Chemical behaviour of geothermal silica after precipitation from geothermal fluids with inorganic flocculating agents at the Hawaii Geothermal Project Well-A (HGP-A)
The report summarizes the results of experiments dealing with the problem of removal of waste-silica from spent fluids at the experimental power generating facility in the Puna District of the island of Hawaii. Geothermal discharges from HGP-A represent a mixture of meteoric and seawaters which has reacted at depth with basalts from the Kilauea East Rift Zone under high pressure and temperature. After separation of the steam phase of the geothermal fluid from the liquid phase and a final flashing stage to 100 degrees Celsius and atmospheric pressure, the concentration of the silica increases to approximately 1100 mg/L. This concentration represents five to six times the solubility of amorphous silica in this temperature range. We have evaluated and successfully developed bench scale techniques utilizing adsorptive bubble flotation for the removal of colloidal silica from the spent brine discharge in the temperature range of 60 to 90 degrees C. The methods employed resulted in recovery of up to 90% of the silica present above its amorphous solubility in the experimental temperature range studied.
- Research Organization:
- Hawaii Univ., Honolulu (USA)
- DOE Contract Number:
- FG03-85SF15799
- OSTI ID:
- 6784371
- Report Number(s):
- DOE/SF/15799-T11; ON: DE87003991
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CHALCOGENIDES
CHEMICAL COMPOSITION
ENERGY SYSTEMS
FEDERAL REGION IX
FLOTATION
FLUIDS
GEOTHERMAL FLUIDS
GEOTHERMAL POWER PLANTS
GEOTHERMAL SYSTEMS
Geothermal Legacy
HAWAII
HYDROTHERMAL SYSTEMS
MANAGEMENT
MATERIALS RECOVERY
MINERALS
NORTH AMERICA
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POWER PLANTS
PROCESSING
RECOVERY
REMOVAL
SEPARATION PROCESSES
SILICA
SILICON COMPOUNDS
SILICON OXIDES
THERMAL POWER PLANTS
USA
WASTE MANAGEMENT
WASTE PROCESSING