Sodium water, leaching

Use of excess sodium drives the reaction, usually done under an argon or helium blanket, to completion. After cooling, the excess sodium is leached with alcohol and the sodium and potassium fluorides are extracted with water, leaving a mass of metal powder. The metal powder is leached with hydrochloric acid to remove iron contamination from the cmcible. 

Tin ores and concentrates can be brought into solution by fusing at red heat in a nickel cmcible with sodium carbonate and sodium peroxide, leaching in water, acidifying with hydrochloric acid, and digesting with nickel sheet. The solution is cooled in carbon dioxide, and titrated with a standard potassium iodate—iodide solution using starch as an indicator. 

Decomposition with Bases. Alkaline decomposition of poUucite can be carried out by roasting poUucite with either a calcium carbonate—calcium chloride mix at 800—900°C or a sodium carbonate—sodium chloride mix at 600—800°C foUowed by a water leach of the roasted mass, to give an impure cesium chloride solution that is separated from the gangue by filtration (22). The solution can then be converted to cesium alum [7784-17-OJ, CS2SO4 Al2(S0 2 24H20. Extraction of cesium from the poUucite is almost complete. Solvent extraction of cesium carbonate from the cesium chloride solution using a phenol in kerosene has also been developed (23). 

Titanium sponge is separated from sodium chloride and excess sodium by leaching with water. 

The subsamples were split and sent to different laboratories to be subjected to ten commonly-used and proprietary leach/digestion techniques (a) aqua regia partial digestion method at Acme Analytical Laboratories (b) sodium pyrophosphate and cold hydroxylamine leaches at ALS Chemex (c) enzyme and TerraSol leach methods at Skyline Labs (d) Bioleach and soil gas hydrocarbon analyses at Activation Laboratories (e) Mobile metal ion (MMI) extraction at SGS Minerals (f) 4-acid near-total and sodium peroxide sinter total digestions (under the uses contract) at SGS Minerals and (g) de-ionized water leach at the USGS laboratories. 

The hypochlorite/water solutions were pretitrated to pH 8.5 with 1.0 N HCl in order to neutralize the presence of inherent sodium hydroxide. Leaching out of non-crystalline amylose from the native starch granules has been previously described in systems with pH values greater than 9.0 (24). 

The Determination of Boron. After dry ashing in the manner used in the lithium, beryllium, etc., procedure, the ash is fused with sodium carbonate, leached in water, and acidified with sulfuric acid. The colorimetric carminic acid method is then used to determine the boron. 

Soluble barium may be determined by S-198 (12) using a hot water leach, hydrochloric acid dissolution, and nitrous oxide/acetylene flame. In this method, 1000-2000 ppm sodium as sodium chloride is used to minimize ionization of barium in the flame. Although background correction is not mentioned in this method, it is strongly recommended when calcium is present. 

Commercial production of lithium and sodium is by electrolysis of their fused chlorides. For the former, spodumene is washed with H2 SO4 at 250 °C and water-leached to give Li2S04-H20 successive treatment with Na2C03 and HCl affords insoluble Li2C03 and LiCl. Alternatively,... 

Derivation (1) Alkali or acid extraction from vanadium minerals. (2) By igniting ammonium metavanadate. (3) From concentrated ferrophosphorus slag by roasting with sodium chloride, leaching with water and purification by solvent extraction followed by precipitation and heating. 

Pellets of CUAI2 alloy (53 wt. % Cu, 47 wt. % Al) and Cu-Al-Zn alloy (43.2 wt. % Cu, 39 wt. % Al, 17.8wt. % Zn), (3.8 mm x 5.4 mm dia), were leached in large excesses of two different leach solutions, 6.1 M sodium hydroxide and 0.62 M zincate in 6.1 M sodium hydroxide. Leaching was terminated by washing the pellets in distilled water to a pH of 7. The catalyst preparation procedure is described in greater detail elsewhere [7]. To simplify references to the four Raney catalysts Table 1 identifies them according to the precursor alloys and leach conditions used. 

A dilute water leach of the residue will extract tin and arsenic and leave antimony as insoluble sodium antimonite. This residue will also contain any tellurium, indium and selenium contained in the bulUon and if these elements are present in recoverable amounts then a two-stage Harris process can be employed (see below). 

In 1761 the mineral that disturbed the tin production was subjected to chemical examination. J. G. Lehmann, known from the history of the chromium discovery, investigated a wolframite from Zinnwald (Cinovec in today s Czech Repubhc). When he melted the mineral sample in sodium nitrate, leached it in water and added hydrochloric acid he observed a white precipitate that gradually became yellow. He had in fact seen tungstic acid, but did not reahze that there was a new element in it. 

Let us consider an allcali-modified silica glass. Because of mobile modifiers, the glass will undergo ion exchange, alkali being leached. Let us consider for instance sodium. Water diffusion (in feet HsC ) into the glass network is as follows ... 

Adams catalyst, platinum oxide, Pt02 H20. Produced by fusion of H2PtCl6 with sodium nitrate at 500-550 C and leaching of the cooled melt with water. Stable in air, activated by hydrogen. Used as a hydrogenation catalyst for converting alkenes to alkanes at low pressure and temperature. Often used on Si02... 

Historically, soda ash was produced by extracting the ashes of certain plants, such as Spanish barilla, and evaporating the resultant Hquor. The first large scale, commercial synthetic plant employed the LeBlanc (Nicolas LeBlanc (1742—1806)) process (5). In this process, salt (NaCl) reacts with sulfuric acid to produce sodium sulfate and hydrochloric acid. The sodium sulfate is then roasted with limestone and coal and the resulting sodium carbonate—calcium sulfide mixture (black ash) is leached with water to extract the sodium carbonate. The LeBlanc process was last used in 1916—1917 it was expensive and caused significant pollution. 

Opa.nte. There are two methods used at various plants in Russia for loparite concentrate processing (12). The chlorination technique is carried out using gaseous chlorine at 800°C in the presence of carbon. The volatile chlorides are then separated from the calcium—sodium—rare-earth fused chloride, and the resultant cake dissolved in water. Alternatively, sulfuric acid digestion may be carried out using 85% sulfuric acid at 150—200°C in the presence of ammonium sulfate. The ensuing product is leached with water, while the double sulfates of the rare earths remain in the residue. The titanium, tantalum, and niobium sulfates transfer into the solution. The residue is converted to rare-earth carbonate, and then dissolved into nitric acid. 

The roasted pellets or extmdes are ground and leached in water. The hexavalent selenium dissolves as sodium selenate [13410-01 -0] Na2Se04. Sodium teUurate, being highly insoluble in the now very strongly alkaline solution, remains in the residue. The separation between selenium and tellurium is readily achieved, provided all tellurium is oxidized to the hexavalent state. 

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