Traditional pyrometallurgical and hydrometallurgical methods to extract bismuth from sulfide ores face problems such as high cost,low-concentration SO_(2)generation,and long process time.In this study,the cyclone tech...Traditional pyrometallurgical and hydrometallurgical methods to extract bismuth from sulfide ores face problems such as high cost,low-concentration SO_(2)generation,and long process time.In this study,the cyclone technology and slurry electrolysis method were combined.The bismuth sulfide ore was dissolved directly at the anode,while the high purity bismuth was deposited efficiently at the cathode under the advantages of the two methods.The short process and high-efficiency extraction of bismuth sulfide ore were realized,and the pollution of low-concentration SO_(2)was avoided.Then,the effects of several crucial experimental conditions(current density,reaction time,temperature,pH,liquid-solid ratio,and circulation flow rate)on the leaching efficiency and recovery efficiency of bismuth were investigated.The leaching and electrowinning mechanisms during the recovery process were also analyzed according to the research results of this paper to better understand the cyclone slurry electrolysis process.The experimental results showed that 95.19%bismuth was leached into the acid solution in the anode area under optimal conditions,and the recovery efficiency and purity of bismuth on the cathode reached 91.13%and 99.26%,respectively,which were better than those by the traditional hydrometallurgy recovery process.展开更多
Based on the properties of antimony(Sb)and arsenic(As),a method was proposed to enhance gold recovery during iron matte smelting.The impact of Sb and As on gold enhancement capture was investigated using an exclusion ...Based on the properties of antimony(Sb)and arsenic(As),a method was proposed to enhance gold recovery during iron matte smelting.The impact of Sb and As on gold enhancement capture was investigated using an exclusion method.The results demonstrated that both Sb and As significantly improved the gold recovery rate.As the Sb or As content increased,the gold recovery rate increased.The enhancement effect of Sb was better than that of As,and the optimal results were achieved through the synergistic effects of Sb and As.Under optimized conditions,the gold recovery rate reached 97.12%,whereas the gold content in the slag decreased to 1.70 g/t.Sb captured and aggregated free gold as an Au-Sb alloy,whereas As-Fe alloy also captured free gold.The growth of the gold-captured phase size enhanced the settling velocity,thereby promoting gold recovery.展开更多
BACKGROUND Although limited clinical evidence exists,such as case reports of azoospermia treatment in humans using bone marrow aspirate concentrate(BMAC)injection,these findings provide a compelling foundation for exp...BACKGROUND Although limited clinical evidence exists,such as case reports of azoospermia treatment in humans using bone marrow aspirate concentrate(BMAC)injection,these findings provide a compelling foundation for exploring mesenchymal stem cell therapy in male infertility.AIM To evaluate the safety and efficacy of autologous BMAC injection into human testis for men with severe oligospermia or azoospermia over the existing standard of care pharmacotherapy and lifestyle modifications.METHODS We included patients diagnosed with male infertility of the age group between 35–45 years in this trial comparing BMAC injection therapy with pharmacotherapy and lifestyle modifications over a 6-month follow-up period.Semen analysis was used to evaluate the efficacy of the interventions analyzed.RESULTS We enrolled 30 patients in the trial with 10 patients in each arm of the trial.Compared to the baseline,neither the BMAC group(P=0.139)or pharmacotherapy group(P=0.056)nor the lifestyle modification group(P=0.112)demonstrated a statistically significant increase in sperm count at 6 months.However,the BMAC group demonstrated a significant increase in sperm count(mean 19.2 million;P=0.001)compared to the pharmacotherapy group(mean 3.5 million)and lifestyle modification group(mean 2.2 million)at 6 months.Significant improvement was noted in the motility grade(P<0.001)only in the BMAC group while no changes were noted in the other groups.CONCLUSION This trial highlights the potential of autologous BMAC as a promising therapeutic option for male infertility.Despite the absence of significant changes within individual treatment arms,BMAC therapy demonstrated superior efficacy in improving both sperm count and motility compared to standard pharmacotherapy and lifestyle modifications.These findings underscore the potential role of regenerative medicine in addressing severe oligospermia and azoospermia,warranting further research to solidify its clinical applicability.展开更多
Sodium fluoride(NaF)is a daily necessity consumed as the major ingredient of fluorinated drinking water,milk,salts,mouthwashes,toothpaste,and dentistry medications.However,the use of NaF products has also been associa...Sodium fluoride(NaF)is a daily necessity consumed as the major ingredient of fluorinated drinking water,milk,salts,mouthwashes,toothpaste,and dentistry medications.However,the use of NaF products has also been associated with increased fluoride anion distribution in the body,leading to hypertension.AIM This study evaluated the antihypertensive effect of sweet orange peels-enriched white melon seed protein concentrate(WSP)biscuit meal in eight-week-old albino rats exposed to NaF for 14 days.METHODS Forty-two(42)male Wistar albino rats were assigned at random into 7 groups of 6 rats per group(control group and six experimental groups).The experimental groups received various treatments that lasted for two weeks.Twenty-four hours after the last administration,hemodynamic parameters were evaluated,rats were sacrificed,blood samples were collected,and the heart was harvested.Blood serum was assessed for cardiac troponin I(cTnI),creatine kinase-MB(CK-MB),and lactate dehydrogenase(LDH).At the same time,the heart homogenate was assayed for angiotensin-1 converting enzyme(ACE)activity,proinflammatory cytokines,nitric oxide concentrations,and antioxidant status.Cardiac tissues were stained with Hematoxylin and Eosin,Masson’s Trichrome,and cTnI.Also,the safety of the WSP biscuit diet was evaluated.RESULTS Results obtained showed that NaF administration elevated the collagen content of cardiac tissues,activities of ACE,and concentrations of cTnI,CK-MB,LDH,tumor necrosis factor-alpha,and interleukin 1 beta,while there was a reduction in the concentration of nitric oxide and antioxidants;however,their alterations were significantly prevented in WSP-biscuit-fed rats.The WSP biscuit meal is safe for consumption and possesses dose-dependent antihypertensive ability at 10%and 20%inclusion.CONCLUSION The WSP biscuit diet may be recommended in diet formulation for the management of individuals or communities that are predisposed to NaF contaminations.展开更多
BACKGROUND Knee osteoarthritis(OA)imposes a substantial burden through pain,functional limitation,and progressive cartilage loss.Bone marrow aspirate concentrate(BMAC)has emerged as a promising regenerative therapy fo...BACKGROUND Knee osteoarthritis(OA)imposes a substantial burden through pain,functional limitation,and progressive cartilage loss.Bone marrow aspirate concentrate(BMAC)has emerged as a promising regenerative therapy for OA due to its rich composition of mesenchymal stromal cells(MSCs)and bioactive factors.While intra-articular BMAC injections provide short-term symptomatic relief,recent literature suggests that targeting the subchondral bone—an area crucial to OA progression—may offer superior and longer-lasting clinical benefits.AIM To compares the outcomes of subchondral vs intra-articular BMAC injections in patients with primary knee OA.METHODS In this unicentric,double-blinded,randomized controlled trial,30 patients with radiologically confirmed primary knee OA(Kellgren-Lawrence grades II and III)will be equally randomized to receive either subchondral(Group A)or intra-articular(Group B)BMAC injections.BMAC will be harvested from the posterior iliac crest,processed using a standardized centrifugation protocol to yield a product with>85%cell viability,and administered under image guidance.The primary outcome is the change in pain intensity at 12 months as measured by the Visual Analog Scale(VAS).Secondary outcomes include functional improvement assessed by Knee Injury and Osteoarthritis Outcome Score(KOOS),International Knee Documentation Committee(IKDC),and Western Ontario and McMaster Universities Arthritis Index(WOMAC)scores,structural changes evaluated through advanced magnetic resonance imaging using(MRI)the whole-organ MRI Score,and safety as determined by the incidence of adverse events.RESULTS This study aims to evaluate pain reduction at 12 months post-injection,using the VAS as the primary outcome.Secondary outcomes include functional improvement(KOOS,WOMAC,IKDC),cartilage regeneration(T2 cartigram),adverse event incidence,patient satisfaction(standardized questionnaires,Likert scale),and quality of life(EQ-5D).Ethical considerations follow the Declaration of Helsinki and Good Clinical Practice,with institutional review board approval and participant informed consent ensured.Confidentiality and data security comply with regulations,and a data safety monitoring board oversees trial safety.Results will be shared via peer-reviewed journals,presentations at international orthopedic conferences,and detailed summaries for stakeholders and participants.The trial is registered under clinical trial registry of India/2024/04/065284.Findings emphasize patient-centered advancements in knee osteoarthritis management.CONCLUSION This trial aims to refine regenerative strategies for knee OA by comparing subchondral vs intra-articular BMAC injections,addressing long-term efficacy,safety,and treatment standardization to guide targeted interventions.This trial will provide critical insights into the comparative efficacy and safety of subchondral vs intra-articular BMAC injections in treating primary knee OA.展开更多
The hydrogen-based reduction and electric smelting technology is a green and low-carbon process for treating low-grade ore and complex symbiotic iron ore.In this study,the hydrogen-based reduction of boron-bearing iro...The hydrogen-based reduction and electric smelting technology is a green and low-carbon process for treating low-grade ore and complex symbiotic iron ore.In this study,the hydrogen-based reduction of boron-bearing iron concentrate and the low-temperature separation compared with the high-temperature melting separation of slag and iron from a boron-bearing iron concentrate were studied.The metallization rate of the boron-bearing iron concentrate reached 99.63%after hydrogen-based reduction at 1050℃,and the metallic iron was interwoven with olivine(Mg_(2)SiO_(4))in the reduced ore.In addition,the high-temperature melting separation of iron and slag could be accomplished at 1550℃for 60 min,where boron was mainly distributed in the form of a glass phase in the slag with a mass fraction of B_(2)O_(3)of 22.69%,and 0.35%of boron(mass fraction)was melted into liquid iron.By contrast,iron and slag were efficiently separated at a lower temperature(1300℃)for 10 min and enhanced by super-gravity.Almost all the boron content was enriched into a suanite phase in the slag with a considerably high mass fraction of B_(2)O_(3)(35.61%)and a high recovery ratio(99.37%),and the mass fraction of boron decreased to 0.15%in iron.Compared with high-temperature melting separation,low-temperature separation combined with hydrogen-based reduction greatly improved the enrichment of boron in slag and prevented the melting of boron into iron.展开更多
Complex concentrated alloys(CCAs)containing the L2_(1)phase are recognized for their exceptional strength and thermal stability,positioning them as strong candidates for transformative applications in aerospace,energy...Complex concentrated alloys(CCAs)containing the L2_(1)phase are recognized for their exceptional strength and thermal stability,positioning them as strong candidates for transformative applications in aerospace,energy,and structural sectors.This investigation delves into the AlFexNiTiV_(40-x)(x=0,10,20,30,35,40;at%)CCAs,aiming to unlock the synergistic potential of BCC and L2_(1)phases.By conducting an in-depth analysis of microstructure,phase behavior,and mechanical properties,the intricate relationships between chemistry,structure,and properties are illuminated within this alloy system.The Al_(15)Fe_(35)Ni_(3)0Ti_(15)V_(5)alloy demonstrates remarkable mechanical properties,achieving a yield strength of 2140.9 MPa and ultimate compressive strength of 2699.7 MPa,primarily through solid solution strengthening and precipitation hardening.Notably,its low lattice mismatches and nanoprecipitate strengthening yield an impressive specific yield strength at 600℃(245.2 MPa(g·cm^(-3))^(-1)).Phase modulation achieves the synergistic optimization of specific strengths at both room and high temperatures in CCAs containing the L2_(1)phase,opening new avenues for designing advanced lightweight and high strength alloys for elevated-temperature applications.展开更多
Zinc perchlorate(Zn(ClO_(4))_(2))electrolytes have demonstrated favorable low-temperature performance in aqueous zinc-ion batteries(AZIBs).However,the Zn anode encounters serious dendrite formation and parasitic react...Zinc perchlorate(Zn(ClO_(4))_(2))electrolytes have demonstrated favorable low-temperature performance in aqueous zinc-ion batteries(AZIBs).However,the Zn anode encounters serious dendrite formation and parasitic reactions in zinc perchlorate electrolytes,which is caused by the fast corrosive kinetics at room temperature.Herein,a concentrated perchlorate-based electrolyte consisting of 4.0 M Zn(ClO_(4))_(2)and saturated NaClO_(4)solution is developed to achieve dendrite-free and stable AZIBs at room temperature.The ClO_(4)−participates in the primary solvation sheath of Zn^(2+),facilitating the in situ formation of Zn_(5)(OH)_(8)Cl_(2)·H_(2)O-rich solid electrolyte interphase(SEI)to suppress the corrosion effect of ClO_(4)^(−).The Zn anode protected by the SEI achieves stable Zn plating/stripping over 3000 h.Furthermore,the MnO_(2)||Zn full cells manifest a stable specific capacity of 200 mAh·g^(−1)at 28℃and 101 mAh·g^(−1)at−20℃.This work introduces a promising approach for boosting the room-temperature performance of perchlorate-based electrolytes for AZIBs.展开更多
In order to investigate the oxidation roasting of molybdenite concentrate in pure oxygen atmosphere, experiments at 673, 723, 773, 873 and 973 K were carried out. The phase transitions and morphology evolutions of the...In order to investigate the oxidation roasting of molybdenite concentrate in pure oxygen atmosphere, experiments at 673, 723, 773, 873 and 973 K were carried out. The phase transitions and morphology evolutions of the samples obtained at different temperatures after reacting for different time were analyzed by X-ray diffraction（XRD） and scanning electron microscopy（SEM）. The results showed that molybdenite concentrate was oxidized directly to Mo O3 in pure oxygen atmosphere. There were remarkable changes of the morphologies of products with the increase of the roasting temperature. It was also found that sintering phenomenon occurred during the roasting process in pure oxygen when the temperature was above 873 K. The composition of sintered sample was mainly comprised of Mo O3 and some unreacted Mo S2.展开更多
The effects of Ca-based additives on roasting properties of low-grade molybdenum concentrate were studied. The resultsshow that calcium-based additives can react with molybdenum concentrate to form CaSO4 and CaMoO4. T...The effects of Ca-based additives on roasting properties of low-grade molybdenum concentrate were studied. The resultsshow that calcium-based additives can react with molybdenum concentrate to form CaSO4 and CaMoO4. The initial oxidationtemperature of MoS2 is 450℃, while the formation of CaMoO4 and CaSO4 occurs above 500℃. The whole calcification reactionsare nearly completed between 600 and 650℃. However, raising the temperature further helps for the formation of CaMoO4 but isdisadvantageous to sulfur fixing rate and molybdenum retention rate. Calcification efficiency of Ca-based additives follows theorder： Ca（OH）2〉CaO〉CaCO3. With increasing the dosage of Ca（OH）2, the molybdenum retention rate and sulfur-fixing rate rise, butexcessive dosages would consume more acid during leaching process. The appropriate mass ratio of Ca（OH）2 to molybdenumconcentrate is 1：1. When roasted at 650 ℃ for 90 min, the molybdenum retention rate and the sulfur-fixing rate of low-grademolybdenum concentrate reach 100% and 92.92%, respectively, and the dissolution rate of molybdenum achieves 99.12% withcalcines being leached by sulphuric acid.展开更多
The leaching behavior of main metallic sulphides in zinc concentrate under atmospheric oxygen-rich direct leaching conditions was studied through mineralogical analysis. The results show that the sulphides dissolve ob...The leaching behavior of main metallic sulphides in zinc concentrate under atmospheric oxygen-rich direct leaching conditions was studied through mineralogical analysis. The results show that the sulphides dissolve obviously except pyrite. Based on the relationship between elemental sulfur and the residual sulphides in the leaching residue, the dissolution of sphalerite, chalcopyrite, covellite and galena is assumed to follow the indirect oxidation reactions, where the acidic dissolution takes place firstly and then the released H2S transfers from the mineral surface into bulk solution and is further oxidized into elemental sulfur. The interface chemical reaction is further supposed as the controlling step in the leaching of these sulphides. The direct electrochemical oxidation reactions are assumed to contribute to the dissolution of pyrrhotite, which is controlled by the diffusion through elemental sulfur layer.展开更多
Effects of initial pH, temperature, liquid volume, rotation speed, galvanic interaction （pyrite ratio） and pulp density on bioleaching of complex Cu-polymetallic concentrate were investigated. The results indicated ...Effects of initial pH, temperature, liquid volume, rotation speed, galvanic interaction （pyrite ratio） and pulp density on bioleaching of complex Cu-polymetallic concentrate were investigated. The results indicated that the copper extraction at pH 1.5 was 1.5 and 1.4 times that at pH 1.0 and pH 2.0 respectively. The copper extraction obtained at 45 ℃ was 1236.8%higher than that at 50 ℃. With the increase of rotation speed or the decrease of liquid volume, copper extraction was improved obviously. Copper extraction was improved gradually with the increase of pyrite ratio. However, when the ratio was higher than 20.0%, no further increase in copper extraction was observed. And the statistically significant interactive effects on copper extraction were found between temperature and pH, and temperature and pyrite ratio.展开更多
The reduction behaviors of FeO·V2O3 and FeO·Cr2O3 during coal-based direct reduction have a decisive impact on the efficient utilization of high-chromium vanadium-bearing titanomagnetite concentrates. The ef...The reduction behaviors of FeO·V2O3 and FeO·Cr2O3 during coal-based direct reduction have a decisive impact on the efficient utilization of high-chromium vanadium-bearing titanomagnetite concentrates. The effects of molar ratio of C to Fe n(C)/n(Fe) and temperature on the behaviors of vanadium and chromium during direct reduction and magnetic separation were investigated. The reduced samples were characterized by X-ray diffraction(XRD), scanning election microscopy(SEM) and energy dispersive spectrometry(EDS) techniques. Experimental results indicate that the recoveries of vanadium and chromium rapidly increase from 10.0% and 9.6% to 45.3% and 74.3%, respectively, as the n(C)/n(Fe) increases from 0.8 to 1.4. At n(C)/n(Fe) of 0.8, the recoveries of vanadium and chromium are always lower than 10.0% in the whole temperature range of 1100-1250 °C. However, at n(C)/n(Fe) of 1.2, the recoveries of vanadium and chromium considerably increase from 17.8% and 33.8% to 42.4% and 76.0%, respectively, as the temperature increases from 1100 °C to 1250 °C. At n(C)/n(Fe) lower than 0.8, most of the FeO·V2O3 and FeO·Cr2O3 are not reduced to carbides because of the lack of carbonaceous reductants, and the temperature has little effect on the reduction behaviors of FeO·V2O3 and FeO·Cr2O3, resulting in very low recoveries of vanadium and chromium during magnetic separation. However, at higher n(C)/n(Fe), the reduction rates of FeO·V2O3 and FeO·Cr2O3 increase significatly because of the excess amount of carbonaceous reductants. Moreover, higher temperatures largely induce the reduction of FeO·V2O3 and FeO·Cr2O3 to carbides. The newly formed carbides are then dissolved in the γ(FCC) phase, and recovered accompanied with the metallic iron during magnetic separation.展开更多
The original strain HY-7 was isolated from the bauxite mine drainage（BMD） taken from a reservoir in Sanmenxia Mine,Henan Province,China.The optimum temperature and pH for the growth of strain HY-7 were 30 ℃ and 7.0...The original strain HY-7 was isolated from the bauxite mine drainage（BMD） taken from a reservoir in Sanmenxia Mine,Henan Province,China.The optimum temperature and pH for the growth of strain HY-7 were 30 ℃ and 7.0,respectively.The optimum UV radiating time was 20 s and the positive mutation rate was 23.0%.The growth curves show that strain HY-7 needs144 h to reach the stationary phase after its mutagenesis,which is 24 h earlier than that of the original strain.Sequence homology analysis indicated that this community consisted of mainly two branches：one sharing high homology with Paenibacillus stellifer and the other sharing high homology with Sporolactobacillus laevolacticus.The experimental results showed that the TiO2 grade of mtile concentrate increased from 78.21%to 91.80%and the recovery of TiO2 reached 95.24%after 7 d of bioleaching.The bio-desilication process can not only effectively improve the TiO2 grade of rutile concentrate but also meet the requirements of environmental protection.展开更多
In order to improve the bio-oxidation efficiency of Axi refractory gold concentrate, a two-step process including a high temperature chemical oxidation and a subsequent bio-oxidation, combined with p H control during ...In order to improve the bio-oxidation efficiency of Axi refractory gold concentrate, a two-step process including a high temperature chemical oxidation and a subsequent bio-oxidation, combined with p H control during the bio-oxidation step was used. The results revealed that the optimum mode was to maintain solution p H at 1.0-1.2 during the biological oxidation stage. Under this condition, the activity of mixed culture could be sustained and the formation of jarosite could be diminished, thus the oxidation efficiency was improved. The oxidation levels of iron and sulfur were improved by 12.50% and 15.49%, and the gold recovery was increased by 21.02%. Therefore, the two-step process combined with p H control is an effective method for oxidizing the biohydrometallurgical process of Axi gold concentrate, and it will have a broad prospect of application in dealing with complex refractory gold concentrate.展开更多
A novel method of roasting high-titanium slag with concentrated sulfuric acid was proposed to prepare titanium dioxide, and the roasting kinetics of titania was studied On the basis of roasting process. The effects of...A novel method of roasting high-titanium slag with concentrated sulfuric acid was proposed to prepare titanium dioxide, and the roasting kinetics of titania was studied On the basis of roasting process. The effects of roasting temperature, particle size, and acid-to-ore mass ratio on the rate of roasting reaction were investigated. The results showed that the roasting reaction is fitted to a shrinking core model. The results of the kinetic experiment and SEM and EDAX analyses proved that the reaction rate of roasting high-titanium slag with concentrated sulfuric acid is controlled by the internal diffusion on the solid product layer. According to the Arrhenius expression, the apparent activation energy of the roasting reaction is 18.94 kJ/mol.展开更多
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 c...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.展开更多
An artificial neural network model was developed to predict the oxidation of refractory gold concentrate （RGC） by ozone and ferric ions. The concentration of ozone and ferric ions, pulp density, oxygen amount, leach...An artificial neural network model was developed to predict the oxidation of refractory gold concentrate （RGC） by ozone and ferric ions. The concentration of ozone and ferric ions, pulp density, oxygen amount, leaching time and temperature were employed as inputs to the network; the output of the network was the percentage of the ferric extraction iron from RGC. The multilayered feed-forward networks were trained by 33 sets of input-output patterns using a back propagation algorithm; a three-layer network with 8 neurons in the hidden layer gave optimal results. The model gave good predictions of high correlation coefficient （R2=0.966）. The predictions by ANN are more accurate when compared with conventional multivariate regression analysis （MVRA）. In addition, calculation with ANN model indicates that temperature is the predominant parameter and ozone concentration is the lesser influential parameter in the pre-oxidation process of refractory gold ore. The ANN neural network model accurately estimates the ferric extraction during pretreatment process of RGC in gold smelter plants and can be used to optimize the process parameters.展开更多
Based on the equivalence principle of deflection and stress, the concentrated vehicle load which acts on the center of continuously reinforced concrete pavement （CRCP） is translated into the equivalent half-wave sin...Based on the equivalence principle of deflection and stress, the concentrated vehicle load which acts on the center of continuously reinforced concrete pavement （CRCP） is translated into the equivalent half-wave sine load by the Fourier transform. On the basis of this transform and the small deflection theory of elastic thin plates, the deflection and stress formulae of CRCP under the concentrated vehicle load with a hollow foundation are put forward. The sensitivity of parameters is analyzed. The results show that maximum deflection is directly proportional to the concentrated vehicle load and the slab width, and inversely proportional to the lateral bending stiffness and slab thickness. The effects of slab width and thickness are significant with regard to maximum deflection. Maximum stress is directly proportional to the concentrated vehicle load and the slab width as well as inversely proportional to slab thickness. The effect of slab thickness is significant with regard to maximum stress. According to the calculation results, the most effective measure to reduce maximum deflection and stress is to increase slab thickness.展开更多
The pyrolysis characteristics of Shendong Shangwan coal and its macerals concentrate were investigated using thermogravimetry （TG） coupled with mass spectrometry （MS）. The evolved gases were analyzed online by MS ...The pyrolysis characteristics of Shendong Shangwan coal and its macerals concentrate were investigated using thermogravimetry （TG） coupled with mass spectrometry （MS）. The evolved gases were analyzed online by MS spectroscopy. The results of TG/DTG （derivative thermogravimetry） show ths vitrinite concentrate has greater weight loss rate and higher volatile yield than the other two samples. More light hydrocarbons C1-C5 are released from the vitfinite concentrate than from the Shendong Shangwan coal and inertinite concentrated in the process of pyrolysis. Three samples have similar shape curves of evolved gases of C2~C5 with different intensities. When the pyrolysis temperature was lower than 418℃, the amount of C6H6 evolved in the process of pyrolysis of inertinite concentrated was higher than that of raw coal and vitrinite concentrate. As the temperature rising, the production rate of C6H6 increased. Below 672℃, C6H6 evolution rate of vitrinite concentrate was far greater than the other two samples; the main evolution temperature range of C7H8 was 400℃ to 700℃ for the three samples. The amount of HE and H20 released first increased and then decreased with the temperature increase while more H2 released for pyrolysis of inertinite concentrated and more H20 released for the pyrolysis of vitrinite concentrate.展开更多
基金Projects(52104355,52074363,52374364)supported by the National Natural Science Foundation of ChinaProject(2023YFC2907904)supported by the National Key R&D Program of China。
文摘Traditional pyrometallurgical and hydrometallurgical methods to extract bismuth from sulfide ores face problems such as high cost,low-concentration SO_(2)generation,and long process time.In this study,the cyclone technology and slurry electrolysis method were combined.The bismuth sulfide ore was dissolved directly at the anode,while the high purity bismuth was deposited efficiently at the cathode under the advantages of the two methods.The short process and high-efficiency extraction of bismuth sulfide ore were realized,and the pollution of low-concentration SO_(2)was avoided.Then,the effects of several crucial experimental conditions(current density,reaction time,temperature,pH,liquid-solid ratio,and circulation flow rate)on the leaching efficiency and recovery efficiency of bismuth were investigated.The leaching and electrowinning mechanisms during the recovery process were also analyzed according to the research results of this paper to better understand the cyclone slurry electrolysis process.The experimental results showed that 95.19%bismuth was leached into the acid solution in the anode area under optimal conditions,and the recovery efficiency and purity of bismuth on the cathode reached 91.13%and 99.26%,respectively,which were better than those by the traditional hydrometallurgy recovery process.
基金financially supported from the National Natural Science Foundation of China(No.52274358)the Natural Science Foundation of Hunan Province,China(No.2020JJ4718)+2 种基金the Major Science and Technology Projects of Gansu Province,China(No.22ZD6GC017)the Young Scientists Fund of National Natural Science Foundation of China(No.51404296)the National Key Research and Development Program of China(No.2018YFC1901604).
文摘Based on the properties of antimony(Sb)and arsenic(As),a method was proposed to enhance gold recovery during iron matte smelting.The impact of Sb and As on gold enhancement capture was investigated using an exclusion method.The results demonstrated that both Sb and As significantly improved the gold recovery rate.As the Sb or As content increased,the gold recovery rate increased.The enhancement effect of Sb was better than that of As,and the optimal results were achieved through the synergistic effects of Sb and As.Under optimized conditions,the gold recovery rate reached 97.12%,whereas the gold content in the slag decreased to 1.70 g/t.Sb captured and aggregated free gold as an Au-Sb alloy,whereas As-Fe alloy also captured free gold.The growth of the gold-captured phase size enhanced the settling velocity,thereby promoting gold recovery.
文摘BACKGROUND Although limited clinical evidence exists,such as case reports of azoospermia treatment in humans using bone marrow aspirate concentrate(BMAC)injection,these findings provide a compelling foundation for exploring mesenchymal stem cell therapy in male infertility.AIM To evaluate the safety and efficacy of autologous BMAC injection into human testis for men with severe oligospermia or azoospermia over the existing standard of care pharmacotherapy and lifestyle modifications.METHODS We included patients diagnosed with male infertility of the age group between 35–45 years in this trial comparing BMAC injection therapy with pharmacotherapy and lifestyle modifications over a 6-month follow-up period.Semen analysis was used to evaluate the efficacy of the interventions analyzed.RESULTS We enrolled 30 patients in the trial with 10 patients in each arm of the trial.Compared to the baseline,neither the BMAC group(P=0.139)or pharmacotherapy group(P=0.056)nor the lifestyle modification group(P=0.112)demonstrated a statistically significant increase in sperm count at 6 months.However,the BMAC group demonstrated a significant increase in sperm count(mean 19.2 million;P=0.001)compared to the pharmacotherapy group(mean 3.5 million)and lifestyle modification group(mean 2.2 million)at 6 months.Significant improvement was noted in the motility grade(P<0.001)only in the BMAC group while no changes were noted in the other groups.CONCLUSION This trial highlights the potential of autologous BMAC as a promising therapeutic option for male infertility.Despite the absence of significant changes within individual treatment arms,BMAC therapy demonstrated superior efficacy in improving both sperm count and motility compared to standard pharmacotherapy and lifestyle modifications.These findings underscore the potential role of regenerative medicine in addressing severe oligospermia and azoospermia,warranting further research to solidify its clinical applicability.
文摘Sodium fluoride(NaF)is a daily necessity consumed as the major ingredient of fluorinated drinking water,milk,salts,mouthwashes,toothpaste,and dentistry medications.However,the use of NaF products has also been associated with increased fluoride anion distribution in the body,leading to hypertension.AIM This study evaluated the antihypertensive effect of sweet orange peels-enriched white melon seed protein concentrate(WSP)biscuit meal in eight-week-old albino rats exposed to NaF for 14 days.METHODS Forty-two(42)male Wistar albino rats were assigned at random into 7 groups of 6 rats per group(control group and six experimental groups).The experimental groups received various treatments that lasted for two weeks.Twenty-four hours after the last administration,hemodynamic parameters were evaluated,rats were sacrificed,blood samples were collected,and the heart was harvested.Blood serum was assessed for cardiac troponin I(cTnI),creatine kinase-MB(CK-MB),and lactate dehydrogenase(LDH).At the same time,the heart homogenate was assayed for angiotensin-1 converting enzyme(ACE)activity,proinflammatory cytokines,nitric oxide concentrations,and antioxidant status.Cardiac tissues were stained with Hematoxylin and Eosin,Masson’s Trichrome,and cTnI.Also,the safety of the WSP biscuit diet was evaluated.RESULTS Results obtained showed that NaF administration elevated the collagen content of cardiac tissues,activities of ACE,and concentrations of cTnI,CK-MB,LDH,tumor necrosis factor-alpha,and interleukin 1 beta,while there was a reduction in the concentration of nitric oxide and antioxidants;however,their alterations were significantly prevented in WSP-biscuit-fed rats.The WSP biscuit meal is safe for consumption and possesses dose-dependent antihypertensive ability at 10%and 20%inclusion.CONCLUSION The WSP biscuit diet may be recommended in diet formulation for the management of individuals or communities that are predisposed to NaF contaminations.
文摘BACKGROUND Knee osteoarthritis(OA)imposes a substantial burden through pain,functional limitation,and progressive cartilage loss.Bone marrow aspirate concentrate(BMAC)has emerged as a promising regenerative therapy for OA due to its rich composition of mesenchymal stromal cells(MSCs)and bioactive factors.While intra-articular BMAC injections provide short-term symptomatic relief,recent literature suggests that targeting the subchondral bone—an area crucial to OA progression—may offer superior and longer-lasting clinical benefits.AIM To compares the outcomes of subchondral vs intra-articular BMAC injections in patients with primary knee OA.METHODS In this unicentric,double-blinded,randomized controlled trial,30 patients with radiologically confirmed primary knee OA(Kellgren-Lawrence grades II and III)will be equally randomized to receive either subchondral(Group A)or intra-articular(Group B)BMAC injections.BMAC will be harvested from the posterior iliac crest,processed using a standardized centrifugation protocol to yield a product with>85%cell viability,and administered under image guidance.The primary outcome is the change in pain intensity at 12 months as measured by the Visual Analog Scale(VAS).Secondary outcomes include functional improvement assessed by Knee Injury and Osteoarthritis Outcome Score(KOOS),International Knee Documentation Committee(IKDC),and Western Ontario and McMaster Universities Arthritis Index(WOMAC)scores,structural changes evaluated through advanced magnetic resonance imaging using(MRI)the whole-organ MRI Score,and safety as determined by the incidence of adverse events.RESULTS This study aims to evaluate pain reduction at 12 months post-injection,using the VAS as the primary outcome.Secondary outcomes include functional improvement(KOOS,WOMAC,IKDC),cartilage regeneration(T2 cartigram),adverse event incidence,patient satisfaction(standardized questionnaires,Likert scale),and quality of life(EQ-5D).Ethical considerations follow the Declaration of Helsinki and Good Clinical Practice,with institutional review board approval and participant informed consent ensured.Confidentiality and data security comply with regulations,and a data safety monitoring board oversees trial safety.Results will be shared via peer-reviewed journals,presentations at international orthopedic conferences,and detailed summaries for stakeholders and participants.The trial is registered under clinical trial registry of India/2024/04/065284.Findings emphasize patient-centered advancements in knee osteoarthritis management.CONCLUSION This trial aims to refine regenerative strategies for knee OA by comparing subchondral vs intra-articular BMAC injections,addressing long-term efficacy,safety,and treatment standardization to guide targeted interventions.This trial will provide critical insights into the comparative efficacy and safety of subchondral vs intra-articular BMAC injections in treating primary knee OA.
文摘The hydrogen-based reduction and electric smelting technology is a green and low-carbon process for treating low-grade ore and complex symbiotic iron ore.In this study,the hydrogen-based reduction of boron-bearing iron concentrate and the low-temperature separation compared with the high-temperature melting separation of slag and iron from a boron-bearing iron concentrate were studied.The metallization rate of the boron-bearing iron concentrate reached 99.63%after hydrogen-based reduction at 1050℃,and the metallic iron was interwoven with olivine(Mg_(2)SiO_(4))in the reduced ore.In addition,the high-temperature melting separation of iron and slag could be accomplished at 1550℃for 60 min,where boron was mainly distributed in the form of a glass phase in the slag with a mass fraction of B_(2)O_(3)of 22.69%,and 0.35%of boron(mass fraction)was melted into liquid iron.By contrast,iron and slag were efficiently separated at a lower temperature(1300℃)for 10 min and enhanced by super-gravity.Almost all the boron content was enriched into a suanite phase in the slag with a considerably high mass fraction of B_(2)O_(3)(35.61%)and a high recovery ratio(99.37%),and the mass fraction of boron decreased to 0.15%in iron.Compared with high-temperature melting separation,low-temperature separation combined with hydrogen-based reduction greatly improved the enrichment of boron in slag and prevented the melting of boron into iron.
基金supported by the National Natural Science Foundation of China(Nos.52301043 and 51871077)Guangdong Basic and Applied Basic Research Foundation(No.2021A1515012626),Shenzhen Knowledge Innovation Plan-Fundamental Research(Discipline Distribution)(No.JCYJ20180507184623297)+1 种基金Shenzhen Science and Technology Plan-Technology Innovation(No.KQJSCX20180328165656256)the Startup Foundation from Shenzhen(Nos.NA25501001,and NA11409005).
文摘Complex concentrated alloys(CCAs)containing the L2_(1)phase are recognized for their exceptional strength and thermal stability,positioning them as strong candidates for transformative applications in aerospace,energy,and structural sectors.This investigation delves into the AlFexNiTiV_(40-x)(x=0,10,20,30,35,40;at%)CCAs,aiming to unlock the synergistic potential of BCC and L2_(1)phases.By conducting an in-depth analysis of microstructure,phase behavior,and mechanical properties,the intricate relationships between chemistry,structure,and properties are illuminated within this alloy system.The Al_(15)Fe_(35)Ni_(3)0Ti_(15)V_(5)alloy demonstrates remarkable mechanical properties,achieving a yield strength of 2140.9 MPa and ultimate compressive strength of 2699.7 MPa,primarily through solid solution strengthening and precipitation hardening.Notably,its low lattice mismatches and nanoprecipitate strengthening yield an impressive specific yield strength at 600℃(245.2 MPa(g·cm^(-3))^(-1)).Phase modulation achieves the synergistic optimization of specific strengths at both room and high temperatures in CCAs containing the L2_(1)phase,opening new avenues for designing advanced lightweight and high strength alloys for elevated-temperature applications.
基金supported by Hainan Provincial Joint Project of Sanya Yazhou Bay Science and Technology City(No.2021JJLH0069)the Project of Sanya Yazhou Bay Science and Technology City(No.SCKJ-JYRC-2023-55)Hainan Provincial Natural Science Foundation of China(No.522CXTD516).
文摘Zinc perchlorate(Zn(ClO_(4))_(2))electrolytes have demonstrated favorable low-temperature performance in aqueous zinc-ion batteries(AZIBs).However,the Zn anode encounters serious dendrite formation and parasitic reactions in zinc perchlorate electrolytes,which is caused by the fast corrosive kinetics at room temperature.Herein,a concentrated perchlorate-based electrolyte consisting of 4.0 M Zn(ClO_(4))_(2)and saturated NaClO_(4)solution is developed to achieve dendrite-free and stable AZIBs at room temperature.The ClO_(4)−participates in the primary solvation sheath of Zn^(2+),facilitating the in situ formation of Zn_(5)(OH)_(8)Cl_(2)·H_(2)O-rich solid electrolyte interphase(SEI)to suppress the corrosion effect of ClO_(4)^(−).The Zn anode protected by the SEI achieves stable Zn plating/stripping over 3000 h.Furthermore,the MnO_(2)||Zn full cells manifest a stable specific capacity of 200 mAh·g^(−1)at 28℃and 101 mAh·g^(−1)at−20℃.This work introduces a promising approach for boosting the room-temperature performance of perchlorate-based electrolytes for AZIBs.
基金Projects(5147414151174022)supported by the National Natural Science Foundation of China
文摘In order to investigate the oxidation roasting of molybdenite concentrate in pure oxygen atmosphere, experiments at 673, 723, 773, 873 and 973 K were carried out. The phase transitions and morphology evolutions of the samples obtained at different temperatures after reacting for different time were analyzed by X-ray diffraction（XRD） and scanning electron microscopy（SEM）. The results showed that molybdenite concentrate was oxidized directly to Mo O3 in pure oxygen atmosphere. There were remarkable changes of the morphologies of products with the increase of the roasting temperature. It was also found that sintering phenomenon occurred during the roasting process in pure oxygen when the temperature was above 873 K. The composition of sintered sample was mainly comprised of Mo O3 and some unreacted Mo S2.
基金Project(51304245)supported by the National Natural Science Foundation of ChinaProject(2014T70691)supported by the Postdoctoral Science Foundation of China+1 种基金Project(2015CX005)supported by the Innovation Driven Plan of Central South University,ChinaProject supported by the Hunan Provincial Co-innovation Center for Clean and Efficient Utilization of Strategic Metal Mineral Resources,China
文摘The effects of Ca-based additives on roasting properties of low-grade molybdenum concentrate were studied. The resultsshow that calcium-based additives can react with molybdenum concentrate to form CaSO4 and CaMoO4. The initial oxidationtemperature of MoS2 is 450℃, while the formation of CaMoO4 and CaSO4 occurs above 500℃. The whole calcification reactionsare nearly completed between 600 and 650℃. However, raising the temperature further helps for the formation of CaMoO4 but isdisadvantageous to sulfur fixing rate and molybdenum retention rate. Calcification efficiency of Ca-based additives follows theorder： Ca（OH）2〉CaO〉CaCO3. With increasing the dosage of Ca（OH）2, the molybdenum retention rate and sulfur-fixing rate rise, butexcessive dosages would consume more acid during leaching process. The appropriate mass ratio of Ca（OH）2 to molybdenumconcentrate is 1：1. When roasted at 650 ℃ for 90 min, the molybdenum retention rate and the sulfur-fixing rate of low-grademolybdenum concentrate reach 100% and 92.92%, respectively, and the dissolution rate of molybdenum achieves 99.12% withcalcines being leached by sulphuric acid.
基金Project (50964004) supported by the National Natural Science Foundation of China
文摘The leaching behavior of main metallic sulphides in zinc concentrate under atmospheric oxygen-rich direct leaching conditions was studied through mineralogical analysis. The results show that the sulphides dissolve obviously except pyrite. Based on the relationship between elemental sulfur and the residual sulphides in the leaching residue, the dissolution of sphalerite, chalcopyrite, covellite and galena is assumed to follow the indirect oxidation reactions, where the acidic dissolution takes place firstly and then the released H2S transfers from the mineral surface into bulk solution and is further oxidized into elemental sulfur. The interface chemical reaction is further supposed as the controlling step in the leaching of these sulphides. The direct electrochemical oxidation reactions are assumed to contribute to the dissolution of pyrrhotite, which is controlled by the diffusion through elemental sulfur layer.
基金Project (2012zzts026) supported by the Fundamental Research Funds for the Central Universities,ChinaProject (201205020) supported by Scientific Research Program of Marine Public Welfare Industry of China+2 种基金Project (51074195) supported by the National Natural Science Foundation of ChinaProject (CX2012B123) supported by Research Innovation for Graduate Student of Hunan Province,ChinaProject (12C517) supported by Education Department of Hunan Province,China
文摘Effects of initial pH, temperature, liquid volume, rotation speed, galvanic interaction （pyrite ratio） and pulp density on bioleaching of complex Cu-polymetallic concentrate were investigated. The results indicated that the copper extraction at pH 1.5 was 1.5 and 1.4 times that at pH 1.0 and pH 2.0 respectively. The copper extraction obtained at 45 ℃ was 1236.8%higher than that at 50 ℃. With the increase of rotation speed or the decrease of liquid volume, copper extraction was improved obviously. Copper extraction was improved gradually with the increase of pyrite ratio. However, when the ratio was higher than 20.0%, no further increase in copper extraction was observed. And the statistically significant interactive effects on copper extraction were found between temperature and pH, and temperature and pyrite ratio.
基金Projects(2013CB632601,2013CB632604)supported by the National Basic Research Program of ChinaProject(51125018)supported by the National Science Foundation for Distinguished Young Scholars of China+1 种基金Project(KGZD-EW-201-2)supported by the Key Research Program of the Chinese Academy of SciencesProjects(51374191,21106167,51104139)supported by the National Natural Science Foundation of China
文摘The reduction behaviors of FeO·V2O3 and FeO·Cr2O3 during coal-based direct reduction have a decisive impact on the efficient utilization of high-chromium vanadium-bearing titanomagnetite concentrates. The effects of molar ratio of C to Fe n(C)/n(Fe) and temperature on the behaviors of vanadium and chromium during direct reduction and magnetic separation were investigated. The reduced samples were characterized by X-ray diffraction(XRD), scanning election microscopy(SEM) and energy dispersive spectrometry(EDS) techniques. Experimental results indicate that the recoveries of vanadium and chromium rapidly increase from 10.0% and 9.6% to 45.3% and 74.3%, respectively, as the n(C)/n(Fe) increases from 0.8 to 1.4. At n(C)/n(Fe) of 0.8, the recoveries of vanadium and chromium are always lower than 10.0% in the whole temperature range of 1100-1250 °C. However, at n(C)/n(Fe) of 1.2, the recoveries of vanadium and chromium considerably increase from 17.8% and 33.8% to 42.4% and 76.0%, respectively, as the temperature increases from 1100 °C to 1250 °C. At n(C)/n(Fe) lower than 0.8, most of the FeO·V2O3 and FeO·Cr2O3 are not reduced to carbides because of the lack of carbonaceous reductants, and the temperature has little effect on the reduction behaviors of FeO·V2O3 and FeO·Cr2O3, resulting in very low recoveries of vanadium and chromium during magnetic separation. However, at higher n(C)/n(Fe), the reduction rates of FeO·V2O3 and FeO·Cr2O3 increase significatly because of the excess amount of carbonaceous reductants. Moreover, higher temperatures largely induce the reduction of FeO·V2O3 and FeO·Cr2O3 to carbides. The newly formed carbides are then dissolved in the γ(FCC) phase, and recovered accompanied with the metallic iron during magnetic separation.
基金Project(2011-622-40)supported by the Mineral Exploration Foundation of Henan Province,ChinaProject(51104189)supported by the National Natural Science Foundation of ChinaProject(2013M531814)supported by the 53rd China Postdoctoral Science Foundation
文摘The original strain HY-7 was isolated from the bauxite mine drainage（BMD） taken from a reservoir in Sanmenxia Mine,Henan Province,China.The optimum temperature and pH for the growth of strain HY-7 were 30 ℃ and 7.0,respectively.The optimum UV radiating time was 20 s and the positive mutation rate was 23.0%.The growth curves show that strain HY-7 needs144 h to reach the stationary phase after its mutagenesis,which is 24 h earlier than that of the original strain.Sequence homology analysis indicated that this community consisted of mainly two branches：one sharing high homology with Paenibacillus stellifer and the other sharing high homology with Sporolactobacillus laevolacticus.The experimental results showed that the TiO2 grade of mtile concentrate increased from 78.21%to 91.80%and the recovery of TiO2 reached 95.24%after 7 d of bioleaching.The bio-desilication process can not only effectively improve the TiO2 grade of rutile concentrate but also meet the requirements of environmental protection.
基金Project(2010CB630901)supported by the National Basic Research Program of ChinaProject(2013M531814)supported by the 53rd China Postdoctoral Science Foundation
文摘In order to improve the bio-oxidation efficiency of Axi refractory gold concentrate, a two-step process including a high temperature chemical oxidation and a subsequent bio-oxidation, combined with p H control during the bio-oxidation step was used. The results revealed that the optimum mode was to maintain solution p H at 1.0-1.2 during the biological oxidation stage. Under this condition, the activity of mixed culture could be sustained and the formation of jarosite could be diminished, thus the oxidation efficiency was improved. The oxidation levels of iron and sulfur were improved by 12.50% and 15.49%, and the gold recovery was increased by 21.02%. Therefore, the two-step process combined with p H control is an effective method for oxidizing the biohydrometallurgical process of Axi gold concentrate, and it will have a broad prospect of application in dealing with complex refractory gold concentrate.
基金Project(2007CB613603)supported by the National Basic Research Program of China
文摘A novel method of roasting high-titanium slag with concentrated sulfuric acid was proposed to prepare titanium dioxide, and the roasting kinetics of titania was studied On the basis of roasting process. The effects of roasting temperature, particle size, and acid-to-ore mass ratio on the rate of roasting reaction were investigated. The results showed that the roasting reaction is fitted to a shrinking core model. The results of the kinetic experiment and SEM and EDAX analyses proved that the reaction rate of roasting high-titanium slag with concentrated sulfuric acid is controlled by the internal diffusion on the solid product layer. According to the Arrhenius expression, the apparent activation energy of the roasting reaction is 18.94 kJ/mol.
基金Project (2006BAK04B03) supported by the National Science and Technology Pillar Program during the 11th Five-Year Plan Period of ChinaProject (kjdb200902-7) supported by Doctoral Candidate Innovation Research Support Program of Science & Technology Review, China+1 种基金Project (1960-71131100023) supported by Postgraduate Dissertation Innovation Foundation of Central South University, ChinaProject (ZKJ2009008) supported by Precious Apparatus Opening Center Foundation of Central South University, China
文摘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.
基金Project (2006AA06Z132) supported by High-tech Research and Development Program of ChinaProject (B604) supported by Leading Academic Discipline Project of Shanghai
文摘An artificial neural network model was developed to predict the oxidation of refractory gold concentrate （RGC） by ozone and ferric ions. The concentration of ozone and ferric ions, pulp density, oxygen amount, leaching time and temperature were employed as inputs to the network; the output of the network was the percentage of the ferric extraction iron from RGC. The multilayered feed-forward networks were trained by 33 sets of input-output patterns using a back propagation algorithm; a three-layer network with 8 neurons in the hidden layer gave optimal results. The model gave good predictions of high correlation coefficient （R2=0.966）. The predictions by ANN are more accurate when compared with conventional multivariate regression analysis （MVRA）. In addition, calculation with ANN model indicates that temperature is the predominant parameter and ozone concentration is the lesser influential parameter in the pre-oxidation process of refractory gold ore. The ANN neural network model accurately estimates the ferric extraction during pretreatment process of RGC in gold smelter plants and can be used to optimize the process parameters.
基金The Science Foundation of Ministry of Transport of the People's Republic of China(No.200731822301-7)
文摘Based on the equivalence principle of deflection and stress, the concentrated vehicle load which acts on the center of continuously reinforced concrete pavement （CRCP） is translated into the equivalent half-wave sine load by the Fourier transform. On the basis of this transform and the small deflection theory of elastic thin plates, the deflection and stress formulae of CRCP under the concentrated vehicle load with a hollow foundation are put forward. The sensitivity of parameters is analyzed. The results show that maximum deflection is directly proportional to the concentrated vehicle load and the slab width, and inversely proportional to the lateral bending stiffness and slab thickness. The effects of slab width and thickness are significant with regard to maximum deflection. Maximum stress is directly proportional to the concentrated vehicle load and the slab width as well as inversely proportional to slab thickness. The effect of slab thickness is significant with regard to maximum stress. According to the calculation results, the most effective measure to reduce maximum deflection and stress is to increase slab thickness.
文摘The pyrolysis characteristics of Shendong Shangwan coal and its macerals concentrate were investigated using thermogravimetry （TG） coupled with mass spectrometry （MS）. The evolved gases were analyzed online by MS spectroscopy. The results of TG/DTG （derivative thermogravimetry） show ths vitrinite concentrate has greater weight loss rate and higher volatile yield than the other two samples. More light hydrocarbons C1-C5 are released from the vitfinite concentrate than from the Shendong Shangwan coal and inertinite concentrated in the process of pyrolysis. Three samples have similar shape curves of evolved gases of C2~C5 with different intensities. When the pyrolysis temperature was lower than 418℃, the amount of C6H6 evolved in the process of pyrolysis of inertinite concentrated was higher than that of raw coal and vitrinite concentrate. As the temperature rising, the production rate of C6H6 increased. Below 672℃, C6H6 evolution rate of vitrinite concentrate was far greater than the other two samples; the main evolution temperature range of C7H8 was 400℃ to 700℃ for the three samples. The amount of HE and H20 released first increased and then decreased with the temperature increase while more H2 released for pyrolysis of inertinite concentrated and more H20 released for the pyrolysis of vitrinite concentrate.
