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The selective effect of food-grade guar gum on chalcopyrite-monoclinic pyrrhotite separation using mixed aerofloat(CSU11) as collector

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International Journal of Minerals,Metallurgy and Materials 2018年第10期25卷 1123-1131页

作者： Xiong Chen guo-hua gu Li-juan Li Ren-feng Zhu School of Minerals Processing and Bioengineering Central South UniversityChangsha 410083China Zhaojin Mining Industry Company Limited Yantai 264000China

The flotation separation of chalcopyrite from monoclinic pyrrhotite using food-grade guar gum(FGG) as a depressant was studied through flotation tests, kinetic studies, dynamic potential measurements, adsorption experiments, and infrared spectral analyses. The microflotation results showed that the flotation separation of chalcopyrite from monoclinic pyrrhotite could not be realized by adding mixed aerofloat(CSU11) alone. The depressant FGG exhibited a selective depression effect on monoclinic pyrrhotite by controlling the pulp pH range from 5.0 to 6.0, with a maximum floatability variation of 79.36% in the presence of CSU11. The flotation kinetics, zeta-potential, adsorption, and infrared spectroscopy studies revealed that the FGG could absorb more strongly on the surface of monoclinic pyrrhotite than on the surface of chalcopyrite. In addition, the results revealed that the interaction of FGG with the monoclinic pyrrhotite surface was governed primarily by strong chemisorption, whereas FGG mainly bonded to chalcopyrite through hydrogen bonding. This difference was responsible for the excellent depression selectivity of FGG toward monoclinic pyrrhotite flotation and weak depression effect toward chalcopyrite flotation.

关键词： chalcopyrite monoclinic pyrrhotite flotation separation food-grade guar gum

Selective depression behavior of guar gum on talc-type scheelite flotation

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International Journal of Minerals,Metallurgy and Materials 2017年第8期24卷 857-862页

作者： Yong-zhong Zhang guo-hua gu Xiang-bin Wu Kai-le Zhao School of Geosciences and Info-Physics Central South University Department of Land and Resources of Hunan Province School of Minerals Processing and Bioengineering Central South University

The depression behavior and mechanism of guar gum on talc-type scheelite flotation were systematically investigated by flotation experiments, adsorption tests, zeta-potential measurements, and infrared spectroscopic analyses. The flotation results for monominerals, mixed minerals, and actual mineral samples indicated that guar gum exhibited much higher selective depression for talc than for scheelite. Bench-scale closed-circuit tests showed that a tungsten concentrate with a WO_3 grade of 51.43% and a WO_3 recovery of 76.18% was obtained. Adsorption tests, zeta-potential measurements, and infrared spectral analyses confirmed that guar gum absorbed more strongly onto the talc surface than onto the scheelite surface because of chemisorption between guar gum and talc. This chemisorption is responsible for the guar gum's highly selective depression for talc and small depression for scheelite. The flotation results provide technical support for talc-type scheelite flotation.

关键词： scheelite talc guar gum flotation depression mechanism

Flotation mechanisms of molybdenite fines by neutral oils

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International Journal of Minerals,Metallurgy and Materials 2018年第1期25卷 1-10页

作者： Qing-quan Lin guo-hua gu Hui Wang You-cai Liu Jian-gang Fu Chong-qing Wang Jiangxi Copper Technology Research Institute Co.Ltd. Jiangxi Copper Corporation School of Chemistry and Chemical Engineering Central South University School of Minerals Processing and Bioengineering Central South University

The flotation mechanisms of molybdenite fines by neutral oils were investigated through microflotation test, turbidity measure- ments, infrared spectroscopy, and interracial interaction calculations. The results of the flotation test show that at pH 2-11, the floatability of molybdenite fines in the presence of transformer oil is markedly better than that in the presence of kerosene and diesel oil. The addition of transformer oil, which enhances the floatability of molybdenite fines, promotes the aggregation of molybdenite particles. Fourier transform infrared measurements illustrate that physical interaction dominates the adsorption mechanism of neutral oil on molybdenite. Interracial inte- raction calculations indicate that hydrophobic attraction is the crucial force that acts among the oil collector, water, and molybdenite. Strong hydrophobic attraction between the oily collector and water provides the strong dispersion capability of the collector in water. Furthermore, the dispersion capability of the collector, not the interaction strength role in the flotation system of molybdenite fines. Our findings provide between the oily collectors and molybdenite, has a highly significant insights into the mechanism ofmolybdenite flotation.

关键词： molybdenite fines flotation mechanisms neutral oils interfacial interaction hydrophobic attraction

Preparation of manganese sulfate from low-grade manganese carbonate ores by sulfuric acid leaching

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International Journal of Minerals,Metallurgy and Materials 2016年第5期23卷 491-500页

作者： Qing-quan Lin guo-hua gu Hui Wang Ren-feng Zhu You-cai Liu Jian-gang Fu School of Minerals Processing and Bioengineering Central South University School of Chemistry and Chemical Engineering Central South University

In this study, a method for preparing pure manganese sulfate from low-grade ores with a granule mean size of 0.47 mm by direct acid leaching was developed. The effects of the types of leaching agents, sulfitric acid concentration, reaction temperature, and agitation rate on the leaching efficiency of manganese were investigated. We observed that sulfuric acid used as a leaching agent provides a similar leach- ing efficiency of manganese and superior selectivity against calcium compared to hydrochloric acid. The optimal leaching conditions in sul- furic acid media were determined; under the optimal conditions, the leaching efficiencies of Mn and Ca were 92.42% and 9.61%, respec- tively. Moreover, the kinetics of manganese leaching indicated that the leaching follows the diffusion-controlled model with an apparent ac- tivation energy of 12.28 kJ·mol-l. The purification conditions of the leaching solution were also discussed. The results show that manganese dioxide is a suitable oxidant of ferrous ions and sodium dimethyldithiocarbamate is an effective precipitant of heavy metals. Finally, through chemical analysis and X-ray diffraction analysis, the obtained product was determined to contain 98% of MnSOa4·H20.

关键词： manganese ore treamaent manganese carbonate leaching leaching kinetics manganese sulfate

Effect of pH values on the extracellular polysaccharide secreted by Acidithiobacillus ferrooxidans during chalcopyrite bioleaching

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International Journal of Minerals,Metallurgy and Materials 2014年第4期21卷 311-316页

作者： Run-lan Yu Jing Liu Jian-xi Tan Wei-min Zeng Li-juan Shi guo-hua gu Wen-qing Qin guan-zhou Qiu School of Minerals Processing and Bioengineering Central South University Key Laboratory of Biometallurgy Ministry of Education Hunan Entry-Exit Inspection and Quarantine Bureau

The pH value plays an important role in the bioleaching of sulphide minerals. The effect of pH values on the extracellular poly-saccharide secreted by Acidithiobacillus ferrooxidans was investigated in different phases of bacterial growth during chalcopyrite bioleach-ing. It is found that extracellular polysaccharide secretion from the cells attached to chalcopyrite is more efficiently than that of the free cells in the bioleaching solution. Three factors, pH values, the concentration of soluble metal ions, and the bacterial growth and metabolism, affect extracellular polysaccharide secretion in the free cells, and are related to the bacterial growth phase. Extracellular polysaccharide secretion from the attached cells is mainly dependent on the pH value of the bacterial culture.

关键词： chalcopyrite bioleaching polysaccharides acidity Acidithiobacillusferrooxidans

Galvanic effect of magnetite on electrochemical oxidation of arsenopyrite in acidic culture medium

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Transactions of Nonferrous Metals Society of China 2022年第11期32卷 3744-3752页

作者： Sha DENG guo-hua gu Tao LONG Wei XIAO Wei YANG School of Resources Engineering Xi’an University of Architecture and TechnologyXi’an 710055China School of Minerals Processing and Bioengineering Central South UniversityChangsha 410083China

The galvanic interaction of arsenopyrite−magnetite in acidic culture medium was investigated by electrochemical measurements,X-ray photoelectron spectroscopy characterization and leaching *** results indicated that the rest potential of magnetite was 321 mV,which was more anodic than 223 mV of arsenopyrite,and the galvanic current was 7.40μA,verifying the existence of the galvanic interaction between arsenopyrite and *** galvanic potential and polarization curves suggested that the redox behaviors of arsenopyrite dominated the overall galvanic *** galvanic interaction enhanced the electrochemical dissolution of arsenopyrite with the generation of more oxidation products(S^(0),SO_(3)^(2−),SO_(4)^(2−)and AsO_(3)^(3−)) on arsenopyrite and an increase in the chemical reactivity of the *** experiments of 6 days showed that the presence of magnetite improved the arsenic release from arsenopyrite by 30 mg/L,and further confirmed the enhanced oxidation of arsenopyrite when coupled with magnetite.

关键词： arsenopyrite magnetite galvanic interaction electrochemistry surface properties leaching

Flotation and electrochemical behaviors of chalcopyrite and pyrite in the presence of N-propyl-N′-ethoxycarbonyl thiourea

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Transactions of Nonferrous Metals Society of China 2018年第6期28卷 1241-1247页

作者： Shuang-ke LI guo-hua gu guan-zhou QIU Zhi-xiang CHEN School of Minerals Processing and Bioengineering Central South UniversityChangsha 410083China

The characteristics of N-propyl-N′-ethoxycarbonyl thiourea（PECTU） were studied in the flotation experiments of chalcopyrite and pyrite compared with butyl xanthate（BX）. The interaction mechanism between mineral and PECTU was investigated according to zeta potential and electrochemistry measurements in the presence of PECTU. The results proved that PECTU performed a stronger ability to capture chalcopyrite and a better selectivity against pyrite. The zeta potential of chalcopyrite was positively shifted after interacting with PECTU, which indicated that the collector PECTU was obviously adsorbed on chalcopyrite surface. The cyclic voltammetry and Tafel curves results indicated that the oxidation and corrosion rates of chalcopyrite surface were limited in the presence of PECTU, while the effect of PECTU on pyrite in weak alkaline solution can be neglected basically according to the results of zeta potential and electrochemical tests.

关键词： chalcopyrite pyrite flotation N-propyl-N'-ethoxycarbonyl thiourea electrochemical behavior

Pathogenesis, diagnosis, and treatment of epilepsy: electromagnetic stimulation-mediated neuromodulation therapy and new technologies

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Neural Regeneration Research 2025年第4期20卷 917-935页

作者： Dian Jiao Lai Xu Zhen gu hua Yan Dingding Shen Xiaosong gu Academy of Medical Engineering and Translational Medicine Tianjin UniversityTianjinChina Key Laboratory of Advanced Drug Delivery Systems of Zhejiang Province College of Pharmaceutical SciencesZhejiang UniversityHangzhouZhejiang ProvinceChina Affiliated Hospital of Nantong University NantongJiangsu ProvinceChina

Epilepsy is a severe,relapsing,and multifactorial neurological *** regarding the accurate diagnosis,prognosis,and in-depth pathogenesis are crucial for the precise and effective treatment of *** pathogenesis of epilepsy is complex and involves alterations in variables such as gene expression,protein expression,ion channel activity,energy metabolites,and gut microbiota *** results are lacking for conventional treatments for *** resection of lesions,drug therapy,and non-drug interventions are mainly used in clinical practice to treat pain associated with ***-pharmacological treatments,such as a ketogenic diet,gene therapy for nerve regeneration,and neural regulation,are currently areas of research *** review provides a comprehensive overview of the pathogenesis,diagnostic methods,and treatments of *** also elaborates on the theoretical basis,treatment modes,and effects of invasive nerve stimulation in neurotherapy,including percutaneous vagus nerve stimulation,deep brain electrical stimulation,repetitive nerve electrical stimulation,in addition to non-invasive transcranial magnetic stimulation and transcranial direct current *** studies have shown that electromagnetic stimulation-mediated neuromodulation therapy can markedly improve neurological function and reduce the frequency of epileptic ***,many new technologies for the diagnosis and treatment of epilepsy are being ***,current research is mainly focused on analyzing patients’clinical manifestations and exploring relevant diagnostic and treatment methods to study the pathogenesis at a molecular level,which has led to a lack of consensus regarding the mechanisms related to the disease.

关键词： diagnosis drug treatment electroencephalography epilepsy monitoring epilepsy nerve regeneration neurostimulation non-drug interventions pathogenesis prediction

Rapid and scalable preparation of highly quaternized polymer networks to achieve efficient simultaneous adsorption of iodide and pertechnetate

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Science China Chemistry 2025年第1期68卷 337-349页

作者： Meiyun Xu Song gu Fulong Chen Zhe Zhao Peng Liu Daoben hua State Key Laboratory of Radiation Medicine and Protection School of Radiological and Interdisciplinary Sciences (RAD-X) Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions Soochow University

The efficient separation of fission products,such as TcO4-and I-,holds strategic significance for the management of radioactive wastes and environmental *** this study,we propose an ultrafast strategy for scalable preparation of a highly quaternized organic network to facilitate efficient and synchronous separation of iodide and *** network can be prepared within a few minutes at room temperature,using polyethylenimine and 1,2,4,5-tetrakis（bromomethyl）benzene as building *** chlorine replacement,the network,abundantly decorated with quaternary ammonium groups （Cl@QPN）,exhibits an ultrahigh positive charge density of 7.6 mmol/*** enables the rapid and efficient enrichment of target anions through strong electrostatic Coulomb *** a result,Cl@QPN exhibits significantly higher adsorption rate constants of 0.830 g/（mg min） for ReO4-（a nonradioactive surrogate of TcO4-） and 0.677 g/（mg min） for I-compared to other ***,it possesses high adsorption capacities,reaching 1,681 mg/g for ReO4-and 917.4 mg/g for I-.Cl@QPN also demonstrates good selectivity towards target ions and shows efficient adsorption for99TcO4-.Additionally,Cl@QPN exhibits high dynamic processing capacities,handling up to 3,100 and 7,400 kg of simulated streams per kilogram of material for I-and ReO4-,respectively.

关键词： quaternized polymer networks adsorption pertechnetate iodide liquid radioactive streams