Ammonium Phosphate Salts Research Articles

Kinetic study of reaction formation of phosphate products from thermal dissolution of wolframite using fusion technique

This study examined an alternative technique of extracting tungsten from wolframite ore using a fusion method with ammonium phosphate salt. Current techniques use alkali salts to decompose tungsten ores and use various purification methods to produce ammonium paratungstate, which is a key intermediate precursor in the extraction of tungsten. In this study, a two-step extraction process, which involves thermal decomposition of the ore using fusion and a separation stage, is examined. The novelty of this technique is the ability to completely decompose wolframite ore and form an unstable tungsten oxide phosphate (WO2(PO3)2) compound. The instability of WO2(PO3)2 in deionized water enables selective isolation of tungsten as insoluble precipitates of WO3 and WO2. The decomposition reaction of WO2(PO3)2 is influenced by the presence of oxygen and determined to be first order under ambient conditions. Scanning electron micrographs and X-ray diffraction analysis showed above 80% of the tungsten precipitated compared with the amount that remained in the filtrate solution.

Sequential Steps for Purifying Wet Processed Phosphoric Acid for Producing a High-Tech Grade and Barium or Ammonium Phosphate Salts

Sequential Steps for Purifying Wet Processed Phosphoric Acid for Producing a High-Tech Grade and Barium or Ammonium Phosphate Salts

Investigation into struvite precipitation: A commonly encountered problem during fermentations on chemically defined media.

Chemically defined mineral media are widely used in bioprocesses, as these show less batch to batch variation compared with complex media. Nonetheless, the recommended media formulations often lead to the formation of precipitants at elevated pH values. These precipitates are insoluble and reduce the availability of macronutrients to the cells, which can result in limiting growth rates and lower productivity. They can also damage equipment by clogging pipes, hoses, and spargers in stirred tank fermenters. In this study, the observed precipitate was analyzed via X-ray fluorescence spectroscopy and identified as the magnesium ammonium phosphate salt struvite (MgNH4 PO4 × 6H2 O). The solubility of struvite crystals is known to be extremely low, causing the macronutrients magnesium, phosphate, and ammonium to be bound in the struvite crystals. Here, it was shown that struvite precipitates can be redissolved under common fermentation conditions. Furthermore, it was found that the struvite particle size distribution has a significant effect on the dissolution kinetics, which directly affects macronutrient availability. At a certain particle size, struvite crystals rapidly dissolved and provided unlimiting growth conditions. Therefore, struvite formation should be considered during media and bioprocess development, to ensure that the dissolution kinetics of struvite are faster than the growth kinetics.

Fusion Extraction of Base Metals (Al, Cr, Fe, Ti and V) Using Ammonium Phosphate Salt as Flux

The fusion method of using ammonium phosphate salt as flux was assessed for its ability to precipitate metaphosphate compounds containing trivalent ions M3+ = Al, Cr, Fe, Ti, and V as M(PO3)3 in inorganic salts and a certified reference material (CRM) mineral ore sample. Fusion analysis using mixtures of inorganic salts containing AlCl3, CrCl3, FeCl3, and VCl3 showed variable amounts of precipitates isolated as metaphosphate compounds in the order of iron (12%) < vanadium (13%) < chromium (30%) < (44%) aluminum. However, an analysis of the CRM (AMIS 0368) where magnetite (Fe3+/Fe2+) and ilmenite (Ti4+) are the dominant phases, showed that the obtained precipitates were in the order of chromium (less than 0.1%) < vanadium (1%) < aluminum (2%) < titanium (9%) < iron (68%). The metaphosphate compounds isolated via the use of this method were identified using XRD analysis. SEM–EDX analysis showed micro-crystalline particles from the inorganic salts that were irregular and clustered, contrary to the amorphous micro particles which were produced from the CRM. The degree of specificity improved considerably using CRM ore (AMIS 0368) with high iron content (~76%, Fe3+/Fe2+). This method was shown to be highly selective towards metals with a stable trivalent oxidation state. No other elements of a different oxidation state were precipitated.

Fusion–Extraction Technique of Vanadium(III) Using Ammonium Phosphate Salt as Flux

This study presents an alternative fusion method for sample dissolution and extraction of vanadium from an inorganic (V2O3) compound and mineral ore sample (AMIS 0501) using phosphate salts as flux. Complete sample dissolution was achieved at 800 °C within ±20 min using both the sodium and ammonium phosphate flux. The precipitation of vanadium was subsequently achieved after the fusion of the sample using ammonium phosphate flux, and no precipitate was obtained using sodium phosphate flux. The differences in cations between the two fluxes (NH4+ and Na+) influenced the precipitation of vanadium. The XRD analysis of the precipitate from V2O3 using ammonium phosphate showed a monoclinic structure of vanadium (III) tris(metaphosphate) (V(PO3)3) compound, which belonged to the Ic space group with lattice parameters a = 10.6071, b = 19.0871 and c = 9.4230. A remarkable vanadium recovery of 98% was obtained from inorganic compounds, V2O3, and up to 70% from the AMIS mineral ore sample using the ammonium phosphate flux method. The vanadium precipitates from AMIS contained Fe (20.97%) and Ti (44.97%), which occurred as impurities in the recovery of vanadium using the ammonium phosphate flux method.

Extraction of Tungsten from Wolframite Sample Using Ammonium Phosphate Salt as Flux

Extraction of Tungsten from Wolframite Sample Using Ammonium Phosphate Salt as Flux

Densities and Speeds of Sound for Sucrose in Aqueous Solutions of Ammonium Phosphate Salts at Different Temperatures through Density and Speed of Sound Measurements

Volumetric and acoustic studies of sucrose with ammonium phosphate salts, namely, ammonium dihydrogen phosphate (ADP) and diammonium hydrogen phosphate (DAP), have been carried out using an oscilla...

Production and Characterization of Porous Polymeric Membranes of PLA/PCL Blends with the Addition of Hydroxyapatite

Polymer membranes have been widely used in guided tissue regeneration (GTR) and guided bone regeneration (GBR). The literature recognizes that poly (lactic acid) (PLA)/poly (ε-caprolactone) (PCL) blends have better physicochemical properties and that a porous polymer surface facilitates cell adhesion and proliferation. In addition, hydroxyapatite (HAp) incorporated into the polymer matrix promotes osteoinduction properties and osteoconduction to the polymer-ceramic biocomposite. Therefore, polymer membranes of PLA/PCL blend with the addition of HAp could be an alternative to be used in GBR. HAp was obtained by precipitation using the mixture of solutions of tetrahydrate calcium nitrate and monobasic ammonium phosphate salts. The porous membranes of the PLA/PCL (80/20) blend with the addition of HAp were obtained by solvent casting with a controlled humidity method, with the dispersion of HAp in chloroform and subsequent solubilization with the components of the blend. The solution was poured into molds for solvent evaporation under a controlled humidity atmosphere. The membranes showed the formation of pores on their surface, together with dispersed HAp particles. The results showed an increase in the surface porosity and improved bioactivity properties with the addition of HAp. Moreover, in biological studies with cell culture, it was possible to observe that the membranes with HAp have no cytotoxic effect on MC3T3 cells. These results indicate a promising use of the new biomaterial for GBR.

Characterization of molybdenum and tungsten phosphates compounds prepared using ammonium phosphate salt as flux

Fusion of powdered molybdenum and tungsten oxide using ammonium phosphate salt as flux (ratio: 1:25 respectively) yielded soluble products which were unstable. The yellow (Mo) and purple-blue (W) solutions in deionized water, methanol and acetone decolorized within 3–5 hours. Infrared analysis of molybdenum and tungsten products revealed characteristic broad bands bearing two minor peaks in the region of 1040–1130 cm -1 which reflects the simultaneous existence of PO 2 and PO 3 groups. SEM-EDX quantitative analysis results showed percentage weight of the identified elements in the increasing order of Mo or W < P < O with molybdenum product having 7.1%wt (Mo), 37.2%wt (P) and 53.5%wt (O) whilst tungsten product had 10.3%wt (W), 24.7%wt (P) and 46.5%wt (O). The EDX results indicated the presence of polyphosphate products whilst the SEM images showed microscopic crystalline product of molybdenum and a hygroscopic product of tungsten. XRD patterns of both molybdenum and tungsten products corresponded to the standard (JCPDS) pattern of molybdenum oxide phosphate MoO 2 (PO 3 ) 2 and tungsten oxide phosphate (WO 2 (PO 3 ) 2 ), respectively. KEY WORDS : Molybdenum, Tungsten, Ammonium phosphate flux, Polyphosphates Bull. Chem. Soc. Ethiop. 2019 , 33(1), 103-112 DOI: https://dx.doi.org/10.4314/bcse.v33i1.10

Characterization of Chromium (III) Compounds Isolated from Different Mineral Ores Using Ammonium Phosphate as Flux

Complete isolation of chromium (III) from the reference material (SARM 131), Upper Group 2 (UG2) chromite ore, and Merensky Reef mineral ore was achieved using ammonium phosphate salt as flux. Optimum pH (3.2–3.8) conditions and sample to flux ratios (1:25) were some of the factors that were critical for the complete isolation of chromium. Increasing the sample to flux ratio (1:50 excess) however resulted in the conversion of all the elements in the melt into a green solution (pH, 5.8–6.7). A different chromium compound was subsequently isolated from the green solution by allowing this solution to stand in an open vessel in a cupboard for a month during which time the pH decreased to pH 3.5–4.2. Quantitative analyses of chromium from the isolated precipitates of SARM 131, UG2 chromite ore, and Merensky Reef mineral ore indicated chromium contents of 41.87, 60.41, and 23.93% respectively which were very close to the chromium content in the original samples. Analysis of the chromium precipitates using IR indicated the presence of phosphates (1100–1200 cm−1) while SEM-EDX analysis showed the presence of microscopic crystalline particles with Cr, P, and O as the major elements. Further characterization of the chromium precipitates using XRD and Raman successfully identified the product as chromium (III) metaphosphate C-type (Cr(PO3)3, JCPDS no. 01-077-0672), in the isolated chromium precipitates.

Fire Extinguishing Efficiency of Magnesium Hydroxide Powders under Different Particle Size

After Montreal protocol, more and more new materials have been applied as the substitutes of Halon. Much attention has been paid to fire extinguishing efficiency of alkali metal salts and ammonium phosphate salts, but the effects of particle sizes have not been studied sufficiently. The fire-extinguishing efficiency of a new kind of agent based on magnesium hydroxide of different particle size was studied in this paper. Four different size powders have been used to study their fire-suppression efficiency through laboratory scale experiments in a confine space of 1*1*1m. The physical and chemical characteristics of the magnesium hydroxide powders were characterized by scanning electron microscopy (SEM) and thermal gravity analysis (TGA). The results have exhibited that these four kinds of powders are all high efficient for the fire suppression efficiency and there is a threshold value of 5μm for the fire suppression efficiency of magnesium hydroxide. The efficiency can be affected by the morphology of powders and particle size. The powders of larger specific surface area and smaller particle size are more efficient to suppress fire. Fire extinguishing and possible fire-suppression mechanisms have also been analyzed from three aspects: chemical inhibition, cooling effect and asphyxiation effect.

Semi-Automated Hydrophobic Interaction Chromatography Column Scouting Used in the Two-Step Purification of Recombinant Green Fluorescent Protein

BackgroundHydrophobic interaction chromatography (HIC) most commonly requires experimental determination (i.e., scouting) in order to select an optimal chromatographic medium for purifying a given target protein. Neither a two-step purification of untagged green fluorescent protein (GFP) from crude bacterial lysate using sequential HIC and size exclusion chromatography (SEC), nor HIC column scouting elution profiles of GFP, have been previously reported.Methods and ResultsBacterial lysate expressing recombinant GFP was sequentially adsorbed to commercially available HIC columns containing butyl, octyl, and phenyl-based HIC ligands coupled to matrices of varying bead size. The lysate was fractionated using a linear ammonium phosphate salt gradient at constant pH. Collected HIC eluate fractions containing retained GFP were then pooled and further purified using high-resolution preparative SEC. Significant differences in presumptive GFP elution profiles were observed using in-line absorption spectrophotometry (A395) and post-run fluorimetry. SDS-PAGE and western blot demonstrated that fluorometric detection was the more accurate indicator of GFP elution in both HIC and SEC purification steps. Comparison of composite HIC column scouting data indicated that a phenyl ligand coupled to a 34 µm matrix produced the highest degree of target protein capture and separation.ConclusionsConducting two-step protein purification using the preferred HIC medium followed by SEC resulted in a final, concentrated product with >98% protein purity. In-line absorbance spectrophotometry was not as precise of an indicator of GFP elution as post-run fluorimetry. These findings demonstrate the importance of utilizing a combination of detection methods when evaluating purification strategies. GFP is a well-characterized model protein, used heavily in educational settings and by researchers with limited protein purification experience, and the data and strategies presented here may aid in development other of HIC-compatible protein purification schemes.

Flame retardancy and mechanical properties of flax reinforced woven for composite applications

This paper investigates the flame retardant and mechanical properties of a flax woven fabric that can be used to prepare biocomposites. The flame retardant properties of the fabric are first considered using different ammonium phosphate salts and intumescent systems. It is demonstrated that satisfactory performances can be achieved using this approach. Better performances were obtained with pure phosphate salts in comparison to intumescent systems. This was attributed first, to the carbonization effect of the flax that could thus react with the phosphate and/or its degradation products leading to a stabilisation of the system and second to the lower phosphorus content when the full intumescent system is considered. On the other hand, despite a loss of biaxial tensile properties, the ability of the fire retardant treated fabric to form complex shape such as a tetrahedron was successfully demonstrated. Finally, the flame retardant properties of one-ply composites, using a bio-based matrix (Bioplast from Biotec), was evaluated. It was shown that good fire retardancy performances could be achieved considering only the flame retardancy of the reinforcement phase. This approach has potential for developing future flame retarded biocomposites.

Synergistic effect of diisopropyl phosphite and ashless organic ammonium phosphate salt additives on tribological properties of AISI 52100 steel/Al2O3 ceramics

The friction-reducing and antiwear effects of the 500SN base oil containing diisopropyl phosphite (T451) and ashless organic ammonium phosphate salt (KT139) on AISI 52100 steel/Al2O3 ceramic were investigated with a ball-on-disc tribometer at a light load of 200 N and a high load of 400 N. The results indicate that the 500SN base oil containing T451 and KT139 appears with a synergistic effect on AISI 52100 steel/Al2O3 ceramic. Under a single additive, increasing percentage of T451 or KT139 can decrease the friction coefficient and the wear rate of the pair monotonously. However, under the compound system, the tribological behaviour of the pair is strongly dependent of the concentrations of additives. Within the experimental data, the most effective compositions for the loads 200 and 400 N are 2 wt%T451 + 2 wt%KT139 and 1 wt%T451 + 3 wt%KT139, respectively. The scanning electron microscopic images showed that plowed grooves, spalling, and corrosion are the dominant wear modes for the pair. The energy dispersive spectroscopy analysis shows that a protective tribochemical film containing both S and P forms on the steel ball worn surface. Nevertheless, the atom concentrations of P and S are too low to be referred for further analysis of the tribochemical reaction mechanism.

Thermodynamics of aqueous solutions of poly ethylene glycol di-methyl ethers in the presence or absence of ammonium phosphate salts

Precise measurements of density and sound velocity at different temperatures ranging from 283.15 to 308.15 K for solutions of PEGDME250, PEGDME500 and PEGDME2000 in water and of PEGDME500 in aqueous solutions of 0.500 mol kg −1 ammonium di-hydrogen phosphate ((NH 4)H 2PO 4) and di-ammonium hydrogen phosphate ((NH 4) 2HPO 4), binodal curves at temperature ranges 293.15–318.15 K for the aqueous PEGDME500 + (NH 4) 2HPO 4, PEGDME500 + (NH 4) 3PO 4, PEGDME2000 + (NH 4)H 2PO 4, PEGDME2000 + (NH 4) 2HPO 4, PEGDME2000 + (NH 4) 3PO 4 and PPG400 + (NH 4) 2HPO 4 two-phase systems, and liquid–liquid equilibrium data at temperature ranges 298.15–318.15 K for the aqueous PEGDME500 + (NH 4) 2HPO 4 and PEGDME2000 + (NH 4) 2HPO 4 two-phase systems have been taken. From the experimental density and sound velocity data, the apparent specific volume, excess specific volume, isentropic compressibility and isentropic compressibility deviation values have been determined and the effect of temperature, charge on the anion of electrolytes and molar mass of PEGDME on the volumetric and compressibility properties of the investigated polymer solutions as well as on the salting-out effect of PEGDMEs produced by ammonium phosphate salts has been studied.

Thermal properties of biostimulant-infused potato fibers

Crushing or otherwise processing potato and subsequent mild washing of the pulp produces mostly granular and fibrous starch. These fibers are experimental carrier material for microbes in bioremediation of polluted waters. This method offers the benefit of increasing the exposure of the microbes to the pollutant by increasing their residency within the site. Because of the physical nature of the material, it also offers the possibility of carrying, in addition to the microbes, essential macronutrients such as nitrogen and phosphorous that would be limited in availability in contaminated waters. We have previously reported on the physical nature of these fibers through thermal analysis and on their ability to bind/aggregate bacteria. We have extended that study in this report by infusing the fibers with a source of nitrogen and phosphorous, namely ammonium phosphate. The TG curves for ammonium phosphate-infused white and sweet potato fibers exhibited three main mass loss steps corresponding to the three exothermic DTG peaks. Infusion with the ammonium phosphate salt also affected the bacterial binding/aggregation capacities. The range of their binding capacities decreased to a range of 26.9–43.3% compared to untreated fibers.

Phosporic acid-modified amino bonded stationary phase for high-performance liquid chromatographic chemical class separation

A new stationary phase for high-performance liquid chromatography was produced by reacting a conventional amino bonded phase with phosphoric acid. Characterization of the modified amino phase indicated that ammonium phosphate salt groups and “free” phosphoric acid were present on the stationary phase surface. The column's capability for separating complex sample mixtures into chemical classes was tested using model compounds representing those typically found in fossil fuels. A solvent gradient program was developed which effectively separated hydrocarbon standards into aliphatic, non-polar aromatic, neutral/acidic polar aromatic, and basic polar aromatic classes.

Anion-exchange high performance liquid chromatography method for the quantitation of nucleotides in human blood cells

An anion-exchange high performance liquid chromatography (HPLC) method is described for the quantitation of intracellular purine and pyrimidine nucleotides. With an ammonium phosphate salt and pH gradient, complete separation is achieved of all major nucleotides and several interfering substances, such as dehydroascorbic acid and NAD. For optimal resolution of the monophosphates, strict control of the equilibration pH is essential. To prevent interference by a degradation product of NADPH with the determination of GDP, the pH of the high-ionic strength buffer has to be in the range of 4.9-5.0. The use of radially compressed, prepacked cartridges filled with Partisil-10 SAX appeared to be a fast and cheap alternative for expensive stainless-steel columns. The use of ammonium phosphate buffers, in combination with precolumns filled with pellicular silica and SAX resin, and interim EDTA washes prevents baseline shift. This allows analysis at 0.01 Absorbance Units Full Scale during the entire column lifetime (about 180 analyses), which is sufficiently sensitive for the quantitation of low levels of nucleotides, especially when the amount of sample is limited. The usefulness of the presented Chromatographie system is demonstrated by the quantitation of the nucleotides in extracts of lymphocytes and neutrophils from the blood of healthy human donors. With this method nucleotide concentrations were measured, with a within-assay variation of 5–10% and an inter-donor variation of 10%.

Adsorption of Ammonium Phosphate Salt by Soils

Adsorption of Ammonium Phosphate Salt by Soils

(200)燐酸アンモニウム塩による金属イオンの定量(第3報)マンガンについて

(200)燐酸アンモニウム塩による金属イオンの定量(第3報)マンガンについて