Polyvalence, uranium

Diphoterine is a polyvalent, hypertonic, amphoteric, chelating hquid. The Equid nature rinses off surface contaminants. Its hypertonicity reduces the penetration of chemicals into the tissue by wicking the chemical agent out of tissue. The amphoteric nature neutralizes acids and bases. Also, Diphoterine can chelate radionuclides such as strontium, cobalt, cesium, or uranium and anions, such as oxalate, but doesn t chelate calcium or magnesium, which would cause biological damage to cells. 

To maintain solvent capacity for uranium and to prevent contamination of extracted uranium by iron, it is necessary to reduce iron to the unextractable ferrous condition before solvent extraction. This is done by contacting the leach liquor with scrap iron, SO2, or sodium sulfide. Because the iron content of leach liquor is high, reduction is costly, and the Amex process, in which ferric iron does not extract, is preferred for sulfuric acid leach liquors. The high distribution coefficient of other polyvalent cations such as Th and in EHPA makes the Dapex process less selective for uranium than the Amex process. 

Humic materials in soil strongly sorb many solutes in soil water and have a particular affinity for heavy polyvalent cations. Soil humic substances may contain levels of uranium more than 10" times that of the water with which they are in equilibrium. Thus, water becomes depleted of its cations (or purified) in passing through humic-rich soils. Humic substances in soils also have a strong affinity for organic... 

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