Separation of silica from spent geothermal fluids by adsorptive bubble techniques

Journal Article · Thu Jan 01 00:00:00 EST 1987 · Sep. Sci. Technol.; (United States)

DOI:https://doi.org/10.1080/01496398708057181· OSTI ID:6014929

De Carlo, E H; Ronay, C

A method is described for the separation of amorphous silica from super-saturated high ionic strength geothermal fluids produced by the Hawaii Geothermal Project Well-A. A bench-scale technique which makes use of adsorptive bubble flotation is employed to remove silica after flocculation by the addition of polyvalent metal ions to hot (60-90/sup 0/C) spent brine discharge. Ferric and aluminum salts are evaluated as flocculants under varying conditions. The anionic surfactant sodium lauryl sulfate and the cationic surfactant lauryl amine hydrochloride (LA) are utilized as the collectors below and above the isoelectric point, respectively. Efficiency of removal of the silica is pH, metal concentration, and surfactant-type dependent. Best results are achieved under slightly alkaline conditions (pH = 8), using 3.75 x 10E/sup -4/ M ferric ion present as its sulfate, La as the collector, and with a gas flow of 15 +/- 3 mL/min. Under these conditions, approximately 70 +/- 2% of the total silica is separated from the brine discharge; this value, although not quantitative, represents more than 85% removal of the silica present above its amorphous solubility at the operating temperature. After the separation process, fluids contain residual concentrations of silica which are not expected to result in scale deposition and which can then be passed through heat exchangers to extract further energy for secondary uses.

• Research Organization: Univ. of Hawaii, Honolulu
• OSTI ID: 6014929
• Journal Information: Sep. Sci. Technol.; (United States), Vol. 22:4
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
15 GEOTHERMAL ENERGY
54 ENVIRONMENTAL SCIENCES
BUBBLES
SORPTIVE PROPERTIES
ADSORPTION
BENCH-SCALE EXPERIMENTS
BRINES
COLLOIDS
EXPERIMENTAL DATA
FLOCCULATION
FLOTATION
GEOTHERMAL FLUIDS
PH VALUE
QUANTITY RATIO
SURFACTANTS
DATA
DISPERSIONS
FLUIDS
INFORMATION
NUMERICAL DATA
PRECIPITATION
SEPARATION PROCESSES
SORPTION
SURFACE PROPERTIES
400105* - Separation Procedures
150600 - Geothermal Energy- Environmental Aspects
520200 - Environment
Aquatic- Chemicals Monitoring & Transport- (-1989)