Characteristics of the Silica Slurry at the Botong Sector of the Bacon-Manit0 Geothermal Production Field

Abstract

The highly concentrated amorphous silica (= 1400 ppm) in Botong geothermal brine, a major concern in the cold injection scheme (Crs) of the fluid collection and disposal system 0, was collected by dropping the fluid's temperature and precipitating colloidal silica in a huge baffled thermal pond (TP-1). The collected silica slurry samples from 19 lanes of the TP-1 were characterized chemically, physically, and microscopically.

Physical characteristics of the slurry has similarity to pure water except in gel strength, 4.0 in 10 minutes. The slurry contains amorphous silica'of about 98.7 % pure in terms of SO2. Sedimenter ana' TEM analyses showed that the colloidal sizes of silica precipitates are 5 ,wn, Tests using a repigerated centrifuge showed satisfactory separation of the gelpom its corresponding brine medium at 4000 rprn for 5 minutes. These results will be further used for evaluation, proper handling, and storage of the accumrlated silica to be produced during the operation of the Backtan-IIpower plant.