Role of ion exchange reactions in the in situ leaching of uraninite by NH{sub 4}HCO{sub 3} -- (NH{sub 4}){sub 2}CO{sub 3} -- H{sub 2}O{sub 2}

Conference · Tue Oct 01 04:00:00 EDT 1996

OSTI ID:372089

Brantner, J; Liddell, K ^[1]

---

1. Washington State Univ., Pullman, WA (United States). Chemical Engineering Dept.

Ion exchange on clay mineral surfaces can alter the concentrations of solution species, the solubility of other minerals that share a common cation, and the porosity and permeability of the host formation. Equilibrium cation exchange reactions involving NH{sub 4}{sup +}, Na{sup +}, K{sup +}, H{sup +}, Ca{sup 2+}, and Mg{sup 2+} were incorporated in a mathematical model for the in situ leaching of UO{sub 2} by solutions of NH{sub 4}HCO{sub 3}, (NH{sub 4}){sub 2}CO{sub 3}, and H{sub 2}O{sub 2}. The clay surface was assumed to be in equilibrium with ground water initially; contact with leach solution resulted in displacement of the Na{sup +}, K{sup +}, H{sup +}, Ca{sup 2+}, and Mg{sup 2+} cations from the clay, often accompanied by precipitation of calcite and magnesite. Development of the ion exchange model is described and implications for successful in situ uranium recovery and ground water restoration are discussed.

• OSTI ID: 372089
• Report Number(s): CONF-960202--; ISBN 0-87339-312-0
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AMMONIA
CALCIUM CARBONATES
CALCIUM IONS
CATIONS
CLAYS
EQUILIBRIUM
EXTRACTION
GROUND WATER
HYDROGEN IONS
MAGNESIUM CARBONATES
MAGNESIUM IONS
MATERIALS RECOVERY
MATHEMATICAL MODELS
MONTMORILLONITE
PERMEABILITY
POROSITY
POTASSIUM IONS
PRECIPITATION
SODIUM IONS
SOLUTION MINING
TIME DEPENDENCE
URANIUM OXIDES