Elemental sulfur effects on Pb and Zn uptake by Indian mustard and winter wheat

A pot experiment was conducted to investigate the influence of elemental sulfur to contaminated soil on plant uptake by a heavy metal hyperaccumulator, Indian mustard(Brassica juncea) and a field crop, winter wheat(Triticum.aestivum). Elemental sulfur(S) with different rates was carried out, they were 0(S 0), 20(S 20), 40(S 40), 80(S 80), and 160(S 160) mmol/kg respectively. Extra pots with the same rates of S but without plants were used for soil sampling to monitor pH and CaCl 2-extractable heavy metal changes. The results showed that S enhanced phytoextraction of Pb and Zn from contaminated soil. Application S effectively decreased soil pH down to 1.1 as the most at the rate of S 160. The concentrations of CaCl 2-extractable Pb and Zn in soil and uptake of Pb and Zn by the plants were increased with soil pH decreased. A good correlation between CaCl 2-extractable Pb/Zn and soil pH was found(R 2 Pb = 0.847 and R 2 Zn = 0.991, n=25). With S application, soil CaCl 2-extractable Pb and Zn concentrations, concentration of Pb and Zn in plants and the amount of removal by plant uptake were significantly higher than those without S. Under the treatment of S 160, the highest CaCl 2-extractable Pb and Zn were observed, they were 4.23 mg/kg and 0.40 mg/kg, 2.7 and 2.0 times as that of the control(S 0) respectively. At the highest rates of S(S 160), both Indian mustard and winter wheat reached the highest uptake of Pb and Zn. The highest Pb concentrations in wheat and Indian mustard were 32.8 mg/kg and 537.0 mg/kg, all 1.8 times as that of the control, and the highest Zn concentrations in wheat and Indian mustard were 215.5 mg/kg and 404.0 mg/kg, 2.4 and 2.0 times as that of the control respectively. The highest removals of Pb and Zn from the contaminated soil were 0.41 mg/pot and 0.31 mg/pot by Indian mustard in the treatment of S 160 through 50 days growth.

Process and mechanism of hydrothermal stabilization for arsenic sulfide sludge containing elemental sulfur

An optimized hydrothermal treatment was employed to stabilize the arsenic sulfide sludge(ASS). Under the optimal conditions(160 ℃, 2 h, liquid-to-solid(L/S) ratio of 1:1, and initial pH of 2), the leaching concentrations of As and Cd decreased from 504.0 and 12.0 mg/L to 1.23 and 0.03 mg/L of the treated ASS, respectively. The results indicate that the stabilization of the ASS was achieved through structure transformation from the particles into a bulk and the speciation transformation of As and Cd. Besides, sulfur in the ASS could significantly improve the stabilization property due to its melting and polymerization.

Effects of Surface-Active Elements Sulfur on Flow Patterns of Welding Pool

A 3D mathematical model is developed to calculate the temperature and velocity distributions in a moving gas tungsten arc (GTA) welding pool with different sulfur concentrations. It has been shown that, the weld penetration increases sharply with increasing sulfur content. When sulfur content increases beyond 80 × 10-6, the increase in sulfur content does not have an appreciable difference on the welding pool size and shape, and the depth/width remains constant. Sulfur changes the temperature dependence of surface tension coefficient from a negative value to a positive value and causes significant changes on flow patterns. The increase in soluble sulfur content and the decrease at free surface temperature can extend the region of positive surface tension coefficient. As sulfur content exceeds 125×10-6, the sign of surface tension coefficient is positive. Depending upon the sulfur concentrations, three, one or two vortexes that have different positions, strength and directions may be found in the welding pool. The contrary vortexes can efficiently transfer the thermal energy from the arc, creating a deep welding pool. An optimum range of sulfur content is 20-150×10-6.

Simultaneous nitrification and autotrophic denitrification in fluidized bed reactors using pyrite and elemental sulfur as electron donors

In this study, simultaneous nitrification and autotrophic denitrification (SNAD) with either elemental sulfur or pyrite were investigated in fluidized bed reactors in mesophilic conditions. The reactor performance was evaluated at different ammonium (12-40 mg/L of NH4+-N), nitrate (35-45 mg/L of NO3--N), and dissolved oxygen (DO) (0.1-1.5 mg/L) concentrations, with a hydraulic retention time of 12 h. The pyrite reactor supported the SNAD process with a maximum nitrogen removal efficiency of 139.5 mg/(L·d) when the DO concentration was in the range of 0.8-1.5 mg/L. This range, however, limited the denitrification efficiency of the reactor, which decreased from 90.0% ± 5.3% in phases II-V to 67.9% ± 7.2% in phases VI and VII. Sulfate precipitated as iron sulfate (FeSO4/Fe2(SO4)3) and sodium sulfate (Na2SO4) minerals during the experiment. The sulfur reactor did not respond well to nitrification with a low and unstable ammonium removal efficiency, while denitrification occurred with a nitrate removal efficiency of 97.8%. In the pyrite system, the nitrifying bacterium Nitrosomonas sp. was present, and its relative abundance increased from 0.1% to 1.1%, while the autotrophic denitrifying genera Terrimonas, Ferruginibacter, and Denitratimonas dominated the community. Thiobacillus, Sulfurovum, and Trichlorobacter were the most abundant genera in the sulfur reactor during the entire experiment.

Oxidant-elemental sulfur as an effective promoter for transformation of organic matter to hydrocarbons at moderate-low temperatures

Elemental sulfur is widely dispersed in the hydrocarbon source rocks and its depositional environment is usually thought as a reducing environment. The presence or absence of free oxygen is a key to identify oxidizing or reducing environment. But elemental sulfur is often present as an oxidant in this environment. When elemental sulfur meets with organic matter, redox reaction will occur. In our simulation experiments at 200-400℃, the existence of elemental sulfur can sharply increase the amounts of hydrocarbons, hence leading to the production of immature or low-mature oils and natural gases. At the temperature of 300℃, the addition of elemental sulfur will further enhance the relative yields of hydrocarbons, and the final yield of total extracts and gaseous hydrocarbons of similitude kerogens by more than 463% and 2760%, respectively, while those of oil shales are increased by about 71% and 2044%, respectively. But at the temperature of 450℃, elemental sulfur plays a negative role in liquid hydrocarbon formation. The presence of elemental sulfur is probably a key factor in the gypsolyte environment leading to the formation of immature or low-mature oils, as well as the coexistence of immature or low-mature oils and natural gases.

Coupled trace element and SIMS sulfur isotope geochemistry of sedimentary pyrite:Implications on pyrite growth of Caixiashan Pb-Zn deposit

Colloform pyrite with core-rim texture is commonly deposited in carbonate platforms associated with the sulfide ores such as the Caixiashan Pb-Zn deposit.However,the genesis of colloform pyrite in Pb-Zn deposits,its growth controls and their geological implication are insufficiently understood.Integration of in-situ trace element and SIMS sulfur isotopes has revealed geochemical variations among these pyrite layers.These colloform pyrite occur as residual phases of core-rim aggregates,the cores are made up of very fine-grained anhedral pyrite particles,with some rims being made up of fine-grained and poorlycrystallized pyrite,while the other rims were featured with euhedral cubic pyrite.which are cemented by fine-grained calcite and/or dolomite with minor quartz.Sulfur isotope analysis shows that some wellpreserved rims have negative δ^34 S values(-28.12‰to-0.49‰),whereas most of the cores and rims have positive δ^34 S values(>0 to+44.28‰;peak at+14.91‰).Integrating with the methane and sulfate were observed in previous fluid inclusion study,we suggest that the 34 S depleted rims were initially formed by bacteria sulfate reduction(BSR),whereas the positive δ^34 S values were resulted from the sulfate reduction driven by anaerobic methane oxidation(AOM).The well-developed authigenic pyrite and calcite may also support the reaction of AOM.Combined with petrographic observations,trace element composition of the colloform pyrite reveals the incorporation and precipitation behavior of those high abundance elements in the pyrite:Pb and Zn were present as mineral inclusion and likely precipitated before Fe,as supported by the time-resolved Pb-Zn signal spikes in most of the analyzed pyrite grains.Other metals,such as Hg,Co and Ni,may have migrated as chloride complexes and entered the pyrite lattice.Arsenic and Sb,generally influenced by complex-forming reactions rather than substitution ones,could also enter the pyrite lattice,or slightly predate the precipitation of colloform pyrite as mineral inclusions,which are controlled by their hydrolysis constant in the ore fluids.The colloform pyrite may have grown inward from the rims.The successive BSR reaction process would enrich H^32/2S in the overlying water column but reduce the metal content,the nucleation of these pyrite rims was featured by strongly negative sulfur isotopes.The following AOM process should be activated by deformation like the turbidity sediment of the mudstone as the sulfide deposition are associated with fault activities that caused the emission of methane migration upward and simultaneously replenishing the metal in the column.The higher AOM reaction rate and the higher metal supply(not only Fe.but with minor other metals such as Pb and Zn) caused by sediment movement enhanced the metal concentration within the pyrite lattice.

Leaching Gold Using Oxidation Products of Elemental Sulfur in Ca(OH)_2 Solution under Oxygen Pressure

A gold leaching process by using in situ oxidation products of added elemental sulfur in Ca(OH)2 solution was investigated. A gold concentrate containing 45 g/t Au was tested and 85%~87% of gold were leached. The leached gold depends mainly on the initial molar ratio of elemental sulfur to the hydroxyl ion, the consumption of oxygen and the reaction temperature. Adding some surfactants, such as lignosulfonic calcium, at lower concentration increased the leached Au but at higher concentration decreased it. Both of thermodynamic analysis and experimental results show that thiosulfate is the major complexing agent for gold in the process.

Gold leaching with elemental sulfur in alkaline solutions under oxygen pressure

A gold leaching process by using oxidation products of elemental sulfur in alkaline solutions was proposed and investigated. A gold concentrate and a residue from an arsenic refractory gold concentrate by acidic oxidation leaching were tested. The residue contains 16.3% elemental sulfur and no more elemental sulfur was added in tests. For the concentrate elemental sulfur was added before leaching tests. The leaching ratio of gold depends mainly on the initial equivalent ratio of elemental sulfur to hydroxyl ions, the consumption of oxygen and the reaction temperature in the process. Analysis of the experimental results shows that thiosulfate is the majority complexing reagent for gold in the process. Over 90% gold was leached from the residue and 82%87% from the concentrate by using this process.

Genesis of the Bianjiadayuan Pb-Zn polymetallic deposit, Inner Mongolia, China:Constraints from in-situ sulfur isotope and trace element geochemistry of pyrite

The Southern Great Xing’an Range (SGXR) which forms part of the eastern segment of the Central Asian Orogenic Belt (CAOB) is known as one of the most important Cu-Mo-Pb-Zn-Ag-Au metallogenic belts in China,hosting a number of porphyry Mo (Cu),skarn Fe (Sn),epithermal Au-Ag,and hydrothermal veintype Ag-Pb-Zn ore deposits.Here we investigate the Bianjiadayuan hydrothermal vein-type Ag-Pb-Zn ore deposit in the southern part of the SGXR.Porphyry Sn ±Cu ± Mo mineralization is also developed to the west of the Ag-Pb-Zn veins in the ore field.We identify a five-stage mineralization process based on field and petrologic studies including (i) the early porphyry mineralization stage,(ii) main porphyry mineralization stage,(iii) transition mineralization stage,(iv) vein-type mineralization stage and (v) late mineralization stage.Pyrite is the predominant sulfide mineral in all stages except in the late mineralization stage,and we identify corresponding four types of pyrites: Py1 is medium-grained subhedral to euhedral occurring in the early barren quartz vein;Py2 is medium- to fine-grained euhedral pyrite mainly coexisting with molybdenite,chalcopyrite,minor sphalerite and galena;Py3 is fine-grained,subhedral to irregular pyrite and displays cataclastic textures with micro-fractures;Py4 occurs as euhedral microcrystals and forms irregularly shaped aggregate with sphalerite and galena.LA-ICP-MS trace element analyses of pyrite show that Cu,Pb,Zn,Ag,Sn,Cd and Sb are partitioned into pyrite as structurally bound metals or mineral micro/nano-inclusions,whereas Co,Ni,As and Se enter the lattice via isomorphism in all types of pyrite.The Cu,Zn,Ag,Cd concentrations gradually increase from Py1 to Py4,which we correlate with cooling and mixing of ore-forming fluid with meteoric water.Py2 contains the highest contents of Co,Ni,Se,Te and Bi,suggesting high temperature conditions for the porphyry mineralization stage.Ratios of Co/Ni (0.03-10.79,average 2.13) and sulphur isotope composition of sulfide indicate typical hydrothermal origin for pyrites.The δ^34SCDT values of Py1 (0.42‰-1.61‰,average 1.16‰),Py2 (-1.23‰ to 0.82‰,average 0.35‰),Py3 (-0.36‰ to 2.47‰,average 0.97‰),Py4 (2.51‰-3.72‰,average 3.06‰),and other sulfides are consistent with those of typical porphyry deposit (-5‰ to 5‰),indicating that the Pb-Zn polymetallic mineralization in the Bianjiadayuan deposit is genetically linked to the Yanshanian (JurassiceCretaceous) magmatic-hydrothermal events.Variations of d34S values are ascribed to the changes in physical and chemical conditions during the evolution and migration of the ore-forming fluid.We propose that the high Sn content of pyrite in the Bianjiadayuan hydrothermal vein-type PbeZn polymetallic deposit can be used as a possible pathfinder to prospect for Sn mineralization in the surrounding area or deeper level of the ore field in this region.

Distribution Characteristics of Sulfur and the Main Harmful Trace Elements in China's Coal

To promote the rational development and use of clean coal resources in China, data on the regional and age distribution of sulfur, arsenic and other harmful elements in Chinese coal was broadly collected, tested for content, and analyzed. Coal in northwestern China is characterized by low to extremely low levels of sulfur; the coal of the Taiyuan Formation in northern China mainly has high-sulfur content; that of the Shanxi Formation is mainly characterized by low sulfur coal; and the Late Permian coal in southern China has overall higher sulfur content; other regions have low sulfur coal. The average content of harmful trace elements in the bulk of China＇s coal is similar to the corresponding content in the coal of the North America and the rest of the world, whereas the content of various elements （Hg, Sb and Se） is different in magnitude to the corresponding percentage in the crust. The average content of the elements Cr, Se, Co, Be, U, Br in Late Permian coal in S China ranks first in the country whereas the average content of Hg and CI in the coals of Late Carboniferous to Early Permian age in N China are the highest. The average content of Mn in Early and Middle Jurassic coal is higher in NW China. The high content of harmful elements in some coal should cause particular concern both in the development and utilization of coal.

Oxidation of Elemental Sulfur in Selected Soils of China

An incubation experiment was carried out in laboratory to study the effect of temperature, moisture, phosphorus, organic matter, cropping and previous elemental sulfur application on elemental sulfur oxidation in four selected soils, fluvo-aquic soil, black soil, yellow-brown soil and red soil. In all the soils tested, sulfur oxidation rate was influenced by temperature and the temperature coefficient (Q10) values at the range from 10 to 30 ℃ were 4.41, 4.05, 6.19 and 3.71 for the four soils, respectively. The rate of sulfur oxidation was parabolically related to soil Water content. The optimum moisture content for the maximum oxidation rate was different among soils. Phosphorus increased the oxidation rate of elemental sulfur by 57.7%, 33.1%, 21.7% and 26.4% for the above four soils, respectively, compared with the control (no phosphorus applied). Organic material of corn straw which was ground and passed through a 0.5-mm sieve also increased the oxidation rate of elemental sulfur in the four soils by 59.8%, 7.8%, 39.2% and 540.4%, respectively. Elemental sulfur which was applied previously to soils significantly enhanced the oxidation of elemental sulfur subsequently added and increased sulfur-oxidizing populations such as autotrophic elemental sulfur oxidizers with pH optimum 6.8, autotrophic thiosulfate oxidizers with pH optimum 6.8, heterotrophic thiosulfate oxidizers and heterotrophic sulfate producers. Cropping had little effect on elemental sulfur-oxidizing potentiality of soils.

Reduced inorganic sulfur in the sediments of the Yellow Sea and East China Sea

Cold diffusion methods are used to separate and quantify the three reduced inorganic sulfur species into acid volatile sulfide （AVS）, pyrite-S and element sulfur （ES） in the sediments of the Yellow and East China Seas. The results show that up to 25.02 pmol/g of AVS, 113.1 pmol/g of pyrite-S and 44.4 pmol/g of ES are observed in the sediments of the Yellow Sea and East China Sea. Pyrite-S is the predominant sulfide mineral in the sediments, while the concentration of AVS is quite low at most stations in the study area. The amounts and reactivity of organic matter are the primary limited factor for the sulfide formation, while an iron limitation and a sulfate limitation are not observed in the sediments of the Yellow Sea and East China Sea. The irregular profiles of the three reduced inorganic sulfur sediment composition and sedimentation rates. species also reflected the comprehensive influence of

宁东典型中低阶煤热解过程中氮和硫元素赋存形态与其变迁规律的关联性研究

作为分级转化比较理想的中低阶煤,认识和理解宁东典型中低阶煤在热转化过程中氮、硫元素迁移转化行为对污染物的调控至关重要。目前,煤热转化工艺多以气化为主,其中热解作为气化的基础阶段,在煤热转化过程中至关重要,因此在深入认识煤质特性的基础上,研究宁东地区典型中低阶煤所含硫、氮元素在热解过程中的迁移与转化规律,不仅有望为宁东中低阶煤的热转化工艺条件优化及污染物控制提供理论参考,也可为目前的气化工艺过程污染物调控提供基础数据。基于此,以宁东地区的羊场湾煤(YCW)、上湾精煤(SW)与梅花井煤(MHJ)为研究对象,使用固定床反应器,探究三种不同硫含量的煤在热解过程中HCN,NH_(3)与H_(2)S的释放规律,主要考察元素的赋存形态、热解温度(300℃~900℃)与升温速率(3℃/min~10℃/min)对氮、硫元素迁移转化的影响。结果表明:HCN的释放量随着温度升高而逐渐增加,NH_(3)的释放主要集中在500℃~900℃,最大释放峰温为700℃,H_(2)S的释放主要集中在400℃~900℃,最大逸出峰温为600℃和800℃(分别对应于硫铁矿硫与部分不稳定有机硫的分解);较高的灰分含量能够阻止自由基间相互结合,使更多的含氢自由基与含氮自由基结合生成HCN,季氮含量越高,NH_(3)的释放量越大,不稳定有机硫占比越高的煤样,H_(2)S的释放越多;适宜的升温速率有利于HCN发生二次反应生成NH_(3),随着升温速率增大,产生热滞后现象,当升温速率由3℃/min提高至10℃/min时,MHJ的HCN,NH_(3)和H_(2)S转化率均呈明显下降趋势,HCN转化率由4.02%降至1.28%,NH_(3)转化率由13.80%降至3.91%,H_(2)S转化率由38.33%降至26.04%。综上,元素赋存形态、热解温度与升温速率对热解过程中氮、硫元素迁移影响均较大。灰分含量、季氮含量与不稳定有机硫含量较低的煤样在10℃/min热解条件下,氮、硫污染物的释放量较低,对环境影响较小。

Research Progress on High Specific Energy Cathode Materials for Rechargeable Lithium Sulfur Batteries

An overview of the developing survey, research actuality and the future development of high specific energy and power lithium sulfur rechargeable batteries was presented systemically. By introducing the character of sulfur composite material and discussing some promising cathode materials, it may provide some foundation for people to go deep into researching and empoldering the sulfur composite material.

Carbon,Nitrogen,and Sulfur Contents in Marine Phytoplankton Cells and Biomass Conversion

In this study,we isolated and cultured phytoplankton along the coast of China and measured the cellular carbon,nitrogen,and sulfur contents under four temperatures.The results showed that the contents of the cellular elements varied widely among different phytoplankton.We found that temperature is one of the important factors affecting the carbon,nitrogen,and sulfur contents in phytoplankton cells;however,the degree of influence of temperature is different for different kinds of phytoplankton.By measuring the nitrogen content in cells,we found that the C:N ratio indirectly measured in the experiment fluctuated in the range of 3.50-8.97,and the average C:N ratio was 5.52.In this experiment,we accurately measured the cell elemental contents at different temperatures and transformed the cell count results into carbon,nitrogen,and sulfur contents to express the biomass.This method ensures that the contribution of species that are small in number but with a large cell volume in biomass is considered.Moreover,this method comprehensively considers the interspecific differences of species and the uneven distribution of elements in phytoplankton cells,which is of significance in the estimation of marine carbon and nitrogen budget.The distribution of nitrogen content in marine phytoplankton can well indicate the marine eutrophication caused by human activities.Climate change can affect the community structure and element composition of marine phytoplankton,meanwhile marine carbon and nitrogen element can regulate the climate to a certain extent.

Optimization of Fixed-Bed Design for Natural Gas Mercury Removal by Sulfur Doped into Porous Activated Carbon

The present work reports the synthesis and application of sulfur doped into porous activated carbon for removing elemental mercury from natural gas using a bench-scale fixed-bed reactor. A series of experiments were carried out to investigate the optimization of Hg0 capture. Furthermore, our experimental results about optimum conditions to remove Hg0 were 1:10 of sulfur to activated carbon impregnation ratio, 350°C of impregnation temperature, and 3 hours of impregnation time. This research showed that the prepared adsorbents were capable to remove remarkable amount of Hg0 (23.615 mg/g) at high adsorption efficiency. This study may serve as reference on natural gas power plants for the removal of Hg0 using the same conditions.

高含硫气田地面集输系统元素硫沉积化学防治一体化新技术

随着高含硫气田的不断开发,气田地面集输系统不可避免地会出现元素硫沉积堵塞问题。采用停产浸泡硫溶剂循环清洗解堵,面临着稳产周期短、清洗频繁、综合治理成本较高等挑战。为此,基于化学预防-治理相结合的理念,分别开展了停产浸泡硫溶剂循环解堵技术及不停产在线加注硫溶剂预防堵塞技术的研究,完成了配方设计、验证和现场试验,提出了防治一体化方案。研究结果表明:①研发的复合胺高效硫溶剂(CTS-1),较优使用温度为40~60℃,较优清洗时间为1~2 h,饱和溶硫量达45.72 g/100 mL,溶硫能力显著提升,且具有刺激性气味弱、微毒、腐蚀性低等优势,在四川盆地罗家寨气田LJ11H井成功开展了溶硫解堵试验;②创新性提出了不停产在线加注硫溶剂预防元素硫堵塞的技术思路,明确了在线加注硫溶剂的“动态预防-实时溶解”双重作用机制,并针对性地形成了在线加注硫溶剂应用工艺方案;③研发了复合碱硫溶剂(CTS-2),在确保高溶硫能力的同时,有效溶硫时间大幅降低至15~20 min,且适应性良好、环境友好。结论认为:①化学防治一体化技术是有效解决高含硫气田地面集输系统元素硫沉积堵塞的有效手段,新研发的复合胺硫溶剂及复合碱硫溶剂可满足化学防治的技术需求;②下一步需要开展井筒-地面清洗一体化防治、在线加注化学药剂预防堵塞及化学药剂可重复利用等系统性攻关,实现高含硫气田地面集输系统元素硫沉积的长效防治,全面助力高含硫气田长期稳产和规模高效开发。

分段递进式除硫工艺对油井采出含硫废水的处理研究

针对油井采出废水中硫化物去除难的问题,采用分段递进式除硫工艺对油井采出废水经过UASB生物反应池和仿生池进行分段递进式回流处理。实验结果表明,采用分段递进式除硫工艺,调节采出废水中S/N为5.2∶2,补充一定量的HCO_(3)^(-),设置回流比为2.7∶1条件下,采出废水中的硫化物(S_(2)^(-))去除率为95.8%,最大容积载荷6.46 kg/(m^(3)·d);硝酸盐(NO_(3)^(-)-N)去除率达99.6%,最大容积载荷1.13 kg/(m^(3)·d)。经SEM和XRD验证,硫代谢产物以单质硫(S0)为主,回收率83.8%,其次为SO_(4)^(2−)和S_(2)O_(3)^(2-);硝酸盐代谢产物以N_(2)为主,产率72.4%,其次为NO_(2)^(-)。分段递进式除硫工艺不仅解决了采出废水中的硫化物去除难题,同时实现了资源回收(S0)和主要代谢终产物(如N2)的无污染排放。

825合金在含单质硫高温高酸性环境中的局部腐蚀行为

在132℃、H_(2)S分压4.8MPa、CO_(2)分压1.6MPa、氯离子质量浓度42750mg·L^(-1)的气田模拟地层水中,通过腐蚀挂片试验研究了825合金在含单质硫(每升地层水中包裹合金的单质硫质量为10g)与不含单质硫条件下的局部腐蚀行为。结果表明:在不含单质硫条件下825合金几乎不发生腐蚀,腐蚀6d时的腐蚀速率仅为0.0077mm·a^(-1);添加单质硫腐蚀3d时腐蚀速率达到0.0552mm·a^(-1),合金发生了严重的局部腐蚀,随腐蚀时间的延长,合金表面局部腐蚀坑面积、腐蚀坑最大深度和腐蚀速率增大。在不含单质硫条件下合金表面腐蚀产物极少,主要为FeCO_(3),在含单质硫条件下,随着腐蚀时间的延长,表面腐蚀产物增多,主要为FeCO_(3)与FeS;单质硫在高温下发生歧化反应产生H^(+)和S^(2-),使825合金表面腐蚀产物膜破裂,从而加剧了局部腐蚀。