The potential of 2-amino-1-propanol(AP)as a novel depressant in selectively floating ilmenite from titanaugite under weakly acidic conditions was investigated.Micro-flotation results show that AP significantly reduces...The potential of 2-amino-1-propanol(AP)as a novel depressant in selectively floating ilmenite from titanaugite under weakly acidic conditions was investigated.Micro-flotation results show that AP significantly reduces the recovery of titanaugite while having no evident impact on ilmenite flotation.Subsequent bench-scale flotation tests further confirm a remarkable improvement in separation efficiency upon the introduction of AP.Contact angle and adsorption tests reveal a stronger affinity of AP towards the titanaugite surface in comparison to ilmenite.Zeta potential measurements and X-ray photoelectron spectroscopy(XPS)analyses exhibit favorable adsorption characteristics of AP on titanaugite,resulting from a synergy of electrostatic attraction and chemical interaction.In contrast,electrostatic repulsion hinders any significant interaction between AP and the ilmenite surface.These findings highlight the potential of AP as a highly efficient depressant for ilmenite flotation,paving the way for reduced reliance on sulfuric acid in the industry.展开更多
The Damiao Fe-Ti-P deposit,located within the Damiao anorthosite complex in northeastern China,features Fe-Ti oxide ores and nelsonites that occur as irregularly inclined stratiform-like bodies,lenses,or veins with sh...The Damiao Fe-Ti-P deposit,located within the Damiao anorthosite complex in northeastern China,features Fe-Ti oxide ores and nelsonites that occur as irregularly inclined stratiform-like bodies,lenses,or veins with sharp contacts against anorthosite and gabbronorite.This deposit is characterized by abundant titanomagnetite that hosts diverse ilmenite exsolution textures,including blocky,lamellar,and cloth-like forms.In this study,we investigate the geochemistry and mineralogy of ilmenite exsolutions in titanomagnetite to understand their formation mechanisms and implications for the ore-forming process.Detailed petrographic observations and electron microprobe analyses reveal that the exsolution textures result from multiple mechanisms:oxy-exsolution due to titanomagnetite oxidation;subsolidus re-equilibration between magnetite and ilmenite involving elemental diffusion of Fe,Ti,Cr,Co,and Ni;and exsolution related to lattice defects caused by rapid cooling.Thermodynamic modeling using Gibbs free energy calculations,and the QUILF program indicates that blocky,lamellar,and cloth-textured ilmenite exsolutions formed at temperatures above and below the solid-solution solvus under decreasing oxygen fugacity.Additionally,our results indicate that the exsolution of zircon and pleonaste at ilmenite grain boundaries is attributed to the saturation and precipitation of elements like Zr and Al,due to the oxidation of titanomagnetite,rather than interactions between ilmenite and adjacent clinopyroxene.Reconstruction of the cooling history suggests that the oxygen fugacity of oxide-apatite gabbronorites was significantly higher than that of Fe-Ti-P ores.This confirms that increasing oxygen fugacity during magma evolution promoted immiscibility,leading to the formation of nelsonitic melts and ultimately the development of Fe-Ti-P ores.展开更多
n-octylphosphonic acid(OPA)was introduced as a novel collector for ilmenite flotation and its effectiveness was compared with the conventional chelating collector,benzohydroxamic acid(BHA).Micro-flotation tests demons...n-octylphosphonic acid(OPA)was introduced as a novel collector for ilmenite flotation and its effectiveness was compared with the conventional chelating collector,benzohydroxamic acid(BHA).Micro-flotation tests demonstrated that OPA was a highly effective and selective collector for separating ilmenite from titanaugite over acidic conditions(optimal pH around 3),which was also supported by adsorption amount measurements.X-ray photoelectron spectroscopy(XPS)tests indicated that the chemisorption of OPA onto ilmenite surface was much stronger than that of BHA.Solution chemistry diagram analyses indicated that OPA could dissociate well at pH 3.0 and mostly exist in anion form.DFT calculations further confirmed that OPA was much easier to adsorb onto ilmenite surface with shorter bond length and lower adsorption energy in comparison with BHA.Therefore,OPA maintained good collecting ability and selectivity for ilmenite flotation in the strongly acidic pulp,providing valuable insights into new collector design and development.展开更多
The influence of surface dissolution on flotation separation of fine ilmenite from titanaugite was investigated through infrared spectroscopic （FT-IR） analysis and X-ray photoelectron spectroscopy （XPS） test. The ...The influence of surface dissolution on flotation separation of fine ilmenite from titanaugite was investigated through infrared spectroscopic （FT-IR） analysis and X-ray photoelectron spectroscopy （XPS） test. The results show that surface dissolution in weak acid solution is helpful to enlarge the floatability difference between ilmenite and titanaugite. In weak acidic solution, as sodium oleate mainly interacts with Fe which results in ilmenite flotation, and surface dissolution is beneficial to its oxidation, the floatability of ilmenite after surface dissolution is increased; meanwhile, sodium oleate interacts with Ca and Mg which results in titanangite flotation, and the quantities of Ca and Mg on the surface of titanautite are decreased due to the surface dissolution, so the floatability of titanaugite after surface dissolution is depressed. For an ilmenite ore obtained from Panzhihua with TiO2 grade of 8.41%, flotation after surface dissolution treatment could increase TiO2 grade of rough concentrate from 26.7% to 31.73 %.展开更多
The microwave drying of ilmenite was investigated.The effects of power levels and sample mass on drying characteristics of moisture content,drying rate,moisture ratio were studied,with microwave power ranging from 119...The microwave drying of ilmenite was investigated.The effects of power levels and sample mass on drying characteristics of moisture content,drying rate,moisture ratio were studied,with microwave power ranging from 119 W to 700 W and sample mass from 5 g to 25 g.The drying processes were completed within 2-8 min at different conditions.The moisture content and drying rates are found to be dramatically affected by microwave power density.For all drying processes the prior microwave absorption of moisture produces an accelerating peak on the drying rate curves in the initial stage.For the sample mass of 25 g and power of 385 W,the drying kinetics were studied.The experimental results fit better to the Henderson-Pabis index model rather than the Page＇s semi-empirical model;the drying rate constant k is increased with the increase of microwave power and decrease of sample mass.展开更多
The influence of microwave heating on the grinding of Panzhihua ilmenite ore was investigated. Factors that influence the processing are： the microwave exposure time, power density and sample mass. 40 g sample was mi...The influence of microwave heating on the grinding of Panzhihua ilmenite ore was investigated. Factors that influence the processing are： the microwave exposure time, power density and sample mass. 40 g sample was microwave heated for 30 s with 1 kW of microwave power and followed by water quenching. SEM analysis indicated that intergranular fractures occurred between ores and gangues other than transgranular fractures after microwave treatment, which would liberate minerals from each other effectively. The subsequently magnetic separation trials provided evidence that the recovery rate increased from 44% for raw ore to 72% by microwave treatment.展开更多
The permittivity of low grade Panzhuhua ilmenite ore at 2.45 GHz in the temperatures from 20 ℃ up to 100 ℃ was measured using the technology of open-ended coaxial sensor combined with theoretical computation. The re...The permittivity of low grade Panzhuhua ilmenite ore at 2.45 GHz in the temperatures from 20 ℃ up to 100 ℃ was measured using the technology of open-ended coaxial sensor combined with theoretical computation. The results show that both the real （ε′） and imaginary （ε′） part of complex permittivity （ε′-jε′） of the ilmenite significantly increase with temperature. The loss tangent （tanδ） is a quadratic function of temperature, and the penetration depth of ilmenite decreases with temperature increase from 20 ℃to 100 ℃ The increase of the sample temperature under microwave radiation displays a nonlinear relationship between the temperature （T） and microwave heating time （t）. The positive feedback interaction between complex permittivity and sample temperature amplifies the interaction between ilmenite and the microwave radiation. The optimum dimensions for uniform heat deposition vary from 10 cm to 5 cm （about two power penetration depths） in a sample being irradiated from both sides in a 2.45 GHz microwave field when temperature increases from room temperature to 100 ℃展开更多
Phase transitions, morphology changes, and oxidation mechanism of the ilmenite oxidation process were investigated. FeTi03 transforms to hematite and rutile when oxidation at 700-800 ℃, and pseudobrookite is formed w...Phase transitions, morphology changes, and oxidation mechanism of the ilmenite oxidation process were investigated. FeTi03 transforms to hematite and rutile when oxidation at 700-800 ℃, and pseudobrookite is formed when the oxidation temperature reaches 900 ℃. The initial ilmenite powder exhibits paramagnetism; however, after being oxidized at the intermediate temperature （800-850 ℃）, the oxidation product exhibits weak ferromagnetism. The oxidation mechanism was discussed. The microstructure observations show that a lot of micro-pores emerge on the surfaces of ilmenite particles at the intermediate temperature, which is deemed to be caoable ofenhancin~ the mass transfer ofoxgen during oxidation.展开更多
A new combination method consisting of ball milling, carbothermic reduction and hydrochloric acid leaching was proposed for the preparation of nanosized synthetic rutile from natural ilmenite. The ball milling was emp...A new combination method consisting of ball milling, carbothermic reduction and hydrochloric acid leaching was proposed for the preparation of nanosized synthetic rutile from natural ilmenite. The ball milling was employed to grind ilmenite into small particles. The carbothermic reduction was carried out to yield a high titanium slag, which would be easily purified by subsequent leaching procedure. Factors affecting the hydrochloric acid process, namely the leaching time, temperature, and acid concentration, were studied. After leaching and calcining the milled and annealed mixture of FeTiO3/C under the optimal conditions, the TiO2 nanoparticles with size of 10-200 nm and purity〉98.0% were obtained.展开更多
The effects of oxidation-reduction treatment and mechanical activation on the hydrochloric acid leaching performance of Panxi ilmenite concentration were investigated.The results show that both of oxidation-reduction ...The effects of oxidation-reduction treatment and mechanical activation on the hydrochloric acid leaching performance of Panxi ilmenite concentration were investigated.The results show that both of oxidation-reduction treatment and mechanical activation significantly accelerate the extraction of Fe,Ca and Mg from Panxi ilmenite concentration;however,the CaO and MgO contents of the calcined residues obtained from oxidized-reduced ilmenite concentration are higher than the standard values required by chlorination process.The Ca and Mg in oxidized-reduced ilmenite concentration can be leached much faster after mechanical activation,yielding a synthetic rutile which meets the requirements of chlorination process containing 90.50% TiO2 and 1.37% total iron as well as combined CaO and MgO of 1.00%.The optimum oxidation and reduction conditions are as follows：oxidization at 900 ℃ in the presence of oxygen for 15 min and reduction at 750 ℃ by hydrogen for 30 min.展开更多
A systematic investigation on the effect of milling time on carbothermic reduction of ilmenite was carried out by a combination of thermal analysis, X-ray diffraction（XRD）, scanning electron microscopy（SEM） and pa...A systematic investigation on the effect of milling time on carbothermic reduction of ilmenite was carried out by a combination of thermal analysis, X-ray diffraction（XRD）, scanning electron microscopy（SEM） and particle size analysis. It was shown that the graphite crystalline structure was easily destroyed along the（002） crystal plane during milling process. The particle size of ilmenite/graphite mixture was largely decreased and a fully mixed composite structure was obtained after milling for 4 h at high milling intensity. Milling exerts positive effect on the decreasing temperatures of ilmenite reduction and gradual deoxidizing of titanium oxides was completed.展开更多
The hydrogen reduction of Panzhihua ilmenite concentrate in the temperature range of 900?1050 °C was systematicallyinvestigated by thermogravimetric analysis (TG), X-ray diffraction (XRD) and scanning electron mi...The hydrogen reduction of Panzhihua ilmenite concentrate in the temperature range of 900?1050 °C was systematicallyinvestigated by thermogravimetric analysis (TG), X-ray diffraction (XRD) and scanning electron microscopy (SEM) methods. It wasshown that the products of the Panzhihua ilmenite reduced at 900 °C were metallic iron and rutile. Above 1000 °C, ferrouspseudobrookite solid solution was generated. During the reduction process, element Mg gradually concentrated to form Mg-rich zonewhich can influence the metallization process. The reduction reaction proceeded topochemically and its related reduction kineticswere also discussed. The kinetics of the reduction indicated that the rate-controlling step was the diffusion process. The apparentactivation energy of the hydrogen reduction of Panzhihua ilmenite was calculated to be 117.56 kJ/mol, which was larger than that ofsynthetic ilmenite under the same reduction condition.展开更多
This paper researched the enhanced flotation separation performance of ilmenite and titanaugite using the mixed collector benzhydroxamic acid/dodecylamine(BHA/DDA).The interface assembly mechanism was mainly investiga...This paper researched the enhanced flotation separation performance of ilmenite and titanaugite using the mixed collector benzhydroxamic acid/dodecylamine(BHA/DDA).The interface assembly mechanism was mainly investigated through in situ attenuated total reflectance Fourier transform infrared(ATRFTIR)spectroscopy combined with the two-dimensional correlation spectroscopy(2D-COS)and X-ray photoelectron spectroscopy(XPS).It has been found that BHA/DDA mixed collectors successfully separate ilmenite from titanaugite at a molar ratio of 8:1.Zeta potential experiments suggested that,in the presence of mixed collector system,the BHA-DDA complex adsorbed on the ilmenite surface via the chemically adsorbed BHA and the electrostatically adsorbed DDA,however,the complex adsorbed on the surface of titanaugite unstably.According to in situ ATR-FTIR combined with 2D-COS and XPS results,the interface assembly mechanism of BHA/DDA is summarized as:the function group of BHA molecules first binds to the metal sites on minerals to form bidentate ligand,then DDA co-adsorbed with BHA on the surface of minerals through hydrogen bonding.DDA may change the adsorption modes of some BHA on the ilmenite surface from four-membered ring to five-membered ring,while the modes on the titanaugite surface is true opposite.Finally,recommended adsorption configurations of the BHA/DDA complex on the two mineral surfaces are proposed.展开更多
Ilmenite is an essential mineral for the extraction of titanium.Conventional physical separation methods have difficulty recovering fine ilmenite,and dressing plants have begun applying flotation to recover ilmenite.T...Ilmenite is an essential mineral for the extraction of titanium.Conventional physical separation methods have difficulty recovering fine ilmenite,and dressing plants have begun applying flotation to recover ilmenite.The interaction of reagent groups with Ti and Fe sites on the ilmenite surface dramatically influences the ilmenite flotation.However,the investigation on Fe sites has received more attention because the activity of Ti is lower than that of Fe.For the activators on ilmenite flotation,most are metal ions but typically lead ions.The metal ions of activators promote ilmenite flotation by increasing the active sites on the ilmenite surface.Combined reagents have a better selective separation of ilmenite than single reagents due to their synergistic effect.Combining the lead ion(Pb^(2+))and the benzyl hydroxamic acid(BHA)into a Pb-BHA complex has a marked effect on ilmenite flotation,which puts forward a new idea of developing combined reagents for ilmenite flotation.This review considers reagent types and action mechanisms in ilmenite flotation.On the basis of the analysis of previous research,a brief future outlook of reagent types and action mechanisms in ilmenite flotation is also proposed in this study.展开更多
The reduction of ilmenite concentrate by hydrogen gas was investigated in the temperature range of 500 to 1200℃. The microstructure and phase transition of the reduction products were studied by X-ray diffraction （...The reduction of ilmenite concentrate by hydrogen gas was investigated in the temperature range of 500 to 1200℃. The microstructure and phase transition of the reduction products were studied by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and optical microscopy （OM）. It was found that the weight loss and iron metallization rate increased with the increase of reduction temperature and reaction time. The iron metallization rate could reach 87.5% when the sample was reduced at 1150℃ for 80 min. The final phase constituents mainly consist of Fe, M305 solid solution phase （M=Mg, Ti, and Fe）, and few titanium oxide. Microstructure analysis shows that the surfaces of the reduction products have many holes and cracks and the reactions take place from the exterior of the grain to its interior. The kinetics of reduction indicates that the rate-controlling step is diffusion process control with the activation energy of 89 kJ.mo1-1.展开更多
Reduction behavior of preoxidized synthetic ilmenite was studied by means of Mossbauer spectra. In the course of reduction, iron component in the samples is reduced in stepwise: Fe 3+ →Fe 2+ →Fe 0, and some...Reduction behavior of preoxidized synthetic ilmenite was studied by means of Mossbauer spectra. In the course of reduction, iron component in the samples is reduced in stepwise: Fe 3+ →Fe 2+ →Fe 0, and some intermediate compounds, such as Fe 3O 4, Fe 2TiO 4 etc . and their solid solution may be generated besides Fe 2O 3 and FeTiO 3. If the reduction temperature is higher than 1173 K, the metallization needs only half time of the case when the temperature is lower than 1073 K.展开更多
The study on the beneficiation of titanium oxides from Panzhihua ilmenites by reduction of coal bearing pellets was carried out. The iron oxides in pellets were efficiently reduced to metal iron, and titanium oxide sl...The study on the beneficiation of titanium oxides from Panzhihua ilmenites by reduction of coal bearing pellets was carried out. The iron oxides in pellets were efficiently reduced to metal iron, and titanium oxide slag beneficiated was separated from metal iron. The effect of temperature, flux and coal blending ratio on the reduction and separation was investigated, and rational parameters were determined. A new process for the beneficiation of titanium oxides by rotary hearth furnace （RHF） was proposed.展开更多
Dry sliding wear behaviour of stir-cast aluminium matrix composites(AMCs)containing LM13 alloy as matrix and ceramic particles as reinforcement was investigated.Two different ceramic particle reinforcements were used ...Dry sliding wear behaviour of stir-cast aluminium matrix composites(AMCs)containing LM13 alloy as matrix and ceramic particles as reinforcement was investigated.Two different ceramic particle reinforcements were used separately:synthetic ceramic particles(B_(4)C),and natural ceramic particles(ilmenite).Optical micrographs showed uniform dispersion of reinforced particles in the matrix material.Reinforced particles refined the grain size of eutectic silicon and changed its morphology to globular type.B_(4)C reinforced composites(BRCs)showed maximum improvement in hardness of AMCs.Ilmenite reinforced composites(IRCs)showed maximum reduction in coefficient of friction values due to strong matrix−reinforcement interfacial bonding caused by the formation of interfacial compounds.Dry sliding wear behaviour of composites was significantly improved as compared to base alloy.The low density and high hardness of B_(4)C particles resulted in high dislocation density around filler particles in BRCs.On the other hand,the low thermal conductivity of ilmenite particles resulted in early oxidation and formation of a tribo-layer on surface of IRCs.So,both types of reinforcements led to the improvement in wear properties of AMCs,though the mechanisms involved were very different.Thus,the low-cost ilmenite particles can be used as alternative fillers to the high-cost B_(4)C particles for processing of wear resistant composites.展开更多
Triboelectric separation, as an entirely dry technology, is a prospective method to process fine minerals.The aim of this paper is to investigate the performance of triboelectric separation of ilmenite and quartz mine...Triboelectric separation, as an entirely dry technology, is a prospective method to process fine minerals.The aim of this paper is to investigate the performance of triboelectric separation of ilmenite and quartz minerals in a lab unit and to get ready for the separation of ilmenite ore. A tribocharge measurement system was used to test the triboelectric properties of ilmenite and quartz particles with tribochargers respectively made of PVC, PPR, PMMA, Teflon, copper, stainless steel and quartz glass. The results show that the ilmenite particles charged positively while quartz charged negatively when tribocharged with PVC tribocharger. The mixture of 12% ilmenite and 88% quartz was prepared for the triboelectric separation. The recovery of ilmenite increases with the increase of airflow rate, decreases with the increasing feed rate, and grows up firstly and then decreases with the increasing voltage. A maximum ilmenite recovery of 51.71% with ilmenite content 32.72% was obtained at 40 m^3/h airflow rate, 6 g/s feed rate and 20 kV voltage. According to the optimal parameters of the separation of ilmenite and quartz mixture,fine ilmenite ore with 7.55% Ti content was beneficiated using the unit and the Ti content increased to 12.32% in concentrate product.展开更多
A styryl phosphonate ester(SPE) collector was used to improve the flotation performance of ilmenite, and the adsorption mechanism and model were revealed and established, respectively. Microflotation tests showed that...A styryl phosphonate ester(SPE) collector was used to improve the flotation performance of ilmenite, and the adsorption mechanism and model were revealed and established, respectively. Microflotation tests showed that SPE exhibited a stronger collecting ability for ilmenite than the traditional collector styrene phosphonic acid(SPA). Zeta potential measurements revealed that both SPE and SPA could negatively shift the zeta potential of ilmenite, while SPE had more effects than SPA, suggesting the stronger adsorption of SPE. The analysis of X-ray photoelectron spectroscopy confirmed the chemisorption of SPA and SPE onto the Fe/Ti sites of ilmenite. According to frontier orbital theory, the chemical activities of SPE are greater than those of SPA. The partial densities of states analysis indicated that the PO—H groups of the collectors could interact with the Ti/Fe atoms of the ilmenite surface to generate a stable four-membered ring. The bonding model of the collector and(104) ilmenite surface showed that the adsorption energy of SPE was higher than that of SPA. Overall, SPE presented a better collecting ability and interaction effect for ilmenite flotation than SPA, and had the potential to replace SPA in the industry.展开更多
基金supported by the National Key Research and Development Program of China(No.2019YFC1803501)the National Natural Science Foundation of China(No.52074357)+2 种基金the Natural Science Foundation of Hunan Province,China(No.2022JJ30713)the Vanadium Titanium Union Foundationthe Project of Technology Innovation Center for Comprehensive Utilization of Strategic Mineral Resources,Ministry of Natural Resources,China。
文摘The potential of 2-amino-1-propanol(AP)as a novel depressant in selectively floating ilmenite from titanaugite under weakly acidic conditions was investigated.Micro-flotation results show that AP significantly reduces the recovery of titanaugite while having no evident impact on ilmenite flotation.Subsequent bench-scale flotation tests further confirm a remarkable improvement in separation efficiency upon the introduction of AP.Contact angle and adsorption tests reveal a stronger affinity of AP towards the titanaugite surface in comparison to ilmenite.Zeta potential measurements and X-ray photoelectron spectroscopy(XPS)analyses exhibit favorable adsorption characteristics of AP on titanaugite,resulting from a synergy of electrostatic attraction and chemical interaction.In contrast,electrostatic repulsion hinders any significant interaction between AP and the ilmenite surface.These findings highlight the potential of AP as a highly efficient depressant for ilmenite flotation,paving the way for reduced reliance on sulfuric acid in the industry.
基金funded by the National Natural Science Foundation of China(grant 42102094)Natural Science Foundation of Hebei(Grant D2022402028).
文摘The Damiao Fe-Ti-P deposit,located within the Damiao anorthosite complex in northeastern China,features Fe-Ti oxide ores and nelsonites that occur as irregularly inclined stratiform-like bodies,lenses,or veins with sharp contacts against anorthosite and gabbronorite.This deposit is characterized by abundant titanomagnetite that hosts diverse ilmenite exsolution textures,including blocky,lamellar,and cloth-like forms.In this study,we investigate the geochemistry and mineralogy of ilmenite exsolutions in titanomagnetite to understand their formation mechanisms and implications for the ore-forming process.Detailed petrographic observations and electron microprobe analyses reveal that the exsolution textures result from multiple mechanisms:oxy-exsolution due to titanomagnetite oxidation;subsolidus re-equilibration between magnetite and ilmenite involving elemental diffusion of Fe,Ti,Cr,Co,and Ni;and exsolution related to lattice defects caused by rapid cooling.Thermodynamic modeling using Gibbs free energy calculations,and the QUILF program indicates that blocky,lamellar,and cloth-textured ilmenite exsolutions formed at temperatures above and below the solid-solution solvus under decreasing oxygen fugacity.Additionally,our results indicate that the exsolution of zircon and pleonaste at ilmenite grain boundaries is attributed to the saturation and precipitation of elements like Zr and Al,due to the oxidation of titanomagnetite,rather than interactions between ilmenite and adjacent clinopyroxene.Reconstruction of the cooling history suggests that the oxygen fugacity of oxide-apatite gabbronorites was significantly higher than that of Fe-Ti-P ores.This confirms that increasing oxygen fugacity during magma evolution promoted immiscibility,leading to the formation of nelsonitic melts and ultimately the development of Fe-Ti-P ores.
基金supported by the National Natural Science Foundation of China(No.52074357)the Vanadium Titanium Union Foundation,ChinaChina Postdoctoral Science Foundation(No.2019M650188)。
文摘n-octylphosphonic acid(OPA)was introduced as a novel collector for ilmenite flotation and its effectiveness was compared with the conventional chelating collector,benzohydroxamic acid(BHA).Micro-flotation tests demonstrated that OPA was a highly effective and selective collector for separating ilmenite from titanaugite over acidic conditions(optimal pH around 3),which was also supported by adsorption amount measurements.X-ray photoelectron spectroscopy(XPS)tests indicated that the chemisorption of OPA onto ilmenite surface was much stronger than that of BHA.Solution chemistry diagram analyses indicated that OPA could dissociate well at pH 3.0 and mostly exist in anion form.DFT calculations further confirmed that OPA was much easier to adsorb onto ilmenite surface with shorter bond length and lower adsorption energy in comparison with BHA.Therefore,OPA maintained good collecting ability and selectivity for ilmenite flotation in the strongly acidic pulp,providing valuable insights into new collector design and development.
基金Project (2007CB613602) supported by the National Basic Research Program of China Project (20090162110053) supported by Doctoral Fund of Ministry of Education of China Project (CX2009B049) supported by Hunan Provincial Innovation Foundation For Postgraduate, China
文摘The influence of surface dissolution on flotation separation of fine ilmenite from titanaugite was investigated through infrared spectroscopic （FT-IR） analysis and X-ray photoelectron spectroscopy （XPS） test. The results show that surface dissolution in weak acid solution is helpful to enlarge the floatability difference between ilmenite and titanaugite. In weak acidic solution, as sodium oleate mainly interacts with Fe which results in ilmenite flotation, and surface dissolution is beneficial to its oxidation, the floatability of ilmenite after surface dissolution is increased; meanwhile, sodium oleate interacts with Ca and Mg which results in titanangite flotation, and the quantities of Ca and Mg on the surface of titanautite are decreased due to the surface dissolution, so the floatability of titanaugite after surface dissolution is depressed. For an ilmenite ore obtained from Panzhihua with TiO2 grade of 8.41%, flotation after surface dissolution treatment could increase TiO2 grade of rough concentrate from 26.7% to 31.73 %.
基金Project(2007CB613606)supported by the National Basic Research Program of ChinaProject(50734007)supported by the National Natural Science Foundation of China
文摘The microwave drying of ilmenite was investigated.The effects of power levels and sample mass on drying characteristics of moisture content,drying rate,moisture ratio were studied,with microwave power ranging from 119 W to 700 W and sample mass from 5 g to 25 g.The drying processes were completed within 2-8 min at different conditions.The moisture content and drying rates are found to be dramatically affected by microwave power density.For all drying processes the prior microwave absorption of moisture produces an accelerating peak on the drying rate curves in the initial stage.For the sample mass of 25 g and power of 385 W,the drying kinetics were studied.The experimental results fit better to the Henderson-Pabis index model rather than the Page＇s semi-empirical model;the drying rate constant k is increased with the increase of microwave power and decrease of sample mass.
基金Project(51090385)supported by the National Natural Science Foundation of ChinaProject(2007CB613606)supported by the National Basic Research Program of China
文摘The influence of microwave heating on the grinding of Panzhihua ilmenite ore was investigated. Factors that influence the processing are： the microwave exposure time, power density and sample mass. 40 g sample was microwave heated for 30 s with 1 kW of microwave power and followed by water quenching. SEM analysis indicated that intergranular fractures occurred between ores and gangues other than transgranular fractures after microwave treatment, which would liberate minerals from each other effectively. The subsequently magnetic separation trials provided evidence that the recovery rate increased from 44% for raw ore to 72% by microwave treatment.
基金Projects(51090385,5114703)supported by the National Natural Science Foundation of ChinaProject(2012DFA70570)supported by the International S&T Cooperation Program of ChinaProject(2011FZ038)supported by the Applied Basic Research Project of Yunnan Province
文摘The permittivity of low grade Panzhuhua ilmenite ore at 2.45 GHz in the temperatures from 20 ℃ up to 100 ℃ was measured using the technology of open-ended coaxial sensor combined with theoretical computation. The results show that both the real （ε′） and imaginary （ε′） part of complex permittivity （ε′-jε′） of the ilmenite significantly increase with temperature. The loss tangent （tanδ） is a quadratic function of temperature, and the penetration depth of ilmenite decreases with temperature increase from 20 ℃to 100 ℃ The increase of the sample temperature under microwave radiation displays a nonlinear relationship between the temperature （T） and microwave heating time （t）. The positive feedback interaction between complex permittivity and sample temperature amplifies the interaction between ilmenite and the microwave radiation. The optimum dimensions for uniform heat deposition vary from 10 cm to 5 cm （about two power penetration depths） in a sample being irradiated from both sides in a 2.45 GHz microwave field when temperature increases from room temperature to 100 ℃
基金Project(51074105) supported by the National Natural Science Foundation of ChinaProject(51225401) supported by the China National Funds for Distinguished Young Scientists
文摘Phase transitions, morphology changes, and oxidation mechanism of the ilmenite oxidation process were investigated. FeTi03 transforms to hematite and rutile when oxidation at 700-800 ℃, and pseudobrookite is formed when the oxidation temperature reaches 900 ℃. The initial ilmenite powder exhibits paramagnetism; however, after being oxidized at the intermediate temperature （800-850 ℃）, the oxidation product exhibits weak ferromagnetism. The oxidation mechanism was discussed. The microstructure observations show that a lot of micro-pores emerge on the surfaces of ilmenite particles at the intermediate temperature, which is deemed to be caoable ofenhancin~ the mass transfer ofoxgen during oxidation.
基金Project (2007CB613601) supported by the National Basic Research Program of ChinaProject supported by the Postdoctoral Science Foundation of Central South University, China
文摘A new combination method consisting of ball milling, carbothermic reduction and hydrochloric acid leaching was proposed for the preparation of nanosized synthetic rutile from natural ilmenite. The ball milling was employed to grind ilmenite into small particles. The carbothermic reduction was carried out to yield a high titanium slag, which would be easily purified by subsequent leaching procedure. Factors affecting the hydrochloric acid process, namely the leaching time, temperature, and acid concentration, were studied. After leaching and calcining the milled and annealed mixture of FeTiO3/C under the optimal conditions, the TiO2 nanoparticles with size of 10-200 nm and purity〉98.0% were obtained.
基金Project(2009FJ3082)supported by Research Project of Science and Technology in Hunan Province,ChinaProject(2007CB613606)supported by the National Basic Research Program of China
文摘The effects of oxidation-reduction treatment and mechanical activation on the hydrochloric acid leaching performance of Panxi ilmenite concentration were investigated.The results show that both of oxidation-reduction treatment and mechanical activation significantly accelerate the extraction of Fe,Ca and Mg from Panxi ilmenite concentration;however,the CaO and MgO contents of the calcined residues obtained from oxidized-reduced ilmenite concentration are higher than the standard values required by chlorination process.The Ca and Mg in oxidized-reduced ilmenite concentration can be leached much faster after mechanical activation,yielding a synthetic rutile which meets the requirements of chlorination process containing 90.50% TiO2 and 1.37% total iron as well as combined CaO and MgO of 1.00%.The optimum oxidation and reduction conditions are as follows：oxidization at 900 ℃ in the presence of oxygen for 15 min and reduction at 750 ℃ by hydrogen for 30 min.
基金Project(2014JY0132)supported by the Program for Application Basic Research of Sichuan ProvinceChina+5 种基金Projects(2013CY-G-72014CY-G-26-12015CY-G-18)supported by the Technology Research Program of Panzhihua CityChinaProject(2015TX-11)supported by the Innovative Project of Panzhihua CityChina
文摘A systematic investigation on the effect of milling time on carbothermic reduction of ilmenite was carried out by a combination of thermal analysis, X-ray diffraction（XRD）, scanning electron microscopy（SEM） and particle size analysis. It was shown that the graphite crystalline structure was easily destroyed along the（002） crystal plane during milling process. The particle size of ilmenite/graphite mixture was largely decreased and a fully mixed composite structure was obtained after milling for 4 h at high milling intensity. Milling exerts positive effect on the decreasing temperatures of ilmenite reduction and gradual deoxidizing of titanium oxides was completed.
基金Project(2014CB643403)supported by the National Basic Research Program of ChinaProjects(51225401,51304132,51574164)supported by the National Natural Science Foundation of China+1 种基金Project(14JC1491400)supported by the Science and Technology Commissions of Shanghai Municipality,ChinaProject(2013GZ0146)supported by the Sichuan Province,China
文摘The hydrogen reduction of Panzhihua ilmenite concentrate in the temperature range of 900?1050 °C was systematicallyinvestigated by thermogravimetric analysis (TG), X-ray diffraction (XRD) and scanning electron microscopy (SEM) methods. It wasshown that the products of the Panzhihua ilmenite reduced at 900 °C were metallic iron and rutile. Above 1000 °C, ferrouspseudobrookite solid solution was generated. During the reduction process, element Mg gradually concentrated to form Mg-rich zonewhich can influence the metallization process. The reduction reaction proceeded topochemically and its related reduction kineticswere also discussed. The kinetics of the reduction indicated that the rate-controlling step was the diffusion process. The apparentactivation energy of the hydrogen reduction of Panzhihua ilmenite was calculated to be 117.56 kJ/mol, which was larger than that ofsynthetic ilmenite under the same reduction condition.
基金This work was supported by the National Natural Science Foundation of China(Nos.51904249 and 51922091)the Sichuan Science and Technology Program(No.SYZ202074)the Open Research Fund of State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization(No.CNMRCUKF2001).
文摘This paper researched the enhanced flotation separation performance of ilmenite and titanaugite using the mixed collector benzhydroxamic acid/dodecylamine(BHA/DDA).The interface assembly mechanism was mainly investigated through in situ attenuated total reflectance Fourier transform infrared(ATRFTIR)spectroscopy combined with the two-dimensional correlation spectroscopy(2D-COS)and X-ray photoelectron spectroscopy(XPS).It has been found that BHA/DDA mixed collectors successfully separate ilmenite from titanaugite at a molar ratio of 8:1.Zeta potential experiments suggested that,in the presence of mixed collector system,the BHA-DDA complex adsorbed on the ilmenite surface via the chemically adsorbed BHA and the electrostatically adsorbed DDA,however,the complex adsorbed on the surface of titanaugite unstably.According to in situ ATR-FTIR combined with 2D-COS and XPS results,the interface assembly mechanism of BHA/DDA is summarized as:the function group of BHA molecules first binds to the metal sites on minerals to form bidentate ligand,then DDA co-adsorbed with BHA on the surface of minerals through hydrogen bonding.DDA may change the adsorption modes of some BHA on the ilmenite surface from four-membered ring to five-membered ring,while the modes on the titanaugite surface is true opposite.Finally,recommended adsorption configurations of the BHA/DDA complex on the two mineral surfaces are proposed.
基金financially supported by the National Natural Science Foundation of China(No.51764022)the Fok Ying Tong Education Foundation(No.161046)+3 种基金the China Postdoctoral Science Foundation(No.2020M673551XB)the Fundamental Research Funds for Central UniversitiesChina(No.2020XJHH04)the Yueqi Outstanding Scholar Award of China University of Mining and Technology(Beijing)。
文摘Ilmenite is an essential mineral for the extraction of titanium.Conventional physical separation methods have difficulty recovering fine ilmenite,and dressing plants have begun applying flotation to recover ilmenite.The interaction of reagent groups with Ti and Fe sites on the ilmenite surface dramatically influences the ilmenite flotation.However,the investigation on Fe sites has received more attention because the activity of Ti is lower than that of Fe.For the activators on ilmenite flotation,most are metal ions but typically lead ions.The metal ions of activators promote ilmenite flotation by increasing the active sites on the ilmenite surface.Combined reagents have a better selective separation of ilmenite than single reagents due to their synergistic effect.Combining the lead ion(Pb^(2+))and the benzyl hydroxamic acid(BHA)into a Pb-BHA complex has a marked effect on ilmenite flotation,which puts forward a new idea of developing combined reagents for ilmenite flotation.This review considers reagent types and action mechanisms in ilmenite flotation.On the basis of the analysis of previous research,a brief future outlook of reagent types and action mechanisms in ilmenite flotation is also proposed in this study.
基金supported by the Postgraduate Innovative Foundation of Shanghai University (SHUCX091031)the National Natural Science Foundation of China (No.51074105)the National Basic Research Priorities Program of China (No.2007CB613606)
文摘The reduction of ilmenite concentrate by hydrogen gas was investigated in the temperature range of 500 to 1200℃. The microstructure and phase transition of the reduction products were studied by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and optical microscopy （OM）. It was found that the weight loss and iron metallization rate increased with the increase of reduction temperature and reaction time. The iron metallization rate could reach 87.5% when the sample was reduced at 1150℃ for 80 min. The final phase constituents mainly consist of Fe, M305 solid solution phase （M=Mg, Ti, and Fe）, and few titanium oxide. Microstructure analysis shows that the surfaces of the reduction products have many holes and cracks and the reactions take place from the exterior of the grain to its interior. The kinetics of reduction indicates that the rate-controlling step is diffusion process control with the activation energy of 89 kJ.mo1-1.
文摘Reduction behavior of preoxidized synthetic ilmenite was studied by means of Mossbauer spectra. In the course of reduction, iron component in the samples is reduced in stepwise: Fe 3+ →Fe 2+ →Fe 0, and some intermediate compounds, such as Fe 3O 4, Fe 2TiO 4 etc . and their solid solution may be generated besides Fe 2O 3 and FeTiO 3. If the reduction temperature is higher than 1173 K, the metallization needs only half time of the case when the temperature is lower than 1073 K.
文摘The study on the beneficiation of titanium oxides from Panzhihua ilmenites by reduction of coal bearing pellets was carried out. The iron oxides in pellets were efficiently reduced to metal iron, and titanium oxide slag beneficiated was separated from metal iron. The effect of temperature, flux and coal blending ratio on the reduction and separation was investigated, and rational parameters were determined. A new process for the beneficiation of titanium oxides by rotary hearth furnace （RHF） was proposed.
文摘Dry sliding wear behaviour of stir-cast aluminium matrix composites(AMCs)containing LM13 alloy as matrix and ceramic particles as reinforcement was investigated.Two different ceramic particle reinforcements were used separately:synthetic ceramic particles(B_(4)C),and natural ceramic particles(ilmenite).Optical micrographs showed uniform dispersion of reinforced particles in the matrix material.Reinforced particles refined the grain size of eutectic silicon and changed its morphology to globular type.B_(4)C reinforced composites(BRCs)showed maximum improvement in hardness of AMCs.Ilmenite reinforced composites(IRCs)showed maximum reduction in coefficient of friction values due to strong matrix−reinforcement interfacial bonding caused by the formation of interfacial compounds.Dry sliding wear behaviour of composites was significantly improved as compared to base alloy.The low density and high hardness of B_(4)C particles resulted in high dislocation density around filler particles in BRCs.On the other hand,the low thermal conductivity of ilmenite particles resulted in early oxidation and formation of a tribo-layer on surface of IRCs.So,both types of reinforcements led to the improvement in wear properties of AMCs,though the mechanisms involved were very different.Thus,the low-cost ilmenite particles can be used as alternative fillers to the high-cost B_(4)C particles for processing of wear resistant composites.
基金provided by the National Natural Science Foundation of China (Nos. 51674257 and 51574234)the Fundamental Research Funds for the Central Universities (2014QNB10)the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Triboelectric separation, as an entirely dry technology, is a prospective method to process fine minerals.The aim of this paper is to investigate the performance of triboelectric separation of ilmenite and quartz minerals in a lab unit and to get ready for the separation of ilmenite ore. A tribocharge measurement system was used to test the triboelectric properties of ilmenite and quartz particles with tribochargers respectively made of PVC, PPR, PMMA, Teflon, copper, stainless steel and quartz glass. The results show that the ilmenite particles charged positively while quartz charged negatively when tribocharged with PVC tribocharger. The mixture of 12% ilmenite and 88% quartz was prepared for the triboelectric separation. The recovery of ilmenite increases with the increase of airflow rate, decreases with the increasing feed rate, and grows up firstly and then decreases with the increasing voltage. A maximum ilmenite recovery of 51.71% with ilmenite content 32.72% was obtained at 40 m^3/h airflow rate, 6 g/s feed rate and 20 kV voltage. According to the optimal parameters of the separation of ilmenite and quartz mixture,fine ilmenite ore with 7.55% Ti content was beneficiated using the unit and the Ti content increased to 12.32% in concentrate product.
基金the support from the National Natural Science Foundation of China(Nos.51904214 and 51804238)the Young Elite Scientists Sponsorship Program by CAST(No.YESS20200276)+3 种基金the Natural Science Foundation of Hubei Province,China(No.ZRMS2021000085)the Fundamental Research Funds for the Central Universities,China(No.2021IVA039)the Open Foundation of State Key Laboratory of Mineral Processing,BGRIMM Technology,China(Nos.BGRIMM-KJSKL-202122 and BGRIMM-KJSKL-2022-02)the Open Project of Engineering Research Center of Phosphorus Resources Development and Utilization of Ministry of Education,China(No.201904)。
文摘A styryl phosphonate ester(SPE) collector was used to improve the flotation performance of ilmenite, and the adsorption mechanism and model were revealed and established, respectively. Microflotation tests showed that SPE exhibited a stronger collecting ability for ilmenite than the traditional collector styrene phosphonic acid(SPA). Zeta potential measurements revealed that both SPE and SPA could negatively shift the zeta potential of ilmenite, while SPE had more effects than SPA, suggesting the stronger adsorption of SPE. The analysis of X-ray photoelectron spectroscopy confirmed the chemisorption of SPA and SPE onto the Fe/Ti sites of ilmenite. According to frontier orbital theory, the chemical activities of SPE are greater than those of SPA. The partial densities of states analysis indicated that the PO—H groups of the collectors could interact with the Ti/Fe atoms of the ilmenite surface to generate a stable four-membered ring. The bonding model of the collector and(104) ilmenite surface showed that the adsorption energy of SPE was higher than that of SPA. Overall, SPE presented a better collecting ability and interaction effect for ilmenite flotation than SPA, and had the potential to replace SPA in the industry.
