scholarly journals Determination of Nitrogen Losses in the Sulfuric Acid Solution, Waste of the 15N Separation Plant

2019 ◽  
Vol 70 (8) ◽  
pp. 2883-2884
Author(s):  
Cristina Marcu ◽  
Damian Axente ◽  
Codruta Varodi
Keyword(s):  
Sulfuric Acid ◽  
Nitric Acid ◽  
Nitrogen Oxides ◽  
Acid Solution ◽  
Sulfuric Acid Solution ◽  
Packed Column ◽  
Nitrogen Losses ◽  
Column Type ◽  
Nessler Reagent

The most used method for production of stable isotope 15N is based on the isotopic exchange 15N/14N in the nitrogen oxides-nitric acid solution system, known as Nitrox system. At the bottom of the packed separation column, the reflux is provided by total conversion of nitric acid into nitrogen oxides by reaction with sulfur dioxide, in a packed column type refluxer. The waste of HNO3-SO2 reaction is sulfuric acid, solution of 65-70%, which is evacuated at the bottom of the nitrogen oxides refluxer. The magnitude of the nitrogen losses, as NOx and/or HNO3 in the waste sulfuric acid, were determined by analysing the effluent sulfuric acid by spectrofotometric method with Nessler reagent.

Electrochemical Processing of Metal Wastes of Rhenium-Containing Heat-Resistant Nickel Alloys

2021 ◽  
Vol 316 ◽  
pp. 631-636
Author(s):  
L.Ya. Agapova ◽  
S.K. Kilibayeva ◽  
A.N. Zagorodnyaya
Keyword(s):  
Sulfuric Acid ◽  
Nitric Acid ◽  
Acid Solution ◽  
Sulfuric Acid Solution ◽  
Nickel Alloys ◽  
Anode Slime ◽  
Electrochemical Processing ◽  
Heat Resistant ◽  
Nickel Cobalt ◽  
Acid Addition

The paper presents the results of studies of electrochemical processing of large pieces of metal wastes of rhenium-containing heat-resistant nickel alloys (HRNA) with subsequent processing of the products of electrolysis. It shows the possibility of electrochemical processing of large (up to 2 kg) scrap pieces, without preliminary grinding, in sulfuric acid solution with nitric acid addition, under the current density of 500-1000 A/m2, with a temperature of 30-40о С. Up to 80-90% of rhenium and over 90% of nickel, cobalt, chrome and aluminum can be converted into the solution. Tungsten, tantalum and hafnium remain in the anode slime almost completely. Rhenium, nickel and cobalt remaining in the anode slime can be transferred to the solution, when the slime is chemically processed in sulfuric acid solution with nitric acid addition. The cake remaining after chemical decomposition of anode slimes represents a concentrate of refractory rare metals, containing up to 42% W; 18% Ta; 4% Hf. Rhenium is extracted from the combined solutions from anodic decomposition of HRNA wastes, and chemical dissolution of anode slimes, by the known extraction method in the form of the crude ammonium perrhenate (68,9 mас. % Re). After rhenium extraction the raffinate contains considerable quantities of nickel and cobalt, which can be precipitated by the alkali solution in the form of hydroxides to the nickel-cobalt concentrate, containing 31.5% Ni and 4.8% Co.

Separation and Determination of Trace Amounts of Tin Present as Organotin Residues on Fruits

1970 ◽  
Vol 53 (1) ◽  
pp. 140-146
Author(s):  
Homer B Corbin
Keyword(s):  
Sulfuric Acid ◽  
Acid Solution ◽  
Sulfuric Acid Solution ◽  
Extraction Method ◽  
Colorimetric Method ◽  
Separation Method ◽  
Measuring System ◽  
Accuracy And Precision ◽  
Spray Treatment

Abstract The dithiol colorimetric method has been applied to the determination of trace amounts of tin as residues from the spray treatment of fruit with a miticide containing tricyclohexyltin hydroxide. The samples are prepared by an initial wet combustion to give a sulfuric acid solution of tin in the inorganic form. The tin is separated from other elements in the acid digest by one of two methods. One involves distillation of stannic bromide with a mixture of HBr and HCl. In the second separation method stannic iodide is extracted into n-hexane. Both separation procedures result in a solution of tin in a few milliliters of concentrated H2SO4, which is then measured spectrophotometrically. Data are presented for sensitivity and precision of the measuring system; accuracy and precision of both separation methods are illustrated by duplicate analyses and recovery tests on apples and pears treated with various cyclohexyltin compounds and inorganic tin. The extraction method has been tested for compatibility with 35 elements. Only arsenic (>0.15 mg or 1.5 ppm) and antimony (>2 mg or 20 ppm) are likely to interfere. Procedures are given for elimination of greater amounts of these elements.

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