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    • ChemScan Mini Analyzer >
      • mini oP (Ortho Phosphate)
      • mini oP (Ortho Phosphate) Extended Range
      • mini LoP (Low Ortho Phosphate)
      • mini UV-254
      • mini LowAm (Low Ammonia)
      • mini Mn (Manganese)
      • mini LowChlor (Low Chlorine)
      • mini Sulfite
      • mini Mono (Monochloramine)
      • mini FreeAm (Free Ammonia)
      • mini Cu (Copper)
      • mini CrVI
      • mini Low CrVI
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      • mini Ni (Nickel)
      • mini Silica
    • ChemScan mini Accessories
    • ChemScan Process Analyzers >
      • ChemScan 2150/S Chloramination Analyzer
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      • ChemScan 2150/NoP Chem Feed Analyzer
      • ChemScan 2150/NHoP Nutrient Analyzer
      • ChemScan 2150 Process Analyzer
      • ChemScan UV-3150 Process Analyzer
      • ChemScan 4100 Nutrient Control
      • ChemScan 6101 Nutrient Control
    • ChemScan Alkalinity Analyzer >
      • For Wastewater
      • For Water
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Silica Analysis

​​​​​​​​Silica is the most abundant element after oxygen. It is commonly found in crystalline form such as in quartz or combined with other oxides and metals in a variety of silicates. Silica is only slightly soluble in water, resulting from the gradual degradation of silica-containing minerals. In solution, silica can exist as silicic acid or silicate ion, depending upon pH.

Silica concentration is of particular interest for steam power generation and for cooling water systems. The silica in these systems can form a silicate scale on turbine blades and heat exchange tubes. Thus, analysis of silica is important for safe and efficient operation of these systems. Silica removal, typically through ion exchange or precipitation, can be monitored to assure silica free water for steam production or recirculating cooling water.

ChemScan Analytical Method

The ChemScan analytical method is a variation of ASTM D859-94 and Standard Method 4500-Si.D, sometimes called the Molybdosilicate Method. The method is based on the reaction between ammonium molybdate and reactive forms of silica at low pH.

​Forms of silica that react with ammonium molybdate include dissolved silicate ion, monomeric silica, silicic acid and some polymeric silica. Phosphate is also reactive, but the interference can be eliminated with the addition of oxalic acid. Because the ChemScan analysis is performed at multiple wavelengths in the ultraviolet and near visible wavelength ranges, the effects of phosphate reaction with ammonium molybdate at visible wavelengths may be able to be compensated without oxalic acid. However, if phosphate is to be detected in addition to silica, analysis by ChemScan is performed before and after the oxalic acid introduction to separate molybdate reactive phosphate from molybdate reactive silica.






Applied Spectrometry Associates, Inc.
2325 Parklawn Dr., Suite I, Waukesha, WI 53186
​Phone: 262-717-9500
Toll Free: 800-665-7133

Contact Us

  • Home
  • Applications
    • Municipal Water Monitoring >
      • Ammonia Feed
      • Chloramination Control
      • Chlorination
      • Color Analysis
      • Distribution Monitoring
      • Hardness Monitoring
      • Ion Exchange Breakthrough
      • Natural Organic Matter (NOM) Removal
      • Peak Point Chloramination Control
      • Phosphate Sequesterant Feed Control
      • Reservoir Monitoring
      • Security Monitoring
      • TOC Monitoring
      • Well Blending
    • Wastewater Monitoring and Control >
      • Aeration Control and Energy Cost Reduction
      • Biological Nutrient Removal
      • Biological Phosphorus Removal
      • Chemical Phosphorus Removal
      • Chloramination /Breakpoint Avoidance
      • Chlorination/De-Chlorination
      • De-Nitrification Monitoring
      • Nitrification
      • Nutrient Deficiency Analysis
      • Lagoon Discharge
      • SBR Stage Control
      • TOC Monitoring
      • UV Disinfection Control
    • Industrial Water Treatment >
      • Boiler Water Analysis
      • Cooling Water Analysis (Closed Loop)
    • Industrial Process Monitoring >
      • Electroless Plating
    • ASA Technical Papers (ALL)
    • ChemScan Installation Photos
  • Service
    • Contact Service
    • ChemScan Service Team
    • MSDS
    • Communication Protocols
    • Software Utilities
    • Service Videos
  • Parts
  • Company
    • Terms and Conditions
    • Contact Form (General Inquiry)
    • Contact Service
    • Application Data Sheet
    • Employment Opportunities
    • Representatives and Distributors
  • Products
    • ChemScan Mini Analyzer >
      • mini oP (Ortho Phosphate)
      • mini oP (Ortho Phosphate) Extended Range
      • mini LoP (Low Ortho Phosphate)
      • mini UV-254
      • mini LowAm (Low Ammonia)
      • mini Mn (Manganese)
      • mini LowChlor (Low Chlorine)
      • mini Sulfite
      • mini Mono (Monochloramine)
      • mini FreeAm (Free Ammonia)
      • mini Cu (Copper)
      • mini CrVI
      • mini Low CrVI
      • mini Fe (Iron)
      • mini Ni (Nickel)
      • mini Silica
    • ChemScan mini Accessories
    • ChemScan Process Analyzers >
      • ChemScan 2150/S Chloramination Analyzer
      • ChemScan 2150/DC Chem Feed Analyzer
      • ChemScan 2150/N Aeration Rate Analyzer
      • ChemScan 2150/NoP Chem Feed Analyzer
      • ChemScan 2150/NHoP Nutrient Analyzer
      • ChemScan 2150 Process Analyzer
      • ChemScan UV-3150 Process Analyzer
      • ChemScan 4100 Nutrient Control
      • ChemScan 6101 Nutrient Control
    • ChemScan Alkalinity Analyzer >
      • For Wastewater
      • For Water
    • ChemScan Accessories