Mineral Suspensions Research Articles

Effects of mineral fertilizer applications and suspension in cotton on cotton yield and field technological quality indicators

Effects of mineral fertilizer applications and suspension in cotton on cotton yield and field technological quality indicators

A new statistically-based methodology for variability assessment of rheological parameters in mineral processing

If variability of input data for rheological measurements is not adequately included, their associated uncertainty and subsequent modelling can be underrated. Mineral pulp rheology determination is commonly done through triplicate tests, with such variability reported as multiples of a standard deviation, with the potential for underestimation. In the present work, a novel statistically-based methodology for the estimation of uncertainty in the rheological characterization of mineral suspensions —and other parametric models— is proposed. From the variability of the experimental measurements and the analytical propagation of errors, a set of rheological profiles are generated using Monte Carlo simulations within a variability frame. The corresponding inverse problem for curve-fitting is solved individually, resulting in distributions of fitted parameters, which were statistically-analyzed to obtain representative values for both the parameter and its true variability. The methodology proposed herein has been used to explore the applicability and limitations of the Herschel-Bulkley and Bingham models under specific experimental and data analysis protocols, where the relevance of including low-shear-rate measurement points or yield stress measurements using alternative methods is exposed. Additionally, we present a case study on the effect of the concentration of NaCl on the rheological response of synthetic tailings consisting of quartz suspensions doped with kaolinite, bentonite and kaolinite-bentonite blends, using the proposed methodology with a concentric cylinder rheometer. Results show predominantly decreasing trends in yield stress as salt concentration increases, with non-monotonical behavior and strongest variability associated to the quartz-bentonite blend.

Synergistic impacts of sediment generation and hydrotechnical structures related to forestry on stream fish communities

The increase in anthropogenic sediment has become the most significant factor responsible for degrading flowing waters, preventing them from attaining the good ecological state of rivers requested by Water Framework Directive. After agriculture and mining, forest exploitation is a major source of mineral suspension. The accumulation of fine sediments may reduce fish spawning effectiveness, inhibit migration, and interfere with feeding. Streams degraded by the influx of anthropogenic sediments may be recolonised provided that ecological continuity of the dendritic river network is maintained. The present study focused on mountain stream fish communities whose catchments have undergone natural and intensified soil erosion. We tested the hypothesis that forestry practices transforming the stream habitats combined with the discontinuities created by hydrotechnical structures have had negative impacts on the entire catchment and adversely altered fish communities. The research was carried out in two catchments: i) in the national park, and ii) outside the national park, in an area with forest exploitation. It was observed that the negative effects of the dramatic increases in mineral suspension loads were synergistically aggravated by the presence of objects disturbing fluvial system continuity. The consequences of the synergy between these two factors were evident in local brown trout populations. Sites formerly inhabited by brown trout lacked downstream barriers during our study. After eliminating this parameter, our analysis revealed that channel silting also reduced brown trout abundance downstream from the barrier. The weir in the Muczny Stream inhibited ichthyofaunal re-establishment in streams prone to enhanced mineral suspension input. Forest mountain streams must be preserved also as cold water refugia, hence our results are of significance for forest management. Based on our results, the complete removal of the barrier in Muczny Stream is planned for 2020, and a substantial reduction in the inflow of mineral suspension to stream channels is strongly recommended.

Hydrochemical interfaces and spatial assessment of Usuma River water quality in North-Central Nigeria

Surface water contagion resulting from anthropogenic deeds and bad effluent management due to swift urbanization has cause a dramatic deterioration in river water quality and has threatened the aquatic ecosystem health of Nigeria. Thus, treated and untreated river water usage for domestic purposes is uncertain and, accordingly, requires scientific investigation. Research on the quality of surface water resources and hydrochemical interfaces is vital for monitoring and for determining water contaminant sources. Therefore, river samplings were obtained from 5 sampling points, for a total of 25 water samplings from the Usuma River in Abuja, Nigeria, and these samples were examined for physicochemical parameters by means of standard techniques. Additionally, the results acquired were subjected to hydrochemical scrutinizes and the examined water quality variables demonstrated wide discrepancies from one sampling station to another. The result also showed that Conductivity had the highest mean (50.68mg/l), followed by TDS (37.32mg/l) whereas Nitrite had the lowest mean (0.09mg/l). Similarly, Chloride had the highest Standard deviation (12.77mg/l).This was followed by Conductivity (11.82mg/l) while Nitrite had the lowest value of 0.01mg/l. Furthermore, most parameter (Temp, Turbidity, DO, COD, BOD and Total coliform) for every water samples examined surpassed the maximum permissible criterions of the WHO specifications for drinking water quality. The highest point of substantial correlation was found between chloride and DO (r = 0.92, α = 0.05). Four principal components were obtained that accounted for 23.87% drop in dimensionality that defined 76.13% of the total variance signifying the impact of mineral suspension and human-related actions on the hydrochemistry of the region. Two hydrochemical clusters were recognized with noticeably apportioned water quality. Advance analysis divulged that 43.7, 20.2 and 37.1% of the samples were of the (S04-Cl-Ca, S04 - Cl- CO3HC03-Ca-Mg and Mg - Ca) types, respectively. Multiple pollution effects, anthropogenic activities, the changing ecosystem, and innate features of aquatic ecosystems produce multifaceted data that pose a threat to river water quality in the study locality and this requires serious attention. There is also a need for the schedule monitoring of the Usuma River in Abuja and buffer regions at the riparian zone to enervate the deleterious effects of catchment urbanization.

Connecting particle interactions to agglomerate morphology and rheology of boehmite nanocrystal suspensions

HypothesisThe rheology of complex suspensions, such as nuclear waste slurries at the Hanford and Savannah River sites, imposes significant challenges on industrial-scale processing. Investigating the rheology and connecting it to the agglomerate morphology and underlying particle interactions in slurries will provide important fundamental knowledge, as well as prescriptive data for practical applications. Here, we use suspensions of nano-scale aluminum oxyhydroxide minerals in the form of boehmite as an analog of the radioactive waste slurry to investigate the correlation between particle interactions, agglomerate morphology, and slurry rheology. ExperimentsA combination of Couette rheometry and small-angle scattering techniques (independently and simultaneously) were used to understand how agglomerate structure of slurry changes under flow and how these structural changes manifest themselves in the bulk rheology of the suspensions. FindingsOur experiments show that the boehmite slurries are thixotropic, with the rheology and structure of the suspensions changing with increasing exposure to flow. In the slurries, particle agglomerates begin as loose, system-spanning clusters, but exposure to moderate shear rates causes the agglomerates to irreversibly consolidate into denser clusters of finite size. The structural changes directly influence the rheological properties of the slurries such as viscosity and viscoelasticity. Our study shows that solution pH affects the amount of structural rearrangement and the kinetics of the rearrangement process, with an increase in pH leading to faster and more dramatic changes in bulk rheology, which can be understood via correlations between particle interactions and the strength of particle network. Nearly identical structural changes were also observed in Poiseuille flow geometries, implying that the observed changes are relevant in pipe flow as well.

Phototransformation of perfluorooctane sulfonamide on natural clay minerals: A likely source of short chain perfluorocarboxylic acids

In this study, a new phototransformation pathway for perfluorooctane sulfonamide (FOSA) and underlying degradation mechanisms are described. Phototransformation of FOSA in a natural clay mineral (montmorillonite) suspension was compared to that in an aqueous solution. Results showed that the presence of montmorillonite can significantly promote the transformation of FOSA to perfluocarboxylic acids (increasing rate). The phototransformation reaction was found to be initiated by the activation of adsorbed oxygen molecules on the surface of montmorillonite, which generate superoxide anion and hydroxyl radicals. Hydroxyl radicals can then attack FOSA adsorbed onto the surface of montmorillonite, promoting the transformation process. In this reaction, clay minerals played a dual role: providing hydroxyl radicals and concentrating FOSA on their surfaces. This helped to promote the contact and reaction between FOSA and hydroxyl radicals. This study provides the first evidence that heterogeneous oxidation of FOSA at the surface of natural clay minerals may act as an important source of perfluocarboxylic acids (PFCAs), especially short chain PFCAs (i.e. trifluoroacetic acid, TFA).

Hydro-geochemical features and groundwater attribute evaluation in North - central Abuja, Nigeria

ABSTRACT Groundwater contamination ensuing from poor effluent management and anthropogenic effects is rising in Nigeria. Thus, groundwater utilized for drinking and domestic purposes is hesitant and so demands scientific analysis. Scrutiny of hydrochemical interfaces and attribute of groundwater resource is needed so as to ascertain and monitor sources of water contaminants. Due to this, groundwater samplings were obtained from 25 sites in Abuja North, Nigeria then examined for physicochemical parameters by means of standard techniques. Results acquired were compared with WHO standards as well as subjected to geospatial and hydrochemical analyses. Five principal components which described 82.4% of the disparity in water attribute, were extricated with the PC1 (30.5%) and PC2 (19.67%) representing the anthropogenic effects, influence of mineral suspension, and contamination chemical fertilizers correspondingly, on the hydrochemistry of the region. The extreme level of significant correlation was found to subsist between EC and K+ (r = 0.770, α = 0.05). Groundwater in Abuja displayed a high level of spatial discrepancy and majority of the ions, such as Na+, TDS, SO42−, and Alk, recorded the highest values close to the municipal center. To strengthen the clarification of these geospatial plots, Hierarchical cluster scrutiny was utilized and produced four (4) hydrochemical clusters of the study region Clusters 3 and 4 showed the worst violations of water attribute criteria with percentage violation of 50 and 40% correspondingly. The increasing order of water attribute was Cluster 1 > Cluster 2 > Cluster 4 > Cluster 3. The Schoeller diagram shows the comparative propensity of ions in mg/L which indications Mg > Na > Ca and SO4 > Cl > HCO3. Further analysis revealed that water in the box 1 as carbonated group which symbolizes a water rich in Ca-HCO3, thus revitalizing. At large, the groundwater of the Abuja locality was contaminated by agricultural deeds, ion exchange, and human-induced actions.

Characterization of the shear behavior of mineral suspensions at controlled negative pressure conditions

For concrete and other cement-based materials, cement hydration induces Le Chatelier contraction. This phenomenon creates negative pore water pressure, which increases the bulk and interfacial granular stresses and affects both the interfacial and bulk rheological behavior of the dense mineral suspension.An original device was developed to assess this effect by simulating water suction in the cement-based materials undergoing hydration. An inert material with the same size range as cement was used to mimic the suction effects arising from water consumption, without the physical bonding effects due to cement hydration. Consequently, the effects of water pressure on friction and yield stress were measured on different mix-designs. The main results are an increase of the yield stress with negative water pressure and a decrease of this yield stress with the increase of air content.

Sharp changes in properties of aqueous sodium chloride solution at “critical” concentrations of the salt

It was shown that some physicochemical properties of aqueous solutions of sodium chloride (contact angle, surface tension, pH, and others) demonstrate a nonlinear dependence on the salt concentration. The maxima or minima in the graphs are most frequently observed near the concentrations of NaCl we call "critical": 3, 5, 7, 12, 17, and 21 g/L. Similar nonlinear peak-shape dependence of the property on salinity was observed in more complex systems containing NaCl (sedimentation rate of mineral suspensions, viscosity of clay pastes, rate of a redox reaction of periodate with amine). We hypothesized that the said critical points of salt concentration may exist when the clusters of water molecules rearrange themselves upon the addition of a definite quantity of salt. The obtained results were used in the discussion of avalanche sedimentation of suspended particulate matter and colloids transported by rivers through the river mixing zones (estuary, delta) and the critical salinity under which the river biota gives place to marine biota.

Determination of characteristic properties of mineral suspension for calculating the particle velocity

Calculations of hydraulic devices for separating mineral suspensions and extracting valuable components and waste are based on determining the speed of constrained deposition and surfacing of particles. When determining the speed, it is necessary to know such characteristics of the suspension as viscosity, porosity, density. The article offers a method for analytical calculation of these indicators. Its peculiarity is that the definition of these characteristics is associated with only one parameter – the volume density of the medium (substance). It is easily determined in practice by weighing a sample of suspension in a container of a known volume. This method is illustrated by the characteristics of two water-based mineral suspensions: with a solid particle density of 2.55 g / cm3 (ash and slag waste from a thermal power plant) and a density of 2.0 g/cm3 (crushed tuff). For these suspensions, the approximate dependences of these characteristics on the density of the medium (substance) are established. It is established that the application of the most common suspension model in the form of a discrete cellular structure provides acceptable limitations of the studied characteristics. The obtained values are within the scope of typical indicators of mineral pulps in the working zone of hydro-classifiers and hydro-separators. However, a number of well-known formulas for the speed of restricted movement that use this model are unacceptable for calculating hydraulic devices since they take into account inflated values of characteristics. The described method can be used for dispersed systems of two or more phases, for example, using weighted average values of components. The proposed method for calculating the characteristics of suspensions is suitable for practical use, given that the hydraulic apparatus receives already classified raw materials and the particles have a small variation in shape and size. The obtained analytical dependences of suspension characteristics on density are used for calculating speed of both constrained and free movement of particles, which is the basis for determining technological and design parameters in the design of hydraulic devices and apparatuses.

EFFECT OF ORGANIC AND FINE DISPERSER ADDITIONS ON RHEOLOGICAL PROPERTIES OF MINERAL SUSPENSIONS

In this study, the effect of mineral and organic additives on the properties of mineral suspensions was studied. Disperse mineral additives are used in cement systems to increase the amount of rheological matrix and ensure high fluidity. Due to the high dispersion of mineral additives, high-efficiency plasticizers were used to regulate the rheotechnological properties of cement-based mixtures. The effect of sulfonaphthalene-formaldehyde oligomer and polycarboxylate-based hyperplasticizers on the rheological properties of cement systems as a plasticizer was evaluated according to the methodology proposed by prof. V.I.Kalashnikov. Based on the results obtained, it was determined that limestone powder is more effective than other stone powders. As a result of the research, the optimal amounts of mineral additives and plasticizers were determined and the possibility of obtaining efficient, high-strength cement stone on their basis confirmed.

Abiotic Degradation of Chlorinated Solvents by Clay Minerals and Fe(II): Evidence for Reactive Mineral Intermediates.

For decades, there has been evidence that Fe-containing minerals might contribute to abiotic degradation of chlorinated ethene (CE) plumes. Here, we evaluated whetherFe(II) in clay minerals reduces tetrachloroethene (PCE) and trichloroethene (TCE). We found that structural Fe(II) in both low (SWy-2) and high (NAu-1) Fe clay minerals did not reduce PCE or TCE under anoxic conditions. There was also no reduction of PCE or TCE after adding 5 mM dissolved Fe(II) to the clay mineral suspensions. In the presence of high Fe(II) concentrations (20 mM), however, PCE and TCE reduction products were observed in the presence of low Fe-content clay mineral SWy-2. Mössbauer spectroscopy results indicate that a mixed-valent Fe(II)-Fe(III) precipitate formed in the reactive SWy-2 suspensions. In contrast, in suspensions containing 20 mM Fe(II) alone or Fe-free clay mineral (Syn-1), we observed a purely Fe(II)-containing precipitate (Fe(OH)2) and also PCE and TCE reduction products. Interestingly, the amount of CE products decreased in the order of Fe-free clay mineral Syn-1 > Fe(OH)2 > low Fe-content clay mineral SWy-2, suggesting that clay mineral Fe controlled the formation of the reactive mineral phase. Additional experiments with hexachloroethane (HCA) revealed that faster HCA reduction occurred withdecreasing clay mineral Fe content. Kinetic modeling yielded invariable second-order rate constants and increasing concentrations of reactive Fe(II) as the Fe(II)/Fe(total) content of the precipitates increased. Our data suggest that clay mineral Fe(III) is a sink for electrons from added Fe(II) that otherwise might have reduced the CEs. Furthermore, our findings are consistent with the hypothesis that active precipitation of Fe(II)-containing reactive mineral intermediates (RMI) may be important to CE reduction and suggest that RMI formation depends on clay mineral presence and Fe content.

Evaluation of wettability of mineral particles via cavitation thresholds

An acoustic method was proposed to evaluate the wettability of mineral particles. A high-intensity focused ultrasound (HIFU) device was set up to measure the cavitation thresholds of mineral particles of different wettability and under different conditions. The hydrophobicity and surface topography of different minerals were compared by contact angle tests and scanning electron microscope (SEM) images, respectively. The nuclei (unwetted part) on the particle surface were induced for cavitation by HIFU. Cavitation behaviors were detected by the echo waves reflected by cavitation bubbles. Results indicate that the cavitation threshold of unwetted particles is larger than that of the wetted particles. The difference in cavitation threshold is owning to the number and size of nuclei in mineral suspension. Furthermore, the heterogeneity of the wettability of minerals can be obtained from the cavitation probability curve, which is a unique advantage for this acoustic method compared with other methods.

Mineral-impregnated carbon fiber composites as novel reinforcement for concrete construction: Material and automation perspectives

Mineral-impregnated carbon fiber composites (MCF) constitute a new type of reinforcement for construction. While inheriting the advantages of existing carbon fiber reinforcements, which are composite materials made of carbon filaments embedded in a thermoplastic or thermosetting matrix, MCF surpass the limitations of such polymer-impregnated types. More particularly, mineral impregnation considerably improves the performance of the reinforcement at elevated temperatures, enhances its bond to the concrete matrix, and increases technological flexibility, especially with respect to emerging automated production approaches. The article at hand presents the technology for continuous impregnation of carbon yarns with appropriately chosen fine mineral binder suspensions. Several examples for the automated manufacturing of reinforcement systems made of this new composite material are provided: one-dimensional elements such as bars and strips, two-dimensional reinforcements in the form of mats, and three-dimensional cases as examples of reinforcements for a balcony and shell elements. Furthermore, an outlook on introducing the novel reinforcement into highly automated, additive construction technologies is given.

Dynamics of dissolved inorganic carbon in the Yenisey gulf during open water period

On the materials of several SIO RAS cruises and archival hydrological and hydrochemical data, the dynamics of dissolved inorganic carbon in the Yenisey Gulf was investigated. There are 3 main areas, where mass sedimentation of suspended matter and oxidation of organic matter (OM) in the upper sediment layer takes place. The first region of oxidation of OM was south of 72 N, its existence is associated with mass sedimentation of dissolved and suspended matter on the geochemical barrier. Two other areas of decomposition of the OM (elevated dCtot) are located downstream (between 73 and 74 and north of 75 N) and most likely originated at the orographic barrier, where the change in the dynamic characteristics of the riverine flow and the topography of the bay bottom creates conditions for sedimentation. Comparison of the difference in the observed Ctot value with the AOU value showed that in 1993, the change in the Ctot content was provided by the oxidation processes of OM. In 2011, carbon emission into water was most likely associated with the transformation of mineral suspension and/or carbon exchange in bottom water with bottom sediments. In 2016, a decrease in the Ctot content was observed almost everywhere in bottom layer. It is most realistic to assume that such a distribution is associated with carbon sorption on suspensions. Despite the many similar features of the distribution of hydrochemical characteristics in the bay, the change in the content of dissolved inorganic carbon in the investigated area has differed greatly in different years. In our opinion, the reason for the fact is the variability of the discharge of the Yenisey River in different years.

Aridisols in the Southern Permian Basin of Lithuania: a key to understanding clay cement distribution

The change from fossil to geothermal energy supply includes the necessity to re-evaluate gas reservoirs in the Southern Permian Basin of NW Europe, as higher permeability reservoirs are needed for the exploitation of geothermal energy than natural gas. A key reservoir risk in Permian sandstones in the Southern Permian Basin is the presence of clay cement. The distribution of the clay cement is not properly understood. The negative effect can be attributed to complex grain coatings formed by tangential clay directly around the detrital grains followed by authigenic clay rim cement, both being genetically related. This study presents new results on the origin of the tangential and the authigenic clay. The Southern Permian Basin in Lithuania was a marginal area of the basin with low accommodation rates and extensive aridisol development. Here, sandstones of the Perloja Formation contain abundant clayey matrix in the form of grain and void coatings. The limited burial depth of a few hundreds of metres ensured that the original internal fabric and mineralogy of the clay coatings remained well preserved. Thin section microscopy revealed that the clay coatings are cutans that formed by post-depositional mechanical infiltration (illuviation) of suspensions of clay minerals, iron hydroxides and some clay to silt-sized quartz. Other pedogenic features are the development of nodular calcrete, rootlets, and of infiltrated clay. Aridisols were recurrently eroded by fluvial or aeolian activity causing wide-scale dispersion of siliciclastic grains with more or less complete clay cutans and also carbonate (calcrete) clasts in certain stratigraphic intervals.

Полимеры на основе акрилата натрия в качестве разжижителей минеральных сус-пензий

Полимеры на основе акрилата натрия в качестве разжижителей минеральных сус-пензий

Dynamics of Dissolved Inorganic Carbon in the Yenisei Gulf during the Open Water Period

Based on the materials of several voyages of the Institute of Oceanology, Russian Academy of Sciences, and archival hydrological and hydrochemical data, the dynamics of dissolved inorganic carbon in the Yenisei Gulf was investigated. There are three main areas with extensive sedimentation of suspended material and oxidation of organic matter (OM) in the upper layer of sediments. The first region of OM oxidation was to the south from 72° N; its existence associated with extensive sedimentation of dissolved and suspended matter at the geochemical barrier. Two other areas of OM decomposition were located downstream (between 73° and 74° and to the north from 75° N) and most likely originated at the orographic barrier, where the change in the dynamic characteristics of the riverine flow and the topography of the bay bottom stimulated precipitation of suspension carried by water. Comparison of the difference in the observed Ctot with the AOU value showed that in 1993, oxidation of OM resulted in a change in Ctot. In 2011, carbon emission into water was most likely controlled by the transformation of mineral suspension and/or carbon exchange between bottom water and bottom sediments. In 2016, a decrease in the Ctot content was registered in deep water over the most part of the section. Despite many similar features in the distribution of hydrochemical characteristics in the bay, the change in the content of dissolved inorganic carbon over the section was significant in different years.

Comparative Studies of Quaternary Ammonium Salts on the Aggregation and Dispersion Behavior of Kaolinite and Quartz

Fine particles in the presence of flotation reagents exhibit different dispersion and aggregation behaviors in a mineral suspension, and affect the flotation separation processes. In this study, the effects of three quaternary ammonium salts (i.e., dodecyltrimethylammonium chloride (DTAC), tetradecyltrimethylammonium chloride (TTAC), and hexadecyltrimethylammonium chloride (CTAC)) on the dispersion and aggregation behaviors of kaolinite and quartz were studied. The mechanism was systematically investigated using sedimentation tests, reagent adsorption analysis, zeta potential measurements, and SEM analysis. In the absence of reagents, the kaolinite and quartz particles exhibited good aggregation behaviors at acid and neutral pHs compared with alkaline conditions. Except for CTAC, the presence of DTAC and TTAC improved the aggregation behavior of both minerals in neutral and alkaline conditions. More, the sedimentation yields of both minerals were increased significantly with increasing the concentration of DTAC and TTAC. However, the increasing concentration of CTAC resulted in an increase in the dispersion of kaolinite and quartz particles under the same conditions. At neutral and alkaline conditions, the zeta potentials and adsorbed amounts of all three salts on the mineral surfaces were increased significantly with increasing the concentrations of salts, and the adsorbed amount adopted the following sequence: CTAC > TTAC > DTAC. The zeta potential results showed that the stronger adsorption of quaternary ammonium salts on mineral surfaces at neutral and alkaline conditions was mainly because of electrostatic interactions.

Energy Effects on Structural and Chemical Transformations of Base Minerals of Eudialyte Concentrate in Nitric Acid Leaching

Using the methods of X-ray phase analysis, analytical scanning electron microscopy and inductively coupled plasma mass spectrometry, the influence of preliminary energy effects on transformations of eudialyte concentrate base minerals during nitric acid leaching, their micromorphology and phase composition of the surface is studied. It is found that preliminary mechanical activation of the concentrate provides a 34–45% increase in the recovery of zirconium and the sum of rare-earth metal oxides into pregnant solution. Electrochemical processing of mineral suspension during nitric acid leaching and, to a greater extent, ultrasound effects contribute to an additional increase in the recovery of these elements into pregnant solution by 12–23% due to the cleaning of mineral grain surface from amorphous phases and formation of structural inhomogeneities.