scholarly journals Flotation Separation of Chalcopyrite and Molybdenite Assisted by Microencapsulation Using Ferrous and Phosphate Ions: Part II. Flotation

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 439
Author(s):  
Ilhwan Park ◽  
Seunggwan Hong ◽  
Sanghee Jeon ◽  
Mayumi Ito ◽  
Naoki Hiroyoshi
Keyword(s):  
Separation Efficiency ◽  
Alternative Process ◽  
Phosphate Ions ◽  
Conditioning Process ◽  
High Concentrations

Porphyry-type deposits are the major sources of copper and molybdenum, and flotation has been adopted to recover them separately. The conventional reagents used for depressing copper minerals, such as NaHS, Na2S, and Nokes reagent, have the potential to emit toxic H2S gas when pulp pH was not properly controlled. Thus, in this study the applicability of microencapsulation (ME) using ferrous and phosphate ions as an alternative process to depress the floatability of chalcopyrite was investigated. During ME treatment, the use of high concentrations of ferrous and phosphate ions together with air introduction increased the amount of FePO4 coating formed on the chalcopyrite surface, which was proportional to the degree of depression of its floatability. Although ME treatment also reduced the floatability of molybdenite, ~92% Mo could be recovered by utilizing emulsified kerosene. Flotation of chalcopyrite/molybdenite mixture confirmed that the separation efficiency was greatly improved from 10.9% to 66.8% by employing ME treatment as a conditioning process for Cu-Mo flotation separation.

Bioactivity of a Chitosan Based Nanocomposite

2011 ◽  
Vol 10 ◽  
pp. 95-106 ◽  
Author(s):  
Czeslawa Paluszkiewicz ◽  
Ewa Stodolak-Zych ◽  
Wojciech Kwiatek ◽  
Piotr Jelen
Keyword(s):  
Bone Repair ◽  
Nanocomposite Materials ◽  
Apatite Structure ◽  
Casting Method ◽  
Clay Particles ◽  
Phosphate Ions ◽  
Nano Clay ◽  
Naoh Solution ◽  
High Concentrations ◽  
Kinetics Of

In this work, experiments to produce a series of nanocomposites based on natural chitosan and nano-clay (MMT) were conducted. Commercially available montmorillonite (MMT) was used as a nanofiller. CS-MMT nanocomposites were prepared using the casting method. Thin nanocomposite foils were neutralized in NaOH solution, then the nanocomposite foils were soaked in simulated body fluid (SBF). Kinetics of crystallization of the apatite structure was observed using PIXE, FTIR-ATR and SEM/EDS techniques. It was shown that high concentrations of calcium and phosphate ions were located inside the nanocomposite structure. Bioactivity phenomena was initiated first in the nanocomposite foils (CS/MMT) and then in pure chitosan foils. These results suggest that the nano-clay particles (MMT) distributed in the biopolymer matrix acted as nucleaction centers of apatite. An apatite layer on pure chitosan crystallized much more slowly than in the case of nanocomposite materials. The CS-MMT nanocomposites therefore seem to be promising materials for bone repair implants because of their inherent bioactivity.

An ionic liquid–organics–water ternary biphasic system enhances the 5-hydroxymethylfurfural yield in catalytic conversion of glucose at high concentrations

2015 ◽  
Vol 17 (8) ◽  
pp. 4206-4216 ◽  
Author(s):  
Jinxia Zhou ◽  
Zhi Xia ◽  
Tingyu Huang ◽  
Peifang Yan ◽  
Wenjuan Xu ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Separation Efficiency ◽  
Catalytic Conversion ◽  
Biphasic System ◽  
High Concentrations

An ionic liquid–organics–water ternary biphasic system has high 5-HMF productivity and separation efficiency in the CrCl3 catalyzed conversion of glucose at high concentrations.

scholarly journals THE EFFECT OF DYES ON THE CALCIFICATION OF HYPERTROPHIC RACHITIC CARTILAGE IN VITRO

1952 ◽  
Vol 95 (5) ◽  
pp. 497-508 ◽  
Author(s):  
Zelma B. Miller ◽  
Jerome Waldman ◽  
Franklin C. McLean
Keyword(s):  
Phosphate Esters ◽  
Sulfate Ester ◽  
Acid Dyes ◽  
Phosphate Ions ◽  
Marked Inhibition ◽  
Basic Dyes ◽  
Orange G ◽  
High Concentrations ◽  
Very High

The calcification of rat hypertrophic cartilage slices in vitro is markedly inhibited by preliminary exposure to metachromatic and other basic dyes. The dyes are effective at 10–3 to 10–4 M in the absence of calcium and phosphate. This inhibition does not occur at the same low dye concentration if calcium and phosphate are present. Neither ion alone is effective in preventing the inhibition. The inhibitory action can be removed by placing slices which have been treated with basic dye in a solution which contains calcium and phosphate ions, plus an acid dye, Orange G. Most acid dyes do not inhibit calcification, except at very high concentrations. Alizarin and quinalizarin are exceptional, and produce marked inhibition at 10–3 M, an effect which is perhaps attributable to the tendency of these dyes to form lakes with calcium. Rachitic cartilage slices which no longer calcify in inorganic phosphate as a result of treatment with basic dyes show normal calcification in the presence of organic phosphate esters. These results are discussed in terms of the possibility that chondroitin sulfate ester participates in normal calcification.

Analytical Figures of Merit and Interelement Effects with Air and Nitrogen Microwave-Induced Plasmas

1986 ◽  
Vol 40 (6) ◽  
pp. 877-883 ◽  
Author(s):  
John J. Urh ◽  
Jon W. Carnahan
Keyword(s):  
Matrix Effects ◽  
Detection Limits ◽  
Analytical Signal ◽  
Air Plasma ◽  
Excitation Energies ◽  
Phosphate Ions ◽  
Loading Matrix ◽  
Bond Strengths ◽  
High Concentrations ◽  
Oxygen Bond

A microwave (2450 MHz)-induced plasma (MIP) with nitrogen nebulization and plasma gases was developed and compared with an air-MIP similar to that previously reported in our laboratories. These plasmas were maintained at 300 to 500 W of forward power and were stable with pneumatic nebulized aqueous solution introduction. In general, metals with high metal-oxygen bond strengths, high excitation energies, and low ionization potentials exhibited superior detection limits in the N2-MIP. Several elements with emission lines in N2 and N2+ spectral regions yielded better detection limits in the air plasma. The effects of high concentrations (2%) of calcium, potassium, sodium, and phosphate ions upon the analytical signal intensities were examined. During direct solution nebulization, the analytical signals of both plasmas exhibited significant but predictable interferences from metals of low ionization potential and plasma loading. Matrix effects were more significant in the N2-MIP.

The cytology of heavy metal accumulations in the digestive glands of three marine gastropods

1989 ◽  
Vol 237 (1288) ◽  
pp. 347-362 ◽  
Keyword(s):  
Metal Binding ◽  
Full Range ◽  
Marine Gastropods ◽  
Biochemical Processes ◽  
Phosphate Ions ◽  
Wide Range ◽  
Pore Cells ◽  
High Concentrations ◽  
Top Shell ◽  
Digestive Glands

In the digestive glands of gastropod molluscs, metals are metabolized in the sense that they are subject to inorganic biochemical processes within the epithelial cells and lumen of the digestive tubules and the pore cells in the intervening connective tissue. These systems have been examined in the tower shell Cerithium vulgatum Bruguieres, a sediment feeder, the top shell Monodonta articulata Lam., a grazing herbivore, and in the whelk Murex trunculus L., a carnivore whose prey includes Cerithium . These animals were taken from a Mediterranean environment polluted by heavy metals. In all three species the metals are compartmentalized within mineralized granules as phosphates and within lysosomal residual bodies in association with sulphur. However, the extent to which a particular metal is accumulated and the relative proportions that are bound within the different compartments are factors that are primarily determined by the species and not the concentration available in the environment. Thus Cerithium accumulates high concentrations of a wide range of metals from the ingested sediment and these are rendered insoluble and non-toxic in the digestive gland. This unavailability is transferred to Murex when it eats Cerithium because Murex does not accumulate the full range of metals from its prey. Indeed, for some metals there appears to be bioreduction rather than bioamplification. The grazing herbivore Monodonta articulata accumulates a third distinct spectrum of metals. The accumulations in each species do not reflect the levels of all the metals in the environment. The presence of metals in the digestive glands is associated with the removal of magnesium from the phosphate granules but also with an increase in the concentration of magnesium in the tissue. It is proposed that metals induce the formation of magnesium phosphate as a source of metal-binding phosphate ions.

Phosphate Ions: Does Exposure Lead to Degradation of Cementitious Materials?

2008 ◽  
Author(s):  
Dan J. Naus ◽  
Herman L. Graves ◽  
Catherine H. Mattus ◽  
Leslie R. Dole
Keyword(s):  
Laboratory Investigation ◽  
Nuclear Power ◽  
Power Plants ◽  
Concrete Structures ◽  
Cementitious Materials ◽  
Ion Concentration ◽  
Exposure Limits ◽  
Research Personnel ◽  
Phosphate Ions ◽  
High Concentrations

An assessment of the potential effects of phosphate ions on cementitious materials was made through a review of the literature, contacts with concrete research personnel, and conduct of a “bench-scale” laboratory investigation [1]. The objectives of this limited study were to: (1) review the potential for degradation of cementitious materials due to exposure to high concentrations of phosphate ions; (2) provide an improved understanding of any significant factors that may lead to a requirement to establish exposure limits for concrete structures exposed to soils or ground waters containing high levels of phosphate ions; (3) recommend, as appropriate, whether a limitation on phosphate ion concentration in soils or ground water is required to avoid degradation of concrete structures; and (4) provide a “primer” on factors that can affect the durability of concrete materials and structures in nuclear power plants. Results of a literature review, contacts with industry personnel, and a laboratory investigation indicate that no harmful interactions occur between phosphate ions and cementitious materials unless phosphates are present in form of phosphoric acid. Relative to the “primer,” NUREG/CR-6927, published in February 2007, provides a review of pertinent factors that can affect the durability of nuclear power plant reinforced concrete structures.

Freeze-fracture, freeze-etch complementary pairs of virus-infected cells reveal value of etching even when relatively high concentrations of cryoprotectants are used

1978 ◽  
Vol 36 (2) ◽  
pp. 136-137
Author(s):  
Russell L. Steere ◽  
Eric F. Erbe
Keyword(s):  
Plant Tissue ◽  
Phosphate Buffer ◽  
Infected Plant ◽  
Freeze Fracture ◽  
Distilled Water ◽  
Virus Infected Plant ◽  
Infected Cells ◽  
High Concentrations

It has been assumed by many involved in freeze-etch or freeze-fracture studies that it would be useless to etch specimens which were cryoprotected by more than 15% glycerol. We presumed that the amount of cryoprotective material exposed at the surface would serve as a contaminating layer and prevent the visualization of fine details. Recent unexpected freeze-etch results indicated that it would be useful to compare complementary replicas in which one-half of the frozen-fractured specimen would be shadowed and replicated immediately after fracturing whereas the complement would be etched at -98°C for 1 to 10 minutes before being shadowed and replicated.Standard complementary replica holders (Steere, 1973) with hinges removed were used for this study. Specimens consisting of unfixed virus-infected plant tissue infiltrated with 0.05 M phosphate buffer or distilled water were used without cryoprotectant. Some were permitted to settle through gradients to the desired concentrations of different cryoprotectants.

Effect of verapamil on cytoplasmic distribution of granules and microfilaments in amphibian urinary bladder

1988 ◽  
Vol 46 ◽  
pp. 324-325
Author(s):  
A.J. Mia ◽  
L.X. Oakford ◽  
T. Yorio
Keyword(s):  
Urinary Bladder ◽  
Water Flow ◽  
Morphological Changes ◽  
Granular Cell ◽  
Cytosolic Calcium ◽  
Calcium Storage ◽  
Amphibian Urinary Bladder ◽  
Vesicular Membrane ◽  
High Concentrations ◽  
Cytoskeletal System

The amphibian urinary bladder has been used as a ‘model’ system for studies of the mechanism of action of antidiuretic hormone (ADH) in stimulating transepithelial water flow. The increase in water permeability is accompanied by morphological changes that include the stimulation of apical microvilli, mobilization of microtubules and microfilaments and vesicular membrane fusion events . It has been shown that alterations in the cytosolic calcium concentrations can inhibit ADH transmembrane water flow and induce alterations in the epithelial cell cytomorphology, including the cytoskeletal system . Recently, the subapical granules of the granular cell in the amphibian urinary bladder have been shown to contain high concentrations of calcium, and it was suggested that these cytoplasmic constituents may act as calcium storage sites for intracellular calcium homeostasis. The present study utilizes the calcium antagonist, verapamil, to examine the effect of calcium deprivation on the cytomorphological features of epithelial cells from amphibian urinary bladder, with particular emphasis on subapical granule and microfilament distribution.

Hair cell changes after cationic stimulation of corti's organ

1989 ◽  
Vol 47 ◽  
pp. 798-799
Author(s):  
Cesar D. Fermin ◽  
Hans-Peter Zenner
Keyword(s):  
Organ Of Corti ◽  
Cross Sectional ◽  
Surface Areas ◽  
High K ◽  
Anatomical Arrangement ◽  
Cell Cytosol ◽  
High Concentrations ◽  
K Concentration ◽  
Cell Changes

Contraction of outer and inner hair cells (OHC&IHC) in the Organ of Corti (OC) of the inner ear is necessary for sound transduction. Getting at HC in vivo preparations is difficult. Thus, isolated HCs have been used to study OHC properties. Even though viability has been shown in isolated (iOHC) preparations by good responses to current and cationic stimulation, the contribution of adjoining cells can not be explained with iOHC preparations. This study was undertaken to examine changes in the OHC after expossure of the OHC to high concentrations of potassium (K) and sodium (Na), by carefully immersing the OC in either artifical endolymph or perilymph. After K and Na exposure, OCs were fixed with 3% glutaraldehyde, post-fixed in osmium, separated into base, middle and apex and embedded in Araldite™. One μm thick sections were prepared for analysis with the light and E.M. Cross sectional areas were measured with Bioquant™ software.Potassium and sodium both cause isolated guinea pig OHC to contract. In vivo high K concentration may cause uncontrolled and sustained contractions that could contribute to Meniere's disease. The behavior of OHC in the vivo setting might be very different from that of iOHC. We show here changes of the cell cytosol and cisterns caused by K and Na to OHC in situs. The table below shows results from cross sectional area measurements of OHC from OC that were exposed to either K or Na. As one would expect, from the anatomical arrangement of the OC, OHC#l that are supported by rigid tissue would probably be displaced (move) less than those OHC located away from the pillar. Surprisingly, cells in the middle turn of the cochlea changed their surface areas more than those at either end of the cochlea. Moreover, changes in surface area do not seem to differ between K and Na treated OCs.

Conditioning: Process or Procedure?

1978 ◽  
Vol 23 (4) ◽  
pp. 230-231
Author(s):  
BEN A. WILLIAMS
Keyword(s):  
Conditioning Process
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