Uranium column leaching with variable influent waters

Knowledge graph centered on Uranium column leaching with variable influent waters with 10 nodes and 19 connections. Top connected: Grand Junction, Column-Test Data Analyses and Geochemical Modeling, Riverton, Monticello, Five-percent nitric acid leach.

Method synopsis

Stop-flow and continuous-flow column testing using various influent waters (deionized water, site groundwater, local river water) on uranium-contaminated sediments to determine reactive transport parameters. Includes both vadose zone and saturated zone testing conditions.

Synthesized from method descriptions across 1 paper using this protocol.

Procedure as described in the canonical source

Steps below were extracted from the paper that introduces this protocol — Column-Test Data Analyses and Geochemical Modeling to Determine Uranium Reactive Transport Parameters at a Former Uranium Mill Site (Grand Junction, Colorado) (2022), Minerals. Implementations in other papers (listed below) may differ.

1. Column construction
   Columns were custom built from plastic and plexiglass with a 5-centimeter inside diameter. Three different column lengths were used: 15 cm, 20 cm and 45 cm. The bottom of each column had a mesh filter disk that held the sediment in the column but allowed water to enter. When using 15-centimeter and 20-centimeter columns, they were filled completely with sediment and capped on both ends, with the top cap plumbed to a fraction collector. When using 45-centimeter columns, they were filled with approximately 20 cm of sediment.
   Quantities: 5-centimeter inside diameter, three lengths: 15 cm, 20 cm, 45 cm; 45 cm columns filled with approximately 20 cm sedimentDuration: Not specifiedConditions: Dry packed in lifts of approximately 5 cm with tamping
   Equipment: plastic and plexiglass columns, mesh filter disk, fraction collector, Gilson Model 206
2. Stop-flow column filling
   Stop-flow columns were filled with one pore volume (PV) of influent water at a rate of approximately 3 milliliters per minute. Once a PV was introduced, the flow to the column was stopped and the water was allowed to equilibrate with the sediment for 24 h. The next day, another PV of water was introduced into the column, pushing the prior PV out of the sediment.
   Quantities: One pore volume per filling, 3 mL/min flow rate, 24 h equilibrationDuration: 24 h equilibration between each pore volumeConditions: Laboratory conditions
   Equipment: laboratory peristaltic pumps
3. Continuous-flow column operation
   Influent water was introduced into the continuous-flow columns at a continuous 0.7 mL/min flow rate, which was the slowest constant flow rate that could be achieved with the influent pumps. This flow rate is equivalent to column-flow velocities of 130 to 170 cm/day, with porosities ranging from 0.29 to 0.36. The first PV was allowed to equilibrate with the sediment for 24 h before the continuous flow was started.

Typical Equipment

• plastic and plexiglass columns
• laboratory peristaltic pumps
• fraction collector
• 0.45-micron filter

Output Measurements

• uranium effluent concentrations
• calcium concentrations
• alkalinity
• pH
• specific conductance

Papers Using This Protocol (1)

Places Where Used