Zinc Phosphates Research Articles

The role of surfactants in the electroflotation extraction of copper, nickel, and zinc hydroxides and phosphates

The effect of various surfactants on the physicochemical parameters (particle size and zeta potential) of the disperse phase of copper, nickel, and zinc hydroxides at concentrations of cationic, anionic, and nonionic surfactants of 2, 10, 50, and 100 mg/L at pH of 9.5–10.5 was studied. The efficiency of their electroflotation extraction into a flotation froth was determined in a laboratory electroflotation module with antiwear oxide electrodes with efficiency of higher than 95% (initial concentration 50 mg/L, in the form of flotation sludge, processing time no more than 30 min, current density 0.2 A/L).

Mixing ratio of zinc nitrate and phosphoric acid for preparation of zinc phosphate white pigments

In this work, zinc phosphates were prepared from zinc nitrate and phosphoric acid at various Zn/P ratios as a novel white pigment for use in cosmetics. The chemical composition, powder properties, photocatalytic activity, color phase, moisture retention, and smoothness of the zinc phosphates were studied. Samples prepared at Zn/P = 2/1, 3/2, and 1/1 indicated XRD pattern of Zn3(PO4)2•4H2O. The plane particles were observed in SEM images of sample prepared at Zn/P = 2/1, 3/2 and 1/1. The photocatalytic activity of these zinc phosphate particles was too less to protect the sebum on the skin. The materials prepared at Zn/P = 2/1, 3/2 and 1/1 and their thermal products at 100 °C showed a high reflectance within the range of visible light. Samples prepared at high Zn/P ratio indicated small MIU value.

Facile in situ syntheses of new templates and formations of three zinc phosphates

Three new organically templated zinc phosphates, namely, [dmdabco][Zn2(HPO4)3]·(H2O) (1), [tmpip]0.5[Zn2(HPO4)2(H2PO4)] (2) and [tmpip][Zn3(HPO4)4] (3) (dmdabco=N,N′-dimethyl-1,4-diazabicyclo[2,2,2]octane, tmpip=N,N,N′,N′-tetramethyl-piperazinium), were successfully synthesized under solvothermal reactions and structurally characterized by single-crystal X-ray diffraction. The dmdabco2+ and tmpip2+ templating agents were derived respectively from simple in situ N-alkylation transformations between the methanol solvent and organic cyclic aliphatic diamines, 1,4-diazabicyclo[2,2,2]octane (dabco) in 1 and 1-methylpiperazine in 2 and 3. Such direct methylation feature is unique, and quite different from conventional Eschweiler–Clarke methylation in which an excess of formic acid and formaldehyde was required. Compound 1 exhibits a 4-connected 2D (4, 4) net with pentameric [Zn2(HPO4)3] clusters as secondary building units (SBUs); 2 possesses a complex double layered structure with 12-ring windows. Compound 3 has a (3, 4)-connected 3D pcu architecture with heptameric [Zn3(HPO4)4] clusters as SBUs, forming intersecting 8- and 12-ring channels.

Influence of pH, concentration of sodium lactate as an additive and ultrasonic treatment on synthesis of zinc phosphate white pigments.

Zinc oxide that has the photocatalytic activity is used as a white pigment for cosmetics. A certain degree of sebum on the skin is decomposed by the ultraviolet radiation in sunlight. In this work, zinc phosphates were prepared from zinc nitrate and phosphoric acid at pH 5 and 7 with and without the addition of sodium lactate and ultrasonic treatment as a novel white pigment for use in cosmetics. The chemical composition, powder properties, photocatalytic activity, colour phase, moisture retention and smoothness of the zinc phosphates were studied. The obtained materials had a Zn/P ratio of about 1.5, which corresponds to zinc orthophosphate Zn3 (PO4 )2 . Samples prepared with ultrasonic treatment indicated the high ratios of large particles in scanning electron microscopy images and particle-size distributions. The photocatalytic activity of these zinc phosphate particles was too less to protect the sebum on the skin. The materials obtained and their thermal products at 100°C showed a high reflectance within the range of visible light. The slipping resistance and roughness of the powder were enough low for use in cosmetics.

Dimensionality changes in the solid phase at room temperature: 2D → 1D → 3D evolution induced by ammonia sorption-desorption on zinc phosphates.

Two-dimensional zinc phosphate NH4Zn2(PO4)(HPO4) (), via ammonia vapor interaction at room temperature, transforms to a one-dimensional novel compound NH4Zn(NH3)PO4 (). By ammonia desorption (in air at room temperature) transforms to NH4ZnPO4 () with a well-known ABW-zeolitic topology. The crystal structure of was solved ab initio using synchrotron powder X-ray diffraction data (monoclinic, P21/a, a = 16.5227(2) Å, b = 6.21780(8) Å, c = 5.24317(6) Å, β = 91.000(2)°, Z = 4). The structures of three compounds include extra-framework ammonium cations to the 4-fold coordinated zinc (ZnO4 tetrahedra for and , and ZnO3N tetrahedra for ) and phosphorus (PO4 tetrahedra) with bi-, mono- or three-dimensional linkages, respectively for , or . To our knowledge, the process described here constitutes the first example of dimensionality change in the solid phase promoted by a solid-gas interaction at room temperature in metal phosphates.

Mineralogical Study of a Biologically-Based Treatment System That Removes Arsenic, Zinc and Copper from Landfill Leachate

Mineralogical characterization by X-ray diffraction (XRD) and a high throughput automated quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN) was conducted on samples from a sulphate-reducing biochemical reactor (BCR) treating high concentrations of metals (As, Zn, Cu) in smelter waste landfill seepage. The samples were also subjected to energy dispersive X-ray (EDX) analysis of specific particles. The bulk analysis results revealed that the samples consisted mainly of silicate and carbonate minerals. More detailed phase analysis indicated four different classes: zinc-arsenic sulphosalts/sulphates, zinc-arsenic oxides, zinc phosphates and zinc-lead sulphosalts/sulphates. This suggests that sulphates and sulphides are the predominant types of Zn and As minerals formed in the BCR. Sphalerite (ZnS) was a common mineral observed in many of the samples. In addition, X-ray point analysis showed evidence of As and Zn coating around feldspar and amphibole particles. The presence of arsenic-zinc-iron, with or without cadmium particles, indicated arsenopyrite minerals. Copper-iron-sulphide particles suggested chalcopyrite (CuFeS2) and tennantite (Cu,Fe)12As4S13. Microbial communities found in each sample were correlated with metal content to describe taxonomic groups associated with high-metal samples. The research results highlight mineral grains that were present or formed at the site that might be the predominant forms of immobilized arsenic, zinc and copper.

Precision affinage of copper from crow-bar and wastes

The model of the deep copper refining from the secondary raw materials using methods of physical and chemical analysis was considered. The theoretical and experimental results of copper refining from the secondary raw materials using phosphide Cu3P were proposed. The copper phosphide Cu3P was added into melting during fire refining. The copper phosphide Cu3P influence on the refining level was estimated on the tin, lead, zink and antimony impurities. Reactions analysis showed that the Cu3P addition helps to form stable oxidiger P2O5 and copper oxides recoverability. It was determined that the reaction, of conversion the remaining impurities into slag place at the first stage by P2O5 formation and was followed by phosphates of lead, zinc and tin impurities formation. Keywords: melting, fusion, five refining, impurities, copper phosphide Cu3P.

Nonaqueous synthesis of molecular zinc amide phosphate

Three new molecular zinc compounds were prepared by nonaqueous reactions of Zn[N(SiMe3)2]2 and ZnEt2 with trimethylsilylesters of phosphoric acid, OP(OSiMe3)3 and OP(OSiMe3)2(OH). Single-crystal X-ray diffraction analyses of crystalline products revealed molecular structures of two mononuclear complexes [ZnX2OP(OSiMe3)3] (X = N(SiMe3)2 (1), hfacac = hexafluoroacetylacetonate, (2)) and one dinuclear zinc phosphate [(Zn{(py)N(SiMe3)2}{μ2-O2P(OSiMe3)2})2] (3). Compound 1 is only the second structurally characterized adduct of zinc bisamide with an oxygen donor and a three-coordinate Zn atom. The cyclic inorganic core {Zn(μ2-O2PO2)}2 in 3 is a model for the most common single four-ring (S4R) building unit of open-framework zinc phosphates. The molecule of 3 possesses reactive amide and trimethylsiloxy groups that can be employed in further studies on the formation of extended structures by condensation reactions. Spectroscopic properties and thermal behavior of the molecular products were examined. Compounds 1 and 3 were converted to α-Zn2P2O7 by calcination.

Preparation and powder properties of zinc phosphates with additives

In this work, zinc phosphates were prepared from zinc nitrate and phosphoric acid as a novel white pigment for use in cosmetics. The chemical composition, powder properties, photocatalytic activity, color phase, moisture retention, and smoothness of the zinc phosphates were studied. The obtained materials had a Zn/P ratio of about 1.5, which corresponds to zinc orthophosphate Zn3(PO4)2. Spherical particles were formed in a sample prepared using sodium lactate and glycerin, and in a sample prepared using urea, sodium lactate, and glycerin. The photocatalytic activity of these zinc phosphate particles was too less to protect the sebum on the skin. The materials obtained and their thermal products showed a high reflectance within the range of ultraviolet and visible light at 100°C. The slipping resistance and roughness of the powder decreased as a result of the addition of sodium lactate.

Morphology control of open-framework zinc phosphate Zn4(H3O)(NH4)3(PO4)4 via microwave-assisted technique

Abstract Open-framework zinc phosphates were synthesized by microwave-assisted technique, and it was shown that the morphology of as-prepared materials could be easily tailored by changing synthesis temperature, reaction time and pH value. During the synthesis, when the reaction temperature increases from 130 °C to 220 °C, the products transformed from hexagonal prisms to polyhedron along with the disappearance of the hexagonal prisms vertical plane. Simultaneously, both the reaction time and pH value could promote the nucleation and growth of crystal particles. More interestingly, the target products with different morphologies could be obtained by varying the usage of NaOH or NH3·H2O at 130 °C during the microwave synthesis process.

Synthesis and tribological behavior of ashless alkylphosphorofluoridothioates

Ashless alkylphosphorofluoridothioates were synthesized and their tribological performance was comparatively studied with zinc dialkyldithiophosphates (ZDDP) by high frequency reciprocating ball tests. Formulations with alkylphosphorofluoridothioates in base oil at 0.1% (w/w) phosphorus level show significantly better antiwear performance than that with ZDDP, in particular for compounds with medium or long alkyl chains. The tribofilms generated from HFRB tests were examined using X-ray absorption near edge structure spectroscopy (XANES). XANES analysis demonstrates that tribofilms from alkylphosphorofluoridothioates are made up of oxides, sulfides, sulfates and short chain phosphates of iron while tribofilm from ZDDP is made up of oxides, sulfides, sulfates and short chain phosphates of iron in addition to sulfides, sulfates and short chain phosphates of zinc.

Vibrational spectroscopic characterization of the phosphate mineral phosphophyllite – Zn2Fe(PO4)2·4H2O, from Hagendorf Süd, Germany and in comparison with other zinc phosphates

This research was undertaken on phosphophyllite sample from the Hagendorf Süd pegmatite, Bavaria, Germany. Chemical analysis was carried out by Scanning Electron Microscope in the EDS mode and indicates a zinc and iron phosphate with partial substitution of manganese, which partially replaced iron. The calculated chemical formula of the studied sample was determined to be: Zn2(Fe0.65, Mn0.35)∑1.00(PO4)2·4(H2O). The intense Raman peak at 995cm−1 is assigned to the ν1PO43- symmetric stretching mode and the two Raman bands at 1073 and 1135cm−1 to the ν3PO43- antisymmetric stretching modes. The ν4PO43- bending modes are observed at 505, 571, 592 and 653cm−1 and the ν2PO43- bending mode at 415cm−1. The sharp Raman band at 3567cm−1 attributed to the stretching vibration of OH units brings into question the actual formula of phosphophyllite. Vibrational spectroscopy enables an assessment of the molecular structure of phosphophyllite to be assessed.

Organic acids inhibit the formation of pyromorphite and Zn-phosphate in phosphorous amended Pb- and Zn-contaminated soil

Pyromorphite (PY) and some zinc phosphates (Zn-P) are very sparingly soluble minerals and hence can immobilize Pb and Zn in contaminated soils. However, mechanisms leading to the poor efficiency of PY and Zn-P formation in contaminated soils amended with P still remain unclear. We studied the influence of two low molecular weight organic acids (LMWOA) – oxalic acid and citric acid and diethylene triamine pentaacetic acid (DTPA) – in PY and Zn-P formation in a P-amended contaminated soil. Despite the high levels of metals (∼4% Pb and 21% Zn) in the study soil, the addition of up to 1% inorganic P transformed only up to 37% and 17% of the total Pb and Zn to PY and Zn-P, respectively. Semi-quantitative estimates from a linear combination fitting of X-ray absorption near edge spectra (LC-XANES fitting) showed that the formation of PY decreased from 37% to 3% of the total Pb in the presence of oxalic acid and the addition of 1% P. The reduced PY formation may be associated with the increase in organic-bound Pb from 9% to 54% and decrease in carbonate associated Pb from 42% to 12% with oxalic acid addition as indicated by a chemical sequential extraction (SE) technique. Citric acid seemed to have a less adverse effect in PY formation than oxalic acid. Our data also suggests both oxalic and citric acids have less adverse effects on the efficiency of Zn-P formation. From this study we conclude that the abundance of LMWOA in soil environments can be one factor contributing to the poor efficiency of P amendments practices to effectively immobilize Pb and Zn in metal contaminated soils.

Ionothermal synthesis and characterization of two zinc phosphates from a protic ionic liquid

Protic ionic liquids (PILs) are a subset of ionic liquids, which are cost-effective and easily produced through the combination of a Brønsted acid and a Brønsted base. In this work, we have taken an organic amine, triethylenetetramine (TETA), as an example to form a PIL with acetic acid, and described the ionothermal synthesis of zinc phosphate in a PIL for the first time. Two crystalline zinc phosphate materials, ZnPO–TETA1 and ZnPO–TETA2, were successfully produced by using this PIL as the solvent and template. Powder X-ray diffraction, SEM, TGA and CHN analysis were used to characterize the two materials. The two crystalline solids are very similar to two known zinc phosphates. ZnPO–TETA1 has an open-framework and ZnPO–TETA2 has a ladder structure, and the TETA cation was incorporated into their final structure to balance the framework negative charge. It was found that the P/Zn ratio is crucial to the phase selectivity in a protic ionic liquid. Low P/Zn ratios favor the structure with higher dimensions and high P/Zn ratios tend to form the lower dimensional structures.

Synthesis and antiwear behaviour of ashless alkylthioperoxydiphosphates

A series of ashless alkylthioperoxydiphosphates antiwear lubricant additives were synthesised via oxidation of O,O'-dialkyldithiophosphoric acids under mild condition. The compounds were characterised using NMR, FT-IR and mass spectrometry, and their antiwear performance was systematically evaluated using a high frequency reciprocating ball (HFRB). Tribofilms generated by alkylthioperoxydiphosphates were investigated by scanning electron microscopy, optical profilometry and X-ray absorption near edge structure (XANES) spectroscopy. Formulations with alkylthioperoxydiphosphates in base oil at 0·1% (w/w) phosphorus level exhibit significantly better antiwear performance compared to zinc dialkyldithiophosphate (ZDDP), in particular for compounds with medium or long alkyl chains. The XANES analysis of thermal films and tribofilms indicate that thermal films are made up of short chain zinc phosphates when ZDDP is used and short to medium chain iron phosphates when the alkylthioperoxydiphosphates are used. Tribofilms from ZDDP have Zn3(PO4)2 while tribofilms from alkylthioperoxydiphosphates have Fe4(P2O7)3 near the surface with both tribofilms having sulphates near the surface of the tribofilms.

The effect of zinc oxide–phosphate core–shell pigments on the properties of blend rubber composites

In this work the rheological, physico-mechanical, thermal and morphology studies were performed on a blend of EPDM/SBR (ethylene propylene diene monomer/styrene butadiene rubber) (50/50) loaded with a new prepared core–shell pigment based on a core of zinc oxide which presents the major component of the prepared pigment (≈90%) covered with a shell of phosphate, this shell comprises only about (≈10%). The new pigments were added in different concentration to the rubber blend and were compared to blends pigmented with commercial zinc oxide and zinc phosphate. The results showed that the new pigments exhibited better rheometric, and physico-mechanical properties. In addition, these prepared pigments showed decrease of equilibrium swelling in toluene solvent and increase in crosslink density for EPDM/SBR blend. The efficiency of prepared core–shell pigments were also evaluated by studying the surface morphology (SEM) and thermal properties TGA (thermal gravimetric analysis). The prepared pigments loading of 10phr (parts per hundred parts of rubber) showed the optimum properties of EPDM/SBR blend than rubber loaded with higher concentration of the commercial pigments, which indicated that the new core–shell pigment is more economic with better performance than commercial zinc oxide and phosphates individually.

ToF‐SIMS of polyphosphate glasses

The increasing interest in phosphate glasses is due to the fact that they are considered to be bioactive functional materials in applications such as hard and soft tissue engineering and also that they possess interesting optical properties. These include low dispersion, high refractive index and high transparency for ultraviolet light. They have also been found to be responsible for the good anti‐wear properties of phosphorus‐based engine‐oil additives. More recently, the low processing temperature of zinc and iron phosphates, as well as their chemical durability, has opened the possibility for new applications, such as the immobilization of nuclear wastes. Understanding the surface chemistry of such glasses turns out to be a key step for inferring their underlying mechanisms of action. In this work, zinc phosphate and iron phosphate glasses of different chain lengths were synthesized and characterized by means of time‐of‐flight secondary ion mass spectroscopy (ToF‐SIMS). ToF‐SIMS was able to successfully differentiate between the samples of different composition. A characteristic pattern of phosphate fragments was observed in the negative‐mode ToF‐SIMS spectra. The most intense peaks could be assigned to the phosphate fragments PO−, PO2−, PO3− and PO4−. Toward higher masses, fragments containing up to four phosphorus atoms with a periodicity of PO2 were observed: FePO3−, ZnPO3−, FePO4−, ZnPO4−, FeP2O6−, ZnP2O6−, FeP2O7−, ZnP2O7−; FeP3O8−, ZnP3O8−, FeP3O9− and ZnP3O9−. This pattern characterizes the spectra of all the glasses under investigation. For the first time, a method is proposed that allows the discrimination between polyphosphates of different chain lengths, by comparing the intensities of the relevant ToF‐SIMS peaks. Copyright © 2012 John Wiley & Sons, Ltd.

Preparation and tribological properties of zinc dialkyl(aryl)ethoxy dithiophosphates

PurposeEnvironmental regulations have called for reduction of phosphorus content in engine oils because this element strongly deactivates the catalyst in automotive catalytic converters. The primary source of phosphorus is zinc dialkyl(aryl)dithiophosphate (ZDDP). Therefore, to protect catalyst ZDDP is replaced with other additives or its amount in engine oil is reduced. Zinc dialkyl(alkylaryl)ethoxy dithiophosphates (ZEDPs), a novel derivative of dithiophosphate additive, soluble in lubricating base oils were synthesized and used to replace containing more phosphorus ZDDP.Design/methodology/approachTribological properties of ZEDPs were evaluated using four‐ball and the ball‐disc tribometers. The ZEDPs thermal stability and worn surface were analysed using TGA, XPS techniques.FindingsZEDPs significantly reduce the friction and wear under boundary, mixed and hydrodynamic lubrication regimes. Friction and wear properties are dependent on chemical structure of additives, their surface active behavior in tribological system and frictional parameters. The effectiveness of friction and wear reduction increases with the concentration of lubricating oil additive solution and depend on the amount of the additive adsorbed on the surfaces. ZEDPs are much more thermally stable than ZDDPs. The XPS shows that the tribochemical films formed on rubbing surfaces contain zinc and iron phosphates and sulphates.Research limitations/implicationsThe effect of the number of etoxy groups in ZEDPs molecules on their tribological properties was not investigated.Practical implicationsZEDPs were synthesized and can be a potential replacement for ZDDP.Originality/valueZEDPs were first investigated in lubrication of steel‐steel frictional contact and results indicate that they can be used as additives in combustion engine base oil.

Exopolysaccharides (EPS) as anti-corrosive additives for coatings

Exopolysaccharides (EPS) are a class of renewable polymers that show interesting anti-corrosive properties and could potentially be used as an alternative for zinc phosphates. When combined with a waterborne styrene-acrylic polymer dispersion (SA-1), exopolysaccharides were shown to give an improvement in the anti-corrosive performance. Electrochemical studies show higher charge transfer resistance (Rct) values for the SA-1/EPS combinations as compared to the SA-1 itself suggesting that in the presence of EPS less corrosion took place. Outdoor exposure test shows that the presence of EPS188 gave good corrosion protection for up to a year when exposed under marine conditions. The distribution of EPS modification throughout the coating was made visible using Confocal Laser Scanning Microscopy and indicated that EPS was distributed rather homogeneously. A working mechanism was proposed in which the carboxylic acid groups on the oxidised EPS form a complex with iron ions formed by the anodic reaction and this insoluble complex forms a protective layer between the coating and metal. The results in this paper show that by using renewable polysaccharide additives the anti-corrosive coating performance can be improved.

Morphology, structure and chemistry of extracted diesel soot: Part II: X-ray absorption near edge structure (XANES) spectroscopy and high resolution transmission electron microscopy

Chemical composition of diesel soot extracted from used diesel engine has been investigated using X-ray Absorption Near Edge Structure (XANES) spectroscopy and high-resolution transmission electron microscopy (HRTEM). The XANES spectra indicate the presence of phosphates of zinc and calcium and sulfates of zinc and calcium as well as the presence of sulfides of zinc. HRTEM coupled with EDS and lattice imaging indicates the presence of nanoparticles of Ca3(PO4)2 and Fe2O3 embedded in the turbostratic soot structure. Both Ca3(PO4)2 and Fe2O3 are hard particles and appear to have been incorporated within the turbostratic soot structure during third body wear.