Acid dissolution

Chemical analysis methods maybe used for assay of silver alloys containing no interfering base metals. Nitric acid dissolution of the silver and precipitation as AgCl, or the Gay-Lussac-VoUiard titration methods are used iaterchangeably for the higher concentrations of silver. These procedures have been described (4). 

Cobalt(II) nitrate hexahydrate [10026-22-9], Co(N02)2 6H20, is a dark reddish to reddish brown, monoclinic crystalline material containing about 20% cobalt. It has a high solubiUty in water and solutions containing 14 or 15% cobalt are commonly used in commerce. Cobalt nitrate can be prepared by dissolution of the simple oxide or carbonate in nitric acid, but more often it is produced by direct oxidation of the metal with nitric acid. Dissolution of cobalt(III) and mixed valence oxides in nitric acid occurs in the presence of formic acid (5). The ttihydrate forms at 55°C from a melt of the hexahydrate. The nitrate is used in electronics as an additive in nickel—ca dmium batteries (qv), in ceramics (qv), and in the production of vitamin B 2 [68-19-9] (see Vitamins, VITAMIN B22)-... 

Bar-code readers (like those in grocery stores) are to identify equipment in a plant. Suggest a way that this may be used to check the temperature, acid type and quantity, and aluminum quantity for acid dissolution of aluminum. 

In the case of a mixture of hydrofluoric and sulfuric acids, the process is more complex. It can be noted that sulfuric acid most probably interacts mainly with iron and manganese, whereas hydrofluoric acid serves mostly in the dissolution of tantalum and niobium and their conversion into soluble fluoride complexes. Nevertheless, due to the high acidity of the solution, here too the formation of hexafluorotantalate and hexafluoroniobate complex ions, TaF6" and NbF6, is expected. Hence, it is noted that the acid dissolution of tantalum-and niobium-containing raw material leads to the formation of hexafluoro-acids — HTaF6 and HNbF6. 

An overview is presented of plutonium process chemistry at Rocky Flats and of research in progress to improve plutonium processing operations or to develop new processes. Both pyrochemical and aqueous methods are used to process plutonium metal scrap, oxide, and other residues. The pyrochemical processes currently in production include electrorefining, fluorination, hydriding, molten salt extraction, calcination, and reduction operations. Aqueous processing and waste treatment methods involve nitric acid dissolution, ion exchange, solvent extraction, and precipitation techniques. 

MDHS 14 General method for the gravimetric determination of respirable and total dust MDHS 15 Carbon disulphide MDHS 16 Mercury vapour in air Laboratory method using hopcalite adsorbent tubes, and acid dissolution with cold vapour atomic absorption spectrometric analysis MDHS 17 Benzene in air Laboratory method using charcoal adsorbent tubes, solvent desorption and gas chromatography MDHS 18 Tetra alkyl lead compounds in air Continuous on-site monitoring method using PAC Check atomic absorption spirometry... 

The principal member of the first class is tributyl phosphate (TBP). It is convenient to use this organic reagent in the refining of yellow cake consequent to nitric acid dissolution. After dilution, the solution is subjected to filtration through vacuum filters prior to intro-... 

Applications Quantitative dry ashing (typically at 800 °C to 1200°C for at least 8h), followed by acid dissolution and subsequent measurement of metals in an aqueous solution, is often a difficult task, as such treatment frequently results in loss of analyte (e.g. in the cases of Cd, Zn and P because of their volatility). Nagourney and Madan [20] have compared the ashing/acid dissolution and direct organic solubilisation procedures for stabiliser analysis for the determination of phosphorous in tri-(2,4-di-t-butylphenyl)phosphite. Dry ashing is of limited value for polymer analysis. Crompton [21] has reported the analysis of Li, Na, V and Cu in polyolefins. Similarly, for the determination of A1 and V catalyst residues in polyalkenes and polyalkene copolymers, the sample was ignited and the ash dissolved in acids V5+ was determined photo-absorptiometrically and Al3+ by complexometric titration [22]. 

Mineral acid dissolution is an important sample preparation process for instrumental analysis, as it liberates element ions into a solution that can be directly introduced into an analytical instrument. For quantitative analysis, most instruments require a solution. 

Since dosage forms contain more than just active drug, it is of practical interest to understand how the various components from a multicomponent solid influence their own dissolution and release. Nelson [18] was one of the first pharma-ceuticists to ponder this question and perform the initial dissolution studies. Unfortunately, Nelson initially considered the dissolution of interacting solids (benzoic acid + trisodium phosphate), which is a more complicated and more complex situation than simple multicomponent dissolution of noninteracting solids. Nelson did show that for his benzoic acid and trisodium phosphate pellets, there was a maximum increase in benzoic acid dissolution in water at a mole fraction ratio of 2 1 (benzoic acid trisodium phosphate) and that the benzoic acid dissolution rate associated with the maximum rate was some 40 times greater than that of benzoic acid alone. 

A variety of strong acid dissolutions, e.g., 4-acid (near-total) extraction and aqua regia (total recoverable) extraction, are used by different agencies for the purpose of determining trace-element concentrations in environmental materials. 

Hproblems associated with all the trihalides of this review of the presence of small amounts of hydrates or oxochlorides. While on the matter of possible impurities, it may be recalled that in Bommer and Hohmann s early work there is a discrepancy between enthalpies of solution of anhydrous trichlorides and of respective metals in hydrochloric acid. Here the more likely impurity to be responsible is unreacted potassium metal in the lanthanide metal used in the hydrochloric acid dissolution experiments. 

Zarcinas and Cartwright [6] studied the acid dissolution of boron from soils prior to determination by inductively coupled plasma atomic emission spectrometry. 

A distinct minimum in NiO solubility is observed in plots of log (NiO solubility) versus basicity (-log aM2o), which can be demarcated into two branches corresponding to acidic and basic dissolution. Acidic dissolution is represented by a straight line with a slope of+1, and a NiO solubility that decreases with an increase in aM20- Basic dissolution is represented by a straight line with a slope of to either -1 or -V4, corresponding to Equations (6-9) and (6-10), respectively. The CO2 partial pressure is an important parameter in the dissolution of NiO in carbonate melts because the basicity is directly proportional to log Pcc>2 An MCFC usually operates with a molten carbonate electrolyte that is acidic. 

Wilkins. S.J., Coles, B.A., Compton, R.G., and Cowley, A. Mechanism and kinetics of salicylic acid dissolution in aqueous solutionunder defined hydrod3mamic conditions via atortric force trricrosopy the effects of the ionic additives NaCl, LiCl, and MgCb, the organic additives 1-propanol, 2-propanol, and the surfactant sodium dodecyl sulfate. J. Rhys. Chem. B, 1061(106) 4763-4774, 2002. 

Rock samples collected from archived core, mine workings and outcrop were pulverized, homogenized, then analyzed using four-acid dissolution (SGS Lab, Toronto) to determine the near-total lithogeochemical composition (cassiterite, rutile, monazite, zircon, sphene, gahnite, chromite and barite are partially dissolved). Gold analyses were done by Fire Assay with Atomic Absorption finish on 30g samples and have a detection limit of 5 ppb. 

Hg carbon coated filter/acid dissolution cold vapor 32... 

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