Phase formation and composition of Mn–Zn ferrite powders prepared by hydrothermal method

1999 ◽  
Vol 14 (1) ◽  
pp. 204-208 ◽  
Author(s):  
Wen-Hao Lin ◽  
Shiuh-Ke Jang Jean ◽  
Chii-Shyang Hwang

Mn–Zn ferrite powders were prepared by hydrothermally aging the coprecipitates of compositional metal ions using ammonium hydroxide as a precipitant. R value (alkalinity) = (moles of added OH−)/[(moles of added Zn2+) × 2 + (moles of added Mn2+) × 2 + (moles of added Fe3+) × 3] was introduced to adjust the amount of added ammonia. The results show that the R value of starting suspension and hydrothermal time have similar and dominant effects on the composition, spinel ratio, and crystallite size of synthesized powders. From the analyses of x-ray diffraction (XRD) and inductively-coupled plasma (ICP), it notes that no α–Fe2O3 peak in the XRD patterns of powders synthesized at R = 2–3, 150 °C × 2 h, may be due to lower degree of crystallinity and less amount of α–Fe2O3 existing in these powders. Both the increase of hydrothermal time and of R value can promote the crystallinity of powders and also cause a significant loss of zinc, hinting that in the hydrothermal process, the loss of zinc may play a crucial role in the crystallinity of hydrothermally synthesized powders.

2012 ◽  
Vol 05 ◽  
pp. 291-298 ◽  
Author(s):  
N. S. Tabrizi ◽  
A. Schmidt-Ott

Spark discharge is a technique for producing nanoparticles from conductive materials. We had previously used this method to produce Au - Pd bimetallic nanoparticles with a mean diameter of around 6 nm. In this study we changed the operating parameters (e.g. spark energy and frequency, carrier gas type and flow rate) and analyzed the generated particles for their structures and compositions. X ray diffraction (XRD) patterns showed evidence of the formation of alloy phase in all the samples. Compositional analysis by Inductively Coupled Plasma (ICP) revealed that the average mixing ratio was influenced by the polarity, the spark frequency and the gap distance between anode and cathode.


2020 ◽  
Vol 9 (1) ◽  
pp. 1586-1593
Author(s):  
Tingting Yan ◽  
Shengwen Zhong ◽  
Miaomiao Zhou ◽  
Xiaoming Guo ◽  
Jingwei Hu ◽  
...  

Abstract The extraction of Li from the spent LiFePO4 cathode is enhanced by the selective removal using interactions between HCl and NaClO to dissolve the Li+ ion while Fe and P are retained in the structure. Several parameters, including the effects of dosage and drop acceleration of HCl and NaClO, reaction time, reaction temperature, and solid–liquid ratio on lithium leaching, were tested. The Total yields of lithium can achieve 97% after extraction process that lithium is extracted from the precipitated mother liquor, using an appropriate extraction agent that is a mixture of P507 and TBP and NF. The method also significantly reduced the use of acid and alkali, and the economic benefit of recycling is improved. Changes in composition, morphology, and structure of the material in the dissolution process are characterized by inductively coupled plasma optical emission spectrometry, scanning electron microscope, X-ray diffraction, particle size distribution instrument, and moisture analysis.


2006 ◽  
Vol 118 ◽  
pp. 639-644
Author(s):  
Hye Sung Kim ◽  
Su Chak Ryu

Hydroxyapatite (Ca10(PO4)6(OH)2, HAp) powders is synthesized using the mixed powders of CaCO3 refined from oyster shells and phosphoric acid (H3PO4-98%, Daejung) as starting materials. The characteristic evaluation and chemical analysis of the synthesized powders is performed by X-ray diffraction (XRD), Fourier-transformed infra-red spectroscopy (FT-IR), and inductively-coupled plasma atomic emission spectroscopy (ICPAES). XRD analysis of synthetic powder by heat treatment at 1300°C for 2hrs shows only HAp peaks corresponding to stoichiometric HAp. It is confirmed by ICP-AES test that impurities such as Zn, In, Ti, Ba, Cd, Pb, and Mn, is not detected at all, but small amounts of Ti and Be is observed (0.099ppm Ti and 0.002ppm Ba). Variation of bone density is measured by giving medication of HAp powder with drinking water into human body continuously for three month. After the medication, the bone density is higher than the medication before. This means that HAp powder made from this process can be used as improver of bone density.


2012 ◽  
Vol 9 (4) ◽  
pp. 1788-1795 ◽  
Author(s):  
Olushola S. Ayanda ◽  
Olalekan S. Fatoki ◽  
Folahan A. Adekola ◽  
Bhekumusa J. Ximba

In this study, fly ash was obtained from Matla power station and the physicochemical properties investigated. The fly ash was characterized by x-ray fluorescence, x-ray diffraction, scanning electron microscopy, and inductively coupled plasma mass spectrometry. Surface area, particle size, ash and carbon contents, pH, and point of zero charge were also measured. The results showed that the fly ash is alkaline and consists mainly of mullite (Al6Si2O13) and quartz (SiO2). Highly toxic metals As, Sb, Cd, Cr, and Pb as well as metals that are essential to health in trace amounts were also present. The storage and disposal of coal fly ash can thus lead to the release of leached metals into soils, surface and ground waters, find way into the ecological systems and then cause harmful effect to man and its environments.


Author(s):  
Shiying Zhang ◽  
Lei Zhang ◽  
Yueyao Zhong ◽  
Guodong Wang ◽  
Qingjun Xu

High crystal quality GaN nanorod arrays were fabricated by inductively coupled plasma (ICP) etching using self-organized nickel (Ni) nano-islands mask on GaN film and subsequent repaired process including annealing in ammonia and KOH etching. The Ni nano-islands have been formed by rapid thermal annealing, whose density, shape, and dimensions were regulated by annealing temperature and Ni layer thickness. The structural and optical properties of the nanorods obtained from GaN epitaxial layers were comparatively studied by high-resolution X-ray diffraction (HRXRD), Raman spectroscopy and photoluminescence (PL). The results indicate that damage induced by plasma can be successfully healed by annealing in NH3 at 900 °C. The average diameter of the as-etched nanorod was effectively reduced and the plasma etch damage was removed after a wet treatment process in a KOH solution. It was found that the diameter of the GaN nanorod was continuously reduced and the PL intensity first increased, then reduced and finally increased as the KOH etching time sequentially increased.


2018 ◽  
Vol 56 ◽  
pp. 23-33
Author(s):  
Mar Rey-Solé ◽  
Maria Pilar García-Argüelles ◽  
Jordi Nadal ◽  
Xavier Mangado ◽  
Anders Scherstén ◽  
...  

The l’Hort de la Boquera site is located in the northeastern part of Iberia and its stone tool assemblage includes up to 25,000 flint artefacts. This is the first approach to the analysis of the raw material through an archaeopetrological study. Results were obtained by use of mineralogi¬cal techniques: macroscopic and petrographic analysis, Scanning Electronic Microscopy (SEM), Micro-Raman and X-Ray diffraction (XRD); additionally, Laser Ablation Inductively Coupled Plasma Mass Spectrometry was applied. It has been possible to discriminate at least four flint categories, the ‘Evaporitic flint type’ (with two local subvarieties – ‘Common evaporitic’ and ‘Garnet’ varieties) that comes from local outcrops of the Ulldemolins Complex, and two flint types that had their origin further afield: the ‘Charophyta flint type’ (coming from the Torrente de Cinca Unit) and the ‘Dark flint type’ (from the La Serra Llarga Formation).These results make this study the most comprehensive analysis of raw materials that has been carried out in the area so far


2006 ◽  
Vol 71 (11) ◽  
pp. 1153-1160 ◽  
Author(s):  
Chang Hu-Yuan ◽  
Feng Li ◽  
Li. Hua ◽  
Bin Zhang

As prepared carbon nanotubes were pretreated with nitric acid (CNTs-HNO3) or ammonia (CNTs-NH3). Fourier transform infrared spectroscopy (FTIR) measurements showed that the surface of the nanotubes was functionalized with carboxylic and hydroxyl functional groups after the acid treatment and that basic groups containing nitrogen, such as N-H and C-N, were introduced to the surface of the nanotubes after the ammonia treatment. X-Ray diffraction analysis implied that the nickel residue in the CNTs was effectively removed by acid treatment. However, the nickel residue was only partially eliminated by ammonia pretreatment. NiB amorphous catalysts supported on CNTs-HNO3 and CNTs-NH3 were prepared by the impregnation-chemical reduction method and characterized by transmission electron microscopy (TEM), as well as inductively coupled plasma (ICP) spectroscopy and studied in the selective hydrogenation of acetylene. TEM measurements showed that a high density NiB particles of about 9 nm were homogeneously dispersed on the CNTs-NH3. However, NiB particles (13-23 nm)with amean size of 16 nm were scattered on the CNTs-HNO3.As a result, the activity and selectivity of NiB/CNTs-NH3 were higher than those of NiB/CNTs-HNO3 in the selective hydrogenation of acetylene.


2021 ◽  
Vol 116 ◽  
pp. 5-14
Author(s):  
Marta Babicka ◽  
Magdalena Woźniak ◽  
Kinga Szentner ◽  
Sławomir Borysiak ◽  
Krzysztof Dwiecki ◽  
...  

The aim of this study was to compare parameters of nanocellulose obtained by two different procedures: hydrolysis with ionic liquids (1-allyl-3-methylimidazolium chloride and 1-ethyl-3-methylimidazolium acetate) and hydrolysis with ionic liquids in combination with hydrolysis using a cellulolytic enzyme from Trichoderma reesei. Avicel cellulose was treated with two ionic liquids: 1-allyl-3-methylimidazolium chloride (AmimCl) and 1-ethyl 3-methylimidazolium acetate (EmimOAc). In the two-step hydrolysis cellulose after treatment with ionic liquids was additionally hydrolyzed with a solution of enzymes. In order to characterize the obtained material, the following analyses were used: infrared spectroscopy, X-ray diffraction and dynamic light scattering. The results indicated that cellulose obtained by two-step nanocellulose production methods (first hydrolysis with ionic liquids and then with enzymes) showed similar parameters (particle size, XRD patterns and degree of crystallinity) as the material after the one-step process, i.e. hydrolysis with ionic liquids.


Author(s):  
Nitu Bhatnagar ◽  
Avani Pareek

The present study is aimed to observe the difference in the Physico-Chemical characteristics of the marketed and formulated bhasma samples through X-Ray Diffraction analysis (XRD), Dynamic Light Scattering (DLS), Zeta potential, Thermo-Gravimetric analysis (TGA), Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray analysis (EDAX), apart from organoleptic methods. Inductively Coupled Plasma Mass Spectroscopy (ICPMS) analysis was also done to observe the presence of trace and heavy metals so that the safety of all these samples could be ensured. XRD shows variation in oxide nature of zinc as well crystallite size in all bhasma samples. DLS and SEM results show difference in particle size of marketed bhasma samples as compared to formulated Yashada bhasma. EDAX and ICPMS also confirm the alteration in elemental composition of all these bhasma samples. Thus, it can be concluded that these ayurvedic medicines should be prepared strictly using the formulation methods as mentioned in the Ayurvedic texts. This will help the prepared products to adopt the inherent quality of the ancient system of medicine, which shall be useful and devoid of any side effects for human consumption.


Minerals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 402 ◽  
Author(s):  
Qin ◽  
Cao ◽  
Wei ◽  
Wang ◽  
Liu

This paper reports the mineral compositions and geochemical characteristics of the No. 5-2 high-sulfur coal (Taiyuan Formation) from Dongpo Mine, Weibei Coalfield, Shaanxi, Northern China via transmitted and reflected light microscopy, scanning electron microscope equipped with an energy-dispersive X-ray spectrometer (SEM-EDS), X-ray diffraction (XRD), inductively coupled plasma mass spectrometry (ICP-MS), and X-ray fluorescence spectrometry (XRF). We also confirmed the input of intermediate-felsic volcanic ashes into the Taiyuan Formation coals in Dongpo Mine, Weibei Coalfield. The results show that Dongpo coals are enriched in Ga and Li compared to the average values for world hard coals, and they are depleted in Al2O3 compared to Chinese coals. The coal low temperature ash contains kaolinite, illite, quartz, calcite, pyrite, and to a lesser extent, chlorite, plagioclase, dolomite, ankerite, and apatite. The concentration anomalies of Ga and Li in No. 5-2 high-sulfur coal were not caused by the Benxi Formation Bauxite, but by the influence of multiple geological factors. The Middle Proterozoic moyite from the Yinshan Oldland led to the slightly higher Ga and Li contents of the No. 5-2 coal than those in world hard coals. Input of synchronization volcanic ash, injection of hydrothermal fluids during the syngenetic or early diagenetic stages and influence of seawater further contributed to the Ga and Li enrichment of the No. 5-2 coal.


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