Analytical Method: Sulfate in Building Materials

Instruments and Reagents

Product No. 173016 Spectroquant^® VIS Spectrophotometer Prove 100 or
Product No. 173017 Spectroquant^® UV/VIS Spectrophotometer Prove 300 or
Product No. 173018 Spectroquant^® UV/VIS Spectrophotometer Prove 600 or
Product No. 109748 Spectroquant^® Photometer NOVA 30 or
Product No. 109751 Spectroquant^® Photometer NOVA 60 or
Product No. 173632 Spectroquant^® Colorimeter Move 100
Product No. 114946 Rectangular cells 10 mm and/or
Product No. 114947 Rectangular cells 20 mm and/or
Product No. 114944 Rectangular cells 50 mm
Product No. 114794 Spectroquant^® Silicate (Silicic Acid) Test
Product No. 101164 Ammonium fluoride for analysis
Product No. 106495 Sodium hydroxide for analysis
Product No. 116754 Water for analysis

Sample Preparation

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.

Analysis

Determine with the above mentioned test kit.

Calculation

Sulfate (water-soluble) content in % = analysis value in mg/l x 0.004
Sulfate (total) content in % = analysis value in mg/l x 0.1