from slightly acidic to slightly alkaline in both groups. At the same time, the variation of exchangeable acidity values between cryoconite samples is significantly greater than in developed soils. Moreover, the density of the solid phase of the studied cryoconites varies in a larger range of values than that of the studied soils due to variety of sources of cryoconite materials. However, the analysis of particle size distribution showed a significant similarity of the studied objects: in almost all samples there is a significant dominance of the sand fraction (d=1-0.05 mm). The obtained data indicate both the difference in the physical and chemical properties of the studied cryoconites among themselves, and the probable influence of cryoconites on soil formation in this region.</p><p>This work was supported by Russian Foundation for Basic Research, project No <strong>19-05-50107</strong>  “The role of microparticles of organic carbon in degradation of ice cover of polar regions of the Earths and in the process of soil-like bodies formation”.</p>

scholarly journals The Effect of Weathering on Salt Release from Coal Mine Spoils

Minerals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 760
Author(s):  
Melinda Hilton ◽  
Mandana Shaygan ◽  
Neil McIntyre ◽  
Thomas Baumgartl ◽  
Mansour Edraki
Keyword(s):  
Particle Size ◽  
Coal Mine ◽  
Chemical Weathering ◽  
Physical Weathering ◽  
Particle Size Fractions ◽  
Mine Spoils ◽  
Weathering Processes ◽  
Three Samples ◽  
Two Samples ◽  
Physical And Chemical

Coal mine spoils have the potential to create environmental impacts, such as salt load to surrounding environments, particularly when exposed to weathering processes. This study was conducted to understand the effect of physical and chemical weathering on the magnitude, rate, and dynamics of salt release from different coal mine spoils. Five spoil samples from three mines in Queensland were sieved to three different particle size fractions (<2 mm, 2–6 mm, and >6 mm). Two samples were dispersive spoils, and three samples were nondispersive spoils. The spoils were subjected to seven wet–dry cycles, where the samples were periodically leached with deionised water. The rate, magnitude, and dynamics of solutes released from spoils were spoil specific. One set of spoils did not show any evidence of weathering, but initially had higher accumulation of salts. In contrast, broad oxidative weathering occurred in another set of spoils; this led to acid generation and resulted in physical weathering, promoting adsorption–desorption and dissolution and, thus, a greater release of salts. This study indicated that the rate and magnitude of salt release decreased with increasing particle size. Nevertheless, when the spoil is dispersive, the degree of weathering manages salt release irrespective of initial particle size. This study revealed that the long-term salt release from spoils is not only governed by geochemistry, weathering degree, and particle size but also controlled by the water/rock ratio and hydrological conditions of spoils.

Parametric Analyses of the TROI Experimental Results by Using the TEXAS-V Code

2008 ◽  
Vol 273-276 ◽  
pp. 474-478
Author(s):  
I.K. Park ◽  
J.H. Kim ◽  
B.T. Min ◽  
S.H. Hong ◽  
H.D. Kim ◽  
...  
Keyword(s):  
Particle Size ◽  
Void Fraction ◽  
Steam Explosion ◽  
Experimental Information ◽  
Water Area ◽  
Experimental Results ◽  
Size Difference ◽  
Depth Effect ◽  
Area Effect ◽  
Melt Composition

The TEXAS-V code was tuned for TROI-13 and used for analyzing the parametric findings of the TROI experiments. The calculations for the melt composition are relatively similar to the TROI experimental results, in which the melt composition has quite an effect on the steam explosion occurrence probabilities and a steam explosion itself. The void fraction difference due to a particle size difference appears to cause this composition dependency of a steam explosion. The water depth effect in the TEXAS-V code seems to be consistent with the TROI experiments to some degree. The water area effect of the TEXAS-V calculations isn’t exactly harmonious with that of the TROI experiments. This indicates that TEXAS-V code as a 1-dimensional code or as a numerical steam explosion has a limitation in estimating an area effect. The experimental information on the particle size and the void fraction during mixing is very helpful for a verification of this relation.

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