The use of naphthidine as indicator in the determination of zinc in metallurgical analysis

Using naphthidine as an internal indicator in the titration of zinc with standard potassium ferrocyanide solutions, suitable procedures are recommended for the determination of zinc in various non-ferrous alloys and in rubber ashes. With aluminium alloys, aluminium bronzes and white metals the zinc is separated from interfering elements by hydrogen sulphide procedures, whereas with tin bronzes the separation is best accomplished by an 8-hydroxyquinoline procedure. After the solution of rubber ashes in hydrochloric acid, the major interfering elements are removed from the zinc by filtration after making the solution ammoniacal. With samples giving large precipitates with ammonia, it is necessary to redissolve them and determine the entrained traces of zinc.     

Determination of niobium and tantalum in binary alloys and zirconium alloys

Recent developments in the metallurgy of niobium, tantalum and zirconium have necessitated provision of analytical procedures for determining niobium and tantalum in the presence of each other and in the presence of zirconium. For this purpose, absorptioinetric procedures based on the formation of yellow coloured complexes, between pyrogallol and niobium or tantalum, have been critically examined. Direct absorptiometric procedures are described, which are suitable for determining niobium or tantalum in the range 2 to 7%; when either of these metals exceeds 7%, differential absorptiometric procedures are recommended. Corrections must lie made for absorption due to the presence of other metals which form complexes with pyrogallol. In tlie determination of niobium or tantalum up to 5%, the precision of the method is about ±0.05%. About 12 determinations can be made in a day, by one analyst.     

Simultaneous determination of lead, nickel, tin and copper in aluminium-base alloys using slurry sampling by electrical discharge and multielement ETAAS

The simultaneous multielement determination of Pb, Sn, Ni and Cu in aluminium alloys by electrothermal atomic absorption spectrometry (ETAAS) was performed by a quick method using slurry sampling. The metallic colloidal slurries were obtained by an electrical discharge operated in liquid medium. In this work, the effects of aluminium were evaluated and the results show that it causes a strong retention of Pb, Ni and Cu at low pyrolysis temperatures which is overcome by employing high pyrolysis temperatures. Aluminium also significantly improves the thermal stabilisation of Pb and Sn, it being possible to reach pyrolysis temperatures of 1100 and 1300 °C, respectively. Such stabilisation indicates that the performance of aluminium as a matrix modifier for Pb is better than that obtained using phosphate and magnesium nitrate without substantial changes of the figures of merit. The effects of aluminium on the atomisation characteristics of the elements and those coming from the simultaneous multielement determination on the figures of merit of the elements are also discussed. In this work, a calibration procedure involving a matrix matching method with aqueous aluminium standards is proposed as a simple and efficient way to solve the inconveniences originated by the aluminium matrix. The proposed method was applied to the simultaneous multielement determination of several aluminium-base alloy standards giving results well within the recommended values.     

Determination of iron, copper and aluminium by gas-liquid chromatography

Gas chromatography has been utilised in the analysis of two National Bureau of Standard alloys for quantitative determination of aluminium, iron and copper. In the analysis of N.B.S. 162a the relative mean errors were 3.13% for aluminium, 2.06% for iron and -1.72% for copper and for N.B.S. 164a the relative mean errors were -1.39%, -0.19% and -0.89% for aluminium, iron and copper, respectively. The procedure for analysis involves solution of the alloy, conversion of the metal ions to trifluoroacetylacetonates by solvent extraction and, finally, complete separation of the metal chelates and quantitative determination by gas chromatography using a column containing Gas Pack F coated with Tissuemat E, a polyethylene wax. Other metals present in the N.B.S. samples did not interfere with the determination of aluminium, iron and copper.     

The determination of lead in copper-base alloys and steel by atomic absorption spectrophotometry

The principle of atomic absorption spectrophotometry has only recently been exploited as an analytical technique and details are given of the development of a procedure for determining lead in copper-base alloys and leaded steels. The recommended method is simple, rapid and provides results as accurate as those obtained by the more time-consuming alternative methods in current use.     

Determination of trace and minor elements in alloys by atomic-absorption spectroscopy using an induction-heated graphite-well furnace as atom source-II

Results are presented for the atomic-absorption spectrophotometric determination of zinc in aluminium and aluminium-silicon alloys, and aluminium, antimony and tin in steels, by means of solid samples dropped into an induction-heated graphite-well furnace to produce the atomic vapour.     

Étude sur le dosage colorimétrique de l'aluminium dans les aciers

Colorimetric determination of aluminium by means of a new reagent, stilbazo, is studied.The investigation leads to a method for the direct determination of aluminiumsteel alloys: nitrided steels, magnetic steels.The aluminium is determined by a technique consisting of electrolysis with mercury cathode, separation of titanium and vanadium, if present, by chloroform extraction of the complexes of these elements with cupferron, and, finally, colorimetric determination.During these experimental investigations, observations have been made concerning the influence of a number of elements on the reaction of aluminium with stilbazo. The reactions of vanadium with various reagents (dicyandiamidine, diantipyrylphenylmethane, a-benzoinoxime) and the silico-vanado-tungstic complex have been studied.     

Extraction with long-chain amines-X Complexometric determination of titanium after extraction of its ascorbate complexes

A highly selective extraction of titanium as its ascorbate complexes from slightly acidic medium into trioctylmethylammonium sulphate is described. After stripping into nitric acid, titanium is determined complexometrically. The method allows separation of titanium from large amounts of iron, aluminium and bivalent metals. The procedure for the determination of iron and aluminium after the titanium extraction is also given. The method has been applied to the determination of titanium in special alloys and minerals.     

A chemical-spectrographic procedure for determination of some trace elements in steel and nickel-base alloys

A chemical-spectrographic procedure, which involves three steps, is proposed for determining certain residual metals in steel and nickel-base alloys: (1) Dissolve the sample with a suitable acid mixture. (2) Separate the iron, chromium or nickel from the residuals by a mercury-cathode electrolysis. (3) Analyse the resulting concentrated residuals in a solution form by the rotating-disk spectrographic technique. Cobalt serves as the internal standard. Metals containing 0.003-0.10% of aluminium, calcium, vanadium and titanium can be determined accurately and rapidly with this procedure. Eight samples in duplicate may be analysed for the above elements in 12 hr.     

Solvent extraction—flame spectrometric methods for the determination of indium in aluminium alloys

Atomic absorption and atomic emission methods for determining trace and minor amounts of indium in aluminium alloys are described. They involve the separation of indium from the aluminium matrix by extraction of indium diethyldithiocarbamate from hydrochloric acid at pH 3, and determination by emission at 451.13 nm or absorption at 303.9 nm in the extract; a nitrous oxide—acetylene or air—acetylene flame is used.     

Determination of niobium and tantalum in some ores and special alloys by inductively coupled plasma atomic emission spectrometry

A fast analytical method for the determination of niobium and tantalum in ores and special alloys by inductively coupled plasma atomic emission spectrometry has been developed. Optimum conditions for the determination of both metals in the plasma were worked out and possible interferences were studied before attempting the determination in the real samples. Ores are dissolved in a mixture of HCl, HF and H₃PO₄ acids while for the special alloy a HCl+H₂O₂ mixture is used. The resulting solutions are diluted to the mark with tartaric acid before their final direct nebulization into the plasma. Other elements present did not interfere in the determination of Nb or Ta at concentration levels similar to those found in the analyzed samples. The results obtained determining niobium and tantalum in pyrochlore and special alloys by the proposed procedure are in good agreement with the certified values.     

Determination of minor elements in steel by carbon furnace atomic emission spectrometry

Procedures are described for the determination of chromium, copper, manganese, nickel and soluble aluminium in steels by carbon-furnace atomic emission spectrometry. A single set of atomization conditions is optimum for all five elements but different dilutions of the sample solution are recommended for different analyte concentrations in the steels. Interferences from iron and nitric acid are small or insignificant and easily compensated.     

Determination of trace elements in metals and alloys by atomic-absorption spectroscopy using an induction-heated graphite well furnace as atom source

An induction-heated graphite furnace, coupled to a Unicam SP 90 atomic-absorption spectrometer, is described for the direct determination of trace elements in metals and alloys. The furnace is capable of operation at temperatures up to 2400 degrees , and has been used to obtain calibration graphs for the determination of ppm quantities of bismuth in lead-base alloys, cast irons and stainless steels, and for the determination of cadmium at the ppm level in zinc-base alloys. Milligram samples of the alloys were atomized directly. Calibration graphs for the determination of the elements in solutions were obtained for comparison. The accuracy and precision of the determination are presented and discussed.     

A modified apparatus for determination of carbon in metals by the low pressure method

The low pressure method of determination of carbon in metals and alloys was modified to include certain new techniques. An isopentane slush bath dispensed with the use of liquid oxygen and the usual McLeod gauge was replaced by a differential oil manometer, which increased the sensitivity. As little as 5 μg of carbon in CaCO₃-quartz standards could be determined with a coefficient of variation of 16.0% which improved to 3.3% at the 100-μg level. The apparatus was used for the determination of carbon in metals such as uranium, zirconium and iron and in steels and cupronickel alloy.     

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.     

The determination of titanium in iron and steel by atomic absorption spectrometry

A method has been developed for the determination of titanium by atomic absorption spectrometry in a wide range of iron and steels containing <1% aluminium. Interferences are overcome by the addition of aluminium to sample and standard solutions. The accuracy and reproducibility of the method have been established at the 0.05,0.15 and 0.50% levels with British Chemical Standard samples. The procedure is time-saving, particularly as aluminium may be determined on the same initial 2% ($\text{w}\text{v}$) sample solution.     

Determination Of Copper in Alloys and Salts With Pyridine-2-Aldehyde-1-Thionaphthylhydrazone

Abstract

Pyridine-2-aldehyde-l-thionaphthylhydrazone (PATNH) reacts with copper in IN hydrochloric acid to give a complex suitable for the absorptiometric determination of copper in non-ferrous alloys and in salts.     

Determination of the types of nitrogen in steels containing aluminium or titanium by an extraction method with hydrogen

The extraction method with hydrogen, hitherto used to determine mobile nitrogen in steels over the temperature range 350–450°C, has been employed at higher temperatures to determine nitrogen bound as aluminium nitride, or as titanium nitride or carbonitride. In steels containing only silicon and titanium as deoxidizers, the nitrogen remaining after passage of hydrogen at 600 or 750°C is present as titanium nitride or carbonitride and can be determined by difference. In steels containing only silicon and aluminium as deoxidizers, the nitrogen remaining after passage of hydrogen at 600°C is present as aluminium nitride and can also be determined by difference. This was verified by determining the aluminium nitride indirectly. The nitrogen released from both the aluminium and titanium steels in hydrogen at 600°C probably results from dissociation of submicroscopic particles of manganese silicon nitride.     

Extractive photometric determination of plutonium(IV) with Aliquat-336 and xylenol orange

A rapid extractive photometric method using Aliquat-336 and xylenol organe for the determination of plutonium(IV) at μg levels has been developed. Quantitative extraction is obtained from ∼4M aqueous HNO₃ medium, affording estimation in the presence of several commonly occurring impurities, viz. iron, uranium, fission products and cladding materials. Effects of acidity, reagent concentration and diverse ions on the estimation have also been invetigated. Unlike the well-known absorptiometric method for determining plutonium(IV) employing Arsenazo III, the procedure presented here tolerates manyfold excesses of uranium(VI) as well as chromium(III), iron(III) and zirconium(IV), which are some of the major contaminants of plutonium during reprocessing.     

Determination of tin, bismuth, antimony, indium, gallium and arsenic by solvent extraction cum atomic absorption spectrophotometry

A rapid atomic absorption spectrometric method for the determination of tin, antimony, bismuth, indium, gallium and arsenic in geological materials, steels and alloys is described. The samples are fused with sodium peroxide (for geological samples such as cassiterite and sulphides) or decomposed with sulphuric/hydrochloric acid mixture or by alkaline fusion (for silicates or bauxites) or by acid treatment (for steels, alloys and certain geological samples). The elements of interest are extracted as their iodides into methyl isobutyl ketone, stripped into aqueous solution by treatment with benzene, concentrated nitric acid and water, and determined by flame atomic-absorption spectrometry. Detailed study is made on stripping of the metals from organic phase as there no simple and rapid stripping procedures available. The method allows the determination of Sn, Sb, Bi and In down to 2 ppm and Ga down to 5 ppm. The relative standard deviations range up to 10% with an average of 2.5%. Apparent recoveries of these metals range from 90 to 110 with an average of 95% for Sb and 99% for others.