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.     

Determination of trace elements in high purity gold by high resolution inductively coupled plasma mass spectrometry

Trace elements were determined in high purity gold by high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS). Sample were decomposed by aqua regia. To overcome some potentially problematic spectral interference, measurements were acquired in both medium and high resolution modes. The matrix effects due to the presence of excessive HCl and Au were evaluated. The optimum conditions for the determination was tested and discussed. The standard addition method was employed for quantitative analysis. The detection limits range from 0.01μg/g to 0.28μg/g depending on the elements. The method is accurate, quick and convenient. It has been applied to the determination of trace elements in high purity gold with satisfactory results. Funded by the Hunan Provincial Natural Science Foundation of China(No. 05JJ40017) and Hunan Provincial Education Department of China (No. 07C029, 08C260)     

Trace amounts of impurities in electrolytic manganese metal by sector field inductively coupled plasma mass spectrometry

An analytical method, using sector field inductively coupled plasma mass spectrometry （SF-ICP-MS） for rapid simultaneous determination of Be, Na, Mg, Si, Ca, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, As, Sn, Sb, Pb and Bi in electrolytic manganese metal, was described. At the beginning, the samples were decomposed by HNO3 and H2504, and then analyzed by SF-ICP-MS. Most of the spectral interferences could be avoided by measuring in different mass resolution modes. The matrix effects due to the excess of sulfuric acid and Mn were evaluated. Correction of matrix effects was conducted by using the internal standard elements. The optimum condition for the determination was investigated and discussed. The detection limit is in the range of 0.001-0.169 gg/L. The current method is applied to the determination of trace impurities in electrolytic manganese metal. And experiments show that good results can be obtained much faster, more accurately and conveniently by current method.     

微波消解ICP—MS法测定水产品中铝含量

采用密闭微波消解水产品,在优化微波消解条件的基础上,建立微波消解-电感耦合等离子体质谱（ICPMS）法测定水产品中铝元素的方法。以Sc作内标,线性范围：0-300μg／L（r=0．9995）,回归方程：y=2945．8x＋46535,方法检出限为0．90μg／L,RSD=2．7％（n=6）。该方法简单快速,准确度好、精密度高,是测定水产品中铝含量的一种有效分析方法。通过对水产品中铝含量的检测分析,为水产品的食用安全性提供了检测数据,同时也可为水产品的养殖和加工业的质量控制提供借鉴。     

微波消解-ICP-MS法测定PET瓶中的锑

采用HNO3-H2O2微波消解电感耦合等离子体质谱法测定PET瓶中的锑。测定结果的相对标准偏差为1.4%,检出限为0.001 8mg/L。该方法具有简便、快速、准确、灵敏度高等优点。经测定5个PET瓶样品中锑的总量均偏高,建议使用钛系催化剂逐步取代锑系催化剂以降低对人身及环境可能造成危害的风险。     

ICP—AES法测定易拉罐铝合金中的有害元素

研究了电感耦合等离子原子发射光谱(ICPAES)测定食品包装铝合金中常见有害元素的方法,考察了铝基体对测定的影响,按GB356285标准方法进行了浸泡实验.方法的检出限为0.5×10     

Dry coal fly ash cleaning using rotary triboelectrostatic separator

More than 80 million metric tons of fly ash is produced annually in the U.S. As coal combustion by-product. Coal fly ash can be converted to value-added products if unburned carbon is reduced to less than 2.5%. However, most of fly ash is currently landfilled as waste due to lack of efficient purification technologies to separate unburned carbon from fly ash. A rotary triboelectrostatic separator has been developed and patented recently at the University of Kentucky with unique features. Several fly ash samples have been used to understand the effects of major process parameters on the separation performance. The results show that compared to existing triboelectrostatic separators, the rotary triboelectrostatic separator has significant advantages in particle charging efficiency, solids throughput, separation efficiency, applicable particle size range.     

Preparation of biological aerated filter media with coal fly ash and coal gangues

A novel kind of filter media has been studied using in biological aerated filter process which is produced by waste coal fly ash and coal gangues.The specific surface area and sum of braking and ware rate are viewed as the main factor for determining preparation conditions,including calcination temperature (in the range of 900 ℃ to 1250 ℃),proportion of coal gangue (in the range of 0 to 25%) and soaking time (in the range of 0 to 40 min).The effects of sintering conditions on the main property parameters are researched and the reasons have been analyzed.Considered with all factors,the optimum technological conditions are chosen as follows:the calcination temperature is 1050 ℃ ;the soaking time is 10 min and the proportion of coal gangue is 5%.When at these condition,the main property parameters of the filter media in the technological conditions are 1.6 m 2 /g for the specific surface area and 2.96 % for sum of braking and are rate respectively.Finally,a scanning electron microscope is used for analyzing the microstructure of the filter media.     

粉煤灰廉价吸附剂资源化利用的现状和对策分析

粉煤灰是燃煤电厂排放的固体废弃物,其大量堆积造成环境污染和资源浪费,对粉煤灰的资源化利用近年来引起人们的广泛关注.粉煤灰呈多孔结构,具有良好的吸附性能,可用作处理废水中污染物质的廉价吸附剂.本文对粉煤灰吸附剂在水污染治理中的研究现状进行分析和总结,在此基础上,根据粉煤灰的组成和性质,提出粉煤灰资源化利用的方向为化学处理提高吸附性能和成型造粒以利于其工业化利用.     

Three-dimensional discharge simulation of inductively coupled plasma (ICP) etching reactor

More and more importance has been attached to inductively coupled plasma (ICP) in semiconductor manufacture. For a deep understanding of the plasma discharge process in the etching reactor, this study made a three-dimensional simulation on the Ar plasma discharge process with the commercial software CFD-ACE, which is according to the real experiment conditions and data supplied by North Microelectronic Corporation. The error of the simulation results is in the range of ±20% with credibility. The numerical results show that the three-dimentional spatial distribution of electron density is reduced from the chamber center to the wall. The distribution of electron density, electron temperature and power deposition is related to the shape and placement of the coil.     

逆向涡流等离子体降解飞灰中二恶英的研究

利用氮气逆向涡流非平衡等离子体反应器,进行医疗垃圾焚烧飞灰中二恶英的降解.考察氮气逆向涡流非平衡等离子体放电特性,从而获得反应器稳定的工作条件.在实验过程中分别测量处理后飞灰中和尾气中的二恶英质量分数,分析利用氮气逆向涡流非平衡等离子体反应器降解飞灰中二恶英的效果,初步探索二恶英的降解机理.结果表明,切向进气体积流量是影响放电电弧特性的关键因素,增大切向进气体积流量,可以提高电弧放电的稳定性;逆向涡流等离子体对飞灰中二恶英有明确的降解作用,单位质量飞灰中PCDD/Fs总质量的平均降解率为49.6%,总毒性当量I-TEQ平均降解率为62.3%,飞灰中PCDFs比PCDDs更容易降解.     

电感耦合等离子体法测定桂郁金中的微量元素

以桂郁金为原料,经浓硝酸-双氧水(30％)处理后用微波消解样品,以电感耦合等离子体发射光谱法(ICP-AES)测定其中的Na、B、Mg、Al、P、Ca、Ti、Zn、Ba、Mn、Fe、K含量,Li、Be、Tl、Mo、Pb、Cd、Sr、V、Cr、Cu、Ni、Co等元素的含量则以电感耦合等离子体质谱法(ICP - MS)测定.方法的准确性用国家一级标准物质GBW - 10015、GBW - 10020对比分析证实.试验结果表明:桂郁金中富含Fe、Mn、Ti等微量元素,其中Fe含量最高为360μg/g,而Be、Cd、Mo、TI、V含量较低,均低于1μg/g.该法快速简便、准确率高、精密度好,完全可以满足样品中元素含量测定要求.     

不同组成粉煤灰吸附亚甲基蓝的性能和机理研究

从三个电厂取得三种不同组成和性质的粉煤灰,研究了粉煤灰对水溶液中亚甲基蓝的吸附性能和机理.结果表明,影响粉煤灰吸附的最重要的因素是粉煤灰粒度而不是C含量.三种粉煤灰对亚甲基蓝的吸附均符合二级吸附动力学模型,渭河、西郊和灞桥粉煤灰的二级吸附速率常数分别为5.580、4.149和2.204×10-2g.mg-1.min-1.吸附过程均由颗粒内扩散控制,渭河、西郊和灞桥粉煤灰的颗粒内扩散速率常数分别为0.067、0.109和0.160mg.g-1.min-1/2.亚甲基蓝浓度增加,粉煤灰对亚甲基蓝的吸附量增加;粉煤灰投加量增加,其对亚甲基蓝的吸附量减小;随着溶液pH值增加,粉煤灰对亚甲基蓝的吸附量先增加后略有下降.     

Main influencing factors and coal fly ash characteristics of gasoues fuel reburning process

The unburned carbon concentration in fly ash and the influence of main factors on the reduction of nitrogen oxides during gaseous fuel reburning process were experimentally studied in a 36 kW down-fired furnace when five typical coals with different qualities were served as the primary fuel. It is found that the higher nitrogen oxide reduction efficiency can be obtained by reburning process when the coal used as the primary fuel contains more volatile matter. But under the optimizational operating conditions, both above 50% nitrogen oxide reduction and low carbon loss can be achieved by reburning process even though the primary fuel is the low-volatile coal. The experimental results show that the reasonable residence time in reburn zone is 0.6–0.9 s, the appropriate gaseous reburn fuel percentage is 10%—15% and the optimal average excess air coefficient in reburn zone is 0.8–0.9. These results extend the ranges of the key parameter values for reburning process with respect to that the low-volatile coals are used as the primary fuel. Foundation item: Projects(50806025; 50721005) supported by the National Natural Science Foundation of China     

Determination of impurity elements in MnZn ferrites by inductively coupled plasma mass spectrometry

An inductively coupled plasma mass spectrometry(ICP-MS) method was developed for the determination of Na, Mg, Al,K, Ca, Ti, Cr, Co, Ni, Cu, Ga, As, Mo, Ag, Cd and Pb in MnZn ferrites. The sample was digested by HNO3+HCl with microwave digestion followed by dilution with ultrapure water, then the above 16 impurity elements in the solution were analyzed directly by ICP-MS. The impurity elements were introduced by the helium gas or hydrogen gas into the octopole reaction system(ORS) to eliminate the polyatomic interferences caused by the high salty matrixes. The matrix effect was minimized through matrix matching,and Be, Y and Rh were used as internal standard elements. The working parameters of the instrument were optimized. The results show that the method has good precision and high accuracy. The detection limits for the investigated elements are in the range of0.9-37.5 ng/L, the relative standard deviation of each element is within 1.1%-4.8%, and the recovery of each element is 90%-108%.     

电感耦合等离子体-质谱法同时测定渔业用水中9种元素

建立同时测定渔业用水中锑、砷、镉、铬、铅、汞、镍、硒、硼等9种元素的电感耦合等离子体质谱（ICP-MS）的分析方法。采用碰撞反应界面技术消除多原子离子干扰。在线添加内标,基体匹配标准外标法定量。结果表明：9种元素线性关系良好（r≥0.999 0）。方法检出限为0.003~0.066μg/L,相同加标量下回收率在97.7%~102.7%之间,相对标准偏差为1.25%~3.30%。该方法简便、准确,完全能够满足渔业用水中微量元素的检测要求。     

延边地区茵陈蒿叶中微量元素的研究

为考察延边地区茵陈蒿叶中微量元素的分布状况,采用电感耦合等离子体质谱(ICP-MS)法测定了25个采样点茵陈蒿叶中Cr、Fe、Cu、Zn、As、Se、Cd、Sb、Pb元素的含量.结果表明:在各采样点都检测出Cr、Fe、Zn、Cd,而Cu、As、Se、Sb、Pb在有的采样点处未能检测到,且各元素的含量差异较大(Fe和Zn的含量较高),这可能与采样点的气候、地质、水质、土壤、植物群落等因素有关.     

大气感应耦合等离子体炬管的设计与仿真实验

为提高大气感应耦合等离子体射流加工装置的工作稳定性,设计一种依靠单一零件定位各层介质管的分体式炬管,并研究炬管内等离子体的传热与流动特性. 利用COMSOL Multiphysics仿真分析发现,等离子体的环形加热和流体淤塞回流现象是导致炬管在使用后出现热损伤和刻蚀损伤的主要原因,选用陶瓷材料作为内管和中层管并调整感应线圈的位置,可有效延长炬管的使用寿命. 使用CCD相机实时监控等离子体射流的形态,发现射频功率(P_w)、工作气流量(Q₂)、冷却气流量(Q₃)与射流的整体长度(L)和半高宽度(W)均呈线性递变关系,P_w、Q₂与Q₃的值过高或过低都会导致等离子体射流的形态波动增大. 实验结果表明:当P_w、Q₂ 与Q₃分别设置为900~1 000 W、650 mL·min^-1、16 L·min^-1时,该分体式炬管可产生稳定性较高的等离子体射流,其L值与W值的波动可分别控制在0.50 mm与0.25 mm内,适用于熔石英等光学表面的加工.     

利用热等离子体熔融垃圾焚烧飞灰

为了评价垃圾焚烧飞灰的热等离子体熔融处理效果, 研究SiO2和CaO对重金属固化效果和重金属毒性浸出特性的影响. 在飞灰中添加一定比例的SiO2和CaO, 配置成不同的配灰样品, 利用纯氩热等离子体在1 400～1 500 ℃下, 对飞灰及配灰进行熔融玻璃化的实验研究, 分别利用X射线能量色散谱仪(EDX)、场发射扫描电子显微镜(FSEM)、X射线衍射仪(XRD)和毒性浸出方法(TCLP)分析飞灰和熔渣的化学组成、微观结构、晶相组成和重金属毒性浸出特性. 结果表明, 热等离子体熔融所得熔渣为无定形的玻璃体, 重金属浸出质量浓度均远低于毒性标准. SiO2和CaO的添加都可以改善重金属固化效果, CaO比SiO2对Cu、Zn、Cd和Pb挥发的抑制效果更好. SiO2的添加可以改善熔渣中重金属的浸出特性, 而CaO的作用与之相反.