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OCR for page 40
40 Name SODIUM ALUMINATE CAS No .: 1302-42-7 Chemical Formula: NaAlO2 Description _: NAS/CWTC 0017/82 Formula Weight: 82 0 . A combination of sodium oxide and aluminum oxide with sufficient excess causticity to stabilize. Solid form usually contains 70-80% sodium aluminate; solutions, approximately 30% sodium aluminate. Used as coagulant . Purity Requirements The RMIC values are based on a maximum dosage of 40 mg of sodium aluminate/liter of water and are to be compared to impurity concentrations obtained by using sample proce- dures described in this monograph. If the actual dosage _ other than 40 mg/liter, the user is cautioned to consult Table 2 for appropriate RMIC values. Impurity Arsenic Cadmium Chromium Lead Mercury Selenium Silver RMIC mg Impurity/kg Sodium Aluminate 100 30 100 100 5 30 100

OCR for page 40
l 41 Bulk Sample Collection: 1 Sample in accordance with Standard for Sodium Aluminate, ANNA B405-60, American Water Works Association, Denver, Colorado (1960). Analytical Sample Preparation: In preparing samples, use acid-washed glassware and make all dilutions with deionized distilled water. Weigh 0.4 g of sodium aluminate (dry weight basis), dissolve, and make up to 1 liter in a volumetric flask. Transfer the solution to a 1.5-liter beaker, add 1 N of NaOH dropwise with constant stirring to adjust to pa 6. Mix well, let stand for 1 hour, and filter through a GF/C filter (or equivalent) with vacuum. Quantitatively transfer filtrate into a beaker, adjust to pH of 2 or less with concentrated HNO3, and evaporate on a hot plate, without boiling, to reduce the volume to less than 1 liter. Cool, quantita- tively transfer to a 1-liter volumetric flask, and make up to volume. Similarly, treat a reagent blank. Sample Analyses: The analyses are to be performed on the sodium aluminate solution in accordance with: Standard Methods for the Examination of Water and Waste- water, 15th Edition, American Public Health Association, Washington, D.C. (1981). Arsenic Cadmium Chromium Lead Mercury Selenium Silver Section 304 Section 304 Section 304 Section 304 Section 303F Section 304 Section 304