Study of silca scaling from geothermal brines. Semiannual progress report May 15, 1975--November 14, 1975. [95/sup 0/C]
Further studies have been made of factors influencing the rate of rejection from true solution of excess silica contained in geothermal brine. Prominent influences on the course of this precursor step in silica scaling include degree of supersaturation with respect to silicic acid monomer, concentration of dissolved salt, brine pH and temperature. Most of the measurements were made at 95/sup 0/C, an especially pertinent temperature because it approximates that of a hot brine after flashing. Concurrent analyses for silicic acid monomer and total dispersed silica in a 2 percent brine at 95/sup 0/C and pH 5 revealed a growth and decay of non-monomeric silica concentration, superimposed on the disappearance of monomer. Consistent with this behavior, the non-monomeric species eventually precipitated out of solution (as floc or as scale), while the monomer concentration approached a saturation value characteristic of the brine composition and temperature. The observed sequence suggests that monomer combines with polymeric species, and the latter grow and aggregate into flocculent silica or scale. A practical implication of these results is the possible retardation of scaling through inhibition of silica polymerization.
- Research Organization:
- Eic, Inc., Newton, Mass. (USA)
- OSTI ID:
- 7198708
- Report Number(s):
- COO-2607-2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
150903* -- Geothermal Engineering-- Corrosion
Scaling & Materials Development
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
BRINES
CHALCOGENIDES
CHEMICAL PREPARATION
CHEMICAL REACTIONS
DISPERSIONS
FLOCCULATION
FLUIDS
GEOTHERMAL FLUIDS
Geothermal Legacy
HYDROGEN COMPOUNDS
INORGANIC ACIDS
MEDIUM TEMPERATURE
MINERALS
MIXTURES
MONOMERS
OXIDES
OXYGEN COMPOUNDS
PH VALUE
POLYMERIZATION
PRECIPITATION
SALINITY
SATURATION
SCALING
SEPARATION PROCESSES
SILICA
SILICIC ACID
SILICON COMPOUNDS
SILICON OXIDES
SOLUTIONS
SUPERSATURATION
SYNTHESIS