Instruments and Reagents:
Cat.No. 173016 Spectroquant® VIS Spectrophotometer Prove 100 or
Cat.No. 173017 Spectroquant® UV/VIS Spectrophotometer Prove 300 or
Cat.No. 173018 Spectroquant® UV/VIS Spectrophotometer Prove 600 or
Cat.No. 109748 Spectroquant® Photometer NOVA 30 or
Cat.No. 109751 Spectroquant® Photometer NOVA 60 or
Cat.No. 173632 Spectroquant® Colorimeter Move 100
Cat.No. 114946 Rectangular cells 10 mm and/or
Cat.No. 114947 Rectangular cells 20 mm and/or
Cat.No. 114944 Rectangular cells 50 mm
Cat.No. 114794 Spectroquant® Silicate (Silicic Acid) Test
Cat.No. 101164 Ammonium fluoride for analysis
Cat.No. 106495 Sodium hydroxide for analysis
Cat.No. 116754 Water for analysis
In a nickel crucible covered with a nickel plate heat about 100 mg of finely ground sample material at 650 °C for 30 minutes, with 8 pellets of sodium hydroxide. When the crucible is cold treat the contents with 10 mL of water for analysis and bring the melt-cake into suspension, with gentle warming.
Transfer the suspension, with water for analysis, into a 1000-mL standard volumetric flask, fill up to volume with water for analysis and mix well.
Transfer this solution immediately to a polyethylene flask, in which 0.2 g of ammonium fluoride has been put. Dissolve the salt completely and mix well. Analyse after a waiting period of 15 minutes.
Determine with the above mentioned test kit.