A methods for inhibiting silica scale formation and corrosion in aqueous systems
where soluble silica (SiO2) can be maintained at residuals below 200
mg/L, but more preferably maintained at greater than 200 mg/L as SiO2,
without silica scale and with control of deposition of source water silica accumulations
as high as 4000 mg/L (cycled accumulation) from evaporation and concentration of
source water. The methods of the present invention also provide highly effective
inhibition of corrosion for carbon steel, copper, copper alloy, and stainless steel
alloys. The methods of the present invention comprise pretreatment removal of hardness
ions from the makeup source water, maintenance of electrical conductivity, and
elevating the pH level of the aqueous environment. Thereafter, specified water
chemistry residual ranges are maintained in the aqueous system to achieve inhibition
of scale and corrosion.
