Adsorption of Oleic Acid on Calcium Minerals

Adsorption of oleic acid on nuorite and calcite was studied by adsorption isotherms and Electro kinetic measurements. The adsorption of oleic acid on calcium minerals was observed to proceed initially by monolayer formation at lower concentrations followed by the physical adsorption of hydrocarbon chains in the second layer and finally the precipitated calcium oleate at higher concentrations. Compared to calcite. oleic acid was found to adsorb on fluorite at very low equilibrium concentrations. From the zeta potential measurements. the iso electric point (iep) values of fluorite and calcite are found to be 10.5 and 8,5 respectively. In presence of oleic acid the iep values of fluorite and calcite are shifted to 3.0 and 5.8 indicating specific chemical-interaction between surface calcium and oleate ions. The Free energy of adsorption was calculated from adsorption and Zetapotential measurements. The sign and magnitude of free energy of adsorption suggest the chemisorption of oleic acid on fluorite

A novel de-tert-butylation of p-tert-butylcalix[n]arenes

A facile de-tert-butylation method was developed for the synthesis of calix[n]arenes. A mixture of p-tert-butylcalix[n]arene, sodium dithionite and tri-fluoro acetic acid were refluxed at 80-90 ºC for 24 h. The calix[n]arenes with yields ranging from 80-92 % was achieved

Studies on the adsorption of arsenic on Cali[6]arene.

p-tert-butyl calix[6]arene (PTC6) was synthesized and characterized by solid- and liquid-state NMR and LC-MS techniques. The adsorption of arsenite and arsenate on calix[6]arene under different pH conditions and adsorbate doses was studied. The maximum adsorption of arsenic species on calix[6]arene was observed around neutral pH and the adsorption density of As (III) was higher than that of As (V). The adsorption of neutral H3AsO3 and negatively charged H2AsOS4 molecules on calix[6]arene was attributed to the condensation reaction between hydroxyl groups of PTC6 and arsenic species. The complexation of arsenite with phenolic oxygen was confirmed by solid-state 13C NMR CP-MAS. Exo attack mechanism was proposed to describe the interaction of arsenous and arsenic acid molecules with PTC6. The specific interaction between calix[6]arene and arsenic species was further substantiated by zeta-potential (z-potential) measurements and free energy of adsorption. The free energy of adsorption (Gads) estimated from Stern–Grahame equation was found to be 25 kJ/mole for As (III) and 19 kJ/mole for As (V)

Studies on the Zetapotential of Calcite/p-Sulfonatocalix[ 4,8]arenes

Zeta potential of calixarenes has been reported for the first time. The water-soluble calixarenes has been used as dispersion media in solid/liquid interface. p-sulfonato-calix[4]arene (PSC4) and p-sulfonato-calix[8]arene (PSC8) were synthesized and characterized by FTIR, NMR, mass spectrometry, and HPLC techniques. It was proved that the zeta potential is a fast and simple measurement to know the adsorption behavior of sufonato calixarnes on calcite. The chemisorption of p-sulfonato-calix[n]arene was confirmed by shift in iso electric point, adsorption studies and FTIR. The calculated free energy of adsorption value and its sign suggests the chemical interaction between the calcite surface and p-sulfonato calix[4]and[8]arene

STUDY ON FLOTATION OF SILLIMANITE USING PLANT-BASED COLLECTOR

The coastal lines of India are rich in placer deposits of valuable heavy minerals such as ilmenite, garnet, rutile, zircon and sillimanite. The conducting and magnetic minerals are separated first, leaving behind the non-conducting and non-magnetic sillimanite along with quartz in the processing of heavies in beach sand. Sillimanite, an important mineral for refractory application is mainly recovered by flotation technique from its associated major gangue mineral, quartz by imparting selective surface hydrophobicity on sillimanite using a suitable collector. A placer sample after the removal of heavies from eastern coast of India was studied for beneficiation using froth flotation technique. Detailed characterization studies of the feed sample and the types of collectors used for this study have been carried out using XRD and FTIR analyses. Sillimanite feed sample assaying 55.4% sillimanite along with 33.9% quartz, 1.7% magnetics, 1.4% rutile, 2.4% zircon, 5.6% kynite was subjected to beneficiation using flotation technique for enriching the sillimanite content using oleic acid and a plant-based reagent SFA as collector. The effect of variation of input parameters such as pH, depressant and collectors were evaluated and flotation process optimization was carried out. Based on the results, it was found that flotation performance of the natural source based collector has better selectivity and improved recovery as compared to that of oleic acid as collector. Weight recovery of 67.8% with 85.1% sillimanite was obtained using the plant-based collector while a weight recovery of 55.5% with 84.9% sillimanite was obtained using oleic acid. The improved sillimanite recovery by using the plant-based collector than that of the conventional oleic acid would be more economical in industrial scale sillimanite recovery in beach sand processing industries

Mechanochemical Synthesis of p-Nitro Calix[6]arene

A novel procedure was developed for the synthesis of p-nitro calix[6]arenes from p-tert-butyl calix[6]arene by mechanical activation. Mixture of p-tert-butyl calix[6]arene dissolved in dichloromethane, glacial acidic acid and anhydrous HNO3 was subjected to intense mechanical activation/agitation in planetary ball mill. The nitro substituted calix[6]arene with 97% purity. and 75% yield was formed within 2.5 h which otherwise takes several hours to complete the reaction

A Novel De-tert-butylation of p-tert-Butylcalix[n]arenes

A facile de-tert-butylation method was developed for the synthesis of calix[n]arenes. A mixture of p-tert-butylcalix [n]arene, sodium dithionite and tri-fluoro acetic acid were refluxed at 80-90 ºC for 24 h. The calix[n]arenes with yields ranging from 80-92 % was achieved

Plastics—Villain or Hero? Polymers and Recycled Polymers in Mineral and Metallurgical Processing—A Review

This review focusses on the use of recycled and virgin polymers in mineral and metallurgical processing, both high and ambient temperature processes, including novel applications. End of life applications of polymers as well as the utilisation of polymers during its life time in various applications are explored. The discussion includes applications in cleaner coal production, iron and steel production, iron ore palletisation, iron alloy manufacturing, manganese processing, E-wastes processing and carbon sequestration. The underlying principles of these applications are also explained. Advantages and disadvantages of using these polymers in terms of energy and emission reductions, reduction in non-renewables and dematerialisation are discussed. Influence of the polymers on controlling the evolution of micro and nanostructures in alloys and advanced materials is also considered

Study on interaction of p-sulfonato calix[6]arene with arsanilic acid

The interaction of p-sulfonatocalix[6]arene (PSC6) with o-arsanilic acid (OASA) and p-arsanilic acid (PASA) was studied by UV-Visible spectroscopy, high-performance liquid chromatography (HPLC) analysis, photoluminescence (PL) spectra, and nuclear magnetic resonance (NMR) studies. The studies confirm the inclusion of PASA in PSC6 cavity

Electrokinetic behavior of Fluorite

The electrokinetic behavior of fluorite mineral was studied under various partical sizes and different concentrations of oleic acid at constant pH. The particle size has been reduced with an increase in activation time. The surface energies of milled fluorite minerals were calculated theoretically and experimentally. The zeta potential of the fluorite/water system has shifted to lower side with an increase in particle size. The isoelectric point (iep) of fluorite minerals has been shifted to lower side with increase in oleic acid concentration. This indicates the chemisorbed oleate formation on fluorite. A sharp decrease in zeta potential in the pH range of 6.5–8.4 and the decrease in calculated free energy of adsorption shows the formation of calcium dioleate precipitate on fluorit