农残水平测试中数据多态性分析及指定值估计研究

对全国农残水平测试中毒死蜱、氯氰菊酯数据进行统计分析,在数据统计分布特征研究基础上,使用内核密度估计进行数据多态性分析,使用bootstrap模拟取样法对数据样本值重复取样,以获得稳健的水平测试样品待测物含量代表值估计、标准误差及置信区间描述,证明以bootstrap模拟取样法获取的均值与标准偏差作为有限单次样本代表值是合理、有效的,解决了四分位稳健统计方法对非正态多态分布代表值估计不稳定问题及取样理论中取样样本数限制的瓶颈,为能力验证计划指定值的获取提供了一种新方法。     

矿产品水分含量代表值Bootstrap模拟取样估计

在对矿产品水分含量基础统计学特征描述的基础上,采用内核密度估计对水分含量数据多态性进行了分析,根据双态分布的特点,使用Bootstrap模拟取样方法对试验样本值模拟重复取样,以多次Bootstrap模拟取样的均值与标准偏差作为矿产品水分含量有限样本代表值及标准偏差的稳健估计,实践证明Bootstrap模拟取样估计对矿产品水分含量代表值的估计是有效的,该项研究为矿产品水分含量代表值的准确评估提供了一种新方法.     

我国进口铁矿石有害元素含量代表值估计及整体特征分析

对我国进口铁矿石中的环境有害元素As、Cr、Cd、Pb、S的含量进行了总体统计分析,选用了四分位稳健统计分析及内核密度估计分别对铁矿中的有害元素As、Cr、Cd、Pb、S的含量的代表值进行估计,探讨了两种方法在代表值估计方面的特点,并使用主成分分析、因子分析等多元统计分析方法对有害元素的含量特征进行整体分类描述,确定了含量特征整体分类的主要有害元素,全面了解进口铁矿中涉及安全、环保等有害元素的质量状况.     

评定进口铁矿品质波动的方法研究

铁矿是我国传统的进口大宗散装货物之一。铁矿贸易通常以卸港的检验结果作为计价、结算的依据，为了更准确、科学、公正地检验以维护贸易双方利益，有必要对铁矿品质特性作进一步的研究。品质波动是交货批不均匀性的量度，是铁矿品质特性之一。品质波动直接影响到取样份数的确定，是整个铁矿检验过程的基础和关键。     

前置取样系统-高效液相色谱-电感耦合等离子体质谱法快速测定进口天然气中4种形态砷的含量

采用前置取样系统-高效液相色谱-电感耦合等离子体质谱法快速测定进口天然气中4种形态砷的含量。样品采用pH 4.3的10mmol·L~(-1)庚烷磺酸钠-10mmol·L~(-1)柠檬酸溶液吸收装置进行前处理,以Hypersil GOLD aQ色谱柱为分离柱,以上述pH 4.3的吸收剂混合溶液为流动相,采用电感耦合等离子体质谱法进行测定。4种形态砷的线性范围均为0.20~5.00μg·L~(-1),方法的检出限(3S/N)为0.044~0.066μg·L~(-1)。加标回收率为81.4%~97.4%,测定值的相对标准偏差(n=6)为3.2%~4.9%。     

痕量组份分析中一个误差控制问题

本文介绍了在测定矿石和矿物这种物料中的痕量组份时,由于痕量组份通常存在于离析的异质矿粒中,由取样量的不同所产生的误差,并提出了利用取样常数控制这种误差的方法。首先对被分析物料实验测定取样标准偏差,或进行一些有关的化学测试和物理测试,以确定取样常数。然后根据取样常数即可确定对于一预定标准偏差的最小取样量。     

计算机模拟取样确定标准物质的最小取样量

本文提出用计算机模拟取样对不同的取样量重复进行测试多次,统计其检测结果的标准偏差,做出标准偏差s对取样量m的拟合曲线,再计算最小取样量。设计的模式是一颗一颗地取样,这样不存在取样操作及测试过程带来的误差,操作是可行的,结果是可靠的。计算机运算速度快,参数转换方便,也可以取毫克甚至亚毫克样进行实验。只要有足够的岩矿鉴定的资料,可以模拟不同状态下的样品取样过程。     

氢化物发生-原子荧光光谱法测定载金炭中砷

提出了氢化物发生-原子荧光光谱法测定载金炭中砷的含量。采用硝酸和高氯酸分解载金炭样品,在盐酸(10+90)溶液中加入溶于5 g.L-1氢氧化钾溶液中的20 g.L-1硼氢化钾溶液使与溶液中砷(Ⅲ)离子反应生成氢化物。分析中采用载气及屏蔽气的流量依次为300 mL.min-1及900 mL.min-1。试样溶液中加入硫脲-抗坏血酸混合溶液作为还原剂。于仪器中引入取样量为1.0 mL的试样溶液,按选定的工作条件操作。砷(Ⅲ)的质量浓度在120μg.L-1以内与其对应的荧光强度呈线性关系,方法的检出限(3s)为0.05μg.L-1。对10及80μg.L-1砷标准溶液连续进样11次,测定值的相对标准偏差分别为1.2%和1.0%。应用此法对载金炭样品进行分析,测得砷的回收率在92.8%~101.9%之间。     

电感耦合等离子体原子发射光谱(ICP-AES)法测定进口酸泥中砷和汞

本文采用硝酸和盐酸的混合酸低温溶解酸泥后,运用ICP-AES法同时测定进口酸泥中砷和汞。建立了最佳实验方法,确立各项分析条件,砷的测定范围：0.01%~10%,汞的测定范围：0.005%~10%。测定值相对标准偏差小于3%,加标回收率在97%~105%之间,该方法简单快速,准确度高,完全满足酸泥中砷和汞的测定要求。     

X射线荧光光谱法在电气石标准物质均匀性检验中的应用

采用粉末压片–X射线荧光光谱法对电气石标准物质候选物的均匀性进行检验。选择Si,Al,Mg,Fe,Ca,Na等6个元素作为检验元素,样品以随机方式进行测量,根据单因素方差分析的F值和测定值的相对标准偏差(RSD)判定样品的均匀性,并计算了检测方法的误差和样品不均匀误差。结果表明,方差检验的F计算值在0.80~1.93之间,小于F临界值1.96,测定结果的相对标准偏差小于0.9%;检测方法相对标准偏差和样品不均匀度(以RSD表示)均小于0.5%,说明制备的电气石标准物质候选物具有良好的均匀性。通过公式计算,确定最小取样量为200 mg。该方法无需湿法分解样品,绿色环保,简便快速,测定结果精密度高。     

Determination of the oxidizing capacity of manganese ores

An accurate method is described for determining the amount of active oxygen in manganese ores, based on the oxidation-reduction reaction between the ore and arsenic(III) in presence of ammonium molybdate, followed by the back-titration of excess of arsenic(III) with cerium(IV), using osmium tetroxide as catalyst and Disulphine Blue V as indicator. A survey has been made of the applicability of this method to various pyrolusite ores containing less than 0.2% phosphorus. Aluminium(III), copper(II), iron(III), manganese(II), and molybdenum(VI) do not interfere. Up to 30% phosphorus(V) causes no interference.     

Determination of arsenic in ores, concentrates and related materials by continuous hydride-generation atomic-absorption spectrometry after separation by xanthate extraction

A recent graphite-furnace atomic-absorption method for determining approximately 0.2 mug/g or more of arsenic in ores, concentrates, rocks, soils and sediments, after separation from matrix elements by cyclohexane extraction of arsenic(III) xanthate from approximately 8-10M hydrochloric acid, has been modified to include an alternative hydride-generation atomic-absorption finish. After the extract has been washed with 10M hydrochloric acid-2% thiourea solution to remove co-extracted copper and residual iron, arsenic(III) in the extract is oxidized to arsenic(V) with bromine solution in carbon tetrachloride and stripped into water. Following the removal of bromine by evaporation of the solution, arsenic is reduced to arsenic(III) with potassium iodide in approximately 4M hydrochloric acid and ultimately determined to hydride-generation atomic-absorption spectrometry at 193.7 nm, with sodium borohydride as reductant. Interference from gold, platinum and palladium, which are partly co-extracted as xanthates under the proposed conditions, is eliminated by complexing them with thiosemicarbazide before the iodide reduction step. The detection limits for ores and related materials is approximately 0.1 mug of arsenic per g. Results obtained by this method are compared with those obtained previously by the graphite-furnace method.     

Determination of arsenic in ores, concentrates and related materials by graphite-furnace atomic-absorption spectrometry after separation by xanthate extraction

A method for determining approximately 0.2 mug/g or more of arsenic in ores, concentrates and related materials is described. After sample decomposition arsenic(V) is reduced to arsenic(III) with titanium(III) and separated from iron, lead, zinc, copper, uranium, tin, antimony, bismuth and other elements by cyclohexane extraction of its xanthate complex from approximately 8-10M hydrochloric acid. After washing with 10M hydrochloric acid-2% thiourea solution to remove residual iron and co-extracted copper, followed by water to remove chloride, arsenic is stripped from the extract with 16M nitric acid and ultimately determined in a 2% nitric acid medium by graphite-furnace atomic-absorption spectrometry, at 193.7 nm, in the presence of thiourea (which eliminates interference from sulphate) and palladium as matrix modifiers. Small amounts of gold, platinum and palladium, which are partly co-extracted as xanthates under the proposed conditions, do not interfere.     

ADSORPTION CAPACITY OF ACTIVATED CARBON FIBER FABRIC IN CYANIDE LEACHING LIQUOR OF GOLD ORES

Adsorption capacity of ACFF in cyanide leaching liquor of gold ores was studied withcyanide leaching liquor of gold ores, containing various kinds of ions. The adsorbed leaching liquorwas analyzed by atomic emission spectroscopy and colorimetric method. The contents of variouskinds of ions in ACFF were determined with X-ray photoctron spectroscopy. ACFF not onlyadsorbed gold but also adsorbed arsenic, nickel, zinc, calcium, sulphur, bismuth, copper, iron. silverand cyanide anion. Atomic percentage of C and those of O, N, Zr, Fe increase and decreaserespectively with the increase of the layer depth, while those of Ca, Au, Ag keep constant.     

ADSORPTION CAPACITY OF ACTIVATED CARBON FIBER FABRIC IN CYANIDE LEACHING LIQUOR OF GOLD ORES

1. INTRODUCTION Reclamation of gold in liquid of gold with activated carbon fiber (ACF) is reported. ACF possessed numerous advantages, such as high adsorption capacity, great adsorption rate and high recovery of gold. It was generally considered tha…     

便携式X射线荧光光谱法同时测定氧化锌富集物中锌铁氯镉砷

氧化锌富集物的进口能弥补我国锌矿资源的不足,但要求ZnO>50%、Fe<10%、Cl<8%、Cd<0.25%、As<0.6%。目前常采用YS/T 1171.1～10-2017《再生锌原料化学分析方法》检测氧化锌富集物中锌铁氯镉砷含量,该系列检测方法均需要繁琐的湿法样品前处理,测量过程较为冗长,不能满足氧化锌富集物大量进口时快速通关的需求。故实验建立了采用便携式X射线荧光光谱法(PXRF)同时测定氧化锌富集物中锌铁氯镉砷的方法。采用YS/T 1171.3-2017和YS/T 1171.5-2017方法对氧化锌富集物样品进行定值,然后选取21个含量具有梯度的氧化锌富集物样品作为校准样品,建立起各元素X射线荧光强度值与含量的校准曲线。各曲线相关系数在0.8164～0.9999,方法检出限为0.013%～1.95%,各元素的相对标准偏差(RSD,n=11)均小于0.05%。采用本方法和化学方法分别检测氧化锌富集物样品,各元素的本方法检测值与化学分析方法检测值的相对误差均小于20%。本方法能应用到口岸现场进口氧化锌富集物快速筛查,检测一个样品仅需1分钟测量时间,极大地加快了进口氧化锌富集物通关速度。     

The determination of Fe,Zn and Pb in Zn-Pb ores by energy-dispersive X-ray fluorescence method

Energy dispersive X-ray fluorescence method for the determination of iron /3.5–26% of Fe/, zinc /0.5–9% of Zn/ and lead /0.05–5% of Pb/in zinc-lead ores containing arsenic has been worked out. In order to eliminate the interelement effect intensity correction equation had been proposed. The relative standard deviation of the determination varies from 3.6 to 9.2% depending on the element.     

Determination of tin in ores, iron, steel and non-ferrous alloys by atomic-absorption spectrophotometry after separation by extraction as the iodide

A simple and moderately rapid method for determining 0.001% or more of tin in ores, concentrates and tailings, iron, steel and copper-, zinc-, aluminium-, titanium- and zirconium-base alloys is described. After sample decomposition, tin is separated from the matrix elements, except arsenic, by toluene extraction of its iodide from a 3M sulphuric acid-1.5M potassium iodide medium containing tartaric and ascorbic acids. It is finally back-extracted into a nitric-sulphuric acid solution containing hydrochloric acid to prevent the formation of an insoluble tin-arsenic compound and the resultant solution is evaporated to dryness. Tin is subsequently determined by atomic-absorption spectrophotometry in a nitrous oxide-acetylene flame, at 235.4 nm in a 10% hydrochloric-0.5% tartaric acid medium containing 250 mug of potassium per ml. Co-extracted arsenic does not interfere. Results obtained by this method are compared with those obtained spectrophotometrically with gallein after the separation of tin by iodide extraction.