Defects‑Rich Heterostructures Trigger Strong Polarization Coupling in Sulfides/Carbon Composites with Robust Electromagnetic Wave Absorption

Defects-rich heterointerfaces integrated with adjustable crystalline phases and atom vacancies,as well as veiled dielectric-responsive character,are instrumental in electromagnetic dissipation.Conventional methods,however,constrain their delicate constructions.Herein,an innovative alternative is proposed:carrageenan-assistant cations-regulated(CACR)strategy,which induces a series of sulfides nanoparticles rooted in situ on the surface of carbon matrix.This unique configuration originates from strategic vacancy formation energy of sulfides and strong sulfides-carbon support interaction,benefiting the delicate construction of defects-rich heterostructures in M_(x)S_(y)/carbon composites(M-CAs).Impressively,these generated sulfur vacancies are firstly found to strengthen electron accumulation/consumption ability at heterointerfaces and,simultaneously,induct local asymmetry of electronic structure to evoke large dipole moment,ultimately leading to polarization coupling,i.e.,defect-type interfacial polarization.Such“Janus effect”(Janus effect means versatility,as in the Greek two-headed Janus)of interfacial sulfur vacancies is intuitively confirmed by both theoretical and experimental investigations for the first time.Consequently,the sulfur vacancies-rich heterostructured Co/Ni-CAs displays broad absorption bandwidth of 6.76 GHz at only 1.8 mm,compared to sulfur vacancies-free CAs without any dielectric response.Harnessing defects-rich heterostructures,this one-pot CACR strategy may steer the design and development of advanced nanomaterials,boosting functionality across diverse application domains beyond electromagnetic response.

Hydrogen sulfide reduces oxidative stress in Huntington's disease via Nrf2

The pathophysiology of Huntington's disease involves high levels of the neurotoxin quinolinic acid. Quinolinic acid accumulation results in oxidative stress, which leads to neurotoxicity. However, the molecular and cellular mechanisms by which quinolinic acid contributes to Huntington's disease pathology remain unknown. In this study, we established in vitro and in vivo models of Huntington's disease by administering quinolinic acid to the PC12 neuronal cell line and the striatum of mice, respectively. We observed a decrease in the levels of hydrogen sulfide in both PC12 cells and mouse serum, which was accompanied by down-regulation of cystathionine β-synthase, an enzyme responsible for hydrogen sulfide production. However, treatment with NaHS(a hydrogen sulfide donor) increased hydrogen sulfide levels in the neurons and in mouse serum, as well as cystathionine β-synthase expression in the neurons and the mouse striatum, while also improving oxidative imbalance and mitochondrial dysfunction in PC12 cells and the mouse striatum. These beneficial effects correlated with upregulation of nuclear factor erythroid 2-related factor 2 expression. Finally, treatment with the nuclear factor erythroid 2-related factor 2inhibitor ML385 reversed the beneficial impact of exogenous hydrogen sulfide on quinolinic acid-induced oxidative stress. Taken together, our findings show that hydrogen sulfide reduces oxidative stress in Huntington's disease by activating nuclear factor erythroid 2-related factor 2,suggesting that hydrogen sulfide is a novel neuroprotective drug candidate for treating patients with Huntington's disease.

Hydrogen sulfide responsive nanoplatforms: Novel gas responsive drug delivery carriers for biomedical applications

Hydrogen sulfide(H_(2)S)is a toxic,essential gas used in various biological and physical processes and has been the subject of many targeted studies on its role as a new gas transmitter.These studies have mainly focused on the production and pharmacological side effects caused by H_(2)S.Therefore,effective strategies to remove H_(2)S has become a key research topic.Furthermore,the development of novel nanoplatforms has provided new tools for the targeted removal of H_(2)S.This paper was performed to review the association between H_(2)S anddisease,relatedH_(2)S inhibitory drugs,aswell as H_(2)S responsive nanoplatforms(HRNs).This review first analyzed the role of H_(2)S in multiple tissues and conditions.Second,common drugs used to eliminate H_(2)S,as well as their potential for combination with anticancer agents,were summarized.Not only the existing studies on HRNs,but also the inhibition H_(2)S combined with different therapeutic methods were both sorted out in this review.Furthermore,this review provided in-depth analysis of the potential of HRNs about treatment or detection in detail.Finally,potential challenges of HRNs were proposed.This study demonstrates the excellent potential of HRNs for biomedical applications.

Insight into the Inhibition of the Poisonous Sulfide Production from Sulfate-Reducing Microbiota in Mariculture Habitat

The production of toxic sulfides is a common environmental problem in mariculture.Therefore,the effective inhibition of sulfidogens is the key to prevent sulfides production.In this study,the possibility and mechanism of nitrate(NO_(3)^(−))inhibiting the activity of the sulfate-reducing microbiota(SRM)from mariculture sediments was investigated.The results showed that 1,3,and 5 mmol L^(−1)NO_(3)^(−)continuously inhibited sulfide production for 1-3 d.As NO_(3)^(−) dosage increased to 7 mmol L^(−1),the duration of inhibition increased to 6 days.Denitrifying product NO_(2)^(−)heavily inhibited the activity of dissimilar sulfate reductase gene(dsrB)by 3 orders,which was the main reason that the sulfate-reducing activity was inhibited.The SRM structure changed significantly with the dosage of NO_(3)^(−),while the abundance of sulfidogens Desulfovibrio species increased due to their capability of detoxifying nitrite through nitrite reductase.Hence,sulfidogens Desulfovibrio species are more adaptable to a high nitrate/nitrite environment,and the traditional control strategies by dosing nitrate/nitrite should be paid more attention to.The findings will serve as helpful guidelines for sulfate-reducing microbiota in the habitat of mariculture to reduce their generation of poisonous sulfide.

Synthesis of High Purity Lithium Sulfide for Sulfide Solid Electrolyte Applications through Hydrogen Reduction of Lithium Sulfate

This paper is aimed to present a clean,inexpensive and sustainable method to synthesize high purity lithium sulfide(Li_(2)S)powder through hydrogen reduction of lithium sulfate(Li_(2)SO_(4)).A three-step reduction process has been successfully developed to synthesize well-crystallized and single-phase Li_(2)S powder by investigating the melting,sintering and reduction behavior of the mixtures of Li_(2)SO_(4)-Li_(2)S.High purity alumina was found to be the most suitable crucible material for producing high purity Li_(2)S,because it was not attacked by the Li_(2)SO_(4)-Li_(2)S melt during heating,as compared with other materials,such as carbon,mullite,quartz,boron nitride and stainless steel.The use of synthesized LizS resulted in higher purity and substantially higher room temperature ionic conductivity(2.77 mS·cm^(-1))for the argyrodite sulfide electrolyte Li_(6)PS_(5)Cl than commercial Li_(2)S(1.12 mS·cm^(-1)).This novel method offers a great opportunity to produce battery grade Li_(2)S for sulfide solid electrolyte applications.

Absorption characteristics,model,and molecular mechanism of hydrogen sulfide in morpholine acetate aqueous solution

The solubility of H_(2)S was measured in solutions of N-butyl-N-methylmorpholine acetate([Bmmorp][Ac])containing 20%-40%(mass)water at experimental temperatures ranged from 298.15 to 328.15 K and pressures up to 320 k Pa.The total solubility of H_(2)S increased with higher temperatures,lower pressures,and reduced water content.The reaction equilibrium thermodynamic model was used to correlate the solubility data.The results indicate that the chemical reaction equilibrium constant decrease with increasing water content and temperature,whereas Henry constant increase with increasing water content and temperature.Compared with other ionic liquids,H_(2)S exhibits a higher physical absorption enthalpy and a lower chemical absorption enthalpy in[Bmmorp][Ac]aqueous solution.This suggests that[Bmmorp][Ac]has a strong physical affinity for H_(2)S and low energy requirement for desorption.Quantum chemical methods were used to investigate the molecular mechanism of H_(2)S absorption in ionic liquids.The interaction energy analysis revealed that the binding of H_(2)S with the ionic liquid in a1:2 ratio is more stable.Detailed analyses by the methods of the interaction region indicator and the atoms in molecules were conducted to the interactions between H_(2)S and the ionic liquid.

Superhydrophobic Co/Fe sulfide nanoparticles and single-atoms doped carbon nanosheets composite air cathode for high-performance zinc-air batteries

Development of a high-performance bifunctional catalyst is essential for the actual implementation of zinc-air batteries in practical applications.Herein,a bifunctional cathode of Co_(3)S_(4)/FeS heterogeneous nanoparticles embedded in Co/Fe single-atom-loaded nitrogen-doped carbon nanosheets is designed.Cobalt-iron sulfides and single atomic sites with Co-N_(4)/Fe-N_(4)configurations are confirmed to coexist on the carbon matrix by EXAFS spectroscopy.3D self-supported super-hydrophobic multiphase composite cathode provides abundant active sites and facilitates gas–liquid-solid three-phase interface reactions,resulting in excellent electrocatalytic activity and batteries performance,i.e.,an OER overpotential(η_(10))of 260 mV,a half-wave potential(E_(1/2))of 0.872 V for ORR,aΔE of 0.618 V,and a discharge power density of 170 mW cm^(−2),a specific capacity of 816.3 mAh g^(−1).DFT analysis shows multiphase coupling of sulfide heterojunction through single-atomic metal doped carbon nanosheets reduces offset on center of electronic density of states before and after oxygen adsorption,and spin density of adsorbed oxygen with same spin orientation,leading to weakened charge/spin interactions between adsorbed oxygen and substrate,and a lowered oxygen adsorption energy to accelerate OER/ORR.

Interface and mechanical degradation mechanisms of the silicon anode in sulfide-based solid-state batteries at high temperatures

Silicon(Si)is a competitive anode material owing to its high theoretical capacity and low electrochemical potential.Recently,the prospect of Si anodes in solid-state batteries(SSBs)has been proposed due to less solid electrolyte interphase(SEI)formation and particle pulverization.However,major challenges arise for Si anodes in SSBs at elevated temperatures.In this work,the failure mechanisms of Si-Li_(6)PS_(5)Cl(LPSC)composite anodes above 80℃are thoroughly investigated from the perspectives of interface stability and(electro)chemo-mechanical effect.The chemistry and growth kinetics of Lix Si|LPSC interphase are demonstrated by combining electrochemical,chemical and computational characterizations.Si and/or Si–P compound formed at Lix Si|LPSC interface prove to be detrimental to interface stability at high temperatures.On the other hand,excessive volume expansion and local stress caused by Si lithiation at high temperatures damage the mechanical structure of Si-LPSC composite anodes.This work elucidates the behavior and failure mechanisms of Si-based anodes in SSBs at high temperatures and provides insights into upgrading Si-based anodes for application in SSBs.

Advances in depressants for flotation separation of Cu–Fe sulfide minerals at low alkalinity:A critical review

The flotation separation of Cu–Fe sulfide minerals at low alkalinity can be achieved using selective depressants.In the flotation system of Cu–Fe sulfide minerals,depressants usually preferentially interact with the pyrite surface to render the mineral surface hydrophilic and hinder the adsorption of the collector.This review summarizes the advances in depressants for the flotation separation of Cu–Fe sulfide minerals at low alkalinity.These advances include use of inorganic depressants (oxidants and sulfur–oxygen compounds),natural polysaccharides (starch,dextrin,konjac glucomannan,and galactomannan),modified polymers (carboxymethyl cellulose,polyacrylamide,lignosulfonate,and tricarboxylate sodium starch),organic acids (polyglutamic acid,sodium humate,tannic acid,pyrogallic acid,salicylic acid,and lactic acid),sodium dimethyl dithiocarbamate,and diethylenetriamine.The potential application of specific inorganic and organic depressants in the flotation separation of Cu–Fe sulfide minerals at low alkalinity is reviewed.The advances in the use of organic depressants with respect to the flotation separation of Cu–Fe sulfide minerals are comprehensively detailed.Additionally,the depression performances and mechanisms of different types of organic depressants on mineral surfaces are summarized.Finally,several perspectives on depressants vis-à-vis flotation separation of Cu–Fe sulfide minerals at low alkalinity are proposed.

Nano-Au-decorated hierarchical porous cobalt sulfide derived from ZIF-67 toward optimized oxygen evolution catalysis:Important roles of microstructures and electronic modulation

Enhancing both the number of active sites available and the intrinsic activity of Co-based electrocatalysts simultaneously is a desirable goal.Herein,a ZIF-67-derived hierarchical porous cobalt sulfide decorated by Au nanoparticles(NPs)(denoted as HP-Au@CoxSy@ZIF-67)hybrid is synthesized by low-temperature sulfuration treatment.The well-defined macroporous-mesoporous-microporous structure is obtained based on the combination of polystyrene spheres,as-formed CoxSy nanosheets,and ZIF-67 frameworks.This novel three-dimensional hierarchical structure significantly enlarges the three-phase interfaces,accelerating the mass transfer and exposing the active centers for oxygen evolution reaction.The electronic structure of Co is modulated by Au through charge transfer,and a series of experiments,together with theoretical analysis,is performed to ascertain the electronic modulation of Co by Au.Meanwhile,HP-Au@CoxSy@ZIF-67 catalysts with different amounts of Au were synthesized,wherein Au and NaBH4 reductant result in an interesting“competition effect”to regulate the relative ratio of Co^(2+)/Co^(3+),and moderate Au assists the electrochemical performance to reach the highest value.Consequently,the optimized HP-Au@CoxSy@ZIF-67 exhibits a low overpotential of 340 mV at 10 mA cm^(-2)and a Tafel slope of 42 mV dec-1 for OER in 0.1 M aqueous KOH,enabling efficient water splitting and Zn-air battery performance.The work here highlights the pivotal roles of both microstructural and electronic modulation in enhancing electrocatalytic activity and presents a feasible strategy for designing and optimizing advanced electrocatalysts.

Nano-Ni-Induced Electronic Modulation of MoS_(2) Nanosheets Enables Energy-Saving H_(2) Production and Sulfide Degradation

Electrocatalytic hydrogen evolution and sulfion(S^(2-))recycling are promising strategies for boosting H_(2)production and removing environmental pollutants.Here,a nano-Ni-functionalized molybdenum disulfide(MoS_(2))nanosheet was assembled on steel mesh(Ni-MoS_(2)/SM)for use in sulfide oxidation reaction-assisted,energy-saving H_(2)production.Experimental and theoretical calculation results revealed that anchoring nano-Ni on high-surface-area slack MoS_(2)nanosheets not only optimized catalyst adsorption of polysulfides but also played an important role in promoting hydrogen evolution reaction kinetics by absorbing OH_(ad),thereby greatly enhancing the catalytic performance toward sulfide oxidation reaction and hydrogen evolution reaction.Meanwhile,the Ni/MoS^(2-)based hydrogen evolution reaction+sulfide oxidation reaction system achieved nearly 100%hydrogen production efficiency and only consumed 61%less power per kWh than the oxygen evolution reaction+hydrogen evolution reaction system,which suggested our proposed Ni-MoS_(2)and novel hydrogen production system are promising for sustainable energy production.

Incorporation of Ionic Conductive Polymers into Sulfide Electrolyte-Based Solid-State Batteries to Enhance Electrochemical Stability and Cycle Life

Sulfide-based inorganic solid electrolytes are promising materials for high-performance safe solid-state batteries.The high ion conductivity,mechanical characteristics,and good processability of sulfide-based inorganic solid electrolytes are desirable properties for realizing high-performance safe solid-state batteries by replacing conventional liquid electrolytes.However,the low chemical and electrochemical stability of sulfide-based inorganic solid electrolytes hinder the commercialization of sulfide-based safe solid-state batteries.Particularly,the instability of sulfide-based inorganic solid electrolytes is intensified in the cathode,comprising various materials.In this study,carbonate-based ionic conductive polymers are introduced to the cathode to protect cathode materials and suppress the reactivity of sulfide electrolytes.Several instruments,including electrochemical spectroscopy,X-ray photoelectron spectroscopy,and scanning electron microscopy,confirm the chemical and electrochemical stability of the polymer electrolytes in contact with sulfide-based inorganic solid electrolytes.Sulfide-based solid-state cells show stable electrochemical performance over 100 cycles when the ionic conductive polymers were applied to the cathode.

Metallogenic characteristics of Shitoukengde intrusion and its implications for Ni-Co-(Cu)sulfide mineralization in East Kunlun

Xiarihamu deposit is the only super-large Ni-Co deposit found in East Kunlun orogenic belt(EKOB)until present.Shitoukengde(STKD)intrusion is considered to have the potential to become a large Ni-Co deposit in East Kunlun.In order to discuss the metallogenic potential,this study present petrographical,geochemical data,and zircon U-Pb dating for the STKD intrusion.The STKD intrusion is hosted within mafic-ultramafic rocks which contain peridotite,pyroxenite and gabbro,and mainly intruded into the marble of the Paleoproterozoic Jinshuikou Group.Harzburgite and orthopyroxenite are the main country rocks for the Cu-Ni sulfide mineralization.Combine with the positiveε_(Hf)(t)values(+1.1 to+8.6)of zircons,the enrichment of LILEs,depletion of HFSEs,and lower Ce/Pb ratios of whole rocks indicate that the parental magma was originated from the depleted asthenospheric mantle and experienced 5%–15%crustal contamination.Troctolite formed during the Early Devonian and it has weighted mean^(206)Pb/^(238)U age of 412 Ma.Regional background information has indicated that the post-collisional extension setting has already existed during the Early Devonian,leading to the formation of STKD intrusion and Cu-Ni sulfide mineralization.STKD intrusion may have the potential to be one economic Cu-Ni sulfide deposit but seems unlikely to be a super-large one.

Internal electric field modulation by copper vacancy concentration of cuprous sulfide nanosheets for enhanced selective CO_(2) photoreduction

Although the internal electric field(IEF)of photocatalysts is acknowledged as a potent driving force for photocharge separation,modulating the IEF intensity to achieve enhanced photocatalytic performances remains a challenge.Herein,cuprous sulfide nanosheets with different Cu vacancy concentration were employed to study IEF modulation and corresponding direct charge transfer.Among the samples,Cu_(1.8)S nanosheets possessed intensified IEF intensity compared with those of Cu_(2)S and Cu_(1.95)S nanosheets,suggesting that an enhanced IEF intensity could be achieved by introducing more Cu vacancies.This intensified IEF of Cu_(1.8)S nanosheets induced numerous photogenerated electrons to migrate to its surface,and the dissociative electrons were then captured by Cu vacancies,resulting in efficient charge separation spatially.In addition,the Cu vacancies on Cu_(1.8)S nanosheets accumulated electrons as active sites to lower the energy barrier of rate-determining step of CO_(2)photoreduction,leading to the selective conversion of CO_(2)to CO.Herein,the manipulation of IEF intensity through Cu vacancy concentration regulation of cuprous sulfide photocatalysts for efficient charge separation has been discussed,providing a scientific strategy to rationally improve photocata lytic performances for solar energy conversion.

Synergistic Coupling of Sulfide Electrolyte and Integrated 3D FeS_(2)Electrode Toward Long-Cycling All-Solid-State Lithium Batteries

FeS_(2)cathode is promising for all-solid-state lithium batteries due to its ultra-high capacity,low cost,and environmental friendliness.However,the poor performances,induced by limited electrode-electrolyte interface,severe volume expansion,and polysulfide shuttle,hinder the application of FeS_(2)in all-solid-state lithium batteries.Herein,an integrated 3D FeS_(2)electrode with full infiltration of Li6PS5Cl sulfide electrolytes is designed to address these challenges.Such a 3D integrated design not only achieves intimate and maximized interfacial contact between electrode and sulfide electrolytes,but also effectively buffers the inner volume change of FeS_(2)and completely eliminates the polysulfide shuttle through direct solid-solid conversion of Li2S/S.Besides,the vertical 3D arrays guarantee direct electron transport channels and horizontally shortened ion diffusion paths,endowing the integrated electrode with a remarkably reduced interfacial impedance and enhanced reaction kinetics.Benefiting from these synergies,the integrated all-solid-state lithium battery exhibits the largest reversible capacity(667 mAh g^(-1)),best rate performance,and highest capacity retention of 82%over 500 cycles at 0.1 C compared to both a liquid battery and non-integrated all-solid-state lithium battery.The cycling performance is among the best reported for FeS_(2)-based all-solid-state lithium batteries.This work presents an innovative synergistic strategy for designing long-cycling high-energy all-solid-state lithium batteries,which can be readily applied to other battery systems,such as lithium-sulfur batteries.

Comparative study on the hydrogen storage performance of as-milled MgRENi rapid quenched alloy catalyzed by metal sulfides

The composites of Mg_(20)Pr_(1)Sm_(3)Y_(1)Ni_(10)as-quenched alloy and 3 wt.%M(M=CoS,CoS_(2),MoS_(2))catalyst were prepared by high-speed vibration ball mill.The effects of metal sulfides on the hydrogenation and dehydrogenation dynamics of alloys were compared.The results show that the as-milled composites contain a large number of amorphous embedded by a small amount of nanocrystals,and there are many point defects.After ball milling,the crystal grain size in the composites containing CoS is relatively larger,followed by CoS_(2)and MoS_(2)again.After hydrogenation,the amorphous phase is crystallized to form Mg_(2)NiH_(4),YH_(3),Pr_(8)H_(18.96),Sm_(3)H_7,Mg,Co or Mo phases,however,Mg_(2)Ni,YH_(2),PrH_(2)and Ni_(3)Y phases appeared after dehydrogenation.The maximum hydrogenation capacity of the composites containing CoS,CoS_(2)and MoS_(2)are 3.939,4.265 and 4.507 wt.%,respectively.The hydrogenation saturation ratio of composite containing MoS_(2)is higher than that of the composites containing CoS and CoS_(2).The dehydrogenation activation energy of the composites containing CoS,CoS_(2)and MoS_(2)is 107.76,68.43 and 63.28 kJ.mol^(-1).H_(2).On the improvement of hydrogen storage performance of Mg_(20)Pr_(1)Sm_(3)Y_(1)Ni_(10)alloy,the catalytic effect of MoS_(2)sulfide is better than that of CoS_(2)sulfide,and which is better than CoS sulfide.

Effect of pyrite, elemental sulfur and ferrous ions on EPS production by metal sulfide bioleaching microbes

Extracellular polymeric substances （EPS） produced by acidophilic bioleaching microorganisms play an important role in the production of acid mine drainage and metal sulfide bioleaching. EPS mediate the contact between microbial cells and growth substrates, having a pivotal role in organic film formation and bacterium-substratum interactions. The production and chemical composition of EPS produced by seven bioleaching strains grown with different substrates were studied. Analysis of the EPS extracted from these strains indicated that the EPS consisted of carbohydrates, proteins and galacturonic acid. The contents of EPS, carbohydrates, proteins and galacturonic acid of EPS were largely related to the kind of strain used and culture condition. The results show that EPS productions of microbes grown with pyrite were significantly higher than those of microbes grown with sulfur or FeSO4·7H2O. The highest EPS production of the seven acidiphilic strains was （159.43±3.93） mg/g, which was produced by Leptospirillum ferriphilum CBCBSUCSU208015 when cultivated with pyrite.

Density functional theory study on natural hydrophobicity of sulfide surfaces

Adsorption of water on sulfide surfaces and natural floatability of sulfide minerals were studied using density functional theory （DFT） method. All computational models were built in a vacuum environment to eliminate the effects of oxygen and other factors. H2O molecule prefers to stay with pyrite and sphalerite surfaces rather than water, whereas for galena, chalcocite, stibnite, and molybdenite, H2O molecule prefers to stay with water rather than the mineral surfaces. On the other hand, pyrite surface favors N2 more than water, while sphalerite surface cannot adsorb N2. These results show that galena, stibnite, chalcocite, and molybdenite are hydrophobic, while sphalerite is hydrophilic. Although pyrite has certain hydrophilicity, it tends to be aerophilic because the reaction of pyrite with H2O is weaker than pyrite with N2. Thus, pyrite, galena, chalcocite, stibnite and molybdenite all have natural floatability.

Infrared thermography for prediction of spontaneous combustion of sulfide ores

The method of infrared thermography to predict the temperature of the sulfide ores has a large error. To solve this problem, the temperature of the sulfide ores is measured by thermal infrared imager and recording thermometric instrument contrastively. The main factors, including emissivity, distance, angle and dust concentration that affect the temperature measurement precision, are analyzed. The regression equations about the individual factors and comprehensive factors are obtained by analyzing test data. The application of the regression equations improves the precision of the thermal infrared imager. The geometric information lost in traditional infrared thermometry is determined by visualization grid method and interpolation method, the relationship between the infrared imager and geometry information is established. The geometry location can be measured exactly.

Apparent activation energy for spontaneous combustion of sulfide concentrates in storage yard

In order to evaluate the spontaneous combustion hazard of sulfide concentrates in storage, three different kinds of sulfide concentrates （sulfur-rich sulfide concentrate, iron sulfide concentrate and copper sulfide concentrate） were obtained from a storage yard in Dongguashan Copper Mine, China. The reaction processes at different heating rates of 5, 10, 15, 20, and 25 ℃/min in air flow from ambient temperature to 1 000 ℃ were studied by TG-DTG-DSC analysis. By the peak temperatures of DTG curves, the whole reaction process for each sample was divided into different stages, and the corresponding apparent activation energies were calculated by the Ozawa-Flynn-Wall method. It is found that the reaction process of each sample is considerably complex; the apparent activation energy values change from 36 to 160 kJ/mol in different temperature ranges; sulfur-rich sulfide and iron sulfide concentrates have lower apparent activation energy than copper sulfide concentrate below 150 ℃; so they are more inclined to cause spontaneous combustion at ambient temperature.