Fluid Alkali Metals at High Temperatures and Pressures

1993 ◽  
pp. 147-166
Author(s):  
F. Hensel
Keyword(s):  
High Temperatures ◽  
Alkali Metals

Thermodynamic properties of bcc crystals at high temperatures: The alkali metals

1984 ◽  
Vol 29 (12) ◽  
pp. 6489-6499 ◽  
Author(s):  
Rosemary A. MacDonald ◽  
Ramesh C. Shukla ◽  
David K. Kahaner
Keyword(s):  
Thermodynamic Properties ◽  
High Temperatures ◽  
Alkali Metals

scholarly journals XII.—On the Behaviour of the Hydrates and Carbonates of the Alkali-Metals, and of Barium, at High Temperatures, and on the Properties of Lithia and the Atomic Weight of Lithium

1890 ◽  
Vol 35 (2) ◽  
pp. 429-469
Author(s):  
W. Dittmar
Keyword(s):  
High Temperatures ◽  
Alkali Metals ◽  
Atmospheric Oxygen ◽  
Atomic Weight ◽  
Suitable Material ◽  
Corrosive Action ◽  
Chemical Inertness

The fragmentary nature of our knowledge of the behaviour of the more strongly basilous hydrates and carbonates at high temperatures is owing chiefly to the absence of a suitable material for the necessary crucibles. Unfortunately there is no metal which combines the infusibility of platinum with the chemical inertness of gold, in opposition to fiery-fluid caustic alkalies. But the corrosive action of these on platinum, as I showed some years ago, is a function only of the peroxides formed from them by the action of atmospheric oxygen, and, consequently, can easily be prevented by operating in an atmosphere of hydrogen or nitrogen.

Trace element removal from hot gasification flue gases using solid sorbents

2013 ◽  
Vol 8 (2) ◽  
pp. 137-145
Keyword(s):  
Trace Elements ◽  
Gas Phase ◽  
High Temperatures ◽  
Alkali Metals ◽  
Coal Gasification ◽  
Fixed Bed ◽  
Fly Ashes ◽  
Metallic Oxide ◽  
Solid Sorbents ◽  
Element Removal

Coals contain elements which, although usually found in concentrations lower than 1% (trace elements), can give rise to environmental or technological problems. After gasification most of these elements may occur in gas phase in different proportions. In order to avoid the problems that the presence of trace elements in gas phase can originate during coal gasification processes, a suitable technology needs to be developed. The systems currently being studied and developed for gas cleaning in coal gasification, focus on the removal of sulphur, particulate matter, nitrogen, alkali metals and halogens but not on corrosive or toxic trace elements. Nevertheless, the reduction of trace elements using solid sorbents in gas phase at high temperatures appears to be a promising method for combustion systems. The main objectives of this work were to determine the capacity of different solid sorbents for retaining arsenic, selenium, cadmium and zinc species in gases from coal gasification systems at 550 and 750 ºC and to find out how the sorbent characteristics and operational variables (temperature and gas composition) influence retention. To attain these objectives the sorption capacity (mg of element per g of sorbent) and the efficiency (percentage of element retention) were determined. The study was carried out in a laboratory scale reactor, in which the sorbent was employed as a fixed bed, using synthetic gas mixtures. At the end of each experiment, the sorbent bed (mixture of sorbent + sand) was finely ground and dissolved in a microwave oven with HF, HNO3 and H3BO3, and the element in solution was determined by ICP-MS. The results are discussed in the light of the data for combustion conditions reported in the literature, and possible retention mechanisms are proposed. Different amounts of arsenic, selenium, cadmium, and zinc can be retained in solid sorbents at high temperatures. It was observed that, in a coal gasification atmosphere, limestone, fly ashes and metallic oxide mixtures containing spinels, were the best sorbents, though in each case the retention capacity depended on temperature and atmosphere. Retention capacities between 16-24 mg g-1 were obtained using limestone and fly ashes for arsenic retention. For selenium, the maximum retention capacities ranging between 50-56 mg g-1 were attained using limestone. Alumina in a gasification atmosphere containing HCl was the best sorbent for zinc removal (52 mg g-1). The lowest retention capacities were obtained for cadmium, these being <1 mg g-1 for the different sorbents tested. Retention probably proceeds through different mechanisms, but in most cases a chemical reaction is involved.

Liquid metals and semiconductors under pressure

1987 ◽  
Vol 65 (3) ◽  
pp. 266-285 ◽  
Author(s):  
Hirohisa Endo ◽  
Kozaburo Tamura ◽  
Makoto Yao
Keyword(s):  
Thermodynamic Properties ◽  
Electronic Properties ◽  
High Temperatures ◽  
Alkali Metals ◽  
High Pressures ◽  
Liquid Metals ◽  
Chain Structure ◽  
Metal Metal ◽  
Impurity Elements ◽  
Liquid Alkali Metals

Studies on the electronic and thermodynamic properties of liquid metals and semiconductors at high temperatures and high pressures are reviewed. A substantial decrease of volume for liquid alkali metals is brought about by the application of pressure. The interference function of liquid alkali metals with high pressure can be described by the hard-sphere model with a fixed packing fraction when one proceeds along the melting curve. For liquid Cs, the s–d resonance scattering plays an important role in the electron-transport properties at high pressures. In expanded liquid Hg, a metal–nonmetal transition occurs at a density near 9 g∙cm−3, and anomalous behaviour is found in the thermodynamic properties such as equation-of-state and density fluctuations. At low densities, substantial volume contraction and a large increase in conductivity are brought about by the addition of a small amount of Bi. At high temperatures and high pressures, liquid Se is transformed from a semiconducting state to a metallic state, accompanied by modification of chain structure. The measurements of sound velocity and optical properties reveal that the temperature and pressure at which the semiconductor–metal transition occurs are lowered by the addition of Te. It is suggested that the semiconductor–metal transition observed in liquid Se is induced by increasing fluctuations in the interchain distance and increasing interchain coupling. The electronic properties of liquid Se are substantially changed by the addition of impurity elements such as alkalis and halogens. Modification of chain structure is associated with the charge transfer between Se chains and impurity elements. To understand how the interchain coupling affects the electronic properties of liquid Se, the properties of the isolated Se chains confined in the pores of mordenite are studied. The pressure effects on the two-phase separation of liquid binary mixtures, such as metal–metal, metal–semiconductor, and metal – ionic salt mixtures, are also discussed.

The Structure Factor of Expanded Liquid Alkali Metals at the Long-Wavelength Limit

1986 ◽  
Vol 41 (6) ◽  
pp. 823-825 ◽  
Author(s):  
K. N. Khanna ◽  
G. Shanker
Keyword(s):  
High Temperatures ◽  
Structure Factor ◽  
Random Phase Approximation ◽  
Alkali Metals ◽  
Random Phase ◽  
Phase Approximation ◽  
Long Wavelength ◽  
Wavelength Limit ◽  
Component Plasma ◽  
Liquid Alkali Metals

S (0 ) values of expanded alkali metals are calculated in random phase approximation. The results reproduce positive values of S (0) at sufficiently high temperatures showing the validity of RPA in one-component plasma systems.

X-ray Compton scattering experiments for fluid alkali metals at high temperatures and pressures

2015 ◽  
Author(s):  
K. Matsuda ◽  
T. Fukumaru ◽  
K. Kimura ◽  
K. Tamura ◽  
M. Katoh ◽  
...  
Keyword(s):  
Compton Scattering ◽  
High Temperatures ◽  
Alkali Metals ◽  
X Ray
Sign in / Sign up

Export Citation Format

Share Document