Finding appropriate flotation reagents to separate copper-nickel sulfide ores from various magnesium silicate gangue minerals has always been a challenge in the mineral processing industry.This study introduced xantha...Finding appropriate flotation reagents to separate copper-nickel sulfide ores from various magnesium silicate gangue minerals has always been a challenge in the mineral processing industry.This study introduced xanthan gum(XG)as a non-toxic and environmentally friendly depressant of talc,olivine,and serpentine.The effects and mechanisms of XG on the aggregation and flotation behavior of talc,olivine and serpentine were investigated by flotation tests,sedimentation tests,IC-FBRM particle size analysis tests,adsorption quantity tests,Fourier transform infrared spectroscopy(FTIR)tests,X-ray photoelectron spectroscopy(XPS)analysis tests and Zeta potential tests.The flotation results indicated that when the three minerals were mixed,XG caused the talc-serpentine aggregation in the solution to shift to olivine-serpentine aggregation,with the remaining XG adsorbing on talc to depress its flotation.In addition,combining XPS and zeta potential tests,the-OH(hydroxyl)groups in XG molecules preferentially adsorbed on Mg sites on the surface of olivine through chemical bonding.The surface potential of olivine significantly shifted to a more negative value,with the negative charge on the olivine surface far exceeding that on the talc surface.This resulted in an increased aggregation effect between positively charged serpentine and negatively charged olivine due to enhanced electrostatic forces.展开更多
Malachite,being highly hydrophilic and difficult to be floated conventionally,is usually beneficiated by sulfidation flotation in industry.However,the complex crystal structure of malachite leads to the formation of v...Malachite,being highly hydrophilic and difficult to be floated conventionally,is usually beneficiated by sulfidation flotation in industry.However,the complex crystal structure of malachite leads to the formation of various fracture surfaces with distinct properties during crushing and grinding,resulting in surface anisotropy.In this study,we explored the surface anisotropy of malachite and further investigated its sulfidation mechanism from the coordination chemistry perspective,considering the influence of the Jahn-Teller effect on malachite sulfidation.Computational results reveal that the penta-coordinated Cu ions on the malachite(201)and(010)surfaces exhibit stronger activity compared to those on the malachite(201)surface.Additionally,the tetra-coordinated structure formed by HS^(−)adsorption on the malachite(010)and(201)surfaces is more stable,with more negative adsorption energy,compared to the hexa coordinated structure formed by HS−adsorption on the(201)surface.The sulfidized malachite surface has an additional pair ofπelectron and smaller HOMO(highest occupied molecular orbital)-LUMO(lowest unoccupied molecular orbital)gap with xanthate molecules,causing strongerπbackbonding with xanthate.This study provides new insights into the surface sulfidation mechanism of malachite and offers a theoretical reference for the design of targeted flotation reagents.展开更多
Flotation behavior of stibiconite after sulfidation roasting with sulfur at a high temperature and the sulfidation mechanisms were investigated by ultraviolet spectrophotometry,X-ray diffraction(XRD)combining with the...Flotation behavior of stibiconite after sulfidation roasting with sulfur at a high temperature and the sulfidation mechanisms were investigated by ultraviolet spectrophotometry,X-ray diffraction(XRD)combining with thermodynamic calculation,X-ray photoelectron spectroscopy(XPS)and electron probe microanalysis(EPMA).The XRD and thermodynamic analyses revealed that the Sb_(3)O_(6)(OH)was reduced into Sb_(2)O_(4)and Sb_(2)O_(3),and was transformed into Sb_(2)S_(3)after introducing sulfur at high temperatures.Flotation test results show that flotation recovery of the stibiconite after sulfidation reaches 90.3%.Ultraviolet spectrophotometry tests confirm that adsorption capacity of sodium butyl xanthate(SBX)on surface of the roasted products has a positive relationship with S/Sb mole ratio.XPS analyses indicate that Sb-bearing species including mainly Sb_(2)S_(3),Sb_(2)O_(3)and Sb_(2)(SO_(4))_(3) are formed at the surface of particle after sulfidation.The EPMA analyses verify that the Sb_(2)S_(3)is generated at the outer layer of sample after sulfidation roasting,but the particle interior is mainly composed of antimony oxides.The sulfur atmosphere induces the outward migration of oxygen to form Sb_(2)O_(4).Then,the Sb_(2)O_(4)is transformed into Sb_(2)O_(3)in two pathways,and the Sb_(2)S_(3)is formed.These findings will provide theoretical support for recovering antimony from antimony oxide ores by xanthate flotation methods.展开更多
The lime-Cu^(2+)-xanthate process is commonly used for the flotation separation of sphalerite from pyrite.In this process,lime is added to the pulp to inhibit the floatability of pyrite.However,the excessive use of li...The lime-Cu^(2+)-xanthate process is commonly used for the flotation separation of sphalerite from pyrite.In this process,lime is added to the pulp to inhibit the floatability of pyrite.However,the excessive use of lime can result in pipeline blockage and inadequate recovery of associated precious metals.Therefore,it is necessary to develop new flotation process that minimizes or eliminates the use of lime.In this paper,a novel Fe^(3+)-Cu^(2+)-butyl xanthate process was developed as an alternative to lime for separating of sphalerite from pyrite.The flotation results indicated that with the artificially-mixed minerals,the flotation recovery of pyrite was lower than 16%and that of sphalerite was higher than 47%at pH 5.0−10.0.The zeta potential measurements revealed that ferric ion preferred to adsorb on pyrite,and copper ion displaced with zinc ion from the lattice at the interface of sphalerite.The wettability analyses indicated that the hydrophobicity of sphalerite surface increased apparently after being treated with Fe^(3+)-Cu^(2+)-BX,while the hydrophobicity of pyrite surface remained nearly unchanged.With XPS analysis,Cu-S bond and hydrophilic ferric hydroxide were detected separately on the surface of sphalerite and pyrite after conditioning with Fe^(3+)-Cu^(2+)-BX,which facilitated the flotation separation of sphalerite from pyrite with butyl xanthate collector.展开更多
Magnetic seeding agglomeration(MSA),i.e.,adding magnetic seeds and a low intensity pre-magnetization for fine agglomeration,was applied to the flotation of coal,pyrite and hematite ore slimes.Size analysis and flotati...Magnetic seeding agglomeration(MSA),i.e.,adding magnetic seeds and a low intensity pre-magnetization for fine agglomeration,was applied to the flotation of coal,pyrite and hematite ore slimes.Size analysis and flotation tests highlight that the MSA improved flotation recovery and kinetics of pyrite ore while causing some loss in selectivity,and in the presences of the polyacrylamide for coal and starch for hematite the agglomeration flotation was further strengthened due to the synergetic effect between the flocculants and magnetic seeds.Magnetism analyses and calculation confirmed the adsorption of magnetic seeds onto minerals,resulting in a decreased threshold magnetic field intensity for the MSA to happen.Then atomic force microscope(AFM)study found that there exists a long range force between magnetic seeds and minerals,which facilitates the adsorption of magnetic seeds on minerals.FTIR shows both the polyacrylamide and starch adsorbed onto minerals and magnetic seeds,thus acting as the bridging media between minerals and magnetic seeds,intensifying the agglomeration in flotation.Surface characterization of the MSA was understood by SEM imaging,and models of the MSA were proposed.展开更多
An effective flotation approach is proposed for improving the recovery of molybdenite fines from a finely-disseminated molybdenum ore. To maximize the flotation recovery of molybdenum, process mineralogy of raw ore, c...An effective flotation approach is proposed for improving the recovery of molybdenite fines from a finely-disseminated molybdenum ore. To maximize the flotation recovery of molybdenum, process mineralogy of raw ore, contrast tests, optimization of operation conditions and particle size analysis were systematically investigated. Process mineralogy suggests that in the raw ore, 61.63% of molybdenite particles distribute in the 〈20 pm size fraction, and intergrow with muscovite and pyrite as the contained and disseminated type. Contrast tests indicate that conventional flotation responds to poor collection efficiency for particles less than 25 pm. Oil agglomerate flotation （OAF） process demonstrates an obvious superiority in improving the flotation recovery of molybdenite fines. Furthermore, the flotation results of OAF process reveal that the dosage of transformer oil plays a critical role on the average size of collected mineral particles （d（0）, agglomerates （d^0） and the molybdenum recovery. In addition, industrial tests illustrate that compared with the Mo-S bulk flotation approach, OAF process not only increases Mo recovery and grade of molybdenum concentrate by 22.75% and 17.47% respectively, but also achieves a sulfur concentrate with a superior grade of 38.92%.展开更多
Flotation column is widely used as the separation equipment for fine mineral due to its high selectivity. However, this device may be unsuitable for the coarse particle flotation and has high handling ability. A two-s...Flotation column is widely used as the separation equipment for fine mineral due to its high selectivity. However, this device may be unsuitable for the coarse particle flotation and has high handling ability. A two-stage flotation column with dimensions of 2 000 mm×1 000 mm×4 000 mm was designed to enhance the column flotation process. The energy input was modified by adjusting the flow rate and the head of circulating pump. The flotation column was designed with low energy input in the first stage(speed flotation stage) to recover easy-to-float materials quickly, and high energy input in the second stage(recovery stage) to recover difficult-to-float minerals compulsorily. Contrast experiments on the throughput and coarse coal recovery of high ash coal from the Kailuan Mine were conducted using conventional single-stage flotation column and the two-stage flotation column. The results show that the combustible matter recovery of the two-stage flotation column is 5.25% higher than that of the conventional single-stage flotation column. However, the ash contents of clean coal for both columns are similar. Less coarse coals with low ash are obtained using the two-stage flotation column than that using the single-stage column flotation with the same handling ability. The two-stage flotation column process can enhance coal flotation compared with the conventional single-stage column flotation.展开更多
Frothers facilitate the reduction of bubbles size by preventing bubbles coalescence and produce more stable froths.The collision probability of the bubbles and particles substantially increases by decreasing bubble si...Frothers facilitate the reduction of bubbles size by preventing bubbles coalescence and produce more stable froths.The collision probability of the bubbles and particles substantially increases by decreasing bubble size.For the same volume system,fewer bubbles result from a distribution of large-sized bubbles,and more bubbles result from a distribution of small-sized bubbles.In this research,fundamental two-phase frother characterization parameters were aimed to link with three-phase coal and talc flotation behavior.For this purpose,the effect of single and dual frother systems on inhibiting bubble coalescence was investigated with methyl isobutyl carbinol(MIBC),isooctanol(2 ethyl hexanol),pine oil,and Dowfroth 250.Based on the results of single frothers,isooctanol at the lowest critical coalescence concentration(CCC)value of 6×10^(−6) achieved the smallest bubbles with Sauter mean diameter of 0.80 mm.By blending Dowfroth 250 and pine oil,the bubbles size decreased significantly,reaching 0.45 mm.While the highest recoveries in coal flotation were obtained in single and frother blends where the bubbles size was measured as the smallest in two-phase system,and such a relationship was not found for talc flotation.展开更多
Effective fault detection techniques can help flotation plant reduce reagents consumption,increase mineral recovery,and reduce labor intensity.Traditional,online fault detection methods during flotation processes have...Effective fault detection techniques can help flotation plant reduce reagents consumption,increase mineral recovery,and reduce labor intensity.Traditional,online fault detection methods during flotation processes have concentrated on extracting a specific froth feature for segmentation,like color,shape,size and texture,always leading to undesirable accuracy and efficiency since the same segmentation algorithm could not be applied to every case.In this work,a new integrated method based on convolution neural network(CNN)combined with transfer learning approach and support vector machine(SVM)is proposed to automatically recognize the flotation condition.To be more specific,CNN function as a trainable feature extractor to process the froth images and SVM is used as a recognizer to implement fault detection.As compared with the existed recognition methods,it turns out that the CNN-SVM model can automatically retrieve features from the raw froth images and perform fault detection with high accuracy.Hence,a CNN-SVM based,real-time flotation monitoring system is proposed for application in an antimony flotation plant in China.展开更多
Reverse flotation technology is one of the most efficient ways to improve the quality and reduce impurity of iron concentrate. Mineral processors dealing with hematite face a challenge that the flotation results of re...Reverse flotation technology is one of the most efficient ways to improve the quality and reduce impurity of iron concentrate. Mineral processors dealing with hematite face a challenge that the flotation results of reverse flotation of hematite are poor in presence of siderite using fatty acid as collector, starch as depressant of iron minerals and calcium ion as activator of quartz at strong alkaline pH. In this work, the effect of siderite on reverse anionic flotation of quartz from hematite was investigated. The effect mechanism of siderite on reverse flotation of hematite was studied by solution chemistry, ultraviolet spectrophotometry(UV) and Fourier transform infrared spectroscopy(FTIR). It was observed that siderite had strong depressive effect on quartz in flotation using sodium oleate as collector, corn starch as depressant of iron minerals and calcium chloride as activator of quartz at strong alkaline pH. The starch was adsorbed onto calcium carbonate by chemical reaction which was formed by CO^(2-)_3 from siderite dissolution and Ca^(2+) from calcium chloride as activator of quartz and precipitated on the surface of quartz, which resulted in improving the hydrophilic ability of quartz.展开更多
In order to improve the recovery of tungsten ores containing tin minerals,anisic hydroxamic acid(p-methoxy benzohydroxanic acid,PMOB)was synthesized and introduced as novel collector in the flotation of scheelite,wolf...In order to improve the recovery of tungsten ores containing tin minerals,anisic hydroxamic acid(p-methoxy benzohydroxanic acid,PMOB)was synthesized and introduced as novel collector in the flotation of scheelite,wolframite and cassiterite.The flotation performance and adsorption mechanism were investigated by micro/batch flotation,zeta potential measurements and density functional theory(DFT).The micro flotation results showed that the recoveries of scheelite,wolframite and cassiterite using PMOB as collector are 97.45%,95.77% and 90.08%,respectively,and the corresponding recoveries are 91.00%,84.30% and 84.67% for benzohydroxamic acid(BHA).The batch flotation results revealed that the collector dosage could be reduced by about 45% for PMOB compared with BHA,in the case of similar flotation indicators.Zeta potential measurements indicated that PMOB could be adsorbed on the mineral surfaces by chemisorption.Moreover,density functional theory(DFT)calculation results showed that the substituent group—OCH_(3)endues PMOB stronger electron donation ability and hydrophobicity compared with benzohydroxamic acid(BHA),pmethyl benzohydroxamic acid(PMB)and p-hydroxyl benzohydroxamic acid(PHB).展开更多
The flotation properties of single minerals such as diaspore, kaolinite and pyrophllite in bauxites were investigated using RL as collector. The effects of regulators and unavoidable ions on flotation were studied. Ba...The flotation properties of single minerals such as diaspore, kaolinite and pyrophllite in bauxites were investigated using RL as collector. The effects of regulators and unavoidable ions on flotation were studied. Based on the results of single minerals flotation, the separation experiments of mixed minerals and bauxite ore were carried out. The results of closed circuit test on the ore show that, using RL as collector, Na 2CO 3 and (NaPO 3) 6 as modifiers, the grade of Al 2O 3 and SiO 2 are respectively 70.74% and 6.37% in concentrate (Al/Si 11.11), and the recovery of Al 2O 3 can reach 90.52%.展开更多
A laboratory scale up-flow biological activated carbon(BAC) reactor was constructed for the advanced treatment of synthetic flotation wastewater. Biodegradation of a common collector(i.e., ethyl xanthate) for non-ferr...A laboratory scale up-flow biological activated carbon(BAC) reactor was constructed for the advanced treatment of synthetic flotation wastewater. Biodegradation of a common collector(i.e., ethyl xanthate) for non-ferrous metallic ore flotation was evaluated. The results show that the two stages of domestication can improve microbial degradation ability. The BAC reactor obtains a chemical oxygen demand(COD) reduction rate of 82.5% for ethyl xanthate and its effluent COD concentration lowers to below 20 mg/L. The kinetics equation of the BAC reactor proves that the activated carbon layers at the height of 0 mm to 70 mm play a key role in the removal of flotation reagents. Ultraviolet spectral analysis indicates that most of the ethyl xanthate are degraded by microorganisms after advanced treatment by the BAC reactor.展开更多
The floatability of different crystalline structures of pyrrhotite(monoclinic and hexagonal) was studied.It is shown that the floatability of monoclinic and hexagonal has obvious difference,and that the flotation reco...The floatability of different crystalline structures of pyrrhotite(monoclinic and hexagonal) was studied.It is shown that the floatability of monoclinic and hexagonal has obvious difference,and that the flotation recovery of monoclinic pyrrhotite is larger than that of hexagonal pyrrhotite using different collectors.When butyl dithiophosphate is used as the collector,the recovery is larger than that by sodium butyl xanthate and sodium diethyl dithiocarbamate.At the pH values ranging from 6 to 9,monoclinic pyrrhotite can be floated well,and the flotation recovery is higher than 90%.Monoclinic and hexagonal pyrrhotites are more easily activated by Cu2+ in acidic conditions than in alkaline conditions.But Cu2+ cannot activate hexagonal pyrrhotite using sodium diethyldithiocarbamate as the collector.By the measurement of contact angle,it is indicated that monoclinic and hexagonal pyrrhotites float well and are easily activated by Cu2+ when dithiophosphate is used as the collector.Using sodium diethyl dithiocarbamate as a collector,the relationship between potential and pH range for pyrrhotite flotation is established.At pH 5,the optimal potential range for flotation of monoclinic pyrrhotite is about 125-580 mV(vs SHE),with the maximum flotation occurring at about 350 mV(vs SHE);the optimal potential range for flotation of hexagonal pyrrhotite is 200?580 mV(vs SHE),with the maximum flotation occurring at about 300 mV(vs SHE).展开更多
The interaction mechanism of collector DLZ in the flotation process of chalcopyrite and pyrite was investigated through flotation experiments,zeta potential measurements and infrared spectrum analysis.Flotation test r...The interaction mechanism of collector DLZ in the flotation process of chalcopyrite and pyrite was investigated through flotation experiments,zeta potential measurements and infrared spectrum analysis.Flotation test results indicate that DLZ is the selective collector of chalcopyrite.Especially,the recovery of chalcopyrite is higher than 90% in neutral and weak alkaline systems,while the recovery of pyrite is less than 10%.When using CaO as pH regulator,at pH=7-11,the floatability of pyrite is depressed and the recovery is less than 5%.Zeta potential analysis shows that the zeta potential of chalcopyrite decreases more obviously than that of pyrite after interaction with DLZ,confirming that collector DLZ shows selectivity to chalcopyrite and pyrite.And FTIR results reveal that the flotation selectivity of collector DLZ is due to chemical absorption onto chalcopyrite surface and only physical absorption onto pyrite surface.展开更多
Effect of frothers in preventing bubble coalescence during flotation of minerals has long been investigated.To evaluate the performance of a frother,an apparatus to measure the bubble size is a basic necessity.McGill ...Effect of frothers in preventing bubble coalescence during flotation of minerals has long been investigated.To evaluate the performance of a frother,an apparatus to measure the bubble size is a basic necessity.McGill Bubble Size Analyzer(MBSA) or bubble viewer that has been developed and completed by McGill University's Mineral Processing Group during the last decade is a unique instrument to serve this purpose.Two parameters which are thought to influence the bubble size measurements by McGill bubble viewer include water quality and frother concentration in the chamber.Results show that there is no difference in Sauter mean(D32) when tap or de-ionized water was used instead of process water.However,the frother concentration,in this research DowFroth 250(DF250),inside the chamber exhibited a pronounced effect on bubble size.Frother concentration below a certain point can not prevent coalescence inside the chamber and therefore caution must be taken in plant applications.It was also noted that the frother concentration which has been so far practiced in plant measurements(CCC75-CCC95) is high enough to prevent coalescence with the bubble viewer.展开更多
The composition of a collector directly affects its collecting performance in mineral flotation.In this study,three vegetable oils were used as the collectors,the flotation performance of scheelite and the differentia...The composition of a collector directly affects its collecting performance in mineral flotation.In this study,three vegetable oils were used as the collectors,the flotation performance of scheelite and the differential analysis were studied through flotation experiments,zeta potential,contact angle measurement and Fourier transform infrared spectrum(FTIR)analysis.Flotation results show that the recovery of scheelite increases in the order of oleic acid<rapeseed oil<rice bran oil<soybean oil,especially in the pH range of 5-8.The distinction in the scheelite recovery is due to the different compositions of these collectors.The addition of LA,LNA and PA(<5%)can increase the recovery of scheelite with OA,but the addition of SA deteriorates the scheelite flotation.Results of zeta potential,contact angle measurement and FTIR analysis indicate that the collector adsorption on scheelite surface is enhanced when using the three vegetable oils.For the raw ore with 0.086%WO3,a rough concentrate containing 1.423%WO3 with the recovery of 84.22%is obtained using soybean oil as the collector.展开更多
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 ch...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 p H 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 p H 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 Mn_2+/Fe_2+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.展开更多
Based on the working principles of particle bed comminution, particles produced by high-pressure grinding rolls （HPGR） have surface properties different from particles produced by other grinding patterns, which exer...Based on the working principles of particle bed comminution, particles produced by high-pressure grinding rolls （HPGR） have surface properties different from particles produced by other grinding patterns, which exert great influence on mineral flotation. Flotation performances of calcite particles under different grinding patterns involving the use of HPGR, a jaw crusher, a dry ball mill, a wet ball mill, and a wet rod mill were studied using single mineral flotation tests. The surface properties of the particles under different grinding patterns were characterized to determine the flotation performance variation in terms of specific surface area, particle size distribution, AFM, XPS, and zeta potential. The results show that particles ground by HPGR exhibited improved flotation performance within the lower range of grinding fineness in both NaOL and dodecyl amine flotation systems compared to the particles prepared using other grinding patterns. Specific surface area, particle size distribution, surface roughness, Fe（III） contamination, binding energy, and zeta potential are greatly influenced by grinding patterns, which is the main cause of the flotation performance variation.展开更多
Electronic structures of monoclinic and hexagonal pyrrhotite were studied using density functional theory method,together with their flotation behavior. The main contribution of monoclinic pyrrhotite is mainly from Fe...Electronic structures of monoclinic and hexagonal pyrrhotite were studied using density functional theory method,together with their flotation behavior. The main contribution of monoclinic pyrrhotite is mainly from Fe 3d, while that of hexagonal pyrrhotite is from Fe 3d, Fe 3p and S 3s. The hexagonal pyrrhotite is more reactive than monoclinic pyrrhotite because of large density of states near the Fermi level. The hexagonal pyrrhotite shows antiferromagnetism. S—Fe bonds mainly exist in monoclinic pyrrhotite as the covalent bonds, while hexagonal pyrrhotite has no covalency. The main contributions of higest occupied molecular orbital(HOMO) and lowest unoccupied molecular obital(LUMO) for monoclinic pyrrhotite come from S and Fe. The main contribution of HOMO for hexagonal pyrrhotite comes from Fe, while that of LUMO comes from S. The coefficient of Fe atom is much larger than that of S atom of HOMO for hexagonal pyrrhotite, which contributes to the adsorption of Ca OH+ on the surface of hexagonal pyrrhotite when there is lime. As a result, lime has the inhibitory effect on the floatation of hexagonal pyrrhotite and the coefficient of Fe is very close to that of S for monoclinic pyrrhotite. Therefore, the existence of S prevents the adsorption of Ca OH+on the surface of monoclinic pyrrhotite, which leads to less inhibitory effect on the flotation of monoclinic pyrrhotite.展开更多
基金Project(52264022)supported by the National Natural Science Foundation of ChinaProject(BGRIMM-KJSKL-2025-17)supported by the Open Foundation of State Key Laboratory of Mineral Processing,China。
文摘Finding appropriate flotation reagents to separate copper-nickel sulfide ores from various magnesium silicate gangue minerals has always been a challenge in the mineral processing industry.This study introduced xanthan gum(XG)as a non-toxic and environmentally friendly depressant of talc,olivine,and serpentine.The effects and mechanisms of XG on the aggregation and flotation behavior of talc,olivine and serpentine were investigated by flotation tests,sedimentation tests,IC-FBRM particle size analysis tests,adsorption quantity tests,Fourier transform infrared spectroscopy(FTIR)tests,X-ray photoelectron spectroscopy(XPS)analysis tests and Zeta potential tests.The flotation results indicated that when the three minerals were mixed,XG caused the talc-serpentine aggregation in the solution to shift to olivine-serpentine aggregation,with the remaining XG adsorbing on talc to depress its flotation.In addition,combining XPS and zeta potential tests,the-OH(hydroxyl)groups in XG molecules preferentially adsorbed on Mg sites on the surface of olivine through chemical bonding.The surface potential of olivine significantly shifted to a more negative value,with the negative charge on the olivine surface far exceeding that on the talc surface.This resulted in an increased aggregation effect between positively charged serpentine and negatively charged olivine due to enhanced electrostatic forces.
基金Projects(52074356,U22A20170)supported by the National Natural Science Foundation of ChinaProject(2022YFC2904503)supported by the National Key R&D Program of China+4 种基金Project(2023SK2061)supported by the Special Fund for the Construction of Hunan Innovative Province,ChinaProject(2023CXQD002)supported by the Innovation-driven Project of Central South University,ChinaProject(2022RC1183)supported by the Science and Technology Innovation Program of Hunan Province,ChinaProject(kq2009005)supported by the Changsha Science and Technology Project(Changsha Outstanding Innovative Youth Training Program),ChinaProject supported by the High-performance Computing Centers of Central South University,China。
文摘Malachite,being highly hydrophilic and difficult to be floated conventionally,is usually beneficiated by sulfidation flotation in industry.However,the complex crystal structure of malachite leads to the formation of various fracture surfaces with distinct properties during crushing and grinding,resulting in surface anisotropy.In this study,we explored the surface anisotropy of malachite and further investigated its sulfidation mechanism from the coordination chemistry perspective,considering the influence of the Jahn-Teller effect on malachite sulfidation.Computational results reveal that the penta-coordinated Cu ions on the malachite(201)and(010)surfaces exhibit stronger activity compared to those on the malachite(201)surface.Additionally,the tetra-coordinated structure formed by HS^(−)adsorption on the malachite(010)and(201)surfaces is more stable,with more negative adsorption energy,compared to the hexa coordinated structure formed by HS−adsorption on the(201)surface.The sulfidized malachite surface has an additional pair ofπelectron and smaller HOMO(highest occupied molecular orbital)-LUMO(lowest unoccupied molecular orbital)gap with xanthate molecules,causing strongerπbackbonding with xanthate.This study provides new insights into the surface sulfidation mechanism of malachite and offers a theoretical reference for the design of targeted flotation reagents.
基金Projects(52074139,51964027)supported by the National Natural Science Foundation of ChinaProject(KKS 2202152011)supported by the High-level Talents of Yunnan Province,China。
文摘Flotation behavior of stibiconite after sulfidation roasting with sulfur at a high temperature and the sulfidation mechanisms were investigated by ultraviolet spectrophotometry,X-ray diffraction(XRD)combining with thermodynamic calculation,X-ray photoelectron spectroscopy(XPS)and electron probe microanalysis(EPMA).The XRD and thermodynamic analyses revealed that the Sb_(3)O_(6)(OH)was reduced into Sb_(2)O_(4)and Sb_(2)O_(3),and was transformed into Sb_(2)S_(3)after introducing sulfur at high temperatures.Flotation test results show that flotation recovery of the stibiconite after sulfidation reaches 90.3%.Ultraviolet spectrophotometry tests confirm that adsorption capacity of sodium butyl xanthate(SBX)on surface of the roasted products has a positive relationship with S/Sb mole ratio.XPS analyses indicate that Sb-bearing species including mainly Sb_(2)S_(3),Sb_(2)O_(3)and Sb_(2)(SO_(4))_(3) are formed at the surface of particle after sulfidation.The EPMA analyses verify that the Sb_(2)S_(3)is generated at the outer layer of sample after sulfidation roasting,but the particle interior is mainly composed of antimony oxides.The sulfur atmosphere induces the outward migration of oxygen to form Sb_(2)O_(4).Then,the Sb_(2)O_(4)is transformed into Sb_(2)O_(3)in two pathways,and the Sb_(2)S_(3)is formed.These findings will provide theoretical support for recovering antimony from antimony oxide ores by xanthate flotation methods.
基金Project(52204363)supported by the National Natural Science Foundation of ChinaProject(2024JJ8042)supported by the Hunan Natural Science Foundation,ChinaProject(22C0220)supported by the Education Department of Hunan Province,China。
文摘The lime-Cu^(2+)-xanthate process is commonly used for the flotation separation of sphalerite from pyrite.In this process,lime is added to the pulp to inhibit the floatability of pyrite.However,the excessive use of lime can result in pipeline blockage and inadequate recovery of associated precious metals.Therefore,it is necessary to develop new flotation process that minimizes or eliminates the use of lime.In this paper,a novel Fe^(3+)-Cu^(2+)-butyl xanthate process was developed as an alternative to lime for separating of sphalerite from pyrite.The flotation results indicated that with the artificially-mixed minerals,the flotation recovery of pyrite was lower than 16%and that of sphalerite was higher than 47%at pH 5.0−10.0.The zeta potential measurements revealed that ferric ion preferred to adsorb on pyrite,and copper ion displaced with zinc ion from the lattice at the interface of sphalerite.The wettability analyses indicated that the hydrophobicity of sphalerite surface increased apparently after being treated with Fe^(3+)-Cu^(2+)-BX,while the hydrophobicity of pyrite surface remained nearly unchanged.With XPS analysis,Cu-S bond and hydrophilic ferric hydroxide were detected separately on the surface of sphalerite and pyrite after conditioning with Fe^(3+)-Cu^(2+)-BX,which facilitated the flotation separation of sphalerite from pyrite with butyl xanthate collector.
基金Project(51274256)supported by the National Natural Science Foundation of China
文摘Magnetic seeding agglomeration(MSA),i.e.,adding magnetic seeds and a low intensity pre-magnetization for fine agglomeration,was applied to the flotation of coal,pyrite and hematite ore slimes.Size analysis and flotation tests highlight that the MSA improved flotation recovery and kinetics of pyrite ore while causing some loss in selectivity,and in the presences of the polyacrylamide for coal and starch for hematite the agglomeration flotation was further strengthened due to the synergetic effect between the flocculants and magnetic seeds.Magnetism analyses and calculation confirmed the adsorption of magnetic seeds onto minerals,resulting in a decreased threshold magnetic field intensity for the MSA to happen.Then atomic force microscope(AFM)study found that there exists a long range force between magnetic seeds and minerals,which facilitates the adsorption of magnetic seeds on minerals.FTIR shows both the polyacrylamide and starch adsorbed onto minerals and magnetic seeds,thus acting as the bridging media between minerals and magnetic seeds,intensifying the agglomeration in flotation.Surface characterization of the MSA was understood by SEM imaging,and models of the MSA were proposed.
基金Project（2016zztsl03） supported by the Fundamental Research Funds for the Central Universities, China Project（51374249） supported by the National Natural Science Foundation of China+1 种基金 Project（2015BAB12B02） supported by the National Key Technology R＆D Program of China Project（2013B090800016） supported by Guangdong Provincial Science and Technology Plan, China
文摘An effective flotation approach is proposed for improving the recovery of molybdenite fines from a finely-disseminated molybdenum ore. To maximize the flotation recovery of molybdenum, process mineralogy of raw ore, contrast tests, optimization of operation conditions and particle size analysis were systematically investigated. Process mineralogy suggests that in the raw ore, 61.63% of molybdenite particles distribute in the 〈20 pm size fraction, and intergrow with muscovite and pyrite as the contained and disseminated type. Contrast tests indicate that conventional flotation responds to poor collection efficiency for particles less than 25 pm. Oil agglomerate flotation （OAF） process demonstrates an obvious superiority in improving the flotation recovery of molybdenite fines. Furthermore, the flotation results of OAF process reveal that the dosage of transformer oil plays a critical role on the average size of collected mineral particles （d（0）, agglomerates （d^0） and the molybdenum recovery. In addition, industrial tests illustrate that compared with the Mo-S bulk flotation approach, OAF process not only increases Mo recovery and grade of molybdenum concentrate by 22.75% and 17.47% respectively, but also achieves a sulfur concentrate with a superior grade of 38.92%.
基金Project(2012CB214905)supported by the National Basic Research Program of ChinaProject(51074157)supported by the National Natural Science Foundation of China
文摘Flotation column is widely used as the separation equipment for fine mineral due to its high selectivity. However, this device may be unsuitable for the coarse particle flotation and has high handling ability. A two-stage flotation column with dimensions of 2 000 mm×1 000 mm×4 000 mm was designed to enhance the column flotation process. The energy input was modified by adjusting the flow rate and the head of circulating pump. The flotation column was designed with low energy input in the first stage(speed flotation stage) to recover easy-to-float materials quickly, and high energy input in the second stage(recovery stage) to recover difficult-to-float minerals compulsorily. Contrast experiments on the throughput and coarse coal recovery of high ash coal from the Kailuan Mine were conducted using conventional single-stage flotation column and the two-stage flotation column. The results show that the combustible matter recovery of the two-stage flotation column is 5.25% higher than that of the conventional single-stage flotation column. However, the ash contents of clean coal for both columns are similar. Less coarse coals with low ash are obtained using the two-stage flotation column than that using the single-stage column flotation with the same handling ability. The two-stage flotation column process can enhance coal flotation compared with the conventional single-stage column flotation.
基金Project(ID42787)supported by the Istanbul Technical University,BAP(Scientific Research Project)Department,Turkey。
文摘Frothers facilitate the reduction of bubbles size by preventing bubbles coalescence and produce more stable froths.The collision probability of the bubbles and particles substantially increases by decreasing bubble size.For the same volume system,fewer bubbles result from a distribution of large-sized bubbles,and more bubbles result from a distribution of small-sized bubbles.In this research,fundamental two-phase frother characterization parameters were aimed to link with three-phase coal and talc flotation behavior.For this purpose,the effect of single and dual frother systems on inhibiting bubble coalescence was investigated with methyl isobutyl carbinol(MIBC),isooctanol(2 ethyl hexanol),pine oil,and Dowfroth 250.Based on the results of single frothers,isooctanol at the lowest critical coalescence concentration(CCC)value of 6×10^(−6) achieved the smallest bubbles with Sauter mean diameter of 0.80 mm.By blending Dowfroth 250 and pine oil,the bubbles size decreased significantly,reaching 0.45 mm.While the highest recoveries in coal flotation were obtained in single and frother blends where the bubbles size was measured as the smallest in two-phase system,and such a relationship was not found for talc flotation.
基金Projects(61621062,61563015)supported by the National Natural Science Foundation of ChinaProject(2016zzts056)supported by the Central South University Graduate Independent Exploration Innovation Program,China
文摘Effective fault detection techniques can help flotation plant reduce reagents consumption,increase mineral recovery,and reduce labor intensity.Traditional,online fault detection methods during flotation processes have concentrated on extracting a specific froth feature for segmentation,like color,shape,size and texture,always leading to undesirable accuracy and efficiency since the same segmentation algorithm could not be applied to every case.In this work,a new integrated method based on convolution neural network(CNN)combined with transfer learning approach and support vector machine(SVM)is proposed to automatically recognize the flotation condition.To be more specific,CNN function as a trainable feature extractor to process the froth images and SVM is used as a recognizer to implement fault detection.As compared with the existed recognition methods,it turns out that the CNN-SVM model can automatically retrieve features from the raw froth images and perform fault detection with high accuracy.Hence,a CNN-SVM based,real-time flotation monitoring system is proposed for application in an antimony flotation plant in China.
基金Project(51374079) supported by the National Natural Science Foundation of China
文摘Reverse flotation technology is one of the most efficient ways to improve the quality and reduce impurity of iron concentrate. Mineral processors dealing with hematite face a challenge that the flotation results of reverse flotation of hematite are poor in presence of siderite using fatty acid as collector, starch as depressant of iron minerals and calcium ion as activator of quartz at strong alkaline pH. In this work, the effect of siderite on reverse anionic flotation of quartz from hematite was investigated. The effect mechanism of siderite on reverse flotation of hematite was studied by solution chemistry, ultraviolet spectrophotometry(UV) and Fourier transform infrared spectroscopy(FTIR). It was observed that siderite had strong depressive effect on quartz in flotation using sodium oleate as collector, corn starch as depressant of iron minerals and calcium chloride as activator of quartz at strong alkaline pH. The starch was adsorbed onto calcium carbonate by chemical reaction which was formed by CO^(2-)_3 from siderite dissolution and Ca^(2+) from calcium chloride as activator of quartz and precipitated on the surface of quartz, which resulted in improving the hydrophilic ability of quartz.
基金Projects(2020GDASYL-20200302009,2020GDASYL-20200302004,2019GDASYL-0501007)supported by Guandong Academy of Sciences,ChinaProject(2020YFC1909202)supported by Ministry of Science and Technology of China。
文摘In order to improve the recovery of tungsten ores containing tin minerals,anisic hydroxamic acid(p-methoxy benzohydroxanic acid,PMOB)was synthesized and introduced as novel collector in the flotation of scheelite,wolframite and cassiterite.The flotation performance and adsorption mechanism were investigated by micro/batch flotation,zeta potential measurements and density functional theory(DFT).The micro flotation results showed that the recoveries of scheelite,wolframite and cassiterite using PMOB as collector are 97.45%,95.77% and 90.08%,respectively,and the corresponding recoveries are 91.00%,84.30% and 84.67% for benzohydroxamic acid(BHA).The batch flotation results revealed that the collector dosage could be reduced by about 45% for PMOB compared with BHA,in the case of similar flotation indicators.Zeta potential measurements indicated that PMOB could be adsorbed on the mineral surfaces by chemisorption.Moreover,density functional theory(DFT)calculation results showed that the substituent group—OCH_(3)endues PMOB stronger electron donation ability and hydrophobicity compared with benzohydroxamic acid(BHA),pmethyl benzohydroxamic acid(PMB)and p-hydroxyl benzohydroxamic acid(PHB).
文摘The flotation properties of single minerals such as diaspore, kaolinite and pyrophllite in bauxites were investigated using RL as collector. The effects of regulators and unavoidable ions on flotation were studied. Based on the results of single minerals flotation, the separation experiments of mixed minerals and bauxite ore were carried out. The results of closed circuit test on the ore show that, using RL as collector, Na 2CO 3 and (NaPO 3) 6 as modifiers, the grade of Al 2O 3 and SiO 2 are respectively 70.74% and 6.37% in concentrate (Al/Si 11.11), and the recovery of Al 2O 3 can reach 90.52%.
基金Project(201209013)supported by Special Fund for Environmental Scientific Research in the Public Interest,China
文摘A laboratory scale up-flow biological activated carbon(BAC) reactor was constructed for the advanced treatment of synthetic flotation wastewater. Biodegradation of a common collector(i.e., ethyl xanthate) for non-ferrous metallic ore flotation was evaluated. The results show that the two stages of domestication can improve microbial degradation ability. The BAC reactor obtains a chemical oxygen demand(COD) reduction rate of 82.5% for ethyl xanthate and its effluent COD concentration lowers to below 20 mg/L. The kinetics equation of the BAC reactor proves that the activated carbon layers at the height of 0 mm to 70 mm play a key role in the removal of flotation reagents. Ultraviolet spectral analysis indicates that most of the ethyl xanthate are degraded by microorganisms after advanced treatment by the BAC reactor.
基金Project(50774094) supported by the National Natural Science Foundation of China
文摘The floatability of different crystalline structures of pyrrhotite(monoclinic and hexagonal) was studied.It is shown that the floatability of monoclinic and hexagonal has obvious difference,and that the flotation recovery of monoclinic pyrrhotite is larger than that of hexagonal pyrrhotite using different collectors.When butyl dithiophosphate is used as the collector,the recovery is larger than that by sodium butyl xanthate and sodium diethyl dithiocarbamate.At the pH values ranging from 6 to 9,monoclinic pyrrhotite can be floated well,and the flotation recovery is higher than 90%.Monoclinic and hexagonal pyrrhotites are more easily activated by Cu2+ in acidic conditions than in alkaline conditions.But Cu2+ cannot activate hexagonal pyrrhotite using sodium diethyldithiocarbamate as the collector.By the measurement of contact angle,it is indicated that monoclinic and hexagonal pyrrhotites float well and are easily activated by Cu2+ when dithiophosphate is used as the collector.Using sodium diethyl dithiocarbamate as a collector,the relationship between potential and pH range for pyrrhotite flotation is established.At pH 5,the optimal potential range for flotation of monoclinic pyrrhotite is about 125-580 mV(vs SHE),with the maximum flotation occurring at about 350 mV(vs SHE);the optimal potential range for flotation of hexagonal pyrrhotite is 200?580 mV(vs SHE),with the maximum flotation occurring at about 300 mV(vs SHE).
基金Project(50674102) supported by the National Natural Science Foundation of China
文摘The interaction mechanism of collector DLZ in the flotation process of chalcopyrite and pyrite was investigated through flotation experiments,zeta potential measurements and infrared spectrum analysis.Flotation test results indicate that DLZ is the selective collector of chalcopyrite.Especially,the recovery of chalcopyrite is higher than 90% in neutral and weak alkaline systems,while the recovery of pyrite is less than 10%.When using CaO as pH regulator,at pH=7-11,the floatability of pyrite is depressed and the recovery is less than 5%.Zeta potential analysis shows that the zeta potential of chalcopyrite decreases more obviously than that of pyrite after interaction with DLZ,confirming that collector DLZ shows selectivity to chalcopyrite and pyrite.And FTIR results reveal that the flotation selectivity of collector DLZ is due to chemical absorption onto chalcopyrite surface and only physical absorption onto pyrite surface.
基金Project supported by the Chair in Mineral Processing at McGill University,under the Collaborative Research and Development Program of NSERC(Natural Sciences and Engineering Research Council of Canada)with industrial sponsorship from Vale,Teck Cominco,Xstrata Process Support,Agnico-Eagle,Shell Canada,Barrick Gold,COREM,SGS Lakefield Research and Flottec
文摘Effect of frothers in preventing bubble coalescence during flotation of minerals has long been investigated.To evaluate the performance of a frother,an apparatus to measure the bubble size is a basic necessity.McGill Bubble Size Analyzer(MBSA) or bubble viewer that has been developed and completed by McGill University's Mineral Processing Group during the last decade is a unique instrument to serve this purpose.Two parameters which are thought to influence the bubble size measurements by McGill bubble viewer include water quality and frother concentration in the chamber.Results show that there is no difference in Sauter mean(D32) when tap or de-ionized water was used instead of process water.However,the frother concentration,in this research DowFroth 250(DF250),inside the chamber exhibited a pronounced effect on bubble size.Frother concentration below a certain point can not prevent coalescence inside the chamber and therefore caution must be taken in plant applications.It was also noted that the frother concentration which has been so far practiced in plant measurements(CCC75-CCC95) is high enough to prevent coalescence with the bubble viewer.
基金Project(2016RS2016) supported by Provincial Science and Technology Leader Program,Hunan,ChinaProject(2017zzts807) supported by Postgraduate Innovative Research Projects of Central South University,China
文摘The composition of a collector directly affects its collecting performance in mineral flotation.In this study,three vegetable oils were used as the collectors,the flotation performance of scheelite and the differential analysis were studied through flotation experiments,zeta potential,contact angle measurement and Fourier transform infrared spectrum(FTIR)analysis.Flotation results show that the recovery of scheelite increases in the order of oleic acid<rapeseed oil<rice bran oil<soybean oil,especially in the pH range of 5-8.The distinction in the scheelite recovery is due to the different compositions of these collectors.The addition of LA,LNA and PA(<5%)can increase the recovery of scheelite with OA,but the addition of SA deteriorates the scheelite flotation.Results of zeta potential,contact angle measurement and FTIR analysis indicate that the collector adsorption on scheelite surface is enhanced when using the three vegetable oils.For the raw ore with 0.086%WO3,a rough concentrate containing 1.423%WO3 with the recovery of 84.22%is obtained using soybean oil as the collector.
基金Project(2014CB643402) supported by the National Basic Research Program of ChinaProject(CX2013B082) supported by the Hunan Provincial Innovation Foundation for Postgraduate,China
文摘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 p H 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 p H 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 Mn_2+/Fe_2+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.
基金Project(2013EG132088)supported by Special Program for Research Institutes of the Ministry of Science and Technology,ChinaProject(12010402c187)supported by Key Science and Technology Program of Anhui Province,ChinaProject(GJKJ-14-89)supported by Science and Technology Program of Nanchang Institute of Science and Technology,China
文摘Based on the working principles of particle bed comminution, particles produced by high-pressure grinding rolls （HPGR） have surface properties different from particles produced by other grinding patterns, which exert great influence on mineral flotation. Flotation performances of calcite particles under different grinding patterns involving the use of HPGR, a jaw crusher, a dry ball mill, a wet ball mill, and a wet rod mill were studied using single mineral flotation tests. The surface properties of the particles under different grinding patterns were characterized to determine the flotation performance variation in terms of specific surface area, particle size distribution, AFM, XPS, and zeta potential. The results show that particles ground by HPGR exhibited improved flotation performance within the lower range of grinding fineness in both NaOL and dodecyl amine flotation systems compared to the particles prepared using other grinding patterns. Specific surface area, particle size distribution, surface roughness, Fe（III） contamination, binding energy, and zeta potential are greatly influenced by grinding patterns, which is the main cause of the flotation performance variation.
基金Project supported by the Open Foundation of Guangxi Key Laboratory for Advanced Materials and Manufacturing Technology,China
文摘Electronic structures of monoclinic and hexagonal pyrrhotite were studied using density functional theory method,together with their flotation behavior. The main contribution of monoclinic pyrrhotite is mainly from Fe 3d, while that of hexagonal pyrrhotite is from Fe 3d, Fe 3p and S 3s. The hexagonal pyrrhotite is more reactive than monoclinic pyrrhotite because of large density of states near the Fermi level. The hexagonal pyrrhotite shows antiferromagnetism. S—Fe bonds mainly exist in monoclinic pyrrhotite as the covalent bonds, while hexagonal pyrrhotite has no covalency. The main contributions of higest occupied molecular orbital(HOMO) and lowest unoccupied molecular obital(LUMO) for monoclinic pyrrhotite come from S and Fe. The main contribution of HOMO for hexagonal pyrrhotite comes from Fe, while that of LUMO comes from S. The coefficient of Fe atom is much larger than that of S atom of HOMO for hexagonal pyrrhotite, which contributes to the adsorption of Ca OH+ on the surface of hexagonal pyrrhotite when there is lime. As a result, lime has the inhibitory effect on the floatation of hexagonal pyrrhotite and the coefficient of Fe is very close to that of S for monoclinic pyrrhotite. Therefore, the existence of S prevents the adsorption of Ca OH+on the surface of monoclinic pyrrhotite, which leads to less inhibitory effect on the flotation of monoclinic pyrrhotite.
