Styryl Phosphonic Acid Research Articles

Controlling Extraction of Rare Earth Elements Using Functionalized Aryl-vinyl Phosphonic Acid Esters.

Ligands that can discriminate between individual rare earth elements are important for production of these critical elements. A set of aryl-vinyl phosphonic acid ligands for extracting rare earth elements were designed and synthesized under the hypothesis that the strength of the rare earth-ligand interactions could be tuned by changing the dipole moment of the ligand. The ligands were synthesized via a two-step reaction procedure using a Heck coupling reaction to functionalize vinyl phosphonic acid, followed by Steglich esterification to obtain high-purity styryl phosphonic acid monoesters with varying dipole moments along the P-C bond. The metal binding strength and composition of the rare earth complexes formed with these styryl phosphonic acid monoesters were experimentally studied by liquid-liquid extraction techniques, while DFT calculations were performed to determine the dipole moments of the free and complexed ligands and the electronic structure of the complexes formed. All three prepared ligands were much stronger extracting agents for europium(III) than the dialkylphosphonic acids usually used for this separation. However, the order of increasing extraction strength was found to match the order of the decreasing calculated dipole moment along the P-C bond of the three styryl-based ligands, rather than correlating with increasing ligand basicity, as reflected by the pKa of the ligands. These findings suggest that this approach can be used to systematically alter the extraction strength of aromatic phosphonic monoesters for rare earth element purification.

Flotation separation of bastnaesite and fluorite using styrylphosphonic acid and cinnamohydroxamic acid as collectors

Light rare earth elements (LREEs) with atomic numbers 57 to 60 (lanthanum (La), cerium (Ce), praseodymium (Pr) and neodymium (Nd)) have diverse applications in many fields. Bastnaesite is an important LREE-containing mineral and flotation is a most important method to recover fine grained bastnaesite and to separate bastnaesite and its associated gangue minerals such as fluorite. This study firstly employed styrylphosphonic acid (SPA) and cinnamohydroxamic acid (CHA) with the same nonpolar group (i.e., styryl group) as SPA as the collectors in the flotation separation of bastnaesite and fluorite. Flotation experiments show certain selectivities of SPA and CHA. And CHA has the stronger collecting ability and the poorer selectivity than SPA. The adsorption mechanisms of SPA and CHA on the surfaces of bastnaesite and fluorite were investigated by zeta potential measurements, infrared spectroscopic and X-ray photoelectron spectroscopic tests as well as first-principles calculations. Zeta potential measurements show the greater shift in the zeta potential of bastnaesite caused by the addition of CHA than SPA, which indicates the stronger affinity of CHA on the surface of bastnaesite than SPA, as confirmed by the higher adsorption energy of CHA on the surface of bastnaesite obtained from first-principles calculations.

Behavior and mechanism of sodium sulfite depression of almandine from rutile in flotation system

Sodium sulfite has been utilized in the mineral industry principally as a depressant for a variety of sulfide ores. In this study, it was tested as a depressant in flotation of oxidized ore from its silicate mineral gangue. Selective flotation of rutile from almandine was investigated using sodium sulfite as a regulator and an octadecyl amine polyoxyethylene ether (AC1815) mixed with Styryl phosphonic acid (SPA) as a composite collector. The investigation was conducted through a series of micro-flotation tests of single and artificially mixed minerals. In addition to that, the measurements of contact angle, zeta potential, and X-ray photoelectron spectroscopy (XPS) were also conducted to unravel the adsorption mechanism of the depressant onto the surfaces of the two minerals. The experimental results clearly demonstrated that sodium sulfite acting in the form of SO32− at pH range 6–8 was more selective adsorbed on almandine surface compared to that of rutile, leading to a high selectivity for the flotation of rutile. The XPS results revealed a strong interaction between the active ferrous sites of almandine and SO32− of the sodium sulfite through reduction forming a hydrophilic metal sulphate layer and metal ox-hydroxides surfaces, which in turn reduced adsorption sites for collector and led to a decrease of surface hydrophobicity thereby strongly depressing the flotation of almandine.

Flotation of rutile from almandine using sodium fluorosilicate as the depressant

There is little scientific agreement on the way sodium fluorosilicate (SF) depresses gangue minerals, resulting in a stagnation into in-depth research. Here, we describe a new explanation hoping to advance this step of development. In this study, flotation of rutile from almandine was investigated using SF as the depressant and Styryl phosphonic acid (SPA) as the collector. The study was performed through the measurements of zeta potential, contact angle, and X-ray photoelectron spectroscopy (XPS), in addition to the micro-flotation of single minerals and artificially mixed minerals. The experimental results demonstrated that SF acting in the form of SiF62− at pH 5–6 was a highly selective depressant on almandine, rather than on rutile, leading to a high selectivity for the flotation of rutile. The XPS results revealed a strong interaction between F and active Fe sites on almandine surface, reducing adsorption sites for collector, thereby strongly depressing the flotation of almandine.

Adsorption mechanism of sodium oleate and styryl phosphonic acid on rutile and amphibole surfaces

Abstract A reagent combination of sodium oleate (NaOl) and salicyl hydroximic acid was employed as the roughing and scavenging collectors, whereas styryl phosphoric acid (SPA) and octanol were employed as the cleaning collectors. Results of bench-scale flotation demonstrate that the dosage of SPA can be reduced by about 80%, and that a better flotation index can be obtained using the proposed reagent system. The results of adsorption amount and contact angle measurements indicate that the rutile surface adsorbed not only a large amount of residual NaOl but also SPA and a small amount of NaOl remained on the amphibole surface in strong acidic solution. The hydrophobic difference between rutile and amphibole surfaces was therefore amplified in cleaning, and their further separation became much easier consequently.

Hydrophobic flocculation flotation of rutile fines in presence of styryl phosphonic acid

Abstract The hydrophobic flocculation flotation of rutile fines in the presence of styryl phosphonic acid (SPA) was investigated by flotation tests, zeta-potential measurement, optical microscope observation, laser-based particle size analysis, adsorption measurements and DLVO theory. The flotation tests indicated that rutile fines could be flocculated by SPA, and pH, shear force (stirring speed) and stirring time played significant roles in flocculation. The isoelectric point (IEP) and zeta-potential in whole range all moved to negative values as SPA was added according to the results from zeta-potential measurement. It was demonstrated that the primary reason for above was chemical adsorption. The laser-based particle size results showed the particle size at a stirring speed of 1800 r/min and 1000 mg/L SPA was the largest in all experiments. Furthermore, using the optical microscope observation and flotation tests, it was important for flotation of rutile fines to produce the flocculant. In the light of above-mentioned facts, floc flotation of rutile fines could be induced in the form of chemical adsorption by SPA to increase particle size. The data calculated from DLVO theory also indicated that chemical adsorption was the main reason for the formation of flocculant.

A novel chemical scheme for flotation of rutile from eclogite tailing

A novel chemical scheme for the flotation of rutile from eclogite tailings has been developed in this work. It consists of lead ion as the activator, sodium fluorosilicate (SF) as the depressant, and styryl phosphonic acid (SPA) and n-octyl alcohol (OCT) as the collector. By using the proposed scheme to treat a feed ore of 4.5% TiO2, a rougher concentrate of grade 84.47% TiO2 was achieved with the recovery of 61.5%. Also, the scheme made a high flotation rate for rutile. The scheme was applied to closed-circuit flotation (one-stage rougher flotation, two-stage scavenger flotation and two-stage cleaner flotation), produced a concentrate of 92% TiO2 with the recovery of 70%. It is shown that the new chemical scheme would be a potential one for the effective separation of rutile from eclogite ores.

Synthesis and structural characterization of 2-D layered copper(II) styrylphosphonate coordination polymers

We report the synthesis, physicochemical characterization, and crystal structure of Cu-SP (SP = styrylphosphonic acid, H2O3PCH=CH2(C6H5)), the first reported example of a metal derivative of SP. The starting SP acid was fully characterized by X-ray single-crystal diffractometry, elemental analysis (C and H), 31P-NMR, 13C-NMR, 1H-NMR, HPLC, UV–vis, MS, TG, and FT-IR spectroscopy. The copper(II) derivative was synthesized and characterized by DTA-TG and FT-IR, and also its structure was determined from powder data. The crystal structure was refined by the Rietveld method. The crystal structure of Cu-SP shows a layered 2-D architecture, where the organic moieties are pointed toward the interlamellar space. The inorganic layers are composed of Cu2+ dimers, where the coordination geometry of Cu2+ can be described as distorted trigonal bipyramid. The three coplanar oxygens (O2, O3, and O3) have bond distances of 2.165(9), 1.982(9), and 2.103(11) Å, respectively. The bond lengths for the apical oxygens (O1 and O2) are 1.908(13) and 1.996(11) Å, respectively.

The development of a composite collector for the flotation of rutile

A study was carried out to find a replacement for benzyl arsenic acid (BAA) that was used in the rutile flotation circuit of a hard rock rutile mine in China. Several types of oxide collectors were tested, including sodium oleate, sodium laurate, sodium dodecyl sulphate, amino acids, diphosphonic acid and styryl phosphonic acid. It was found that styryl phosphonic acid (SPA) was the most effective, and that an aliphatic alcohol (e.g., octanol) was required to maintain the effectiveness of SPA. However, octanol was insoluble in water. The composite collector that was mixed with SPA and octanol had to be well emulsified before addition to flotation pulp. Poorly emulsified composite collectors destroyed flotation froths. Several surfactants were tested as emulsifiers and one was found to have the least adverse effects on the selectivity of the composite collector. By using the composite collector that contained SPA, octanol and the emulsifier, a rutile rougher concentrate assaying 71.3% TiO 2 was floated at 81.6% recovery from a feed containing 8.78% Ti0 2 in a single stage rougher flotation.

Fersmite flotation with diphosphonic acid and other collectors

Fersmite, found in the Baiyunebo deposit, China, is a critical source of niobium. The flotation of synthesized fersmite has been studied using different collectors such as cycloalkyl hydroxamic acid, alkyl hydroxamic acid, benzylarsonic acid, styrylphosphonic acid, and diphosphonic acid. Out of all the collectors screened, the diphosphonic acid (DPA) is a particularly good collector and has a good selectivity in fersmite flotation. The interaction of fersmite with diphosphonic acid was studied by electrokinetic measurements, infraredspectroscopy andX-rayphotoelectron spectroscopy analyses. Based on the results of electrokinetic potential measurements and the IRS and XPS analyses, a chemical adsorption mechanism of fersmite with DPA has been proposed. The flotation behavior of fersmite with this collector was consistent with the proposed mechanism and the distribution of diphosphonic species in aqueous solution as a function of pH.

Comparison of Phosphonic and Pyrophosphonic Acids as Collectors for the Cassiterite Flotation

Abstract Styryl phosphonic acid (SPA) is a collector used in the industrial flotation of cassiterite, During its production from styrene and PCl5 by-products are formed in different amounts. One of these is condensed SPA caused by uncomplete hydrolysis of the intermediary phosphonic acid chloride. Attempts were made to synthesize definite forms of condensed SPA in order to study their influence on the results of flotation. Conventional methods-partial hydrolysis of phosphonic acid chlorides or reaction of acid chlorides with the free acid-did not lead to the desired result. Diammonium salt of the pyro-SPA was obtained by the method of (1) using dehydration of phosphonic acid by heating with urea. A series of analogous aromatic pyro-phosphonic acids was synthesized. The hydrophobization effect on Sn02 surfaces was studied by microflotation tests in a modified Hallimond tube. Pyrophosphonic acids are more hydrophobic than the corresponding phosphonic acids. The results of the microflotation experiments were...

Impurity removal and cobalt-nickel separation from sulphate solution by solvent extraction with B312

The sulphate leach solution of cobalt cakes from a nickel refinery, from which iron has been removed using the Jarosite process, is used as the feed liquor. The removal of impurity elements (e.g. Cu, Zn, Mn, Pb and Ca) and the separation of cobalt-nickel from the feed liquor by solvent extraction with Solvent Oil 200 (saturated aliphatic hydrocarbon containing aromatics < 8% wt.) solution of B312 [styryl-phosphonic acid mono sec-alkyl(C 11–13)ester] have been carried out using a bench scale mixer-settler at ambient temperature. Under the selected test conditions, high quality extraction products (viz., CO:Ni>2000; Co:Cu>4200; and Co:Ca>2500 in the solution of cobalt chloride and Ni:Co>660 in the solution of nickel sulphate) have been achieved successfully with high metal recoveries (more than 98% Co and 99% Ni). Preliminary electrolytic testwork on the cobalt strip liquors containing magnesium showed that cobalt could be readily recovered by electrowinning.

ChemInform Abstract: Hetero‐Substituted Norbornenes and Their Derivatives. Part 1. Reaction of Cyclopentadiene with Styrylphosphonic Acid Derivatives.

AbstractCoupling of the styrylphosphonic acid derivatives (I) with cyclopentadiene (II) gives the norbornenylphosphonic acid derivatives (III).

ChemInform Abstract: Reaction of Styrylphosphonic Acid and Its Dichloride with Cyclopentadiene.

ChemInform Abstract: Reaction of Styrylphosphonic Acid and Its Dichloride with Cyclopentadiene.

Derivatives of unsaturated phosphonic acids communication 17. Derivatives of styrylphosphonic acid

??? N-substituted P-styrylphosphonic diamides, two O,O-diesters of ???-diesters of phosphonothioic acid, and two S,S-diesters of stylrylphosphonodithioic acid were synthesized and characterized.