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OCR for page 61
61 NAS/CWTC 0 3 2-82 Name: SODIUM CALCIUM MAGNESIUM POLYPHOSPHATE, GLASSY CAS No.: 65997-17-3 Formula Weight: Unknown Chemical Formula: (MPO3) n M2O Where M = Na, 1/2 Ca, 1/2 Mg n = P2O5 = 66-70% Description: White to colorless plates, granules or powder. Use: 5 Corrosion inhibitor, stabilizer for dissolved copper, iron, and magnesium and as a threshold scale inhibitor. Purity Requirements: Analyses of available grades of sodium calcium magnesium polyphosphate (glassy) show the presence of cadmium and lead, but at levels far below that which would necessitate RMIC values based on a maximum dosage of 15 mg/liter. If analyses are desired, the following protocol is recom- mended. Bulk Sample Collection: Sample in accordance with Standard for Sodium Tripoly- phosphate, AWWA B503-78, American Water Works Associa- tion, Denver, Colorado (1978).

OCR for page 61
62 Analytical Sample Preparation: Weigh out 2.5 g of sodium calcium magnesium polyphosphate. In a 150-ml acid-washed beaker, dissolve the sample in 100 ml of deionized distilled water. Under a hood, acidify the solution with concentrated HNC3 to a pH of less than 2. Gently heat the solution to reduce the volume below 100 ml, making certain that it does not boil. Quantita- tively transfer to a 100-ml acid-washed volumetric flask and make to volume with deionized distilled water. Pro- cess a reagent blank by the same procedure. Sample Analyses: The analyses are to be performed on the sodium calcium magnesium polyphosphate solution in accordance with: Standard Methods for the Examination of Water and Waste- water, 15th Edition, American Public Health Association, Washington, D.C. (1981). Cadmium Lead Section 304 Section 304