Separation of Uranium from Alkaline Earths and Alkalies

1888 ◽  
Vol 26 (653supp) ◽  
pp. 10438-10438
Author(s):  
A. Remele
Keyword(s):  
Alkaline Earths

Investigations on the filtration of natural aquatic suspensions supported by dosing small amounts of Fe(III)-salts (βFe ≤ 0.1 mg.L-1): mode of action and basic design criteria

2002 ◽  
Vol 2 (2) ◽  
pp. 91-98
Author(s):  
R. Winzenbacher ◽  
R. Schick ◽  
H.-H. Stabel ◽  
M. Jekel
Keyword(s):  
Large Scale ◽  
Suspended Solids ◽  
Iron Hydroxides ◽  
Essential Step ◽  
Iron Salts ◽  
Alkaline Earths ◽  
Co Precipitation ◽  
Solid Liquid ◽  
Solid Liquid Separation

Improved removal of particles during the treatment of natural aquatic suspensions has been achieved by pre-ozonation and the addition of small quantities of iron salts (βFe ≤ 0.1 mg.L-1; “Fe(III)-assisted filtration”) followed by rapid filtration. As shown by investigations on a large-scale installation at Lake Constance Water Supply, this procedure reliably reduces suspended solids by at least 2-3 powers of ten in long-term use. However, the high efficacy of Fe(III)-assisted filtration cannot be explained on the basis of known coagulation mechanisms (like adsorption-charge neutralization, co-precipitation). Instead, the essential step was found to be the conditioning of the filter medium by coating it with colloids containing Fe(OH)3, and this “Fe coating” process occurs only in the presence of alkaline earths (especially Ca2+). According to further experiments, the enhanced solid-liquid separation was ultimately traced to chemical interactions such as the formation of calcium-organic association structures between the iron hydroxides and other solids. For design of Fe(III)-assisted filtration steps, finally, a βCa/DOC ratio above 40 mg.mg-1 and pre-oxidation with ozone dosages not exceeding 2 mg O3/mg DOC was recommended.

Weathering mineral facies in altered granites: The importance of local small-scale equilibria

1979 ◽  
Vol 43 (326) ◽  
pp. 261-268 ◽  
Author(s):  
A. Meunier ◽  
B. Velde
Keyword(s):  
Chemical Composition ◽  
Alkaline Earth ◽  
Clay Mineralogy ◽  
Small Scale ◽  
Chemical Potentials ◽  
Silica Activity ◽  
Section Size ◽  
Alkaline Earths ◽  
Last Stage ◽  
Rock Alteration

SummaryClassical clay mineralogy determinations and electron microprobe analyses of weathering minerals developed in altered two-mica granites indicate that the chemical forces that produce new minerals are often constrained to small volumes, frequently on the scale of a mineral grain or contact between two grains in the granite.Chemical potentials such as pH, alkali and alkaline earth and silica activity in the altering aqueous solutions provoke a destabilization of pre-existing minerals, which recrystallize locally to give a new multimineral product. The chemical composition of the new phases is largely governed by the relative concentrations of the elements present in the former minerals.Three mineral facies were observed in the weathered granites: initially a sericite-beidellitic type, then a beidellite-kaolinitic type, and finally a last stage kaolinite-oxide facies assemblage. The position of each facies is not restricted to a given depth in the profile but the relative proportions of each facies found in a thin-section size sample change towards the kaolinite-oxide facies.The global rock chemistry reflects the type facies predominant in each sample. The first two facies are roughly silica conservative while the kaolinite-oxide facies loses silica as well as alkali and alkaline earths.Geochemical and clay mineral studies of rock alteration should consider problems of mineral genesis at very localized sites.

scholarly journals Bonding in Barium Boryloxides, Siloxides, Phenoxides and Silazides. A comparison with the lighter alkaline earths

2021 ◽  
Author(s):  
Erwann Le Coz ◽  
Joanna Hammoud ◽  
Thierry Roisnel ◽  
Marie Dallon ◽  
Vincent Dorcet ◽  
...  
Keyword(s):  
Alkaline Earths

GLASS STABILITY EFFECT OF IRON OXIDE ADDED TO ALKALINE EARTH BORATE GLASSES

2007 ◽  
Vol 21 (05) ◽  
pp. 731-736
Author(s):  
V. SIMON ◽  
P. RIEDL ◽  
E. TATARU
Keyword(s):  
Iron Oxide ◽  
Short Range ◽  
Alkaline Earth ◽  
Structural Changes ◽  
Opposite Effect ◽  
Glass Stability ◽  
Intermediate Range Order ◽  
Alkaline Earths ◽  
Stability Effect

Glass stability and the structural role of iron oxide in x Fe 2 O 3(100-x)[ B 2 O 3– MO ] systems ( M=Ca , Sr or Ba , 0≤x≤30 mol%) were estimated from differential thermal analysis. The results suggest structural changes characteristic for the transition from short range to intermediate range order as the cationic field strength of the alkaline earths increases. In contrast, the iron addition has an opposite effect and determines a higher glass stability of these systems.

scholarly journals CALCULATIONS OF BIOELECTRIC POTENTIALS

1939 ◽  
Vol 23 (1) ◽  
pp. 53-57 ◽  
Author(s):  
W. J. V. Osterhout
Keyword(s):  
Alkali Metals ◽  
Sea Water ◽  
Low Ph ◽  
Electrical Behavior ◽  
Low Concentrations ◽  
Alkaline Earths ◽  
Bioelectric Potentials

Interest in the study of Halicystis and of Valonia has been stimulated by discoveries of marked contrasts and striking similarities existing side by side. This is illustrated by new experiments with the alkali metals and alkaline earths. In Halicystis the apparent mobilities of K+, Rb+, Cs+, and Li+ (calculated by means of Henderson's equation from changes in P.D. produced by replacing sea water by a mixture of equal parts of sea water and 0.6 M of various chlorides) are as follows, uK, = 16, uRb = 16, uCs = 4.4, and uLi = 0.2; uNa is taken as 0.2. These values resemble those in Valonia except that in the latter uCs is about 0.2. No calculation is made for uNHNH4, because in these experiments even at low pH so much NH3 is present that the sign of the P.D. may reverse. This does not happen with Valonia. According to Blinks, NH4+ at pH 5 in low concentrations acts like K+. The calculation gives uMg = 1.9 which is similar to the value found for Valonia. No calculation can be made for CaCl2 since it produces protoplasmic alterations and in consequence Henderson's equation does not apply. This differs from Valonia. Evidently these plants agree closely in some aspects of electrical behavior but differ widely in others.

scholarly journals On a Method for the Separation of Alkaline Earths

1933 ◽  
Vol 54 (12) ◽  
pp. 1215-1222
Author(s):  
Otozo FUNAKOSHI
Keyword(s):  
Alkaline Earths

Renal tubular reabsorption of trace alkaline earths compared with calcium

1965 ◽  
Vol 208 (6) ◽  
pp. 1165-1170 ◽  
Author(s):  
W. Joseph Rahill ◽  
Mackenzie Walser
Keyword(s):  
Protein Binding ◽  
Transport Mechanism ◽  
Tubular Reabsorption ◽  
Constant Infusion ◽  
Constant Power ◽  
Calcium Clearance ◽  
Renal Tubular Reabsorption ◽  
Order Of Magnitude ◽  
Alkaline Earths ◽  
Renal Tubular

Simultaneous clearances of inulin, calcium, and either Be7, Ba140, or Ra226, given by constant infusion, were measured in salt-depleted dogs or dogs undergoing mild saline, mannitol, or sulfate diuresis. Urine-to-plasma ratios of all three cations less than 0.5 were noted, suggesting that all can be actively reabsorbed. Clearances of barium and radium were correlated with calcium clearance, but the clearance of beryllium was unpredictable. Protein binding of beryllium was shown to be of the same order of magnitude as other alkaline earths when errors due to adsorption of Be7 onto containers were minimized. Protein binding of barium averaged 54%. The excreted-to-filtered ratio for barium was a constant power (.54) of the ratio for calcium. The data do not exclude the possibility that these cations are reabsorbed by a common transport mechanism with calcium.

scholarly journals Instantaneous Spectrograms of the Alkaline Earths by Disruptive Discharge

1927 ◽  
Vol 3 (4) ◽  
pp. 208-211 ◽  
Author(s):  
Hantaro NAGAOKA ◽  
Daizo NUKIYAMA ◽  
Tetsugoro FUTAGAMI
Keyword(s):  
Alkaline Earths
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