Extraction with nitric acid after

Elemental composition 86.96%, C 10.41%, H 2.62%. The compound can be identified from its physical properties, elemental analyses and infrared spectra. Mercury can be identified by cold-vapor AA or ICP/AES after cautious extraction with nitric acid. In a suitable organic solvent, it may be analyzed by GC/MS. The characteristic ions are 217, 215, 202, 200, 232 and 230. 

Table IV. Nitrogen and Iron Content in Raw and in Treated Coals Before and After Extraction with Nitric Acid.

CH2CH2— but was little changed when X was varied from —CH2— to —CH=CH—, Dihexyl Ar,AT-diethylcarbamoylmethylenephosphonate (DHDECMP) has been used to extract trivalent ions from HAW. After back extraction with nitric acid or carbonate solution the lanthanides... 

In the production of uranium(lV) oxide in the wet process, the uranium concentrate is first converted into a uranyl nitrate solution with nitric acid. After the purification of the uranyl nitrate by solvent extraction, it can be converted into uranium(IV) oxide by two different routes either by thermal denitration to uranium(VI) oxide which is then reduced to uranium(IV) oxide or by conversion of uranyl nitrate into ammonium diuranate which is reduced to uranium(IV) oxide. Purification proceeds by extraction of the uranyl nitrate hydrate from the acidic solution with tri-n-butylphosphate in kerosene and stripping this organic phase with water, whereupon uranium goes into the aqueous phase. 

An alkaline germanate solution is added to a solution of molybdate or tungstate, and the mixture is acidified with nitric acid. After a classical Et20 extraction process, water is added to the separated Et2 0 layer. Then the mixture of Et2 0 and H2O is put in a vacuum desiccator with concentrated H2SO4, and it is left without disturbance. Finally, yellow or colorless aim crystals with [GeMoi204o] or [GeWi204o] anions are obtained. Detailed synthetic steps can be seen in Reference 105. 

A simple possibility to obtain a detailed information about the stabilizer system in PVC waste can be seen in the classic analysis methods which are common practice in inorganic chemistry of the separation and determination of cations. The only difficulty is to find an easily practical way to get the metallic cations into water phase. For this purpose, the PVC sample is dissolved in cyclohexanone and the received solution used for a liquid/liquid-extraction with nitric acid containing water. After phase separation, the different cations are found in water solution. 

Add, with stirring, a solution of 6 8 g. of the fiis-diazo ketone in 100 ml. of warm dioxan to a suspension of 7 0 g. of freshly precipitated silver oxide in 250 ml. of water containing 11 g. of sodium thiosulphate at 75°. A brisk evolution of nitrogen occurs after 1 5 hours at 75°, filter the liquid from the black silver residue. Acidify the almost colourless filtrate with nitric acid and extract the gelatinous precipitate with ether. Evaporate the dried ethereal extract the residue of crude decane-1 10-dicarboxylic acid weighs 4 -5 g. and melts at 116-117°. RecrystaUisation from 20 per cent, aqueous acetic acid raises the m.p. to 127-128°. 

Soil Leaching. Soil leaching or acid extraction uses acid to solubilize metals for removal from soils, a technique akin to that ia the mining industry. After extraction with an acid such as hydrochloric, sulfuric, or nitric, the soil is separated from the acid, rinsed with water to remove excess acid and metals, dewatered, and neutralized. The acid is regenerated and recycled back to the process. The extracted metals can be precipitated and recovered. 

Elemental composition Co 78.65%, 0 21.35%. The commercial product generally contains 76% Co. The powder is digested with nitric acid and the acid extract, after dilution, is analyzed for Co hy various instrumental techniques (see Cobalt). Cobalt(II) oxide may be analyzed by x-ray directly, without acid digestion. 

Acid soluble rare earth salt solution after the removal of cerium may be subjected to ion exchange, fractional crystalhzation or solvent extraction processes to separate individual rare earths. Europium is obtained commercially from rare earths mixture by the McCoy process. Solution containing Eu3+ is treated with Zn in the presence of barium and sulfate ions. The triva-lent europium is reduced to divalent state whereby it coprecipitates as europium sulfate, EuS04 with isomorphous barium sulfate, BaS04. Mixed europium(ll) barium sulfate is treated with nitric acid or hydrogen peroxide to oxidize Eu(ll) to Eu(lll) salt which is soluble. This separates Eu3+ from barium. The process is repeated several times to concentrate and upgrade europium content to about 50% of the total rare earth oxides in the mixture. Treatment with concentrated hydrochloric acid precipitates europium(ll) chloride dihydrate, EuCb 2H2O with a yield over 99%. 

Elemental composition Pb 86.60%, S 13.40%. Both mineral and synthetic forms can be identified by x-ray measurements. Lead can be analyzed by various instrumental techniques after digestion with nitric acid and appropriate dilution of the acid extract (See Lead). 

The monazite sand is heated with sulfuric acid at about 120 to 170°C. An exothermic reaction ensues raising the temperature to above 200°C. Samarium and other rare earths are converted to their water-soluble sulfates. The residue is extracted with water and the solution is treated with sodium pyrophosphate to precipitate thorium. After removing thorium, the solution is treated with sodium sulfate to precipitate rare earths as their double sulfates, that is, rare earth sulfates-sodium sulfate. The double sulfates are heated with sodium hydroxide to convert them into rare earth hydroxides. The hydroxides are treated with hydrochloric or nitric acid to solubihze all rare earths except cerium. The insoluble cerium(IV) hydroxide is filtered. Lanthanum and other rare earths are then separated by fractional crystallization after converting them to double salts with ammonium or magnesium nitrate. The samarium—europium fraction is converted to acetates and reduced with sodium amalgam to low valence states. The reduced metals are extracted with dilute acid. As mentioned above, this fractional crystallization process is very tedious, time-consuming, and currently rare earths are separated by relatively easier methods based on ion exchange and solvent extraction. 

COj -48.5%, OB to CO -12.1%. Plates, unstable, mp 55 62° with decompn very sol in w eth, in sol in ligioin. Was prepd by mixing acetone with nitric acid(dl. 14) and a little fuming HNO, and allowing the mixt to stand for 8 days at RT. An ether extraction gave on e-apcm seme acstylmethyi-nitrolic acid(Refs 1 2). Krauz Stepanek (Ref 3) attempted and failed to prep tetra-nitromethane by nitration of acet. Instead, they obtd (after treating the nitrated prod with silver salt) an expl compd claimed to be the Ag salt of acetylmethylnitrolic acid, CHj, , CO. C(NOj). N. 0 Ag (see also Acetone, Nitration)... 

The uranium is separated, after dissolving the sample as described for lead, by extraction with tributyl phosphate (TBP) from 4M nitric acid. After the organic phase is scrubbed with 4M nitric acid, the uranium is back-extracted into distilled water and evaporated to dryness. The uranium is loaded on a rhenium filament for analysis by dissolving the purified sample in a small volume of 0.05M nitric acid. 

Reprocessing is based on liquid-liquid extraction for the recovery of uranium and plutonium from used nuclear fuel (PUREX process). The spent fuel is first dissolved in nitric acid. After the dissolution step and the removal of fine insoluble solids, an organic solvent composed of 30% TriButyl Phosphate (TBP) in TetraPropylene Hydrogenated (TPH) or Isopar L is used to recover both uranium and plutonium the great majority of fission products remain in the aqueous nitric acid phase. Once separated from the fission products, back-extraction combined with a reduction of Pu(I V) to Pu(III) allows plutonium to be separated from uranium these two compounds can be recycled.2... 

An example of a method suitable for the determination of cadmium, cobalt, copper, iron, manganese, nickel, and zinc in water, using chelation and sample extraction, is as follows [113]. The sample is filtered through an acid-washed membrane filter as soon as possible after collection. It is then acidified with nitric acid for preservation until analysis. This will give the soluble metal fraction. If the total metal content is to be found, the sample is acidified and allowed to stand for 4 days with occasional shaking. Then it is filtered. 

---