Determination of Potassium, Sodium, and Total Alkalies in Portland Cement, Fly Ash, Admixtures, and Water of Concrete by a Simple Flow Injection Flame Photometric System

Abstract EN

A simple flow injection with flame photometric detection has been developed for determination of sodium, potassium, and total alkalies in portland cement, fly ash, admixtures, and water of concrete.

A liquid sample or a digest of solid sample was injected into a water carrier stream which flowed to a flame photometer.

A change in emission intensity at a selected wavelength was recorded as a peak.

An amplifier circuit was fabricated, which helped improve sensitivity of the flame photometer.

Calibration graphs in the range of 0.05–1.0 mg L−1 and 1.0–20.0 mg L−1 were obtained with a detection limit of 0.02 mg L−1, for both potassium and sodium determination.

Relative standard deviations for 11 replicates of injecting of 10 mg L−1 potassium and sodium solutions were 1.69 and 1.79%, respectively.

Sample throughput of 120 h−1 was achieved.

The proposed method was successfully applied to portland cement, fly ash, admixtures, and water samples validated by the ASTM standard method and certified reference materials of portland cement.