Sulphur speciation of PM10 samples by XANES spectroscopy

Sulphur K-edge X-ray absorption near edge structure (XANES) spectroscopy was used to identify sulphur compounds in PM10 samples collected simultaneously at two sites with different environmental situations in the province of Trieste (NE of Italy), during summer and winter seasons respectively. The first site is an industrial site located near a steel mill plant and the second is a coastal site. The sulphur speciation at the industrial site has shown the presence of the following sulphur compounds in both seasons: organic compounds (thiophenes or Polycyclic Aromatic Sulphur Heterocycles — PAHs) and sulphates while in the winter season sulphites were also present. In the coastal site organic compounds (thiophenes or PASHs) and sulphate were found during winter season, moreover bisulphates were found during summer season. Relative percentages of the different sulphur compounds have shown that sulphate is the most abundant form of sulphur in the industrial site samples during both seasons and in the coastal site sample collected during the winter season (> 98%); in the coastal site sample collected during the summer season the relative percentages of bisulphate and sulphate were around 40% and 60% respectively.      

Fast steel-cleanness characterization by means of laser-assisted plasma spectrometric methods

Laser-assisted plasma spectrometry is a palette of analytical techniques (L-OES, LA-ICP-MS) capable of fast spatially-resolved elemental analysis in the micrometer range. For fast estimation of the occurrence in steel samples of non-metallic inclusions, which degrade the material's technical properties, simultaneous OES detection and sequential ICP-MS detection were compared. Histograms were obtained for the intensity distribution of the acquired signals (laser pulse statistics). The skewness coefficient of the histograms for Al (indicator of non-metallic inclusions) was found to be clearly dependent on the fraction of non-metallic inclusions in the case of scanning L-OES. For LA-ICP-MS less clear dependence was observed, which was influenced by the acquisition characteristics. In fact, less measurement throughput limited for LA-ICP-MS the counting statistics to an extent that overrides the benefit of higher detection power as compared to L-OES.     

CID型ICP光谱仪分析钢中稳定夹杂物的8种组分含量

本文探讨了以CID作检测器的全谱直读ICP光谱仪测定钢中稳定夹杂物化学组分的方法，并从试液制备、谱线选定、介质影响、方法检出限和精密度等方面进行了讨论，样品测定结果较好，满足了工作的需要。     

高速钢牌号元素的看谱检测方法

看谱检测是利用看谱仪，双照光谱图和分析标志表，对样品发射的光谱线进行目视评定，实现检测样品元素及含量的一门应用技术，本文采用光栅波长同步光谱图和定量分析标志表，对高速钢牌号中Ｗ、Ｍｏ、Ｃｒ，Ｖ，Ｃｏ元素进行定量分析试验，其测定值符合ＧＢ２２２－８４标准。本方法具有现场检测，操作简便，成本低，不取样，不损坏样品，精度高，快速，分析范围宽及分析不受钢中元素干扰等特点。     

Determination of diffusible and total hydrogen concentration in coated and uncoated steel using melt and solid extraction techniques: Part I

It is essentially to know the bulk hydrogen concentration in various types of steel because it indicates the amount of hydrogen that can be trapped by the different alloys of steel. This information leads to more knowledge about the interactions of steel alloys with hydrogen containing environment and stability of the steel material during usage. To get this information precise analytical methods are necessary.Although the analytical methods for the determination of hydrogen in steel samples are often discussed, there are no sufficient systematic studies as far as the influence of the sample preparation on the analytical value is concerned.The influence of different sample preparation methods on the hydrogen determination in steel at parts per million levels by melting extracting methods has been investigated in this work. The hydrogen was measured by thermal conductivity and infrared detection. The flat sheet samples were zinc coated and uncoated ferritic types of steel. The zinc coating was removed by chemical (acid etching) and physical (paper scraping) methods. Dichloromethane acetone/ethanol, tetrachloromethane and alkaline steel cleaner (Ridoline C72) have been used for cleaning the surface of uncoated samples. The results of the total hydrogen content obtained by applying the different methods were evaluated.     

Adsorptive stripping voltammetric determination of antimony

A new method is described for the determination of antimony based on the cathodic adsorptive stripping of Sb(III) complexed with 2′,3,4′,5,7-pentahydroxyflavone(morin) at a static mercury drop electrode (SMDE). The reduction current of the adsorbed antimony complex was measured by 1.5th-order derivative linear-sweep adsorption voltammetry. The peak potential is at −0.51 V (vs. SCE). The effects of various parameters on the response are discussed. The optimized analytical conditions were found to be: supporting electrolyte, chloroacetic acid (0.04 mol/l, pH 2.3); concentration of morin, 5×10⁻⁶ mol/l; accumulation potential, −0.25 V (vs. SCE); scan rate, 100 mV/s. The limit of detection and the linear range were 7×10⁻¹⁰ mol/l and 1.0×10⁻⁹3.0×10⁻⁷ mol/l Sb(III) for a 2-min accumulation time, respectively. This method has been applied to the determination of Sb(III) in steel and brass samples and satisfactory results were obtained. The adsorptive voltammetric characteristics and composition of the Sb(III)–morin complex were studied.     

Studies of the adsorption of oligomers and surfactants on carbon and steel surfaces in a hydrocarbon medium

The adsorption isotherms for an (amino) terminally functionalised, oligomeric polyisobutylene and for a series of alkylpropoxylate or alkylbutoxylate surfactant molecules on carbon particles, in isooctane, have been obtained. The isotherms on carbon show that the oligomer is the most strongly adsorbing species. The surfactants show some evidence of forming aggregates on the carbon surface at higher concentrations. Analysis of the adsorption isotherms indicate that the size of these aggregates is similar on the carbon particles and on steel balls, reported previously, but that in some cases the actual adsorbed amounts on the two surfaces differ considerably. Ellipsometric studies carried out in situ on steel surfaces in isooctane show that only the polymer gives a relatively thick adsorbed layer. Addition of surfactant reduces the adsorption of the oligomer. There are some differences between the thickness values reported previously using AFM, compared to those found in the current work using ellipsometry, but in both cases it would seem that some degree of multilayer adsorption is occurring for the oligomer on steel in isooctane.     

Cathodic protection of ships in brackish water

The operation of ice-going vessels depends on the condition of the hull surface. Corrosion increases the roughness of ship hull, which increases drag and fuel consumption. The hull surface smoothness is maintained by using coatings and cathodic protection. The cold brackish water is different from ocean water as it has lower salt content, lower conductivity, and higher concentration of dissolved oxygen. These factors mean that the design of the cathodic protection system for ship hulls requires different design values, such as protection current density and protected length, than those given in cathodic protection standards. In this paper, we have estimated the protection current density with polarization curves and the protected length by using Wagner number and dimension and conductivity scaling. In brackish water the protection current density was two times that in ocean water. The protected length in brackish water varied between 10 and 15% of that in ocean water. In poorly conducting brackish water, the current capacity of a cathodic protection system is used mostly for overcoming the solution resistance, not for delivering protection current.     

Spectrophotometric method for determination of vanadium and its application to industrial, environmental, biological and soil samples

The very sensitive, fairly selective direct spectrophotometric method for the determination of trace amount of vanadium (V) with 1,5-diphenylcarbohydrazide (1,5-diphenylcarbazide) has been developed. 1,5-diphenylcarbohydrazide (DPCH) reacts in slightly acidic (0.0001–0.001 M H₂SO₄ or pH 4.0–5.5) 50% acetonic media with vanadium (V) to give a red–violet chelate which has an absorption maximum at 531 nm. The average molar absorption coefficient and Sandell’s sensitivity were found to be 4.23×10⁴ l mol⁻¹ cm⁻¹ and 10 ng cm⁻² of V^v, respectively. Linear calibration graph were obtained for 0.1–30 μg ml⁻¹ of V^v: the stoichiometric composition of the chelate is 1:3 (V: DPCH). The reaction is instantaneous and absorbance remain stable for 48 h. The interference from over 50 cations, anions and complexing agents has been studied at 1 μg ml⁻¹ of V^v. The method was successfully used in the determination of vanadium in several standard reference materials (alloys and steels), environmental waters (potable and polluted), biological samples (human blood and urine), soil samples, solution containing both vanadium (V) and vanadium (IV) and complex synthetic mixtures. The method has high precision and accuracy (s=±0.01 for 0.5 μg ml⁻¹).     

Fast vacuum slag analysis in a steel works by laser-induced breakdown spectroscopy

Samples taken from the liquid slag layer in a vacuum degasser station of a steel works are analyzed after solidification by laser-induced breakdown spectroscopy (LIBS) without any further sample preparation. The mass fractions of the major components of the vacuum slags are in the range of 50–60% for CaO, 0.5–12% for SiO₂ and 20–40% for Al₂O₃. The species are distributed heterogeneously in the solid samples having diameters of 35 mm. Furthermore the color and structure of the samples is varying significantly. A fast spatial averaging of representative sample areas is realized by spatial laser beam shaping. Multivariate calibration and its validation is carried out with calibration and validation sets of production samples which are analyzed by X-ray fluorescence measurements or as borate beads for reference. The laser-induced breakdown spectroscopy instrument is installed in the steel works at a distance of about 10 m from the vacuum degasser. The laser-induced breakdown spectroscopy analysis runs automatically after the sample placement and it takes 80 s including data transfer to the host computer of the steel works. Operational tests are carried out to demonstrate the feasibility of a fast slag analysis in the harsh environment of the vacuum degasser plant.