In this study,copper extraction from low-grade oxide-sulfide ores was investigated using a leaching method combined with response surface methodology(RSM)to optimize operational conditions and assess leaching kinetics...In this study,copper extraction from low-grade oxide-sulfide ores was investigated using a leaching method combined with response surface methodology(RSM)to optimize operational conditions and assess leaching kinetics.Given copper's extensive industrial applications,sustainable recovery from low-grade ores is critical.Five key parameters-acid concentration,leaching time,particle size,temperature,and solids percentage-were identified as major influences on copper recovery.The results revealed that leaching time and solids percentage,along with interactions between temperature-time and temperature-solids percentage,had the most significant effects.Optimal conditions for 80% copper recovery while minimizing iron recovery below 3% included an acid concentration of 1.21 mol L^(-1),a leaching time of 108 min,a particle size of 438μm,a temperature of 45℃,and a solids percentage of 18.2%.Leaching kinetics were analyzed using shrinking core models,with the Dickinson model best describing the process,showing an activation energy of 32.63 kJ mol^(-1),indicative of mixed diffusion and chemical reaction control.The final kinetic model effectively predicted the influence of key parameters.These findings highlight the importance of optimizing process variables and selecting suitable kinetic models to enhance extraction efficiency,reduce costs,and improve sustainability in copper recovery.展开更多
Polypropylene fibers(PPFs) have been widely used in composite materials due to their sound crack resistance and toughness. In cement-based composites, the incorporation of PPFs can significantly improve their dynamic ...Polypropylene fibers(PPFs) have been widely used in composite materials due to their sound crack resistance and toughness. In cement-based composites, the incorporation of PPFs can significantly improve their dynamic mechanical properties. However, cement-iron ore tailings foam composite(CIFC), a sustainable material utilizing iron ore tailings to partially replace cement, has not been investigated under dynamic loading. This study investigates the dynamic compressive behavior of CIFC with 1%–2.5% PPF content and 3–12 mm PPF lengths under various strain rates. The microstructural characteristics were analyzed prior to dynamic testing. X-ray diffraction(XRD) identified crystalline phases including CaCO_(3)Fe_(2)O_(3), SiO, C-S-H gel, and ettringite. Scanning electron microscopy(SEM) observations demonstrated that appropriate PPF_(2) parameters(e.g., C2L9, a CIFC specimen containing 2% PPF with 9 mm length) enhance fiber-matrix bonding and minimize interconnected pores and microcracks, revealing pronounced fiber bridging effects. Split Hopkinson pressure bar(SHPB) tests were then conducted at strain rates of 120–250 s^(-1), showing that the dynamic properties of CIFC were highly dependent on both strain rates and PPF parameters. Compared to other specimens, C2L9 exhibited a more intact failure pattern with superior compressive strength and energy dissipation capacity, despite showing reduced dynamic increase factor(DIF) and normalized energy dissipation(NED) values. These findings provide practical guidance for applying CIFC with varying PPF parameters in impact-resistant structural designs.展开更多
Microwave roasting self-leaching is an innovative method for recovering gold from high-sulfur refractory gold concentrates,without using deadly toxic cyanide reagents.However,the mechanism of gold self-leaching,which ...Microwave roasting self-leaching is an innovative method for recovering gold from high-sulfur refractory gold concentrates,without using deadly toxic cyanide reagents.However,the mechanism of gold self-leaching,which relies on lixiviants prepared using volatilized sulfur obtained from roasting,has not been fully elucidated.This study employs the response surface methodology to optimize processing parameters,resulting in an increased gold extraction rate of 96.18%.Analytical factorization and the Tafel curve indicate that CuSO_(4) and NH_(3)·H_(2)O significantly influence the self-leaching process.Furthermore,X-ray photoelectron spectroscopy(XPS)analysis reveals that S^(2−),S_(2)^(2−),polysulfides(S_(n)^(2−)),and thiosulfate(S_(2)O_(3)^(2−))are involved in the gold leaching reaction,with S^(2−),S_(2)^(2−),and S_(n)^(2−) serving as primary ligands for gold complexation.The role of S_(2)O_(3)^(2−) in the early stages of the gold-leaching reaction is also noteworthy.The copper–ammonia complex catalyzes the self-leaching gold reaction;however,an improper addition ratio can lead to copper-sulfur compound precipitates,reducing the extraction rate.展开更多
Seabed mining operations have been found to induce significant movement and deformation in overlying rock strata,posing serious threats to mining safety.The presence of geological faults further complicates these defo...Seabed mining operations have been found to induce significant movement and deformation in overlying rock strata,posing serious threats to mining safety.The presence of geological faults further complicates these deformation patterns.This study utilized geophysical surveys and the continuum-based discrete element method(CDEM)to investigate how fault activity influences rock deformation and failure.The results demonstrate that:1)Acting in mechanically weak zones,faults exerted a pronounced barrier effect on deformation propagation and stress redistribution within the surrounding rock,leading to markedly divergent displacement patterns on either side of the fault plane.Comparative analyses between single-fault and double-fault models revealed an 18%−22%expansion of the damage zone under the latter,together with significantly intensified deformation and failure;2)The double-fault model exhibited a larger maximum cumulative vertical displacement and a spatial shift in the location of peak deformation,thereby posing a heightened threat to mine safety;3)Acting in an orebody substitute,backfill effectively constrained surrounding rock deformation,enhanced its load-bearing capacity,and delayed the overburden subsidence.Nevertheless,backfill only reduced the amplitude of deformation;it could not entirely prevent settlement.These findings provide essential theoretical insights and foundational knowledge for safer submarine mining practices.展开更多
The Zijinshan ore field located in southwestern Fujian Province,China,is a representative porphyry-epithermal ore system hosting diverse mineralization types(Mao et al.,2013).The ore field comprises of the Zijinshan h...The Zijinshan ore field located in southwestern Fujian Province,China,is a representative porphyry-epithermal ore system hosting diverse mineralization types(Mao et al.,2013).The ore field comprises of the Zijinshan highsulfidation Cu-Au deposit,the Luoboling porphyry Cu-Mo deposit,the transitional style Cu deposit(Longjiangting and Wuziqilong)and the Yueyang low-sulfidation Agpolymetallic deposit(Zhang,2013;Zhang et al.,2003)展开更多
The giant Pulang porphyry copper deposit,located in the southern Yidun arc segment of southeastern Tibetan Plateau,represents one of the region’s largest mineral systems.This study employs numerical simulation to unr...The giant Pulang porphyry copper deposit,located in the southern Yidun arc segment of southeastern Tibetan Plateau,represents one of the region’s largest mineral systems.This study employs numerical simulation to unravel its metallogenic processes.By integrating field-based geological observations with mineralogical and geochemical data,we developed a coupled model encompassing five key stages of ore formation.The simulation successfully reproduced thermal anomalies and accurately predicted the spatial distribution of mineralization zones at Pulang.Coupling dynamic modeling results with chalcopyrite precipitation rates and average Cu grades enabled quantitative estimation of deposit formation duration(0.99–1.22 Ma).Compared with conventional geochronological approaches,this process-constrained modeling framework provides unprecedented insights into the thermodynamic mechanisms controlling porphyry copper system evolution,offering valuable implications for regional exploration strategies.展开更多
Stainless steel,known for its exceptional properties and diverse applications,conventionally requires a multistage process that generates considerable CO_(2) emissions by using fossil-based carbon reductants.This stud...Stainless steel,known for its exceptional properties and diverse applications,conventionally requires a multistage process that generates considerable CO_(2) emissions by using fossil-based carbon reductants.This study investigated hydrogen plasma smelting reduction as a novel,sustainable,and efficient method for producing stainless steel directly from lateritic nickel and chromite ores.The research aimed to examine the effect of ore proportion on AISI 300 series stainless steel production and assess the reduction process over time through thermochemical calculations and experimental studies.Results showed that increasing the proportion of chromite ore in the feed raises Cr content and reduces Ni content in metals while increasing Cr_(2)O_(3) and Al_(2)O_(3) content in oxides.A briquette comprising 30wt%chromite ore and 70wt%calcined nickel ore yields better results for AISI 300 stainless steel,with Fe,Cr,Ni,and Si content of 62.95wt%,19.37wt%,11.83wt%,and 0.72wt%,respectively,after 180 s of hydrogen plasma exposure.Nearly all NiO compounds are converted into Ni after 60 s of smelting reduction,whereas FeO compounds are almost fully converted into Fe after 120 s of smelting reduction.AISI 300 series stainless steel is successfully produced after 120 s of reduction,achieving Fe,Cr,Ni,and Si content of 64.36wt%,21.92wt%,10.08wt%,and 0.61wt%,respectively.Process optimization remains promising because the Cr_(2)O_(3) content in the slag is still relatively high at 15.52wt%.This ultrafast and direct production method holds considerable potential to transform stainless steel production by reducing environmental impact and enhancing process efficiency.Specifically,the method eliminates the use of an argon oxygen decarburization converter and vacuum oxygen decarburization in stainless steelmaking.展开更多
The semi-molten smelting process of a mixture of saprolitic and limonitic laterite ores was systematically investigated and the effect of slag basicity was deeply analyzed.The results indicate that the slag system can...The semi-molten smelting process of a mixture of saprolitic and limonitic laterite ores was systematically investigated and the effect of slag basicity was deeply analyzed.The results indicate that the slag system can be located in the liquidus region of low melting-point diopside(CaMgSi_(2)O_(6))when slag basicity is kept at 0.3 and limonitic laterite mass fraction is not less than 10%.When the reduction temperature,C/O mass ratio,limonitic laterite mass fraction and slag basicity are kept at the optimum values of 1300℃,0.86,20%and 0.3,respectively,ferronickel products with grades 6.42%Ni and 86.99%Fe are prepared.The recovery rates of Ni and Fe reach 88.60%and 72.25%,respectively.展开更多
The rare earth elements(REEs)extraction by chemical leaching from ion-adsorption type rare earth ores(IAREO)has led to serious ecological and environmental risks.Conversely,demand for bioleaching is on the rise with t...The rare earth elements(REEs)extraction by chemical leaching from ion-adsorption type rare earth ores(IAREO)has led to serious ecological and environmental risks.Conversely,demand for bioleaching is on the rise with the advantage of being environmental-friendly.As one of the organic acids produced by biological metabolism,citric acid was used to leach REEs and explore the performance and process.The results demonstrate that citric acid exhibits higher leaching efficiency(96.00%)for REEs at a relatively low concentration of 0.01 mol/L compared with(NH_(4))_(2)SO_(4)(84.29%,0.1 mol/L)and MgSO_(4)(83.99%,0.1 mol/L).Citric acid shows a preference for leaching heavy rare earth elements,with 99%leaching efficiency in IAREO,which shows higher capacity than(NH_(4))_(2)SO_(4)and MgSO_(4)(as inorganic leaching agents).Kinetic analysis indicates that the leaching process of REEs with citric acid is controlled by both the internal diffusion kinetics and chemical reaction kinetics,which is different from inorganic leaching agents.Visual Minteq calculations confirm that RE-Citrate is the main constituent of the extract solution in the leaching process of the IAREO,thereby enhancing the leaching efficiency of REEs from the IAREO.It suggests that citric acid may be used as a promising organic leaching agent for the environmentalfriendly extraction of REEs from IAREO.展开更多
Detection of ore waste is crucial for achieving automation in mineral metallurgy production.However,deep learning-based target detection algorithms still face several challenges in iron waste screening,including poor ...Detection of ore waste is crucial for achieving automation in mineral metallurgy production.However,deep learning-based target detection algorithms still face several challenges in iron waste screening,including poor lighting conditions in underground mining environments,dust disturbances,platform vibrations during operation,and limited resources for large-scale computing equipment.These factors contribute to extended computation times and unsatisfactory detection accuracy.To address these challenges,this paper proposes an ore waste detection algorithm based on an improved version of YOLOv5.To enhance feature extraction capabilities,the RepLKNet module is incorporated into the YOLOv5 backbone and neck networks.This module enhances the deformation information of feature extraction with the maximum effective Receptive Field to increase the model's accuracy.The Normalizationbased Attention Module(NAM)was introduced to enhance the attention mechanism by focusing on the most relevant features.This improves accuracy in detecting objects against noisy or unclear backgrounds,thereby further enhancing detection performance while reducing model parameters.Additionally,the loss function is optimized to constrain angular deviation using the SIOU loss function,which prevents the training frame from drifting during training and enhances convergence speed.To validate the performance of the proposed method,we tested it using a self-constructed dataset comprising 1,328 images obtained from the crushing station at Jinchuan Group's No.2 mine.The results indicate that,compared to YOLOv5s on the self-constructed dataset,the proposed algorithm achieves an 18.3%improvement in mAP(0.5),a 54%reduction in FLOPs,and a 52.53%decrease in model parameters.The effectiveness and superiority of the proposed algorithm are demonstrated through case studies and comparative analyses.展开更多
The Early Paleozoic porphyry-epithermal Au system of the Songshunangou District sits in the central segment of the North Qilian orogenic belt(NQOB).The porphyry Au mineralization is centered on the quartz diorite porp...The Early Paleozoic porphyry-epithermal Au system of the Songshunangou District sits in the central segment of the North Qilian orogenic belt(NQOB).The porphyry Au mineralization is centered on the quartz diorite porphyry(QDP),which is constrained to the Late Ordovician period.However,the geochemical signatures,the origin,and the tectonic setting of the QDP are not yet known and understood and are thus in the focus here.The QDP is a high-K calc-alkaline metaluminous rocks(K_(2)O+Na_(2)O:6.90-8.13;Al_(2)O_(3)/(CaO+Na_(2)O+K_(2)O):0.69-0.90)characterized by high(^(87)Sr/^(86)Sr)_(t)values(0.7093-0.7101)and lowε_(Nd)(t)values(-2.9 to-2.7)with corresponding T_(DM2)(Nd)ages of 1408 to 1430 Ma.Zirconε_(Hf)(t)values are low(-1.51 to+2.76)with corresponding T_(DM2)(Hf)ages of 1262 to 1533 Ma.The lead isotope values are 17.695-18.476 for(^(206)Pb/^(204)Pb)_(t),15.585-15.629 for(^(207)Pb/^(204)Pb)_(t),and 37.214-37.948 for(^(208)Pb/^(204)Pb)_(t).These data indicate that the QDP formed by the mixing of mantle-derived magmas(50%-70%)with lower crustal melts.The QDP is enriched in LREEs and LILE(Rb,Th,K)and is depleted in HFSE(Nb,Ta,Ti),expressing a clear volcanic arc affinity.High La and Th contents,and Zr/Y and Hf/Yb values suggest that the QDP formed in an Andean-type continental margin arc setting related to the northward subduction of the North Qilian oceanic slab.The Early Paleozoic subduction-related intermediate-acidic intrusions in NQOB have arc magma affinity,indicating that these rocks bear a great potential to discover further fertile porphyry deposits.展开更多
Original sedimentary manganese(Mn)deposits and supergene Mn ores are important Mn resources in China.However,the geochemical information from Chinese supergene Mn ores is scarce,and the relationship between sedimentar...Original sedimentary manganese(Mn)deposits and supergene Mn ores are important Mn resources in China.However,the geochemical information from Chinese supergene Mn ores is scarce,and the relationship between sedimentary Mn deposits and supergene Mn ores is ambiguous.In this study,we collected the original Mn-bearing dolomitic sandstones(ZK20-3 drillcore)and supergene Mn ores(Longmen Section)from eastern Hebei,North China for systematic petrographic,mineralogical and geochemical analyses.Our new data help us to figure out the transformation from original Mn-bearing deposits to supergene ores.The main minerals of original Mn-bearing dolomitic sandstones are quartz and feldspar,with minor muscovite,dolomite,rhodochrosite,ankerite,and kutnohorite.Supergene Mn-oxide ores only emerged in the middle part of the Longmen(LM)Section,and mainly contain quartz,pyrolusite,cryptomelane,todorokite and occasional dolomite.The possible transformation sequence of Mn minerals is:kutnohorite/rhodochrosite→pyrolusite(Ⅰ)→cryptomelane(todorokite)→todorokite(cryptomelane)→pyrolusite(Ⅱ).For Mn-oxide ores,Fe,Na and Si are enriched but Al,Ca,Mg and K are depleted with the enrichment of Mn.For original and supergene ores,the total rare earth element+ytterbium(∑REY)contents range from 105.68×10^(-6)to 250.56×10^(-6)and from 18.08×10^(-6)to 176.60×10^(-6),respectively.Original Mn ores have similar slightly LREE-enriched patterns,but the purer Mn-oxide ore shows a HREE-enriched pattern.In the middle part of the LM Section,positive Ce anomalies in Mn-oxide ores indicate the precipitation of Ce-bearing minerals.It implies the existence of geochemical barriers,which changed p H and Eh values due to the long-time influence of groundwater.展开更多
Against the background of“carbon peak and carbon neutrality,”it is of great practical significance to develop non-blast furnace ironmaking technology for the sustainable development of steel industry.Carbon-bearing ...Against the background of“carbon peak and carbon neutrality,”it is of great practical significance to develop non-blast furnace ironmaking technology for the sustainable development of steel industry.Carbon-bearing iron ore pellet is an innovative burden of direct reduction ironmaking due to its excellent self-reducing property,and the thermal strength of pellet is a crucial metallurgical property that affects its wide application.The carbon-bearing iron ore pellet without binders(CIPWB)was prepared using iron concentrate and anthracite,and the effects of reducing agent addition amount,size of pellet,reduction temperature and time on the thermal compressive strength of CIPWB during the reduction process were studied.Simultaneously,the mechanism of the thermal strength evolution of CIPWB was revealed.The results showed that during the low-temperature reduction process(300-500℃),the thermal compressive strength of CIPWB linearly increases with increasing the size of pellet,while it gradually decreases with increasing the anthracite ratio.When the CIPWB with 8%anthracite is reduced at 300℃for 60 min,the thermal strength of pellet is enhanced from 13.24 to 31.88 N as the size of pellet increases from 8.04 to 12.78 mm.Meanwhile,as the temperature is 500℃,with increasing the anthracite ratio from 2%to 8%,the thermal compressive strength of pellet under reduction for 60 min remarkably decreases from 41.47 to 8.94 N.Furthermore,in the high-temperature reduction process(600-1150℃),the thermal compressive strength of CIPWB firstly increases and then reduces with increasing the temperature,while it as well as the temperature corresponding to the maximum strength decreases with increasing the anthracite ratio.With adding 18%anthracite,the thermal compressive strength of pellet reaches the maximum value at 800℃,namely 35.00 N,and obtains the minimum value at 1050℃,namely 8.60 N.The thermal compressive strength of CIPWB significantly depends on the temperature,reducing agent dosage,and pellet size.展开更多
A transformative beryllium metallurgy theory and method was proposed based on the low-temperature dissociation of hydrofluoric acid and purification by exploiting the large difference of fluoride solubility.Hydrofluor...A transformative beryllium metallurgy theory and method was proposed based on the low-temperature dissociation of hydrofluoric acid and purification by exploiting the large difference of fluoride solubility.Hydrofluoric acid can quickly dissociate berylum ore powder directly at low or room temperature with more than 99%dissociation rate.The solubility of AlF_(3),FeF_(3) CrF_(3) and MgF_(2),is low.Coupled with common ion effect,99.9%-purity beryllium products can be prepared without chemical purification.For high-purity beryllium products of grade 4N or higher,they can be prepared through the superior property that the pH intervals of iron,chromium,and other hydroxide precipitates are distinctly different from those corresponding to Be(OH)_(2),precipitates.This new method can be used to prepare most of the beryllium products that are prepared by modern beryllium metallurgy.展开更多
Methods and procedures of three-dimensional （3D） characterization of the pore structure features in the packed ore particle bed are focused. X-ray computed tomography was applied to deriving the cross-sectional imag...Methods and procedures of three-dimensional （3D） characterization of the pore structure features in the packed ore particle bed are focused. X-ray computed tomography was applied to deriving the cross-sectional images of specimens with single particle size of 1-2, 2-3, 3-4, 4-5, 5-6, 6-7, 7-8, 8-9, 9-10 ram. Based on the in-house developed 3D image analysis programs using Matlab, the volume porosity, pore size distribution and degree of connectivity were calculated and analyzed in detail. The results indicate that the volume porosity, the mean diameter of pores and the effective pore size （d50） increase with the increasing of particle size. Lognormal distribution or Gauss distribution is mostly suitable to model the pore size distribution. The degree of connectivity investigated on the basis of cluster-labeling algorithm also increases with increasing the particle size approximately.展开更多
The images of granular ore media were captured by X-ray CT scanner. Combined with digital image processing and finite element techniques, the three-dimensional geometrical model, which represents the realistic pore st...The images of granular ore media were captured by X-ray CT scanner. Combined with digital image processing and finite element techniques, the three-dimensional geometrical model, which represents the realistic pore structure of the media, was constructed. With this model, three dimensional pore scale fluid flow among particles was simulated. Then the distributions of fluid flow velocity and pressure were analyzed and the hydraulic conductivity was calculated. The simulation results indicate the fluid flow behaviors are mainly dominated by the volume and topological structure of pore space. There exist obvious preferential flow and leaching blind zones simultaneously in the medium. The highest velocities generally occur in those narrow pores with high pressure drops. The hydraulic conductivity obtained by simulation is the same order of magnitude as the laboratory test result, which denotes the validity of the model. The pore-scale and macro-scale are combined and the established geometrical model can be used for the simulations of other phenomena during heap leaching process.展开更多
The application of hydrogen gas in the pre-reduction of manganese ore may replace fossil carbon consumption and reduce CO_(2) emissions in manganese ferroalloy production.The pre-reduction behavior of Nchwaning mangan...The application of hydrogen gas in the pre-reduction of manganese ore may replace fossil carbon consumption and reduce CO_(2) emissions in manganese ferroalloy production.The pre-reduction behavior of Nchwaning manganese ore was investigated using a fixed-bed reactor.The reduction rates at different temperatures and temperature programs were investigated,and the particles were sieved after reduction to measure the decrepitation.The reduction rate was measured by adding a tracer gas to the reducing gas and quantifying the off-gas.Samples with different particle-size distributions of the input material were reduced to investigate the effect of particle size on the reduction rate.Chemical analyses and X-ray diffraction were used to characterize the raw and reduced materials.The effects of particle size distribution and temperature on the oxygen removal rate were investigated.Manganese oxides were mostly reduced to MnO in the samples,whereas some iron oxides and carbonates remained.The degree of reduction was improved by using smaller particles and in-creasing the temperature.展开更多
This study explores a hydrogen-assisted mineral phase transformation process with synergistic desulfurization for the efficient recovery of iron from the high-pressure acid leach(HPAL)tailings of laterite nickel ore.H...This study explores a hydrogen-assisted mineral phase transformation process with synergistic desulfurization for the efficient recovery of iron from the high-pressure acid leach(HPAL)tailings of laterite nickel ore.HPAL tailings containing 51.50wt%iron and 2.09wt%sulfur present environmental challenges due to their sulfur content.Pre-treatment at 950℃ for 15 min successfully reduced the sulfur content to 0.295wt%and increased the iron grade to 57.66wt%.Further hydrogen-assisted mineral phase transformation at 520℃ for 30 min,using 40vol%hydrogen and a gas flow rate of 600 mL·min^(-1),resulted in a product with an iron grade of 61.00wt%and 90.11%iron recovery.The overall desulfurization rate reached 85.83%when wet scrubbing and limestone were used to capture the sulfur.This study demonstrates the efficiency of this hydrogen-assisted process for sustainable iron recovery and sulfur removal from laterite nickel ore tailings,with potential for industrial applications.展开更多
As a refractory iron ore,the clean and efficient beneficiation of limonite is crucial for ensuring a sustainable long-term supply of iron metal.In this study,the microwave fluidization magnetization roasting of limoni...As a refractory iron ore,the clean and efficient beneficiation of limonite is crucial for ensuring a sustainable long-term supply of iron metal.In this study,the microwave fluidization magnetization roasting of limonite was explored.The micromorphology,microstructure,and mineral phase transformation of the roasted products were analyzed using a scanning electron microscope,an automatic surface area and porosity analyzer,an X-ray diffractometer,and a vibrating sample magnetometer.Kinetic analysis was also conducted to identify the factors limiting the roasting reaction rate.Microwave fluidization roasting significantly increased the specific surface area of limonite,increased the opportunity of contact between CO and limonite,and accelerated the transformation from FeO(OH)toα-Fe_(2)O_(3)and then to Fe_(3)O_(4).In addition,the water in the limonite ore and the newly formed magnetite exhibited a strong microwave absorption capacity,which has a certain activation effect on the reduction roasting of limonite.The saturation magnetization and maximum specific magnetization coefficient increased to 23.08 A·m^(2)·kg^(-1)and 2.50×10^(-4)m^(3)·kg^(-1),respectively.The subsequent magnetic separation of the reconstructed limonite yielded an iron concentrate with an Fe grade of 59.26wt%and a recovery of 90.07wt%.Kinetic analysis revealed that the reaction mechanism function model was consistent with the diffusion model(G(α)=α^(2)),with the mechanism function described as k=0.08208exp[-20.3441/(R_(g)T)].Therefore,microwave fluidization roasting shows significant potential in the beneficiation of limonite,offering a promising approach for the exploitation of refractory iron ores.展开更多
Nickel laterite ore is an important nickel-bearing mineral.Research on pre-heating and hydrogen pre-reduction in the pyrometallurgical process of nickel laterite ore is very limited,especially when using fluidized bed...Nickel laterite ore is an important nickel-bearing mineral.Research on pre-heating and hydrogen pre-reduction in the pyrometallurgical process of nickel laterite ore is very limited,especially when using fluidized bed roasting.This study systematically explores the mechanisms of fluidized bed pre-heating treatment and hydrogen pre-reduction in the roasting process of saprolitic nickel laterite ore.According to single-factor experiment results,the appropriate pre-heating and pre-reduction conditions were a pre-heating temperature of 700℃,a pre-heating time of 30 min,a pre-reduction temperature of 700℃,a pre-reduction time of 30 min,and a hydrogen concentration of 80%.Then,the nickel metallization rate and iron metallization rate reached 90.56%and 41.31%,respectively.Various analytical and testing methods were employed to study the changes in phase composition,magnetism,surface element valence states,and microstructure of nickel laterite ore during fluidized pre-heating and pre-reduction.The study shows that hydrogen can achieve nickel reduction at relatively low temperatures.It was also found that pre-heating treatment of nickel laterite ore is beneficial.Pre-heating opens up the mineral structures of serpentine and limonite,allowing the reducing gas and nickel to interact quickly during the reduction process,enhancing the pre-reduction process.展开更多
基金Open Access funding enabled and organized by Projekt DEAL.
文摘In this study,copper extraction from low-grade oxide-sulfide ores was investigated using a leaching method combined with response surface methodology(RSM)to optimize operational conditions and assess leaching kinetics.Given copper's extensive industrial applications,sustainable recovery from low-grade ores is critical.Five key parameters-acid concentration,leaching time,particle size,temperature,and solids percentage-were identified as major influences on copper recovery.The results revealed that leaching time and solids percentage,along with interactions between temperature-time and temperature-solids percentage,had the most significant effects.Optimal conditions for 80% copper recovery while minimizing iron recovery below 3% included an acid concentration of 1.21 mol L^(-1),a leaching time of 108 min,a particle size of 438μm,a temperature of 45℃,and a solids percentage of 18.2%.Leaching kinetics were analyzed using shrinking core models,with the Dickinson model best describing the process,showing an activation energy of 32.63 kJ mol^(-1),indicative of mixed diffusion and chemical reaction control.The final kinetic model effectively predicted the influence of key parameters.These findings highlight the importance of optimizing process variables and selecting suitable kinetic models to enhance extraction efficiency,reduce costs,and improve sustainability in copper recovery.
基金supported by the National Science Foundation for Excellent Young Scholars of China (Grant No.52422809)the National Natural Science Foundation of China (Grant No.52208491)。
文摘Polypropylene fibers(PPFs) have been widely used in composite materials due to their sound crack resistance and toughness. In cement-based composites, the incorporation of PPFs can significantly improve their dynamic mechanical properties. However, cement-iron ore tailings foam composite(CIFC), a sustainable material utilizing iron ore tailings to partially replace cement, has not been investigated under dynamic loading. This study investigates the dynamic compressive behavior of CIFC with 1%–2.5% PPF content and 3–12 mm PPF lengths under various strain rates. The microstructural characteristics were analyzed prior to dynamic testing. X-ray diffraction(XRD) identified crystalline phases including CaCO_(3)Fe_(2)O_(3), SiO, C-S-H gel, and ettringite. Scanning electron microscopy(SEM) observations demonstrated that appropriate PPF_(2) parameters(e.g., C2L9, a CIFC specimen containing 2% PPF with 9 mm length) enhance fiber-matrix bonding and minimize interconnected pores and microcracks, revealing pronounced fiber bridging effects. Split Hopkinson pressure bar(SHPB) tests were then conducted at strain rates of 120–250 s^(-1), showing that the dynamic properties of CIFC were highly dependent on both strain rates and PPF parameters. Compared to other specimens, C2L9 exhibited a more intact failure pattern with superior compressive strength and energy dissipation capacity, despite showing reduced dynamic increase factor(DIF) and normalized energy dissipation(NED) values. These findings provide practical guidance for applying CIFC with varying PPF parameters in impact-resistant structural designs.
基金supported by the National Natural Science Foundation of China(No.51974016).
文摘Microwave roasting self-leaching is an innovative method for recovering gold from high-sulfur refractory gold concentrates,without using deadly toxic cyanide reagents.However,the mechanism of gold self-leaching,which relies on lixiviants prepared using volatilized sulfur obtained from roasting,has not been fully elucidated.This study employs the response surface methodology to optimize processing parameters,resulting in an increased gold extraction rate of 96.18%.Analytical factorization and the Tafel curve indicate that CuSO_(4) and NH_(3)·H_(2)O significantly influence the self-leaching process.Furthermore,X-ray photoelectron spectroscopy(XPS)analysis reveals that S^(2−),S_(2)^(2−),polysulfides(S_(n)^(2−)),and thiosulfate(S_(2)O_(3)^(2−))are involved in the gold leaching reaction,with S^(2−),S_(2)^(2−),and S_(n)^(2−) serving as primary ligands for gold complexation.The role of S_(2)O_(3)^(2−) in the early stages of the gold-leaching reaction is also noteworthy.The copper–ammonia complex catalyzes the self-leaching gold reaction;however,an improper addition ratio can lead to copper-sulfur compound precipitates,reducing the extraction rate.
基金Project(42072305)supported by the National Natural Science Foundation of China。
文摘Seabed mining operations have been found to induce significant movement and deformation in overlying rock strata,posing serious threats to mining safety.The presence of geological faults further complicates these deformation patterns.This study utilized geophysical surveys and the continuum-based discrete element method(CDEM)to investigate how fault activity influences rock deformation and failure.The results demonstrate that:1)Acting in mechanically weak zones,faults exerted a pronounced barrier effect on deformation propagation and stress redistribution within the surrounding rock,leading to markedly divergent displacement patterns on either side of the fault plane.Comparative analyses between single-fault and double-fault models revealed an 18%−22%expansion of the damage zone under the latter,together with significantly intensified deformation and failure;2)The double-fault model exhibited a larger maximum cumulative vertical displacement and a spatial shift in the location of peak deformation,thereby posing a heightened threat to mine safety;3)Acting in an orebody substitute,backfill effectively constrained surrounding rock deformation,enhanced its load-bearing capacity,and delayed the overburden subsidence.Nevertheless,backfill only reduced the amplitude of deformation;it could not entirely prevent settlement.These findings provide essential theoretical insights and foundational knowledge for safer submarine mining practices.
基金financially supported by Zijin Mining Group(No.01612216)the Ministry of Natural Resources,China(No.ZKKJ202426)。
文摘The Zijinshan ore field located in southwestern Fujian Province,China,is a representative porphyry-epithermal ore system hosting diverse mineralization types(Mao et al.,2013).The ore field comprises of the Zijinshan highsulfidation Cu-Au deposit,the Luoboling porphyry Cu-Mo deposit,the transitional style Cu deposit(Longjiangting and Wuziqilong)and the Yueyang low-sulfidation Agpolymetallic deposit(Zhang,2013;Zhang et al.,2003)
基金supported by the National Key R&D Program of China(No.2016YFC0600508).
文摘The giant Pulang porphyry copper deposit,located in the southern Yidun arc segment of southeastern Tibetan Plateau,represents one of the region’s largest mineral systems.This study employs numerical simulation to unravel its metallogenic processes.By integrating field-based geological observations with mineralogical and geochemical data,we developed a coupled model encompassing five key stages of ore formation.The simulation successfully reproduced thermal anomalies and accurately predicted the spatial distribution of mineralization zones at Pulang.Coupling dynamic modeling results with chalcopyrite precipitation rates and average Cu grades enabled quantitative estimation of deposit formation duration(0.99–1.22 Ma).Compared with conventional geochronological approaches,this process-constrained modeling framework provides unprecedented insights into the thermodynamic mechanisms controlling porphyry copper system evolution,offering valuable implications for regional exploration strategies.
文摘Stainless steel,known for its exceptional properties and diverse applications,conventionally requires a multistage process that generates considerable CO_(2) emissions by using fossil-based carbon reductants.This study investigated hydrogen plasma smelting reduction as a novel,sustainable,and efficient method for producing stainless steel directly from lateritic nickel and chromite ores.The research aimed to examine the effect of ore proportion on AISI 300 series stainless steel production and assess the reduction process over time through thermochemical calculations and experimental studies.Results showed that increasing the proportion of chromite ore in the feed raises Cr content and reduces Ni content in metals while increasing Cr_(2)O_(3) and Al_(2)O_(3) content in oxides.A briquette comprising 30wt%chromite ore and 70wt%calcined nickel ore yields better results for AISI 300 stainless steel,with Fe,Cr,Ni,and Si content of 62.95wt%,19.37wt%,11.83wt%,and 0.72wt%,respectively,after 180 s of hydrogen plasma exposure.Nearly all NiO compounds are converted into Ni after 60 s of smelting reduction,whereas FeO compounds are almost fully converted into Fe after 120 s of smelting reduction.AISI 300 series stainless steel is successfully produced after 120 s of reduction,achieving Fe,Cr,Ni,and Si content of 64.36wt%,21.92wt%,10.08wt%,and 0.61wt%,respectively.Process optimization remains promising because the Cr_(2)O_(3) content in the slag is still relatively high at 15.52wt%.This ultrafast and direct production method holds considerable potential to transform stainless steel production by reducing environmental impact and enhancing process efficiency.Specifically,the method eliminates the use of an argon oxygen decarburization converter and vacuum oxygen decarburization in stainless steelmaking.
基金supports from the National Key R&D Program of China(No.2022YFC3901404)the Natural Science Foundation of Chongqing,China(No.CSTB2023NSCQ-BHX0166)the Fundamental Research Funds for the Central Universities,China(No.2023CDJXY-016)are sincerely acknowledged.
文摘The semi-molten smelting process of a mixture of saprolitic and limonitic laterite ores was systematically investigated and the effect of slag basicity was deeply analyzed.The results indicate that the slag system can be located in the liquidus region of low melting-point diopside(CaMgSi_(2)O_(6))when slag basicity is kept at 0.3 and limonitic laterite mass fraction is not less than 10%.When the reduction temperature,C/O mass ratio,limonitic laterite mass fraction and slag basicity are kept at the optimum values of 1300℃,0.86,20%and 0.3,respectively,ferronickel products with grades 6.42%Ni and 86.99%Fe are prepared.The recovery rates of Ni and Fe reach 88.60%and 72.25%,respectively.
基金Project supported by the Thousand Talents Program of Jiangxi Province,China(JXSQ2023201003)National Natural Science Foundation of China(42107254)+4 种基金Science and Technology Major Program of Ordos City(2022EEDSKJZDZX014-2)Technological Innovation Guidance Program of Jiangxi Province(20212BDH81029)Rare Earth Industry Fund(IAGM2020DB06)Selfdeployed Projects of Ganjiang Innovation Academy,Chinese Academy of Sciences(E055A01)the Key Research Program of the Chinese Academy of Sciences(ZDRW-CN-2021-3-3)。
文摘The rare earth elements(REEs)extraction by chemical leaching from ion-adsorption type rare earth ores(IAREO)has led to serious ecological and environmental risks.Conversely,demand for bioleaching is on the rise with the advantage of being environmental-friendly.As one of the organic acids produced by biological metabolism,citric acid was used to leach REEs and explore the performance and process.The results demonstrate that citric acid exhibits higher leaching efficiency(96.00%)for REEs at a relatively low concentration of 0.01 mol/L compared with(NH_(4))_(2)SO_(4)(84.29%,0.1 mol/L)and MgSO_(4)(83.99%,0.1 mol/L).Citric acid shows a preference for leaching heavy rare earth elements,with 99%leaching efficiency in IAREO,which shows higher capacity than(NH_(4))_(2)SO_(4)and MgSO_(4)(as inorganic leaching agents).Kinetic analysis indicates that the leaching process of REEs with citric acid is controlled by both the internal diffusion kinetics and chemical reaction kinetics,which is different from inorganic leaching agents.Visual Minteq calculations confirm that RE-Citrate is the main constituent of the extract solution in the leaching process of the IAREO,thereby enhancing the leaching efficiency of REEs from the IAREO.It suggests that citric acid may be used as a promising organic leaching agent for the environmentalfriendly extraction of REEs from IAREO.
基金supported by the Department of science and technology of Shaanxi Province(NO.2023-ZDLGY-24).
文摘Detection of ore waste is crucial for achieving automation in mineral metallurgy production.However,deep learning-based target detection algorithms still face several challenges in iron waste screening,including poor lighting conditions in underground mining environments,dust disturbances,platform vibrations during operation,and limited resources for large-scale computing equipment.These factors contribute to extended computation times and unsatisfactory detection accuracy.To address these challenges,this paper proposes an ore waste detection algorithm based on an improved version of YOLOv5.To enhance feature extraction capabilities,the RepLKNet module is incorporated into the YOLOv5 backbone and neck networks.This module enhances the deformation information of feature extraction with the maximum effective Receptive Field to increase the model's accuracy.The Normalizationbased Attention Module(NAM)was introduced to enhance the attention mechanism by focusing on the most relevant features.This improves accuracy in detecting objects against noisy or unclear backgrounds,thereby further enhancing detection performance while reducing model parameters.Additionally,the loss function is optimized to constrain angular deviation using the SIOU loss function,which prevents the training frame from drifting during training and enhances convergence speed.To validate the performance of the proposed method,we tested it using a self-constructed dataset comprising 1,328 images obtained from the crushing station at Jinchuan Group's No.2 mine.The results indicate that,compared to YOLOv5s on the self-constructed dataset,the proposed algorithm achieves an 18.3%improvement in mAP(0.5),a 54%reduction in FLOPs,and a 52.53%decrease in model parameters.The effectiveness and superiority of the proposed algorithm are demonstrated through case studies and comparative analyses.
基金jointly funded by the National Natural Science Foundation of China(Nos.42230813,41972084)the National Key R&D Program of China(No.2022YFC2905000)the Everest Scientific Research Program of the Chengdu University of Technology(No.2020ZF11407)。
文摘The Early Paleozoic porphyry-epithermal Au system of the Songshunangou District sits in the central segment of the North Qilian orogenic belt(NQOB).The porphyry Au mineralization is centered on the quartz diorite porphyry(QDP),which is constrained to the Late Ordovician period.However,the geochemical signatures,the origin,and the tectonic setting of the QDP are not yet known and understood and are thus in the focus here.The QDP is a high-K calc-alkaline metaluminous rocks(K_(2)O+Na_(2)O:6.90-8.13;Al_(2)O_(3)/(CaO+Na_(2)O+K_(2)O):0.69-0.90)characterized by high(^(87)Sr/^(86)Sr)_(t)values(0.7093-0.7101)and lowε_(Nd)(t)values(-2.9 to-2.7)with corresponding T_(DM2)(Nd)ages of 1408 to 1430 Ma.Zirconε_(Hf)(t)values are low(-1.51 to+2.76)with corresponding T_(DM2)(Hf)ages of 1262 to 1533 Ma.The lead isotope values are 17.695-18.476 for(^(206)Pb/^(204)Pb)_(t),15.585-15.629 for(^(207)Pb/^(204)Pb)_(t),and 37.214-37.948 for(^(208)Pb/^(204)Pb)_(t).These data indicate that the QDP formed by the mixing of mantle-derived magmas(50%-70%)with lower crustal melts.The QDP is enriched in LREEs and LILE(Rb,Th,K)and is depleted in HFSE(Nb,Ta,Ti),expressing a clear volcanic arc affinity.High La and Th contents,and Zr/Y and Hf/Yb values suggest that the QDP formed in an Andean-type continental margin arc setting related to the northward subduction of the North Qilian oceanic slab.The Early Paleozoic subduction-related intermediate-acidic intrusions in NQOB have arc magma affinity,indicating that these rocks bear a great potential to discover further fertile porphyry deposits.
基金supported by the National Key R&D Program of China(No.2022YFF0800200)the NSFC(Nos.U1812402 and 42072131)+6 种基金Most Special Fund(No.MSFGPMR33)from the State Key Laboratory of GPMRthe CUG Scholar Scientific Research Funds(No.2022036)the NSF of Hebei Province(No.D2021334001)Research Project of Talent Engineering Training of Hebei Province(No.B2020005007)Research Project of Postdoctoral Scientific Research Station of HBGMR(No.454-0602-YBN-Z9E4)Natural Science Foundation of Hebei Province(No.D2021334001)the Central Government Guides Local Funds for Scientific and Technological Development(No.236Z7608 G)。
文摘Original sedimentary manganese(Mn)deposits and supergene Mn ores are important Mn resources in China.However,the geochemical information from Chinese supergene Mn ores is scarce,and the relationship between sedimentary Mn deposits and supergene Mn ores is ambiguous.In this study,we collected the original Mn-bearing dolomitic sandstones(ZK20-3 drillcore)and supergene Mn ores(Longmen Section)from eastern Hebei,North China for systematic petrographic,mineralogical and geochemical analyses.Our new data help us to figure out the transformation from original Mn-bearing deposits to supergene ores.The main minerals of original Mn-bearing dolomitic sandstones are quartz and feldspar,with minor muscovite,dolomite,rhodochrosite,ankerite,and kutnohorite.Supergene Mn-oxide ores only emerged in the middle part of the Longmen(LM)Section,and mainly contain quartz,pyrolusite,cryptomelane,todorokite and occasional dolomite.The possible transformation sequence of Mn minerals is:kutnohorite/rhodochrosite→pyrolusite(Ⅰ)→cryptomelane(todorokite)→todorokite(cryptomelane)→pyrolusite(Ⅱ).For Mn-oxide ores,Fe,Na and Si are enriched but Al,Ca,Mg and K are depleted with the enrichment of Mn.For original and supergene ores,the total rare earth element+ytterbium(∑REY)contents range from 105.68×10^(-6)to 250.56×10^(-6)and from 18.08×10^(-6)to 176.60×10^(-6),respectively.Original Mn ores have similar slightly LREE-enriched patterns,but the purer Mn-oxide ore shows a HREE-enriched pattern.In the middle part of the LM Section,positive Ce anomalies in Mn-oxide ores indicate the precipitation of Ce-bearing minerals.It implies the existence of geochemical barriers,which changed p H and Eh values due to the long-time influence of groundwater.
基金support of the National Natural Science Foundation of China(52074080,52004001,and 51574002).
文摘Against the background of“carbon peak and carbon neutrality,”it is of great practical significance to develop non-blast furnace ironmaking technology for the sustainable development of steel industry.Carbon-bearing iron ore pellet is an innovative burden of direct reduction ironmaking due to its excellent self-reducing property,and the thermal strength of pellet is a crucial metallurgical property that affects its wide application.The carbon-bearing iron ore pellet without binders(CIPWB)was prepared using iron concentrate and anthracite,and the effects of reducing agent addition amount,size of pellet,reduction temperature and time on the thermal compressive strength of CIPWB during the reduction process were studied.Simultaneously,the mechanism of the thermal strength evolution of CIPWB was revealed.The results showed that during the low-temperature reduction process(300-500℃),the thermal compressive strength of CIPWB linearly increases with increasing the size of pellet,while it gradually decreases with increasing the anthracite ratio.When the CIPWB with 8%anthracite is reduced at 300℃for 60 min,the thermal strength of pellet is enhanced from 13.24 to 31.88 N as the size of pellet increases from 8.04 to 12.78 mm.Meanwhile,as the temperature is 500℃,with increasing the anthracite ratio from 2%to 8%,the thermal compressive strength of pellet under reduction for 60 min remarkably decreases from 41.47 to 8.94 N.Furthermore,in the high-temperature reduction process(600-1150℃),the thermal compressive strength of CIPWB firstly increases and then reduces with increasing the temperature,while it as well as the temperature corresponding to the maximum strength decreases with increasing the anthracite ratio.With adding 18%anthracite,the thermal compressive strength of pellet reaches the maximum value at 800℃,namely 35.00 N,and obtains the minimum value at 1050℃,namely 8.60 N.The thermal compressive strength of CIPWB significantly depends on the temperature,reducing agent dosage,and pellet size.
基金National Key Research and Development Program of China(2021YFC2902301,2021YFC2902302)。
文摘A transformative beryllium metallurgy theory and method was proposed based on the low-temperature dissociation of hydrofluoric acid and purification by exploiting the large difference of fluoride solubility.Hydrofluoric acid can quickly dissociate berylum ore powder directly at low or room temperature with more than 99%dissociation rate.The solubility of AlF_(3),FeF_(3) CrF_(3) and MgF_(2),is low.Coupled with common ion effect,99.9%-purity beryllium products can be prepared without chemical purification.For high-purity beryllium products of grade 4N or higher,they can be prepared through the superior property that the pH intervals of iron,chromium,and other hydroxide precipitates are distinctly different from those corresponding to Be(OH)_(2),precipitates.This new method can be used to prepare most of the beryllium products that are prepared by modern beryllium metallurgy.
基金Projects(50934002,51074013,51304076,51104100)supported by the National Natural Science Foundation of ChinaProject(IRT0950)supported by the Program for Changjiang Scholars Innovative Research Team in Universities,ChinaProject(2012M510007)supported by China Postdoctoral Science Foundation
文摘Methods and procedures of three-dimensional （3D） characterization of the pore structure features in the packed ore particle bed are focused. X-ray computed tomography was applied to deriving the cross-sectional images of specimens with single particle size of 1-2, 2-3, 3-4, 4-5, 5-6, 6-7, 7-8, 8-9, 9-10 ram. Based on the in-house developed 3D image analysis programs using Matlab, the volume porosity, pore size distribution and degree of connectivity were calculated and analyzed in detail. The results indicate that the volume porosity, the mean diameter of pores and the effective pore size （d50） increase with the increasing of particle size. Lognormal distribution or Gauss distribution is mostly suitable to model the pore size distribution. The degree of connectivity investigated on the basis of cluster-labeling algorithm also increases with increasing the particle size approximately.
基金Projects (50934002, 51074013, 51104100) supported by the National Natural Science Foundation of China
文摘The images of granular ore media were captured by X-ray CT scanner. Combined with digital image processing and finite element techniques, the three-dimensional geometrical model, which represents the realistic pore structure of the media, was constructed. With this model, three dimensional pore scale fluid flow among particles was simulated. Then the distributions of fluid flow velocity and pressure were analyzed and the hydraulic conductivity was calculated. The simulation results indicate the fluid flow behaviors are mainly dominated by the volume and topological structure of pore space. There exist obvious preferential flow and leaching blind zones simultaneously in the medium. The highest velocities generally occur in those narrow pores with high pressure drops. The hydraulic conductivity obtained by simulation is the same order of magnitude as the laboratory test result, which denotes the validity of the model. The pore-scale and macro-scale are combined and the established geometrical model can be used for the simulations of other phenomena during heap leaching process.
基金supported by the European Union’s Horizon Europe program HAlMan project under the grant number of 101091936.
文摘The application of hydrogen gas in the pre-reduction of manganese ore may replace fossil carbon consumption and reduce CO_(2) emissions in manganese ferroalloy production.The pre-reduction behavior of Nchwaning manganese ore was investigated using a fixed-bed reactor.The reduction rates at different temperatures and temperature programs were investigated,and the particles were sieved after reduction to measure the decrepitation.The reduction rate was measured by adding a tracer gas to the reducing gas and quantifying the off-gas.Samples with different particle-size distributions of the input material were reduced to investigate the effect of particle size on the reduction rate.Chemical analyses and X-ray diffraction were used to characterize the raw and reduced materials.The effects of particle size distribution and temperature on the oxygen removal rate were investigated.Manganese oxides were mostly reduced to MnO in the samples,whereas some iron oxides and carbonates remained.The degree of reduction was improved by using smaller particles and in-creasing the temperature.
基金support from the National Key Research and Development Program of China(No.2021YFC2901000)the National Natural Science Foundation of China(No.U23A20603)+1 种基金China Nonferrous Metal Mining(Group)Co.,Ltd.,Technology Research and Development Project(No.2022_2_KJJH01)the Fundamental Research Funds for the Central Universities,China(No.N25ZLV006).
文摘This study explores a hydrogen-assisted mineral phase transformation process with synergistic desulfurization for the efficient recovery of iron from the high-pressure acid leach(HPAL)tailings of laterite nickel ore.HPAL tailings containing 51.50wt%iron and 2.09wt%sulfur present environmental challenges due to their sulfur content.Pre-treatment at 950℃ for 15 min successfully reduced the sulfur content to 0.295wt%and increased the iron grade to 57.66wt%.Further hydrogen-assisted mineral phase transformation at 520℃ for 30 min,using 40vol%hydrogen and a gas flow rate of 600 mL·min^(-1),resulted in a product with an iron grade of 61.00wt%and 90.11%iron recovery.The overall desulfurization rate reached 85.83%when wet scrubbing and limestone were used to capture the sulfur.This study demonstrates the efficiency of this hydrogen-assisted process for sustainable iron recovery and sulfur removal from laterite nickel ore tailings,with potential for industrial applications.
基金financially supported by the National Key Research and Development Program of China(No.2021YFC2901000)the National Natural Science Foundation of China(No.52104249)+1 种基金the Liaoning Joint Fund General Support Program Project(No.2023-MSBA-126)the Fundamental Research Funds for the Central Universities(No.N2401019)。
文摘As a refractory iron ore,the clean and efficient beneficiation of limonite is crucial for ensuring a sustainable long-term supply of iron metal.In this study,the microwave fluidization magnetization roasting of limonite was explored.The micromorphology,microstructure,and mineral phase transformation of the roasted products were analyzed using a scanning electron microscope,an automatic surface area and porosity analyzer,an X-ray diffractometer,and a vibrating sample magnetometer.Kinetic analysis was also conducted to identify the factors limiting the roasting reaction rate.Microwave fluidization roasting significantly increased the specific surface area of limonite,increased the opportunity of contact between CO and limonite,and accelerated the transformation from FeO(OH)toα-Fe_(2)O_(3)and then to Fe_(3)O_(4).In addition,the water in the limonite ore and the newly formed magnetite exhibited a strong microwave absorption capacity,which has a certain activation effect on the reduction roasting of limonite.The saturation magnetization and maximum specific magnetization coefficient increased to 23.08 A·m^(2)·kg^(-1)and 2.50×10^(-4)m^(3)·kg^(-1),respectively.The subsequent magnetic separation of the reconstructed limonite yielded an iron concentrate with an Fe grade of 59.26wt%and a recovery of 90.07wt%.Kinetic analysis revealed that the reaction mechanism function model was consistent with the diffusion model(G(α)=α^(2)),with the mechanism function described as k=0.08208exp[-20.3441/(R_(g)T)].Therefore,microwave fluidization roasting shows significant potential in the beneficiation of limonite,offering a promising approach for the exploitation of refractory iron ores.
基金Project(2023JH3/10200010)supported by the Excellent Youth Natural Science Foundation of Liaoning Province,ChinaProject(XLYC2203167)supported by the Liaoning Revitalization Talents Program,China+2 种基金Project(RC231175)supported by the Mid-career and Young Scientific and Technological Talents Program of Shenyang,ChinaProject(2023A03003-2)supported by the Key Special Program of Xinjiang,ChinaProject(N2301026)supported by the Fundamental Research Funds for the Central Universities,China。
文摘Nickel laterite ore is an important nickel-bearing mineral.Research on pre-heating and hydrogen pre-reduction in the pyrometallurgical process of nickel laterite ore is very limited,especially when using fluidized bed roasting.This study systematically explores the mechanisms of fluidized bed pre-heating treatment and hydrogen pre-reduction in the roasting process of saprolitic nickel laterite ore.According to single-factor experiment results,the appropriate pre-heating and pre-reduction conditions were a pre-heating temperature of 700℃,a pre-heating time of 30 min,a pre-reduction temperature of 700℃,a pre-reduction time of 30 min,and a hydrogen concentration of 80%.Then,the nickel metallization rate and iron metallization rate reached 90.56%and 41.31%,respectively.Various analytical and testing methods were employed to study the changes in phase composition,magnetism,surface element valence states,and microstructure of nickel laterite ore during fluidized pre-heating and pre-reduction.The study shows that hydrogen can achieve nickel reduction at relatively low temperatures.It was also found that pre-heating treatment of nickel laterite ore is beneficial.Pre-heating opens up the mineral structures of serpentine and limonite,allowing the reducing gas and nickel to interact quickly during the reduction process,enhancing the pre-reduction process.
