Spectrometric determination of arsenic in zinc concentrates and other lead-zinc smelter roasted products

In the zinc electro-winning process arsenic is considered a "problem impurity". Its determination should be fast, accurate and simple to help in-plant control for its effective removal during the iron purification stage. Such a method is presented which is applicable to all zinc concentrates, lead concentrates and smelter residues, with various compositions and matrix components. Results for certified reference samples and for recovery of standard additions are very good.     

Spectrochemical determination of trace bismuth and lead in iron-base and high-temperature superalloys

A method is presented for determination of lead and bismuth in steels and superalloys, based on co-precipitation with manganese dioxide followed by optical-emission or atomic-absorption measurements. The limit of determination is about 0.0001% and the relative standard deviation is 4% at the 0.002% level.     

The determination of bismuth in serum and urine by electrothermal atomic absorption spectrometry

A method for the determination of bismuth in serum and urine is presented. The method includes 1 + 1 dilution of the sample with 1 mM EDTA followed by charring in a graphite furnace under an oxygen atmosphere. The use of oxygen results in the formation of more homogeneous bismuth salts (probably bismuth oxides) during charring, and more efficient burning of the protein and organic components of the sample matrix. The procedure formulated is a standard additions method and is verified for serum and urine samples. The method reduces matrix interferences, gives a detection limit of 0.05 μg l^-1, and has a relative standard deviation of less than 5% for bismuth in the reference range of 2.6–6.0 μg l^-1. The method displays a recovery accuracy of 91, 96, and 100% for urine, serum, and aqueous samples, respectively.     

Determination of volatile hydride-forming metals in steel by atomic absorption spectrometry

A scheme of analysis is presented for the determination of arsenic, antimony, bismuth, lead, selenium, tellurium and tin in steel by evolution of their volatile hydrides and subsequent atomic absorption spectrometry in an argon—hydrogen-entrained air flame. The method is rapid and applicable to a wide range of steels. Detection limits in steel of 1 p.p.m. for arsenic, antimony, bismuth, selenium and tellurium, 2 p.p.m. for tin and 7 p.p.m. for lead are reported. There is some interference in the determination of lead from copper and nickel, but the method could become a viable alternative to existing procedures in the determination of lead in steels of low alloy content, and in irons. Accuracy and precision data are presented.     

Spectrophotometric determination of bismuth in concentrates and non-ferrous alloys by the iodide method after separations by diethyldithiocarbamate and xanthate extraction

A method for determining 0.0001-1% of bismuth in copper, molybdenum, lead, zinc and nickel sulphide concentrates is described. After sample decomposition, bismuth is separated from matrix and other elements, except lead and thallium(III), by chloroform extraction of its diethyldithiocarbamate complex, pH 11.5-12.0, from a sodium hydroxide medium containing citric acid, tartaric acid, EDTA and potassium cyanide as complexing agents. Following back-extraction of bismuth into 12M hydrochloric acid and reduction of thallium to the univalent state, bismuth is separated from co-extracted lead and thallium by chloroform extraction of its xanthate from a 2.5M hydrochloric acid-tartaric acid-ammonium chloride medium. Bismuth is then determined spectrophotometrically, at 337 or 460 nm, as the iodide. Interference from lead, which is co-extracted in mug-amounts as the xanthate and causes high results at 337 nm, is eliminated by washing the extract with a hydrochloric acid solution of the same composition as the medium used for extraction. The proposed method is also applicable to lead-, tin- and copper-base alloys.     

Physicochemical modeling of the behavior of impurities in bismuth oxide in the chemical distillation of the sample matrix

The physicochemical modeling of the behavior of impurities in the course of their preconcentration by the chemical distillation of the sample matrix consisting of granules of a solid solution of impurities in bismuth oxide was carried out. It was supposed that the distillation process is conducted in a kinetic mode. The results of calculations by the model are compared with the earlier results of modeling of the behavior of impurities in distilling a heterophase sample consisting of matrix (bismuth oxide) granules and granules of impurity oxides. The experimental data and results of calculations by the model agree well.     

X-ray photoelectron spectroscopic study of the mechanism of palladium matrix modification in the electrothermal atomic absorption spectrometric determination of lead and bismuth

The mechanism of palladium matrix modification is studied for the determination of lead and bismuth by graphite-furnace atomic absorption spectrometry. The binding energies of the charring products for lead and bismuth in the presence or absence of palladium obtained at the initial stage of atomization were measured. The binding energies indicated the formation of PbPd and BiPd bonds, thus explaining the increase in appearance temperatures of lead and bismuth in the presence of palladium.     

Direct determination of trace metajls in solid samples by atomic absorption spectrometry with electrothermal atomizers: Part 3. Application of an Autosampler to the Determination of Silver,Bismuth, Cadmium and Zinc in Steels

A modification of the Varian-Techtron autosampler ASD-53 to accept solid samples and to operate under non-isothermal as well as isothermal conditions is described. The performance of the autosampler is illustrated for the determination of silver, bismuth, cadmium and zinc in high- and low-alloy steels with the CRA 90 graphite cup and isothermal atomization. Good agreement with certified or reported values was obtained, with relative standard deviations of 3.8–30%. Peak height and peak area evaluations were compared; the use of peak area values gives considerably better precision for silver, bismuth and cadmium. The non-specific absorption caused by the matrix was measured in the region 200–350 nm. For the resonance lines used, the background level was found to be 0.00–0.03 units (absorbance X seconds) depending on element and the age of the cup.     

Metal extraction in activation analysis

Our investigations have shown the perspectives of pyrometallurgical methods in activation analysis based on metal extraction (ME). The technique of rapid micromelting (MM) not requiring special equipment has been developed. It has been shown that in non-mixed liquid metal-molten salt systems different elements such as noble, rare and dispersed ones can be quantitatively extracted from geological samples to be analyzed into metal collectors (bismuth, lead, tin, copper, iron, etc.). The same meltings have been supposed for extraction into the ionic salt melts of the impurity elements from the analyzed metals.     

Stripping voltammetric determination of bismuth in raw gold ores

Stripping voltammetry was used to determine bismuth(III) in raw gold ores. The effect of some matrix elements, Cu(II), Au(III), Pt(IV), Pd(II), etc. on the current of bismuth(III) electrooxidation was studied. The conditions the extraction of bismuth(III) dithizonate with chloroform from a complex matrix are found. A procedure is developed for determining bismuth(III) in raw gold ores.     

Spectrophotometric determination of traces of several metals in ferrous and nonferrous metals and alloys after isolation by iodide extraction

Methods are presented for the determination of traces of lead, cadmium, indium, bismuth, copper, and antimony in most of the important metals and alloys used in industry. The trace metals are isolated by hexone extraction of their iodides from 5% hydrochloric acid solution and then determined spectrophotometrically. The attractive feature of the proposed procedures is that the method used for each of the trace metals is applicable to all of the matrix metals and alloys being considered.     

Simultaneous determination of copper, bismuth and lead by adsorptive stripping voltammetry in the presence of thymolphthalexone.

A novel, sensitive and selective adsorptive stripping procedure for simultaneous determination of copper, bismuth and lead is presented. The method is based on the adsorptive accumulation of thymolphthalexone (TPN) complexes of these elements onto a hanging mercury drop electrode, followed by reduction of adsorbed species by voltammetric scan using differential pulse modulation. The influences of control variables on the sensitivity of the proposed method for the simultaneous determination of copper, lead and bismuth were studied using the Derringer desirability function. The optimum analytical conditions were found to be TPN concentration of 4.0 microM, pH of 9.0, and accumulation potential at -800 mV vs. Ag/AgCl with an accumulation time of 80 s. The peak currents are proportional to the concentration of copper, bismuth and lead over the 0.4-300, 1-200 and 1-100 ng mL(-1) ranges with detection limits of 0.4, 0.8 and 0.7 ng mL(-1), respectively. The procedure was applied to the simultaneous determination of copper, bismuth and lead in the tap water and some synthetic samples with satisfactory results.     

Investigation of the sample characteristics needed for the determination of the origin of uranium-bearing materials

A set of 35 uranium ore and 10 yellow cake samples, collected worldwide from different mines and production sites, were analyzed for their impurity spectrum by ICP-MS. Pattern recognition techniques such as cluster analysis were applied to the data set in order to characterize samples with relation to their geographical origin. The results obtained show a clear relationship between samples taken from the same geological origin and constitute a satisfactory fingerprint for establishing the origin of the material. In addition to the impurity data, data on the isotopic composition of radiogenic lead is used to resolve ambiguity when impurity cluster analysis fails to deliver unambiguous origin data.     

Semi-automated method for the determination of bismuth in rocks

A rapid and accurate method for the determination of bismuth in rock samples is described. Automated equipment is used to generate bismuth hydride from solutions of rock samples prepared by digestion with a mixture of hydrofluoric and perchloric acids. The evolved hydride is carried to a heated quartz tube by a stream of argon, and the atomic absorption of bismuth recorded. Thiosemicarbazide and 1,10-phenanthroline are used as masking agents to minimize interferences from copper and nickel. As little as 20 ng Bi g^-1 can be determined; the average r.s.d. is 5.4%. Results obtained for six USGS standard rocks are in close agreement with the recommended values obtained by an isotope dilution technique.     

A highly selective procedure for the spectrophotometric determination of aluminium with 8-hydroxy-quinoline and its application to the determination of

Aluminium, hydroxyquinolate can be quantitatively extracted by chloroform from an ammoniacal solution containing hydroxyquinoline, complexone and cyanide. Likewise extracted are titanium, vanadium, tantalum, niobium, uranium, zirconium, gallium, antimony, bismuth, indium and traces of beryllium. Aluminium can be separated from the first five elements by an extraction in ammoniacal solution containing hydrogen peroxide.Zirconium, gallium, bismuth and antimony can be eliminated by a cupferron extraction and indium by extraction with diethyldithiocarbamate. Beryllium is eliminated by performing an extraction with hydroxyquinoline at pH 5. The proposed method enables a practically specific photometrical determination of aluminium. Applications are given of the determination of trace and higher amounts of aluminium in steels, non-ferrous alloys and in glass.     

Capabilities of femtosecond laser ablation ICP-MS for the major, minor, and trace element analysis of high alloyed steels and super alloys

Femtosecond laser ablation inductively coupled plasma mass spectrometry was used for the quantification of 23 metallurgical relevant elements in unalloyed, alloyed and highly alloyed steels, and super alloys. It was shown that by using scanning mode ablation with large ablation spot diameters (250 μm), stable and representative sampling can be achieved for the majority of elements, except for bismuth and lead. For Bi and Pb up to 46%, temporal relative standard deviation (TRSD) was encountered, whereas for most other elements, the TRSDs were below 10%. Calibration with matrix-matched and non-matrix-matched standards provided similar agreement within the uncertainty of the certified values. However, the non-matrix-matched standard-based quantification was more influenced by interferences rather than ablation- or excitation-related matrix effects. The method was validated using 34 certified reference materials. ⁵²Cr, ⁵¹V, or ⁵⁵Mn were used as internal standards due to the fact that the Fe concentration was not certified for the majority of reference materials. The determined concentrations for major and minor elements indicate that the total matrix internal standardization (100 wt.%) is applicable, which requires no knowledge about the steel samples prior to analysis.     

Simultaneous determination of bismuth and tellurium in steels by high power nitrogen microwave induced plasma atomic emission spectrometry coupled with the hydride generation technique

An annular-shaped, high power nitrogen microwave induced plasma (N₂-MIP) produced at atmospheric pressure by an Okamoto cavity, as a new excitation source for atomic emission spectrometry (AES), has been used for the simultaneous determination of bismuth and tellurium in steels with the hydride generation method. Under the optimized experimental conditions, the best attainable detection limits at the Bi I 195.389 nm and Te I 200.200 nm lines were 110 and 86 ng/ml for bismuth and tellurium, respectively. The linear dynamic ranges for bismuth and tellurium were 300 to 30,000 ng/ml. The presence of several diverse elements was found to cause a more or less depressing interference with the proposed technique. When bismuth and tellurium in steels were determined, a large amount of Fe(III) in the solution caused a severe depressing interference, while the presence of Fe(II) showed little or no significant interference. Of the several interference-releasing agents examined, l-ascorbic acid was found to be the most preferable to reduce Fe(III) to Fe(II) prior to hydride generation. The concentrations of bismuth and tellurium in steels were determined by the proposed technique. The results obtained by this method were in good agreement with their certified values.     

Solid phase extraction and graphite furnace atomic absorption spectrometric determination of ultra trace amounts of bismuth in water samples

A simple and reliable method for the selective extraction and determination of bismuth in water as well as alloy samples using octadecyl bonded silica cartridge modified with cyanex 301 and graphite furnace atomic absorption spectrometry is described. Extraction efficiency and influence of sample matrix, optimum amount of extraction ligand, type and least amount of proper eluent and flow rates were evaluated. The limit of detection of the proposed method is 0.01 ng ml(-1). The influence of potential interfering cations in water samples on the recovery of bismuth was investigated. The method was successfully applied to the extraction and determination of bismuth in natural water and alloy samples.     

Ionisation corrections in the determination of impurities in solids by means of the M.S.7 mass spectrometer

Determinations on the M.S.7 mass spectrometer of a number of trace elements have been made on standard samples, whose composition had previously been determined by independent techniques and which had been tested for homogeneity. From the ratios of the apparent contents, as determined on the M.S.7, to the true contents, a correction factor is obtained. This factor depends largely on ionisation phenomena at the source, but also includes other errors. It has been shown that for a number of elements such factors depart significantly from unity and that the value for a particular impurity depends on the matrix element. The variation of the factors showed no direct connection with the electrical parameter of the source. Cooling of the electrodes produced a significant reduction in the magnitude of the correction factor in the cases of only very few elements. In the absence of independent standards of similar composition to the sample, any figures obtained by mass spectrometry must be treated with caution unless the ionisation factor for the particular impurity in the particular matrix is known. This is especially the case for certain elements (e.g., S, Zn, Pb) known to be liable to give high factors.