Fine Wolframite Research Articles

Investigations on the effect of Fe2+ and Mn2+ in the flotation of fine wolframite with octyl hydroxamic acid

The effect of Fe2+ and Mn2+ in the flotation of fine wolframite with octyl hydroxamic acid (OHA) as a collector was studied through a series of experiments. The XPS analysis indicates that Fe2+ and Mn2+ species on the wolframite surface are the active sites to interact with OHA collector. However, microflotation and contact angle tests show that the excess Fe2+ and Mn2+ ions in pulps decrease the flotation recovery and surface hydrophobicity of wolframite, playing inhibition roles on the flotation performance. The zeta potentials of wolframite shift toward positive values in the presence of Fe2+ and Mn2+. Fe(OH)2(s) and Mn(OH)2(s) precipitates being dominated species preferentially coat onto wolframite surfaces and then hinder the OHA adsorption. The adsorption results further give evidences that the excess Mn2+ and Fe2+ ions in the aqoeous solution also will consume OHA collector. These two processes decrease the adsorption of OHA and the flotation recovery of wolframite.

Influence of Microbubble on Fine Wolframite Flotation

The recovery of fine wolframite is low when using traditional flotation that does not use a microbubble. In this study, a microbubble was introduced into the fine wolframite flotation system; −20 μm wolframite was used as an experiment sample and octyl hydroxamic acid as the collector. The recovery of microbubble flotation reached 84.07%, which is about 12.04% higher than that of traditional flotation. A single-factor flotation experiment, high-speed camera analysis, and SEM (Scanning Electron Microscopy) analysis were used to study the influence of microbubbles on the flotation of fine wolframite. The results show that fine wolframite will more easily agglomerate under the action of microbubbles. The octyl hydroxamic acid adsorbed on the surface of wolframite treated with microbubbles is denser and more abundant.

The effect of sodium silicate depressant on the flotation separation of fine wolframite from quartz

ABSTRACTQuartz could be activated by metal ions dissolved from wolframite surfaces, making it difficult to separate wolframite from quartz. In this study, sodium silicate used as depressant was investigated in the flotation of fine wolframite. Sodium silicate showed the selective depression on the activated quartz, and the flotation separation of fine wolframite could be achieved by depressing quartz. It was revealed that the adsorption of sodium silicate on activated quartz surfaces was more obvious than that on wolframite. Si(OH)4 and species of aqueous sodium silicate preferentially reacted with activated quartz surfaces and prevented the octyl hydroxamic acid adsorption, further decreasing its floatability.

Effect of temperature on floatability and adsorption behavior of fine wolframite with sodium oleate

The influence of pulp temperature on the floatability and adsorption behavior of fine wolframite with sodium oleate was investigated by microflotation experiments, electric conductivity tests, adsorption measurements, and FT-IR analysis. Microflotation results show that fine wolframite with sodium oleate exhibits a good floatability at pH 8–9. Electric conductivity tests indicate that the high temperature enhances the ionization degree and electric mobility of oleate species, then the flotation recovery of fine wolframite and the adsorption amount of sodium oleate are observed to increase with the rise in pulp temperature. The results of adsorption experiments are found to meet Freundlich isotherms successfully, and the isosteric enthalpy (ΔHΘ) is in conformity with the chemical bonding. The changes in FT-IR analysis provide sufficient evidence that sodium oleate interacts with the metal cations of wolframite surface, and the increase in pulp temperature clearly promotes the chemisorption intensity. These findings will be beneficial to strengthen the flotation behavior of fine wolframite.

The Effect of Quartz on the Flotation of Fine Wolframite with Octyl Hydroxamic Acid

The influence of quartz on the flotation of fine wolframite using octyl hydroxamic acid (OHA) as the collector was investigated by micro-flotation tests, inductively coupled plasma (ICP) measurements, adsorption experiments, zeta potential, and Fourier transform infrared spectroscopy (FT-IR) analysis. Micro-flotation tests showed that a large difference in floatability existed between fine wolframite and quartz in the pH range of 7.0 to 10.0. However, in a synthetic mixture, the flotation separation of fine wolframite from quartz became more difficult as the particle size of the latter decreased. When a dissolved solution of wolframite was used as the flotation medium, quartz floatability improved significantly. Zeta potentials of quartz particles shifted positively in the dissolved solution of wolframite compared to distilled water, especially at a pH level of 7.0–10.0, which was attributed to the metal ions dissolved from the wolframite being adsorbed onto the quartz surface. The surface activation of quartz led to an increase in the OHA adsorption and made the surface hydrophobic. FT-IR analysis further demonstrated that OHA could adsorb onto the activated quartz surface through a dominantly chemical process.

Effect of collector and depressant on monomineralic surfaces in fine wolframite flotation system

Abstract Except wolframite monominerals, other monominerals, such as scheelite, fluorite, calcite, and quartz, exist in wolframite flotation. Therefore, it is necessary to investigate the floatability of main monominerals in wolframite flotation. This paper mainly investigated the effects of benzohydroxamic acid as a collector and sodium silicate as a depressant on different monominerals surfaces by X-ray photoelectron spectroscopy, including wolframite, scheelite, fluorite, calcite, quartz. The results indicated that the chemisorption of GYB followed by formation of five-membered ring chelate on wolframite and scheelite surfaces is responsible for inducing the floatability. A small number of GYB molecules stayed on fluorite surfaces by physical adsorption. GYB did not adsorb on calcite and quartz surfaces. SS did not adsorb on wolframite and scheelite surfaces. For fluorite and calcite, H2SiO3, H SiO 3 - and SiO 3 2 - can absorb on fluorite surface at low silicate concentrations and the depression was also achieved by ligand exchange between F and Si(OH)4. For quartz, H2SiO3, H SiO 3 - and SiO 3 2 - can absorb on quartz surfaces by supply of external pairs.

Flotation characteristics and flotation kinetics of fine wolframite

The flotation characteristics and kinetics of fine wolframite from Shizhuyuan Mine, Hunan, China were studied. Coarse and middle particles entered the concentrate easily. However, because of the reduction of middle particles as carriers and the poor collision and attachment between fine particles and air bubbles, it was difficult to float fine particles. A new kinetic model was proposed and compared with four common kinetic models, including a classical first-order model, a modified first-order model, a first-order kinetic model with a rectangular distribution of floatabilities and a second-order kinetic model with a rectangular distribution of floatabilities. The kinetic model evaluation showed that the author's model fitted the experimental data best. The new model was applied to industrial data in a dressing plant to verify its reliability, and a better imitative effect was obtained compared with other models investigated. The modified first-order model agreed well with experimental and industrial data. The optimum flotation kinetic equations of fine wolframite in the laboratory and dressing plant were ε=87.26−31.74e−3.446t−55.51e−0.879t and ε=85.76−44.67e−2.052t−41.09e−0.434t, respectively.

Effects of surface electrical property and solution chemistry on fine wolframite flotation

Abstract In this paper, the effects of the surface electrical property and solution chemistry on the fine wolframite flotation were investigated by zeta potential measurement and the modified concentration logarithm diagrams. Based on that results, the flotation effects of different monominerals, including wolframite, scheelite, fluorite, calcite and quartz, were studied using different single collector, including sodium oleate, salicylaldoxime, benzohydroxamic acid and fatty-acid collector GYR. However, the wolframite recovery was low, and thus the mixed collectors were used to improve the recovery using benzohydroxamic acid as main collector and other collector as additional collector, including sodium oleate, salicylaldoxime, benzohydroxamic acid, fatty-acid collector GYR and fatty-acid collector TAB-3. The results show that the maximum recovery of wolframite exceeded 86% using GYB and TAB-3 as mixed collectors, which was up 13% compared with single GYB. These results could be explained in terms of the modified concentration logarithm diagrams in conjunction with the IEP values of different monominerals mentioned in this work. The infrared spectrogram indicated that because of different structures and properties of GYB and TAB-3, GYB could be complementary with TAB-3.

Flotation behavior and adsorption mechanism of fine wolframite with octyl hydroxamic acid

Flotation behavior and adsorption mechanism of octyl hydroxamic acid (OHA) on wolframite were investigated through flotation experiments, adsorption tests, zeta-potential measurements, infrared spectroscopy and solution chemistry calculations. Results of flotation and adsorption experiments show that the maximum values of flotation recovery and adsorption capacity occur around pH 9. In term of the solution chemistry calculations, the concentration of metal hydroxamate is greater than that of metal tungstate and metal hydroxyl, and metal hydroxamate compounds are identified to be the main species on wolframite surface at pH region of 8-10, contributing to the increase of OHA adsorption and flotation performance. Results of zeta-potential and IR spectra demonstrate that OHA adsorbs onto wolframite surface by chemisorptions. Hydroxamate ions can bond with Mn2+/Fe2+ cations of wolframite surface, forming metal hydroxamate compounds, which is a key factor in inducing the hydrophobicity of wolframite under the conditions of maximum flotation.

Studies on interaction mechanism of fine wolframite with octyl hydroxamic acid

Interaction mechanism of fine wolframite with octyl hydroxamic acid (OHA) during flotation process was investigated. Flotation and adsorption tests indicated that wolframite showed better floatability as a consequence of OHA adsorption at pH 7.0–10.0. Zeta-potential measurements revealed that OHA adsorbed specifically on wolframite surface. The results of solubility behavior of wolframite indicated that the anion-exchange reaction occurred between OHA− in solution and WO42- in the crystal lattice. OHA− might interact with Mn2+/Fe2+ cations of wolframite surface to form ferrous/manganous hydroxamate precipitations, with a release of WO42- ions. The XPS analysis confirmed that the mechanism of OHA adsorption onto wolframite surface associating coadsorption/surface reaction process was presented in flotation conditions. OHA could bond with ferrous/manganous species on wolframite surface, accompanying molecule OHA physical adsorption onto the chemisorbed layer of ferrous/manganous hydroxamate precipitations. This interaction process appeared to be strong enough to ensure adequate adsorption ability of OHA on wolframite surface and led to good hydrophobicity of wolframite.

ウォルフラマイト微粒子のキャリア磁選に関する研究

Carrier magnetic separation of fine wolframite (-5μm) was investigated using coarse magnetite (37-53μm, etc.) as carriers and sodium oleate as a surfactant by high gradient magnetic separator. Effects of some factors on the carrier magnetic separation were studied. It was found that the recovery of fine wolframite was significantly increased from about 23% by conventional magnetic separation to 94% by carrier magnetic separation at magnetic flux density 0.14T. The recovery of fine wolframite was improved from 50% to 93% by carrier magnetic separation at 0.27T for a mixture of wolframite (-5μm) and quartz (-10μm) containing 10.9% WO3.The improved results of magnetic separation were mainly explained by the size enlargement of the fine wolframite due to the addition of carriers and stirring at high speed. The collision energy between the coarse and fine particles is much greater than that between fine particles. Therefore, aggregation be tween coarse and fine particles occurs more easily. The stability of aggregate of particles is also strengthened due to the hydrophobic forces between particles with the addition of sodium oleate.

Spherical agglomeration of fine wolframite ((Fe,Mn)WO4) mineral particles

The effect of pH and surfactant concentration on the agglomeration of aqueous dispersions of fine (< 10 μm) wolframite ((Fe,Mn)WO4) mineral particles is described. Dodecylamine was used to render them hydrophobic and iso-octane to bind them into agglomerates sufficiently strong to be recovered by screening. The feasibility of selective agglomeration of wolframite from quartz (SiO2) was also established, both in batch and continuous reactors.

Adsorption of dodecyl sulfate and decyl phosphonate on wolframite, (Fe, Mn)WO 4, and their use in the two-liquid flotation of fine wolframite particles

The isotherms for the adsorption of sodium dodecyl sulfate and decyl phosphonic acid at the wolframite/water interface have been determined at various surfactant concentrations and pH values. The form of the adsorption isotherms indicated that both these reagents adsorbed chemically onto the wolframite surface resulting in the formation of iron/manganese-decyl phosphonate or dodecyl sulfate compounds, followed by hydrophobic association at high surfactant concentrations. Sodium dodecyl sulfate increased the solubility of wolframite at pH 2.0 due to the formation of an iron/manganese sulfate complex in solution, whereas at pH 6.1 an anion exchange reaction took place between tungstate ions in the crystal lattice and dodecyl sulfate ions in solution. At alkaline pH values the effect of sodium dodecyl sulfate on the solubility of wolframite was negligible. Decyl phosphonic acid was found to have little effect on the solubility of wolframite at any pH. In two-liquid flotation tests, maximum concentration of the −13.6-μm wolframite particles at the iso-octane/water interface occurred at pH values above 6 for both collectors studied. This was in agreement with the mechanism of adsorption suggested.