Institutional Repository of Institute of Process Engineering, CAS (IPE-IR）
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Performance Enhancement of FeS2 as Cathode Material for Thermal Batteries by Ball Milling After Adding Nano Vacancy-Containing WS2
No full textAs the most commonly used cathode material for thermal batteries, FeS2 has the advantages of low price and abundant resources. However, the preparation of FeS2 by hydrothermal method is complicated, and FeS2 prepared by solid-phase method has a larger particle size. In this study, surface nanoscale FeS2 was synthesized using a milling method, and add nano WS2 with sulfur vacancies (WS2-Vs) to enhance thermal stability and conductivity. The results showed that the thermal decomposition temperature of FeS2 after adding 3% nano WS2-Vs ball milling for 4 h (FeS2@3%WS2-Vs-4h) was 100 °C higher than that of FeS2 ball milling for 4 h (FeS2–4h). In addition, the step-pulse discharge showed that single cell with FeS2@3%WS2-Vs-4h sample as the cathode active material has a lower internal resistance. Therefore, the discharge specific capacity of FeS2@3%WS2-Vs-4h is increased by 10.5% compared to pristine FeS2. The FeS2 doped with nano WS2-Vs retained the small particle size after ball milling, which not only did not excessively reduce the thermal stability, but also effectively improved its electrical conductivity with the increase of the discharge depth during the discharge process, thus achieve the effect of killing two birds with one stone. This work provides a novel cathode additive for thermal battery
Influence of polyethylene glycol inhibitors on properties of electroplated copper layer
No full textAbstract
Inhibitor is one of the important additive components in electrodeposited copper. As a common inhibitor, the concentration of PEG8000 has an important effect on electrodeposited copper. In this article, different concentrations of polyethylene glycol-based organic additives were added to the acidic electrolyte, and their effects on the electrochemical behavior of copper electrodeposition were investigated by galvanostatic test, cathodic polarization curve test, and cyclic voltammetry test. In addition, the surface morphology and crystallographic orientation of the obtained copper layers were analyzed by SEM and XRD. The results show that with the increase of PEG8000 concentration in the electroplating solution system, the inhibitory effect of PEG8000 on electroplating copper becomes stronger, and the copper surface density obtained by electroplating is better
One-step synthesis of t-ZrO2 from Zircon using magnesium-calcium minerals as stabilizers
No full textStabling crystal structure at room temperature is a classic problem in the study of Zirconium dioxide (ZrO2). However, there are few investigations on making tetragonal zirconia (t-ZrO2) in one step at a low cost. In this research, t-ZrO2 is synthesized using a one-step high-temperature solid-state sintering technique with magnesite, dolomite, and limestone as stabilizers and zircon as the raw material. The most suitable stabilizers and reaction conditions are determined, and the mechanism of zirconia structure stabilization is explored. The findings suggest that magnesite has the lowest effect as a crystal structure stabilizer, whereas dolomite and limestone are pretty close, but dolomite introduces more impurities. The ideal reaction conditions were 60% mol limestone at 1500 degrees C. The stabilization mechanism is zirconia gap correction, according to XRD and EPR data. The characterization of the SEM demonstrates that the heat treatment temperature and stabilizer had little effect on the morphology of t-ZrO2. When limestone was introduced throughout the process, EDS data revealed that some amorphous silicon-calcium compounds occurred in the product. The focus of follow-up work will be on how to lessen the impact in this area. This research offers vital reference value for reducing the cost of the synthetic t-ZrO2 process
A new strategy for additive manufacturing ODS steel using Y-containing gas atomized powder
No full textThe 3D printing technology is gradually applied on oxide dispersion strengthened (ODS) steels to address its processing issue and prepare complex components for generation IV nuclear reactor. However, the nanoparticles always aggregate and coarsen during the printing process because of the severe repining behavior in the high temperature melt. This leads to a large degradation of the strengthening effect of nanoparticles. This study proposes a strategy of in situ synthesis of nanoparticles in ODS steel during the printing process by using pre alloyed powder with controlling the partial pressure of oxygen to overcome the abnormal growth behavior of nanoparticles. After printing, a large number of nanoparticles were in situ formed and distributed uniformly in the ODS steel. The average size and number density of nanoparticles were 21.09 nm and 4.1 +/- 0.5 x 10(21)/m(3), respectively. As compared with the majority of 3D printed ODS steels from mechanical alloyed powder, the in situ formed nanoparticles in this study exhibit the combination of smaller size, higher number density, and better distribution homogeneity and size uniformity. This provides an outstanding secondary strengthening effect and produces ODS steel with the UTS and YS of printed ODS steel are 725 and 673 MPa, respectively. In addition, the microstructural characterization and formation mechanism of nanoparticles in this newly printed ODS steel are also given and discussed in detail
Fabrication of gamma-Al2O3 Nanoarrays on Aluminum Foam Assisted by Hydroxide for Monolith Catalysts
No full textHeat distribution and good adhesion of the washcoat on monolith catalysts are critical to improving catalytic activity and long-term stability. Compared with cordierite, metal foam presents a high thermal conductivity coefficient. Also, the availability of "washcoat" in situ grown on metal substrates opens the door to eliminating the problem of coating peeling. Generally, hydrothermal or thermal methods are used for the fabrication of in situ grown washcoat on metal substrates. In this research, the aluminum foam monolith vertically aligned Al2O3 nanowire array is successfully prepared at ambient temperature in an alkaline solution for the first time. Furthermore, the Pt-loaded Al2O3 nanowire array (0.5 gPt/Lmonolith) is applied to C2H4 degradation. The catalyst converts 90% C2H4 at 147 degrees C with a gas hourly space velocity (GHSV) of 20,000 h-1. And a little decrease (1%) is observed in catalytic activity, even in 15 vol % water vapors. The catalysts show good thermal stability and water resistance property over 36 h at 300 degrees C. Above all, this study presents a simple way of in situ growth of washcoat on metal-substrate monolith with potentially scaled manufacturing. And the monolith catalyst shows good catalytic performance on C2H4, which can be applied for volatile organic compound treatment
New insight into oxidative roasting and leaching for NdFeB waste
No full textNdFeB waste is an essential rare earth (RE) resource, which is the unique solid waste to realize large-scale RE recovery via HCl preferential dissolution method. However, the challenges of low oxidation efficiency and high acid consumption are seriously hindering RE efficient recovery. Herein, the mechanism between the phase structure transformation of roasting RE solid waste and RE elements' leaching behavior was first explored. The results showed the oxidation efficiency of NdFeB oil sludge (NOS) was improved from 2.5 % to 99.2 % with the temperature increasing. And a leaching model was proposed: Dense Layer Structure (= 600 degrees C). The analysis of the leaching model indicates the dense oxide layer and the RE insoluble structure (RE insoluble NdFeO3 phase and particle adhesion) will affect the leaching efficiency of RE elements. Based on the oxidation efficiency, XPS, SEM, Raman, FTIR, and EDSmapping analysis, an external oxide layer was verified on the microparticle of roasted NOS. Furthermore, the corresponding mechanism is discussed, and the improvement strategies are put forward. This study will supply a new insight into the theoretical basis for efficient and low HCl consumption recycling of NdFeB waste
NaAlO_2硫酸法合成高质量拟薄水铝石
No full text拟薄水铝石常应用于石油化工、环保等行业,是活性氧化铝的前驱体、分子筛、黏结剂等的重要原料。近年来,我国石油化工行业面临严峻挑战,原油劣质化、重质化,产品轻质化、清洁化和成本高等问题愈加突出,迫切需求拟薄水铝石的低成本生产制备方法。本工作采用NaAlO_2硫酸法结合动态调控pH合成了物相纯、具有特定孔结构的拟薄水铝石产品。通过XRD, BET, SEM, NMR等表征分析得出,硫酸法在pH=7、75℃下反应0.5 h可合成比表面积、孔容和平均孔径分别为341.01 m~2/g, 0.41 cm~3/g, 4.78 nm的γ-AlOOH,在极端合成条件会生成Al(OH)_3杂相。动态调控pH可以有效促进产品相纯化和孔结构改善。在70℃、NaAlO_2和Al_2(SO_4)_3流速15 mL/min、反应10 min、老化10 min的条件下,杂相Al(OH)_3向γ-AlOOH转变,可将含有28.2%的Al(OH)_3杂相经过摆动后降至3.1%,纯化后的γ-AlOOH结晶度增强,其中27Al以六配体形式存在,比表面积、孔容和平均孔径分别增加到358.88 m~2/g, 0.70 cm~3/g和7.83 nm
Co对WO_3-Co_3O_4预还原的影响及其产物碳化性能
No full text为避免超细WC-Co粉体制备过程中形成对烧结过程及其产物带来不利影响的η相(Co_6W_6C或Co_3W_3C),提出了WO_3-Co_3O_4预还原至WO_2-Co,再深度还原碳化至WC-Co的技术路线。主要考察了600℃,H_2-C_2H_4-Ar气氛条件下,Co含量及钴源粒径对WO_3-Co_3O_4预还原过程的影响规律,并对预还原产物进行了深度还原碳化性能测试。结果表明,Co的存在可催化C_2H_4裂解析出H_2和C,显著加快WO_3预还原速率,且随着Co含量增加其预还原速率显著增加;乙烯析碳速率和析碳量也随Co含量增加而增加。钴源粒径对WO_3还原速率和C_2H_4析碳速率有显著影响,本实验体系下,纳米钴源体系中C_2H_4析碳速率大约是微米钴源体系的2倍;同时,纳米钴源体系中WO_3也具有较快的还原速率。8%Co含量的预还原产物在950℃、甲烷分压1.25%条件下焙烧60 min,可获得无η相的WC-Co复合粉体
精馏技术在电子化学品制备中的应用进展
No full text综述了连续精馏、间歇精馏、亚沸精馏、加减压精馏、共沸精馏、萃取精馏、反应精馏、低温精馏等多种精馏技术在电子化学品制备中的应用现状,并对精馏技术在电子化学品制备过程的应用前景做出了展望
废旧电池电解液回收及高值化利用研发进展
No full text随着技术进步和规模生产效应的呈现,锂离子电池成本快速下降,促使其在诸多领域获得广泛的应用。锂离子电池富含能源金属和战略元素,其使用寿命一般为6～8年,如不对退役后的锂电池进行妥善回收处理,将造成巨大资源浪费和严重环境污染。科研人员已对富含有价金属元素的正极材料的回收开展了相对较多的研究。作为电池四大关键材料之一,电解液富含碳酸酯溶剂和六氟磷酸锂(Li PF6),如能将其回收并转化为高值产品将具有重大环保意义及经济效益。本文归纳了已报道的电解液回收技术和工艺,以便有效推动该领域的健康发展,并对其面临的挑战及未来发展趋势进行分析和展望