Simultaneous determination of seven impurities in high-purity cobalt oxide by ICP-AES after matrix separation using 1-nitroso-2-naphthol as a precipitant

A method was developed for the simultaneous determination of seven trace impurities (Cd, Mn, Pb, Zn, Cu, Fe and Ni) in high purity cobalt oxide by ICP AES. The matrix effect was eliminated by preci pitation with 1 nitroso 2 naphthol. The matrix effect of cobalt on the absorptions of trace impurities, the effects of reaction time, pH value, dosage of precipitant on the formation of cobalt 1 nitroso 2 naphthol complex, the effects of hydrochloric acid on the stability of this complex and masking of elements were studied. Recoveries of the impurities in spiked sample are from 90% to 110% with a precision of 1.1% 5.0% RSD. The detection limits of the seven elements are in the range of 0.01 0.24μg/g. The method can be applied to the analysis of high purity cobalt metal, cobalt oxide and other cobalt compounds.

Synthesis of High Purity SiC Powder for High-resistivity SiC Single Crystals Growth

High purity silicon carbide （SIC） powder was synthesized in-situ by chemical reaction between silicon and carbon powder. In order to ensure that the impurity concentration of the resulting SiC powder is suitable for high-resistivity SiC single crystal growth, the preparation technology of SiC powder is different from that of SiC ceramic. The influence of the shape and size of carbon particles on the morphology and phase composition of the obtained SiC powder were discussed. The phase composition and morphology of the products were investigated by X-ray diffraction, Raman microspectroscopy and scanning electron microscopy. The results show that the composition of resulting SiC by in-situ synthesis from Si/C mixture strongly depends on the nature of the carbon source, which corresponds to the particle size and shape, as well as the preparation temperature. In the experimental conditions, flake graphite is more suitable for the synthesis of SiC powder than activated carbon because of its relatively smaller particle size and flake shape, which make the conversion more complete. The major phase composition of the full conversion products is β-SiC, with traces of α-SiC. Glow discharge mass spectroscopy measurements indicated that SiC powder synthesized with this chemical reaction method can meet the purity demand for the growth of high-resistivity SiC single crystals.

Equilibrium between titanium ions and high-purity titanium electrorefining in a NaCl-KCl melt

TiClx （x=2.17） was prepared by using titanium sponge to reduce the concentration of TiCl4 in a NaCl-KCl melt under negative pressure. The as-prepared NaCl-KCl-TiClx melt was employed as the electrolyte, and two parallel crude titanium plates and one high-purity titanium plate were used as the anode and cathode, respectively. A series of electrochemical tests were performed to investigate the influence of electrolytic parameters on the current efficiency and quality of cathodic products. The results indicated that the quality of cathodic products was related to the current efficiency, which is significantly dependent on the current density and the initial concentration of titanium ions. The significance of this study is the attainment of high-purity titanium with a low oxygen content of 30× 10^-6.

Quantification of trace amounts of impurities in high purity cobalt by high resolution inductively coupled plasma mass spectrometry

A An analytical method using high resolution inductively coupled plasma mass spectrometry （HR-ICP-MS） for rapid simultaneous determination of 24 elements （Be, Mg, A1, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, As, Se, Mo, Ag, Cd, Sn Sb, Ba, Pt, Au, and Pb） in high purity cobalt was described. Sample digestions were performed in closed microwave vessels using HNO3 and HCI. The matrix effects because of the presence of excess HCI and Co were evaluated. The usefulness of high mass resolution for overcoming some spectral interference was demonstrated. The optimum conditions for the determination were tested and discussed. The standard addition method was employed for quantitative analysis. The detection limits were 0.016-1.50 ].tg·g^-1, the recovery ratios were 92.2%-111.2%, and the RSD was less than 3.6%. The method was accurate, quick, and convenient. It was applied to the determination of trace impurities in high purity cobalt with satisfactory results.

Quantification of Trace Amounts of Impurities in High Purity Cobalt by High Resolution Inductively Coupled Plasma Mass Spectrometry

An analytical method using high resolution inductively coupled plasma mass spectrometry （HR-ICP-MS） for rapid simultaneous determination of Be, Mg, Al, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, As, Se, Mo, Ag, Cd, Sn, Sb, Ba, Pt, Au and Pb in high purity cobalt was described. Sample digestions were performed in closed microwave vessels using HNO3 and HCl. The matrix effects due to the presence of excess HCl and Co were evaluated. The usefulness of high mass resolution for overcoming some spectral interference was demonstrated. The optimum conditions for the determination was tested and discussed. Correction for matrix effects, Sc, Rh and Bi were used as internal standards. The detection limits is 0.003-0.57 μg/g, the recovery ratio is 92.2%-111.2%, and the RSD is less than 3.6%. The method is accurate, quick and convenient. It has been applied to the determination of trace impurities in high purity cobalt with satisfactory results.

Determination of Trace Impurities of Rare Earth Elements in High Purity Yttrium Oxide by ICPMS

Determination of trace rare earth elements(REEs)in 99. 999% purity yttrium oxide using the inductively coupled plasma mass spectrometric technique (ICPMS) has been developed. Instrumental parameters and factors affecitng analytical results have been studied and then optimized.Samples are analyzed directly following an acid digestion without separation or preconcentration and with limit of detection of 0. 003～0. 02 ng/ml, precision of ±5. 4%(cofficient of variation)and recovery of 90～115%. Correction for isobaric interferences from oxide ions and hydroxide ions is made mathematically. Special internal standard procedures are used to compensate drift in metal:metal oxide ratios and sensitivity. The analytical results of several samples are accurate as compared with inductively coupled plasma atomic emission spectrometry (ICPAES) and spark source mass spectrometry (SSMS).

Direct Determination of Trace Impurities in High Purity Zinc Oxide by High Resolution Inductively Coupled Plasma Mass Spectrometry

The determination of trace impurities in high purity zinc oxide by high resolution inductively coupled plasma mass spectrometry （ HR-ICP-MS ） was investigated. To overcome some poteutially problematic spectral iuterference, measurements were acquired in both middle and high resolution modes. The matrix effects due to the presence of excess HCl and zinc were evaluated. The optimum conditions for the determination were tested and discussed. The standard addition method was employed for quantitative analysis. The detection limits ranged from 0.02μg/ g to 6 μg/ g depending on the elements. The experimental resalts for the determination of Na, Mg, Ca, Cr, Mn, Fe, Co, Ni, Cu, Mo, Cd, Sb and Pb in several high purity zinc oxide powders were presented.

PREPARATION OF HIGH-PURITY AND NANOMETER-SCALE BARIUM TITANATE POWDERS

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Effect of trace yttrium on cube texture of high-purity aluminum foils

The effect of trace yttrium on cube texture of high purity aluminum foils has been investigated by means of orientation distribution functions (ODFs). The results show that a small addition of yttrium to high purity aluminum brings about a considerable increment of the cube texture, and it reduces the content of R texture. The rare earth yttrium may combine with the other impurities to form the metallic compounds, such as FeYAl 8, Fe 6YAl 6, Fe 4YAl 8 and Si 2YAl 2. When the precipitation of these particles in the matrix is nearly completed and the Fe concentration in the matrix becomes low, the cube texture can develop well and the R texture can be suppressed. [

Numerical simulation and experimental verification of axial-directional crystallization purification process for high-purity gallium

A transient numerical model was applied to simulating the axial-directional crystallization purification(ADCP) process of gallium(Ga) raw material at different coolant temperatures(Tc), and the evolutions of melt/crystal(m/c) interface shape, temperature distribution and thermal stresses were simulated and analyzed. The results showed that the m/c interface shape, temperature distribution, and thermal stress in the Ga material were determined by the Tc in the crystallizer during the ADCP process. The temperature gradient and thermal stress in the grown Ga crystal increased with decreasing Tc. At Tc=15 ℃, the m/c interface shape was flat, and the temperature gradient was ideal. Therefore, the Ga materials with lower thermal stresses and suitable m/c interface shape, and an ideal efficiency of impurity removal were obtained. The purity of Ga reached 6 N standard by using ADCP process repeated 6 times at Tc of 15 ℃. The results of the simulation showed good agreement with the experimental results.

Preparation of high-purity indium by electrorefining

The application of indium requires high purity indium as material, and the high purity indium has been prepared by electrorefining. The selection and preparation of electrolyte in electrorefining indium were investigated, and the effect of component of electrolytic solution on electrolytic refining was also studied. Compared with electrolyte of InCl3-HCl, electrolyte of In2（SO4）3-H2SO4 has higher stability and lower corrosivity, electrolytic solution can be heated at low temperature, and bath is open and simple, which makes operation more convenient. The results show that the voltage can be kept at 0.30.5 V, and the content of indium can exceed 99.999% when the content of indium（Ⅲ） ion and sodium chloride are 80120 g/L. The bench-scale test of electrolysis was carried out, and the product of indium reaches the national standard of 99.999% high purity indium.

Effect of Al addition on corrosion behavior of high-purity Mg in terms of processing history

In this study,the effects of Al addition on the corrosion behavior of pure Mg with controlled impurity contents were systematically analyzed according to the processing history.The results revealed that the corrosion behavior of high-purity Mg-Al alloys is strongly related to changes in the microstructure,including theβphase and Al-Mn or Al-Fe phases,and the protectiveness of the surface film according to the Al content and processing history.In the as-cast alloys,the corrosion rate increased due to the increase ofβphase as the Al content increased,but in the as-extruded alloys,the corrosion rate,which was high due to intermetallic compounds caused by impurities in the low Al alloy,decreased as the Al content increased,and then increased again.This is due to the combined effect of the increase of theβphase and decrease of the impurity effect,and the increase of the dissolved Al content.The results suggest that it is necessary to analyze the effect of alloying elements on the corrosion behavior of pure Mg with information concerning the impurity content and processing history.

Preparation of high-purity bismuth by sulphur deleadization in vacuum distillation

The feasibility of separation of impurities in refined bismuth and sulphur deleadization with vacuum distillation was studied theoretically. Experimental studies on sulphur deleadization were carried out under vacuum. The influences of amount of sulphur, distillation temperature, vacuum degree and distillation time on deleadization were investigated and an optimal technical condition was achieved. The content of lead in refined bismuth can be decreased from 30 μg/g to 0.21 μg/g, which has reached the level of “5N” high-purity bismuth. Other impurities in refined bismuth can be also removed effectively under certain conditions.

The Potential of Quartzitic Veins in SW Cameroon for High-Purity Quartz

High-purity quartz (HPQ), the prime source of silica, is increasingly considered a strategic mineral in the world market because it is the raw material for special applications in high-tech industries owing to its unique physical and chemical properties. The expected growth in demand for HPQ implies that more sources have to be found. This is the primary motivation for this study which targets the Supe area, SW Region of Cameroon. The structural occurrences of quartz veins were mapped and samples collected. The chemical nature and textural features of these samples were subsequently analyzed by X-ray tomography, scanning electron microscopy (SEM), and electron microprobe analysis (EMPA). Three deformation events, D1 - D3 are recorded. D1 is marked by the development of the strong S1 foliation defined by the gneissic layering and schistosity. D2 is a NE-SW ductile to brittle sinistral shear that controlled the formation of tension gashes that served as subsequent pathways for quartz-rich hydrothermal fluids to circulate and eventually precipitate quartz. The presence of rutile, tourmaline, and mica inclusions in the Supe veins affects the purity of the quartz. However, quartz can be treated to improve its quality. Taking into consideration the nine determinant trace elements used to classify HPQ, three (Li, P, and B) are below detection limits, Al concentrations are within the HPQ, quartz market standard, and average natural abundance;Ti values are high above all three standards in all except one sample, while Na, Ca, K, and Fe values fluctuate, thus classifying one of the samples as high purity quartz and the others as low purity quartz. These veins define tension gashes which usually occur in an echelon arrangement covering a large surface area, suggesting that more of such veins probably exist in the Supe area. Consequently, the quality and potential quantity of HPQ veins in this area suggest a high potential for HPQ exploration in the region.

Effects of electric field on recrystallization texture evolution in cold-rolled high-purity aluminum sheet during annealing

The effects of an external DC(direct current)electric field on recrystallization texture evolution in the cold-rolled aluminum sheets with 99.99%purity were investigated by means of X-ray diffraction techniques.The cold-rolled high-purity aluminum sheets were annealed for 60 min at 200,300 and 400℃,respectively with and without an external DC electric field of 800 V/mm.The results show that with DC electric field,the recrystallization cube texture is strengthened at the stage of grain growth. Possible reason for the strengthening of the recrystallization cube texture with the applied electric field may be attributed to both selected nucleation and selected growth of cube oriented crystal nuclei.

The Status Quo and Development Trend of High-purity Gold Sputtering Targets

This article gives a brief introduction to manufacturers and markets of sputtering targets as well as the manufacturing technology thereof. Then, it analyzes the application of high-purity gold sputtering targets in the fields of integrated circuit, information storage, flat panel display, etc. Based on the above, the article analyzes the processing development trend for the high-purity gold sputtering targets in aspects of ultra-high purity, manufacturing technology, analysis and testing technologies.

Fujian Normal University Made Research Progress in Separation of High-purity Ethylene with Low Energy Consumption

In July 2021,the research team of Fujian Normal University(FMU)has for the first time constructed the hydrogen-bonded organic framework materials(HOFs)via self-assembly by hydrogen bonding of simple organic molecules to accomplish the efficient separation of ethylene/ethane at work temperature,which would promote the practical application of HOFs in the area of industrial separation with high efficiency and low energy consumption.

Karachi provides a good opportunity for low-cost generation advancement of cotton for breeding and seed purity

Cotton is said to be the backbone of Pakistan's economy.Cotton production is facing many challenges such as climate change,pests and diseases,and competition from food crops(Ali et al.,2019).One of the major issues faced by cotton production is seed purity,as cotton is often cross-pollinated,therefore breeders are hard to maintain seed purity.For example,non-Bt cotton varieties are often contaminated with Bt seeds which is an important limiting factor.Another important consideration in cotton breeding is rapid generation advancement.

Atomic Emission Spectrographic Analysis of High-purity Gallium with Prior Partial Dissolution of Matrix

An improved method has been developed for enriching and determining trace In,Pt,Sn,Co,Hg,Pb,Ni, Bi,Pd,Cu and Ag in high-purity gallium.Sample was treated by PDM(partial dissolution of matrix)with HCl(11mol/L)-HNO_3(0.5mol/L)to a small residue of which Ga was then removed by extraction with 1 ml isopropyl ether.The concentrated impurities were determined by AES procedure.The recoveries for the ele- ments at the range of 0.02～0.2 μg are 95～103％;the relative standard deviations for determined impurities overa rangeofn.10^(-7)～n·10^(-8)％ are 4.3～12％;the detection limit of most elements can reach n·10^(-7)～ n·10^(-8)％ level with the exception of Hg and Pt.This method has been successfully used to analyze many sam- ples sent by factories and institutes.