Ammonium acetate leaching

Sr/ Sr 0.725 0.795 Young granitic moraine, Wind River Ammonium acetate leach River... 

Soil samples were collected along a traverse over the Honerat kimberlite and extended off the kimberlite approximately 75 m SE and 225 m NW from the pipe s centre (Fig. 1). Although it is common practice to collect samples from upper B-horizon soil (Levinson 1980 Bajc 1998 Mann et al. 2005) our samples were collected from C-horizon soil because GAGI samplers were placed at a depth of 60 cm (well below the B horizon). Within 8 hours of sampling, a portion of each soil sample was mixed with Milli-Q water (1 1) to create a slurry. The values of pH and oxidation-reduction potential (ORP) were determined in each slurry. Ammonia acetate leach of the soil samples were performed at Acme Analytical Laboratories, Vancouver, where 20 ml of ammonium acetate was mixed with 1 g soil sample and elements were determined by inductively coupled plasma-mass spectrometry. The GAGI samplers installed at Unknown were placed in piezometers and submerged in water at a depth of approximately 1 m below ground surface. 

Regolith samples were collected from 68 sites along a transect extending from the CTSS in the SW of the island (near napa tou Pcjpiou), across Troodos and into the CTSS and fanglomates on the NE side of Troodos (near AsuKioaia). ICP-MS trace elements concentrations were determined following two conventional (sequential) leaches on the <2mm fraction of the upper (0-25 cm) and lower (50-75 cm) parts of the profile 1M ammonium acetate in pH 5 acetic acid and 1M hydroxylamine.HCI in pH 1 HCI. 

Figure 7.2 Solid-state speciation in a crustal aerosol collected close to the Saharan Desert and an urban aerosol collected in the UK (Spokes et al., 1994). Results are expressed as a percentage of the total elemental concentration and obtained using a three stage sequential leach using the method of Chester et al. (1989). Stage one uses 1.0 M ammonium acetate to release loosely bound metals. Stage two involves addition of 1.0M hydroxylamine hydrochloride in 25% acetic acid to the residue to release metals held within the oxide and carbonate phases. Stage three uses nitric acid and hydrofluoric acid to break down the aluminosilicate lattice and release metals associated with the crustal fraction of the aerosol.

Sometimes these operationally defined procedures have a sound theoretical basis. For example, it is quite reasonable to suppose that leaching with magnesium nitrate solution will displace zinc from cation exchange sites in soils, or leaching with ammonium acetate will displace exchangeable calcium, magnesium, sodium, and potassium. Flame spectrometry, especially flame AAS, is widely used for the analysis of such extracts. 

Nitric acid and ammonium acetate have been recommended for leaching lead and cadmium from such extracts [152]. The oxygen flask method has been proposed as an alternative approach for micro-samples [145]. 

Oxidizable fraction of metals bound to organic matter (leaching with nitric acid and hydrogen peroxide, followed by ammonium acetate)... 

The use of brine as a solvent in the hydrometallurgical separation of lead from its ores was extensively studied by Lyon and Ralston (H8). Saturated sodium chloride solution and neutral ammonium acetate solutions were found to be good solvents for lead chloride and lead sulfate. Lead oxide and lead carbonate became soluble if the brine was first acidified with either sulfuric or hydrochloric acid. The dissolved lead was recovered electrolytically (S18). Marsden (M13) used this method in a process to recover lead from zinc plant residues. About 80% recovery of the lead was obtained by leaching at ambient temperature and the recovery of lead was increased to 98% when hydrochloric acid was added to the brine. 

The cation exchange capacity is usually measured by leaching the soil or colloid with neutral normal ammonium acetate. Then the excess salt is removed by washing with 95% ethanol. The ammonium ion (NH +) is then determined by steam distillation with magnesium oxide in an alkaline medium. The ammonia evolved is adsorbed into a known quantity of the standard acid containing methyl red indicator and the excess acid back titrated with a standard alkali. 

The determination of CEC is commonly made by leaching a soil with a neutral barium acetate solution. It may also be made by extracting a soil with normal ammonium acetate solution, followed by normal potassium chloride. The ammonium removed by the potassium chloride is a measure of the CEC of the.-soil, which includes the cations held by both the organic and inorganic portions. Separate determinations of these portions can be made but less accurately because the separation of one from the other cannot be made without affecting the chemical nature of the organic colloid. 

Leaching agent/CHEMICAL FORM I I Ammonium acetate/CATION EXCHANGE... 

The rate constants (k) for the leaching of galena in an aqueous medium containing ammonium acetate under oxygen pressure at different temperatures are listed below ... 

Chemical fractionation— successive leaching of the fuel in demineralized water, ammonium acetate, and hydrochloric acid, provides critical insights into the reactivity of ash. It is particularly useful in evaluating low rank coals, biomass fuels, and related combustible resources it can be used to evaluate bituminous coals as well, and almost uniformly shows the higher propensity of low rank fuels to create problems. 

A more precise and definitive approach to biomass ash characterization has been developed and employed by researchers at The Energy Institute of Pennsylvania State University [34 - 35], Sandia National Laboratories [6], and numerous commercial and industrial laboratories. This procedure, previously described in Chapter 4, involves successive leaching of the fuel sample in distilled water, ammonium acetate, and hydrochloric acid. The most reactive materials leach in distilled water and ammonium acetate. These include salts of potassium and sodium which readily vaporize when subjected to high temperatures... 

A series of compounded flame retardants, based on finally divided insoluble ammonium phosphate together with char-forming nitrogenous resins, has been developed for thermoplastics.23 These compounds are particularly useful as intumescent flame-retardant additives for polyolefins, ethylene-vinyl acetate, and urethane elastomers. The char-forming resin can be, for example, an ethyle-neurea-formaldehyde condensation polymer, a hydroxyethyl isocyanurate, or a piperazine-triazine resin. Commercial leach-resistant flame-retardant treatments for wood have also been developed based on a reaction product of phosphoric acid with urea-formaldehyde and dicyandiamide resins. 

The organic amine extractants are the most commonly used anion exchangers. Secondary amines have been used to recover uranium from leach liquors (GlO) secondary and tertiary amines to recover molybdenum from uranium mill circuits (L13) a primary amine, diethylenetriamine-penta-acetic acid (DTPA) to extract cerium group lanthanides (B6) tri-,V-butylamine-3-methyl-2-butanonc to separate yttrium and rare earth nitrates (G13) tricaprylyl amine (Alamine 336) and methyltrioctyl-ammonium salt (Aliquat 336) to recover vanadium from acidic solutions (A3) and Aliquat 336 to extract vanadium from slightly acidic or alkaline leach liquor (S36). 

Copper-Chnimlum oxide (Adkins cataiyst HJS 2). I he culalyst is prepared by stirring a solution of copper nitrate and barium nitrate into an aqueous solution of sodium dichromate and ammonium hydroxide. The orange precipitate is washed, dried, and stirred at 350° to effect decomposition. The cooled material is leached with 10% acetic acid, dried, and pulverized. The catalyst so obtained is brownish black. 

The geochemical behaviour of Cs and Pu in Solway floodplain cores, collected from Southwick Water, south-west Scotland, has been studied by Allan et al. (1991) by employing a sequential leaching scheme (Cook et al., 1984 Livens Baxter, 1988b McDonald et al., 1990). This scheme incorporates solutions of calcium chloride (readily available sites), acetic acid (specific adsorption sites), tetra-sodium pyrophosphate (organically associated), ammonium oxalate/oxalic acid, (Fe and Mn secondary minerals), dilute nitric acid (dilute acid soluble sites) and nitric acid/ hydrofluoric acid (residual fraction). This technique has been subject to... 

Moore found that the hexavalent actinides U(VI) and Pu(Vl) could be quantitatively extracted from 1 M acetic acid solutions and 1 M acetic acid - 0.1 M nitric acid solutions by 5% TIOA-xylene. Of the fission products only Ru, Zr, and Nb extracted appreciably, and these could be scrubbed with 5 M HCl. A preliminary ferric (or uranyl) hydroxide precipitation in the presence of niobium carrier improved the decontamination from these elements. The U and Pu were leached from the insoluble NbgOg with 1 M acetic acid. The uranium could be stripped with dilute HNOg or HCl, NH OH or ammonium bicarbonate. The Pu(VI) could be stripped by these reagents or reductively stripped, since PuCIV) and Pu(in) do not extract under these conditions. 

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