A methods of the present invention for inhibiting silica scale formation and
corrosion
in aqueous systems where soluble silica residuals (SiO2) are maintained
in excess of 200 mg/L, and source water silica deposition is inhibited with silica
accumulations as high as 4000 mg/L (cycled accumulation) from evaporation and concentration
of source water. The methods of the present invention also provides inhibition
of corrosion for carbon steel at corrosion rates of less than 0.3 mpy (mils per
year), and less than 0.1 mpy for copper, copper alloy, and stainless steel alloys
in highly concentrated (high dissolved solids) waters. 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.