International Journal of Minerals, Metallurgy and Materials

姓名
邮箱
手机号码
标题
留言内容
验证码

Mechanism research on arsenic removal from arsenopyrite ore during a sintering process

Ri-jin Cheng, Hong-wei Ni, Hua Zhang, Xiao-kun Zhang, Si-cheng Bai

2017, 24(4): 353-359. doi: 10.1007/s12613-017-1414-5

中文摘要(534) PDF(30) SpringerLink

摘要:
The mechanism of arsenic removal during a sintering process was investigated through experiments with a sintering pot and arsenic-bearing iron ore containing arsenopyrite; the corresponding chemical properties of the sinter were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray diffraction (XRD), and scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS). The experimental results revealed that the reaction of arsenic removal is mainly related to the oxygen atmosphere and temperature. During the sintering process, arsenic could be removed in the ignition layer, the sinter layer, and the combustion zone. A portion of FeAsS reacted with excess oxygen to generate FeAsO₄, and the rest of the FeAsS reacted with oxygen to generate As₂O₃(g) and SO₂(g). A portion of As₂O₃(g) mixed with Al₂O₃ or CaO, which resulted in the formation of arsenates such as AlAsO₄ and Ca₃(AsO₄)₂, leading to arsenic residues in sintering products. The FeAsS component in the blending ore was difficult to decompose in the preliminary heating zone, the dry zone, or the bottom layer because of the relatively low temperatures; however, As₂O₃(g) that originated from the high-temperature zone could react with metal oxides, resulting in the formation of arsenate residues.

研究论文

Thin-layer heap bioleaching of copper flotation tailings containing high levels of fine grains and microbial community succession analysis

Xiao-dong Hao, Yi-li Liang, Hua-qun Yin, Hong-wei Liu, Wei-min Zeng, Xue-duan Liu

2017, 24(4): 360-368. doi: 10.1007/s12613-017-1415-4

中文摘要(567) PDF(13) SpringerLink

摘要:
Thin-layer heap bioleaching of copper flotation tailings containing high levels of fine grains was carried out by mixed cultures on a small scale over a period of 210 d. Lump ores as a framework were loaded at the bottom of the ore heap. The overall copper leaching rates of tailings and lump ores were 57.10wt% and 65.52wt%, respectively. The dynamic shifts of microbial community structures about attached microorganisms were determined using the Illumina MiSeq sequencing platform based on 16S rRNA amplification strategy. The results indicated that chemolithotrophic genera Acidithiobacillus and Leptospirillum were always detected and dominated the microbial community in the initial and middle stages of the heap bioleaching process; both genera might be responsible for improving the copper extraction. However, Thermogymnomonas and Ferroplasma increased gradually in the final stage. Moreover, the effects of various physicochemical parameters and microbial community shifts on the leaching efficiency were further investigated and these associations provided some important clues for facilitating the effective application of bioleaching.

研究论文

Dissolution characteristics of sericite in chalcopyrite bioleaching and its effect on copper extraction

Ying-bo Dong, Hao Li, Hai Lin, Yuan Zhang

2017, 24(4): 369-376. doi: 10.1007/s12613-017-1416-3

中文摘要(478) PDF(12) SpringerLink

摘要:
The effects of sericite particle size, rotation speed, and leaching temperature on sericite dissolution and copper extraction in a chalcopyrite bioleaching system were examined. Finer particles, appropriate temperature and rotation speed for Acidithiobacillus ferrooxidans resulted in a higher Al³⁺ dissolution concentration. The Al³⁺ dissolution concentration reached its highest concentration of 38.66 mg/L after 48-d leaching when the sericite particle size, temperature, and rotation speed were -43 μm, 30℃, and 160 r/min, respectively. Meanwhile, the sericite particle size, rotation speed, and temperature can affect copper extraction. The copper extraction rate is higher when the sericite particle size is finer. An appropriately high temperature is favorable for copper leaching. The dissolution of sericite fitted the shrinking core model, 1-(2/3)α-(1-α)^2/3=k₁t, which indicates that internal diffusion is the decision step controlling the overall reaction rate in the leaching process. Scanning electron microscopy analysis showed small precipitates covered on the surface of sericite after leaching, which increased the diffusion resistance of the leaching solution and dissolved ions.

研究论文

Extraction of metals from complex sulfide nickel concentrates by low-temperature chlorination roasting and water leaching

Cong Xu, Hong-wei Cheng, Guang-shi Li, Chang-yuan Lu, Xiong-gang Lu, Xing-li Zou, Qian Xu

2017, 24(4): 377-385. doi: 10.1007/s12613-017-1417-2

中文摘要(778) PDF(32) SpringerLink

摘要:
The recovery of valuable metals from complex sulfide concentrates was investigated via chlorination roasting followed by water leaching. A reaction process is proposed on the basis of previous studies and the results of our preliminary experiments. During the process, various process parameters were studied, including the roasting temperature, the addition of NH₄Cl, the roasting time, the leaching time, and the liquid-to-solid ratio. The roasted products and leach residues were characterized by X-ray diffraction and vibrational spectroscopy. Under the optimum condition, 95% of Ni, 98% of Cu, and 88% of Co were recovered. In addition, the removal of iron was studied in the water leaching stage. The results demonstrate that this process provides an effective approach for extracting multiple metals from complex concentrates or ores.

研究论文

Consolidation mechanism of gold concentrates containing sulfur and carbon during oxygen-enriched air roasting

Qian Li, Fang-zhou Ji, Bin Xu, Jian-jun Hu, Yong-bin Yang, Tao Jiang

2017, 24(4): 386-392. doi: 10.1007/s12613-017-1418-1

中文摘要(455) PDF(9) SpringerLink

摘要:
Consolidation in calcines is a common problem in the oxygen-enriched air roasting of refractory gold concentrates containing sulfur and carbon when the initial temperature is greater than 600℃. To determine the phases that caused consolidation, gold concentrates were roasted under different conditions and the calcines were mainly detected by X-ray diffraction (XRD). The possible underlying mechanism was then studied through comparisons of the XRD patterns of different calcines. The results indicated that the generation of calcium magnesium silicate, iron-doped calcium aluminosilicate, and calcium aluminate caused the consolidation. Furthermore, an enriched oxygen atmosphere accelerated the oxidation reaction and the emitted heat increased the local temperature in calcines. The local temperature was inferred to have increased to the generation temperature zone of the corresponding liquid phases. Oxidation of the pyrite and decomposition of the dolomite and muscovite mainly occurred at the initial stage of oxygen-enriched air roasting. Calcium was confirmed to be essential to the consolidation process.

研究论文

Effect of decarburization annealing temperature and time on the carbon content, microstructure, and texture of grain-oriented pure iron

Hai-jun Wang, Zhe Rong, Li Xiang, Sheng-tao Qiu, Jian-xin Li, Ting-liang Dong

2017, 24(4): 393-400. doi: 10.1007/s12613-017-1419-0

中文摘要(855) PDF(40) SpringerLink

摘要:
In this study, the effect of decarburization annealing temperature and time on the carbon content, microstructure, and texture of grain-oriented pure iron was investigated by optical microscopy and scanning electron microscopy with electron-backscatter diffraction. The results showed that the efficiency of decarburization dramatically increased with increasing decarburization temperature. However, when the annealing temperature was increased to 825℃ and 850℃, the steel's carbon content remained essentially unchanged at 0.002%. With increasing decarburization time, the steel's carbon content generally decreased. When both the decarburization temperature and time were increased further, the average grain size dramatically increased and the number of fine grains decreased; meanwhile, some relatively larger grains developed. The main texture types of the decarburized sheets were approximately the same:{001}<110> and {112~115}<110>, with a γ-fiber texture. Furthermore, little change was observed in the texture. Compared with the experimental sheets, the texture of the cold-rolled sheet was very scattered. The best average magnetic induction (B₈₀₀) among the final products was 1.946 T.

研究论文

Environmental boundary and formation mechanism of different types of H₂S corrosion products on pipeline steel

Lei Zhang, Hui-xin Li, Feng-xian Shi, Jian-wei Yang, Li-hua Hu, Min-xu Lu

2017, 24(4): 401-409. doi: 10.1007/s12613-017-1420-7

中文摘要(514) PDF(13) SpringerLink

摘要:
To establish an adequate thermodynamic model for the mechanism of formation of hydrogen sulfide (H₂S) corrosion products, theoretical and experimental studies were combined in this work. The corrosion products of API X60 pipeline steel formed under different H₂S corrosion conditions were analyzed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. A thermodynamic model was developed to clarify the environmental boundaries for the formation and transformation of different products. Presumably, a dividing line with a negative slope existed between mackinawite and pyrrhotite. Using experimental data presented in this study combined with previously published results, we validated the model to predict the formation of mackinawite and pyrrhotite on the basis of the laws of thermodynamics. The established relationship is expected to support the investigation of the H₂S corrosion mechanism in the oil and gas industry.

研究论文

Surface grain refinement mechanism of SMA490BW steel cross joints by ultrasonic impact treatment

Bo-lin He, Lei Xiong, Ming-ming Jiang, Ying-xia Yu, Li Li

2017, 24(4): 410-414. doi: 10.1007/s12613-017-1421-6

中文摘要(532) PDF(15) SpringerLink

摘要:
Ultrasonic impact treatment (UIT) is a postweld technique for improving the fatigue strength of welded joints. This technique makes use of ultrasonic vibration to impact and plastically deform a weld toe and can achieve surface grain refinement of the weld toe, which is considered as the main reason for the improvement of fatigue strength. In this paper, the microstructure of the surface of a treated weld toe was observed by metallographic microscopy and transmission electron microscopy (TEM). The results show that UIT could produce severe plastic deformation on the surface layer of the weld toe and the maximum depth of plastic deformation extended to approximately 260 μm beneath the treated surface. Repeated processing could exacerbate the plastic deformation on the surface layer, resulting in finer grains. We can conclude that the surface grain refinement mechanism of SMA490BW welded joints is related to the high density of dislocation tangles and dislocation walls.

研究论文

Addition of cerium and yttrium to ferritic steel weld metal to improve hydrogen trapping efficiency

Sung Jin Kim, Kang Mook Ryu, Min-suk Oh

2017, 24(4): 415-422. doi: 10.1007/s12613-017-1422-5

中文摘要(531) PDF(13) SpringerLink

摘要:
The applicability of Ce and Y as promising candidate elements to form irreversible traps in weld metal was investigated by thermal desorption spectroscopy (TDS) with gas chromatography (GC).The precise nature of the precipitate particles newly formed in the weld metal by the addition of Ce and Y to a certain alloy system was characterized.Moreover,the hydrogen trapping efficiency expressed as the reduction of the diffusible hydrogen in the weld metal was analyzed.The results showed that the addition of Ce and/or Y to this alloy system led to the formation of a mixed type of (Ce,Ti)-based oxide,(Y,Ni)-based carbide,or (Ce,Y,Ti)-based oxide particles.Because of the high activation energy of the mixed type of particles (≥ 150 kJ/mol),the trapping efficiency for hydrogen was considered to be sufficiently high to effectively reduce the diffusible hydrogen content.

研究论文

Effects of cupric ions on the corrosion behavior of aluminum alloy 5A02 in ethylene glycol-water solution

Shu-lun Gao, Mei Yu, Jian-hua Liu, Bing Xue, Song-mei Li

2017, 24(4): 423-431. doi: 10.1007/s12613-017-1423-4

中文摘要(515) PDF(12) SpringerLink

摘要:
The effects of cupric ions on the corrosion behavior of aluminum alloy 5A02 in ethylene glycol-water solutions were studied by potentiodynamic polarization, electrochemical noise (EN), and complementary techniques including scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). A positive corrosion potential and increased corrosion current were observed due to the deposition of copper. The results demonstrate that the main corrosion type was pitting and the increasing cupric ion concentration augmented the pitting density. The pits became larger and deeper as a result of the embedment of copper into the surface of the alloy. Cupric ions were preferentially deposited at the defects around the secondary phase, leading to the formation of Al-Cu microgalvanic couples, which increased the corrosion rate. The corrosion rate gradually reached a stable value as the concentration of cupric ions was increased beyond 10 mmol/L.

研究论文

Constitutive behavior and processing maps of low-expansion GH909 superalloy

Zhi-hao Yao, Shao-cong Wu, Jian-xin Dong, Qiu-ying Yu, Mai-cang Zhang, Guang-wei Han

2017, 24(4): 432-443. doi: 10.1007/s12613-017-1424-3

中文摘要(513) PDF(12) SpringerLink

摘要:
The hot deformation behavior of GH909 superalloy was studied systematically using isothermal hot compression tests in a temperature range of 960 to 1040℃ and at strain rates from 0.02 to 10 s-1 with a height reduction as large as 70%. The relations considering flow stress, temperature, and strain rate were evaluated via power-law, hyperbolic sine, and exponential constitutive equations under different strain conditions. An exponential equation was found to be the most appropriate for process modeling. The processing maps for the superalloy were constructed for strains of 0.2, 0.4, 0.6, and 0.8 on the basis of the dynamic material model, and a total processing map that includes all the investigated strains was proposed. Metallurgical instabilities in the instability domain mainly located at higher strain rates manifested as adiabatic shear bands and cracking. The stability domain occurred at 960-1040℃ and at strain rates less than 0.2 s^-1; these conditions are recommended for optimum hot working of GH909 superalloy.

研究论文

Synthesis of titanium oxycarbonitride by carbothermal reduction and nitridation of ilmenite with recycling of polyethylene terephthalate (PET)

Eltefat Ahmadi, Ahmad Fauzi, Hashim Hussin, Norlia Baharun, Kamar Shah Ariffin, Sheikh Abdul Rezan

2017, 24(4): 444-454. doi: 10.1007/s12613-017-1425-2

中文摘要(515) PDF(11) SpringerLink

摘要:
An innovative and sustainable carbothermal reduction and nitridation (CTRN) process of ilmenite (FeTiO₃) using a mixture of polyethylene terephthalate (PET) and coal as the primary reductant under an H₂-N₂ atmosphere was proposed.The use of PET as an alternative source of carbon not only enhances the porosity of the pellets but also results in the separation of Fe from titanium oxycarbonitride (TiO_xC_yN_z) particles because of the differences in surface tension.The experiments were carried out at 1250℃ for 3 h using four different PET contents ranging from 25wt% to 100wt% in the reductant.X-ray diffraction (XRD),scanning electron microscopy (SEM) in conjunction with energy-dispersive X-ray spectroscopy (EDX),and LECO elemental analysis were used to study the phases and microstructures of the reduced samples.In the case of 75wt% PET,iron distinctly separated from the synthesized TiO_xC_yN_z phase.With increasing PET content in the sample,the reduction and nitridation rates substantially increased.The synthesis of an oxycarbonitride with stoichiometry of TiO_0.02C_0.13N_0.85 with minimal intermediate titanium sub-oxides was achieved.The results also showed that the iron particles formed from CTRN of FeTiO₃ exhibited a spherical morphology,which is conducive for Fe removal via the Becher process.

研究论文

One-pot synthesis and optical properties of In-and Sn-doped ZnO nanoparticles

Li-ping Wang, Fu Zhang, Shuai Chen, Zi-heng Bai

2017, 24(4): 455-461. doi: 10.1007/s12613-017-1426-1

中文摘要(661) PDF(13) SpringerLink

摘要:
Colloidal indium-doped zinc oxide (IZO) and tin-doped zinc oxide (ZTO) nanoparticles were successfully prepared in organic solution,with metal acetylacetonate as the precursor and oleylamine as the solvent.The crystal and optical properties were characterized by X-ray diffraction,UV-visible spectrophotometry,and fluorescence spectroscopy,respectively;the surface and structure morphologies were observed by scanning electron microscopy and transmission electron microscopy.The XRD patterns of the IZO and ZTO nanoparticles all exhibited similar diffraction peaks consistent with the standard XRD pattern of ZnO,although the diffraction peaks of the IZO and ZTO nanoparticles were slightly shifted with increasing dopant concentration.With increasing dopant concentration,the fluorescent emission peaks of the IZO nanoparticles exhibited an obvious red shift because of the difference in atomic radii of indium and zinc,whereas those of the ZTO nanoparticles exhibited almost no shift because of the similarity in atomic radii of tin and zinc.Furthermore,the sizes of the IZO and ZTO nanoparticles distributed in the ranges 20-40 and 20-25 nm,respectively,which is attributed to the difference in ionic radii of indium and tin.

研究论文

Cu-Zn-Al₂O₃ nanocomposites:study of microstructure,corrosion,and wear properties

Mohammad Baghani, Mahmood Aliofkhazraei, Mehdi Askari

2017, 24(4): 462-472. doi: 10.1007/s12613-017-1427-0

中文摘要(513) PDF(19) SpringerLink

摘要:
Alumina nanoparticles were added to a Cu-Zn alloy to investigate their effect on the microstructural, tribological, and corrosion properties of the prepared alloys. Alloying was performed using a mixture of copper and zinc powders with 0vol% and 5vol% of α-Al nanopowder in a satellite ball mill. The results showed that the Cu-Zn solid solution formed after 18 h of mechanical alloying. The mechanically alloyed powder was compacted followed by sintering of the obtained green compacts at 750℃ for 30 min. Alumina nanoparticles were uniformly distributed in the matrix of the Cu-Zn alloy. The tribological properties were evaluated by pin-on-disk wear tests, which revealed that, upon the addition of alumina nanoparticles, the coefficient of friction and the wear rate were reduced to 20% and 40%, respectively. The corrosion properties of the samples exposed to a 3.5wt% NaCl solution were studied using the immersion and potentiodynamic polarization methods, which revealed that the addition of alumina nanoparticles reduced the corrosion current of the nanocomposite by 90%.

留言板

2017年第24卷第4期

视频展示更多>

期刊特色

期刊荣誉更多>

友情链接更多>

留言板

2017年 第24卷 第4期

视频展示更多>

期刊特色

期刊荣誉更多>

友情链接更多>

2017年第24卷第4期