TM-46, Analysis of Cements and Fly Ashes

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This method analyzes cements and fly ashes by Inductively Coupled Plasma (ICP) Emission Spectroscopy. Reagents and Apparatus

1) Inductively Coupled Plasma Emission Spectroscopy conforming to the specifications set forth in ASTM C 114.

2) Graphite crucibles, 7.88 ml capacity, made from purified graphite.

3) Clear plastic beakers (Polypropylene), 250 ml capacity.

4) Magnetic stirring bars. The length of the bars used should be approximately 1/2 in. less than the inside diameter of the plastic beakers.

5) Lithium Metaborate (LiBO2), Reagent Grade, anhydrous.

6) Nitric Acid (HNO3). Sp. Gr. 1.42

7) NIST Standard and CCRL Samples. A supply of NIST cement and past CCRL proficiency samples stored in a desiccator. Procedure Selection of Standards

Select a series of NIST and past CCRL proficiency cement samples to bracket the expected concentration of the elements in the cement and/or fly ash samples. Preparation of standard solutions and sample solutions

Place a ¼ teaspoon of anhydrous LiBO2 into a graphite crucible. Using a test tube that just fits into the crucible, press down on the LiBO2 to make a bed at the bottom of the crucible. Weigh 0.2500 +/- .0005 grams of sample into the bed of LiBO2 and cover the sample with an additional ¼ teaspoon of LiBO2. Place the crucible in the mouth of a muffle furnace and heat at 1000°C for at least 30 minutes. Remove from the furnace and gently swirl to coagulate any particles of the fused mixture remaining on the walls of the crucible and immediately drop the fused bead into a clear polypropylene beaker containing 200 ml of 1:24 HNO3 and a Teflon coated magnetic stirring bar. Place the beaker on a magnetic stirring unit and stir for ten to fifteen minutes. Filter through Whatman No. 41 filter paper into a 250 ml volumetric flask. Wash the beaker and filter paper thoroughly with 1:24 HNO3. Dilute to volume with 1:24 HNO3 and mix well by inverting the volumetric flask multiple times. Prepare a fusion-blank solution in the same manner, omitting only the addition of sample.

Calibrate the ICP using the fusion-blank and the fused NIST and CCRL proficiency cement samples of varying concentrations for each analyte. Determine percent CaO, MgO, Fe2O3, TiO2 and SrO by pipetting 5 ml of the fused sample solution and create calibration lines using the same dilution with the NIST and CCRL proficiency cement stock solutions into a 100 ml volumetric flask and dilute to volume. The remaining analytes can be analyzed directly from the sample and stock solutions with no additional dilutions. Calculation and Report

Report the elements determined as follows:

% Silicon Dioxide (SiO2) % Chromium Oxide (Cr2O3)
% Aluminum Oxide (Al2O3) % Zinc Oxide (ZnO)
% Iron Oxide (Fe2O3) % Manganic Oxide (Mn2O3)
% Calcium Oxide (CaO) % Strontium Oxide (SrO)
% Magnesium Oxide (MgO) % Barium Oxide (BaO)
% Potassium Oxide (K2O)
% Sodium Oxide (Na2O)
% Titanium Dioxide (TiO2)
% Phosphorus Pentoxide (P2O5)