Davis’s process

Humphry Davy s process for the isolation of the alkali metals by the aid of the electric current is now regarded as the foundation of dry electrometallurgy, and justly so in spite of the fact that M. van Marum 4 had previously reduced several compounds by subjecting them to the electrical discharge. These methods were described in M. van Marum s pamphlet Experiences, qui font voir, qu il y a de la calorique dans la fluid ilectrique (Haarlem, 1795). He noted that in the reduction oxygen gas is evolved, and he credited the decomposition to the heating effect of the electric current. A few years later, J. W. Ritter decomposed silver salts by the discharge from a small electrical machine. 

Dium i Process,—Guppy B ProcesB.—Thomas s Process.—Potato-Jour in Soap.—Ouna Clay.—Douglas s ImproTemenis.—Puller s Earth Soap.—Davis s Process. 

Davis s Process,—Another method of blending Mer s earth and other substances wi soap, is that proposed by Hr, Davis, in which pipe-clay, pearlash, or calcined soda, are introduced. When pearlash, or soda, is employed it is first calcined and then ground up with the Mer s earth and clay until intimately mixed, and in this condition they are to be incorporated with the soap. The proportions are— To every 136 lbs. of soap, in a melted state, take 50 lbs. of fuller s earth, slaked or dried, 56 lbs. of dried pipe-clay, and 112 lbs. of calcined soda or pearlash, all in powder, and sifted as finely as possible. Incorporate the whole by stiiimg or oiutcbing, as quickly as possible before the pasty mass cools. If it is desirable to omit the fuller s earth in the above formula, the proportions are to be —soap, 120 lbs. dried pipe-clay, ll2 lbs. and calcined alkali, 96 lbs. This soap is said to... 

Davis, S.C., Grate, I.H., Gray, D.R. et al. (2004) Enzymatic processes for the production of 4-substituted 3-hydroxybutyric acid derivatives. W02004015132. 

There are also voices critical of the rTCA cycle Davis S. Ross has studied kinetic and thermodynamic data and concludes that the reductive, enzyme-free Krebs cycle (in this case the sequence acetate-pyruvate-oxalacetate-malate) was not suitable as an important, basic reaction in the life evolution process. Data on the Pt-catalysed reduction of carbonyl groups by phosphinate show that the rate of the reaction from pyruvate to malate is much too low to be of importance for the rTCA cycle. In addition, the energy barrier for the formation of pyruvate from acetate is much too high (Ross, 2007). 

Davis, S., in Handbook of Petroleum Refining Processes, Meyers, R. A., Ed., McGraw-Hill, New York, 1997,13.9. 

Meyer BS (1994) The r-, s-,and p-processes in nucleosynthesis. Annu Rev Astronom Astrophys 32 153-190 Mostefaoui S, Lugmair GW, Hoppe P, El Goresy A (2003) Evidence for live iron-60 in Semarkona and Chervony Kut a nanosims study. Lunar Planet Sci XXXIV 1585 Murthy VR, Sandoval P (1965) Chromium isotopes in meteorites. J Geophys Res 70 4379-4382 Nicolussi GK, Davis AM, Pellin MJ, Lewis RS, Clayton RN, Amari S (1997) s-Process zirconium in presolar silicon carbide grains. Science 277 1281-1283... 

Nicolussi GK, Pellin MJ, Lewis RS, Davis AM, Clayton RN, Amari S (1998b) Strontium isotopic composition in individual silicon carbide grains a record of s-process nucleosynthesis. Phys Rev Lett 81 3583-3586 Nicolussi GK, Pellin MJ, Lewis RS, Davis AM, Clayton RN, Amari S (1998c) Zirconium and molybdenum in individual circumstellar graphite grains new data on the nucleosynthesis of the heavy elements. Astrophys J 504 492-499... 

Electrolysis ol the fused alkali hydroxide.—At the time of Davy s discovery the dynamo had not been invented, and the electric current derived from batteries was far too costly for the production of sodium on a manufacturing scale. In modern works, where cheap electrical energy is available, modifications of Davy s original process—electrolysis of fused sodium hydroxide—are used for preparing sodium industrially —e.g. H. Y. Castner s electrolytic process (1890).a Potassium can also be made by H. Y. Castner s process. 

Masten S J, Galbraith MJ, Davies S HR (1993) Oxidation of Trichlorobenzene Using Advanced Oxidation Processes, Ozone in Water and Wastewater Treatment, 1 llh Ozone World Congress, 20/45-20/49. 

Davis, S. H. R. In Geochemical Processes at Mineral Surfaces Davis, J. A. Hayes, K. F., Eds. ACS Symposium Series 323 American Chemical Society Washington, DC, 1986. 

Masten, S.J., Shu, M., Galbraith, M.J., and Davies, S.H.R., Oxidation of chlorinated benzenes using advanced oxidation processes, Hazardous Waste Hazardous Mater., 13, 265-281, 1996. 

Brief Process Description of Davy s Latest High Efficiency Design. Natural gas is desulfurized over an activated carbon bed or zinc oxide to remove sulfur below 0.2 ppm, suitable for natural gas reforming. 

Future Trends. A critical assessment of Davy s high efficiency design shows that most heat is now rejected at very low levels. Thus, further process development will increase plant efficiency only slightly and will be increasingly costly. Some marginal areas do exist, however, which may become economic as energy costs increase. 

The wood for the above mentioned Brazilian plant can be grown on a regenerable basis from about 90 square miles of forest (57,600 acres). Figure 7 is a block flow diagram showing the many process steps involved in Davy s wood gasification process. 

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