MadSci Network: Environment & Ecology

Re: What will remove silica and silicon from water?

Date: Fri Mar 5 20:57:13 1999
Posted By: Mark Madachik, PD, Heartland Farm/Nursery
Area of science: Environment & Ecology
ID: 920567325.En

Hi Ed.
Silica refers to naturally occurring minerals composed principally of 
silicon dioxide (SiO2). Silicon dioxide exists in both crystalline and 
amorphous forms. Quartz, cristobalite and tridymite are the three most 
common crystalline forms. These forms are interrelated and can change 
their form under different conditions of temperature and pressure. There 
are two different forms of quartz that are designated by the prefixes 
alpha and beta. The most common form is alpha-quartz which is a major 
component of igneous rocks, such as granite and pegmatite, but is also 
found in sandstone and sedimentary rock such as slate and shale. Beta-
quartz is less common. Many synthetic forms of quartz also exist.
Crystaline silica or essentially sand can be removed mechanically with as 
turbo separaterwhich essentially has a container that the sand settles do 
to the swirling motion of the water and then physically  removed.

Silica is found in makeup water from regions of high volcanic activity. 
Parts of California, New Mexico, Mexico, and other regions contain silica 
concentrations in excess of 30 mg/L in the makeup water. 
Silica scale can take many forms. Amorphous silica scale or water glass 
will form in the coolest and lowest pH portions of a system. This is 
opposite of calcium carbonate that will deposit in the hottest and highest 
pH portion of a system.
Silica will react with divalent metal cations such as iron and magnesium. 
The resultant scale will be very hard and difficult to remove. Mineral 
acids such as hydrochloric, sulfamic, citric, and sulfuric have no effect 
on dissolving silica. Toxic acids such as Hydrofluoric (HF) or other 
fluoride compounds such as Ammonium Bifluoride (ABF) must be used to 
remove silica scale. 
Without special treatment schemes, maximum acceptable silica 
concentrations in cooling towers is 150 to Silica chemistry is very site 
specific because silica can react with a wide variety of ions. 

Silicon does not occur as a free element in nature, but it occurs as 
silicates and silicon dioxide as above so what you are telling me about 
silicon cannot be  possible unless it is being place within the water 
source artificially.  You didn't say water your water source is (city, 
well, pond, etc)  but as I say the silicon would have to be added to the 
supply to exist there and I would be more concerned about that if it is 
indeed happening..   
I hope this imformation helps….Mark

Current Queue | Current Queue for Environment & Ecology | Environment & Ecology archives

Try the links in the MadSci Library for more information on Environment & Ecology.

MadSci Home | Information | Search | Random Knowledge Generator | MadSci Archives | Mad Library | MAD Labs | MAD FAQs | Ask a ? | Join Us! | Help Support MadSci

MadSci Network,
© 1995-1999. All rights reserved.