Gold content

Direct Oxidation of Propylene to Propylene Oxide. Comparison of ethylene (qv) and propylene gas-phase oxidation on supported silver and silver—gold catalysts shows propylene oxide formation to be 17 times slower than ethylene oxide (qv) formation and the CO2 formation in the propylene system to be six times faster, accounting for the lower selectivity to propylene oxide than for ethylene oxide. Increasing gold content in the catalyst results in increasing acrolein selectivity (198). In propylene oxidation a polymer forms on the catalyst surface that is oxidized to CO2 (199—201). Studies of propylene oxide oxidation to CO2 on a silver catalyst showed a rate oscillation, presumably owing to polymerization on the catalyst surface upon subsequent oxidation (202). 

Other Cesium Compounds. Cesium acetate [3396-11-0], CsOOCCH, mol wt 191.95, theoretical cesium content 69.24 wt % cesium trifluoroacetate, CF COOCs, mol wt 245.93, theoretical cesium content 54.04 wt % cesium—precious metal compounds such as cesium dicarbonyltetrachloromthenium, [22594-81-6] Cs2RuCl4(CO)2, mol wt 564.71, mthenium content of 17.9 wt %, a yellow crystalline powder and cesium tetrachlorogold [13682-60-5], CsAuCl, mol wt 471.7, gold content of 41.8 wt % a yellow powder are all known. 

Higher currents requite higher gold contents. 

Nowadays, the gold content of ores is much too low for these simple mechanical separation methods to be effective. Instead, the ore is treated with very dilute (0.01 M) sodium cyanide solution, through which air is blown. The following redox reaction takes place ... 

Fig. 7. Changes of the coefficient of recombination, y, of H atoms on the surface of Pd-Au alloy foil catalysts at room temperature. O, Initial values of log y, final values representing catalytic activity of Pd and its alloys containing absorbed hydrogen. Broken line denotes the alloy Pd40Au60 which represents the upper limit of gold content in Pd-Au alloys closing the region of Pd-Au hydride formation. After Dickens et al. (86).

Figure 1.173. Relationship between mercury and gold contents of mercurian gold from the Tsugu gold-antimony deposit (Shikazono and Shimizu, 1988b).

The gold content of the precipitates is anomalously high, compared with those from the other geothermal areas (Table 2.3). 

Approximately 70 elements can be found in sea water, however, only in minuscule amounts. Among these elements is gold. Unfortunately, the average gold content is around 0.01 mg/m3. 

The adsorption of gold on FeOOH at pH=6 and at 80°C was usually accomplished up to 85% of the total gold content for initial concentrations ranging from 6 to 124 mg/L at a solid loading of 7.5 g/L in solution within 20-30 min. The initial rate of adsorption appeared to be of first order nature. 

The Samli Fe-oxide deposit (Balikesir, Western Anatolia-Turkey) is one of the iron-oxide producing mines in western Anatolia. This deposit has long known as a skarn-type Fe-oxide deposit. However, our recent research has revealed that the alteration hosting the iron-oxide mineralization also contains some unusual assemblages, and the sulfide mineralogy with abundant gold content, should not be related to skarn systems. 

Clayton Allsman of Molex, Inc., is dwarfed by large volumetric flasks filled with diluted solutions of plating baths and dissolved electroplated specimens as he prepares to analyze these solutions for gold content. 

The gold contents (in ppb) in the various size fractions from the termite mounds are presented in Table 1 and the geochemical distribution of gold in the various size fractions were compared with the gold content in -125pm fractions as that appeared to be the size fractions used in gold exploration surveys especially in Ghana and West Africa. 

For the purpose of comparison, gold content in -125pm was compared with +125pm, -500pm and +500pm... 

Sb, and As. Likewise, the presence of vuggy (subsequently brecciated) open space quartz veins support this. High gold contents (41%) in the > 149 micron portion of the crushed core indicate that coarse gold may be a factor in variability in duplicate results. 

All these methods use selective features, which are not directly connected with gold contents. 

Drilled samples, 200-1000 fig and sealed in pure quartz vials, are activated and analyzed in a similar way for silver, copper, and gold content. Drill bits of tungsten carbide and stainless steel, materials much harder than silver, were used in taking samples. Since no significant differences in concentrations of the major elements of the drill bit materials could be found in samples taken with either of them, possible contamination by the drill bits can be neglected. 

Combined neutron Howitzer and streak analyses of 125 one- and two-peso coins not only reveal the real gold content of these issues but help to establish the silver standard, which was probably aimed at 900 thousands fine (90% silver), a creditable alloy and better than the 800 thousands (80%) of the federal subsidiary coinage. It was therefore possible to estimate fairly closely the theoretical composition and value of the Zapatista silver coinage. 

Figure 10. Proclaimed gold contents (in peso equivalents) and actual average silver and gold content values for Zapata one- and two-peso coins...

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