How is Silica Reacted upon by Internal Treatment?
In untreated waters silica tends to precipitate out directly as scale at hot spots on the boiler metal or it may combine with calcium to produce a hard calcium silicate scale.Treatment for silica involves keeping the boiler-water alkalinity high enough to hold silica in solution. Usually there is enough magnesium in the water to precipitate some of the silica as sludge. At times proper treatment with magnesium can tie up silica when it is a special problem. Some organic materials such as starches tend to prevent the adherence of silica to the boiler metal probably by a physical action.
