ASTM E248-12 Determination of Manganese in Manganese Ores

Scope:

ASTM E248-12 covers procedure to determine the manganese in manganese ores by pyrophosphate complexed permanganate potentiometric titrimetry. This method can be applied to manganese ores containing manganese in the range from 15% to 60%. This definitive test method is intended to be used as a referee method for compliance with compositional specifications for manganese content.

Test procedure:

The test sample is decomposed by treatment with HCl, HNO₃, HF, and HClO₄. Sodium phosphate addition is done for adjustment of acidity. The manganese content is determined by oxidation of trivalent manganese by using a standard solution of potassium permanganate. Potentiometric titration apparatus is used for determining the end point (Figure 1). The end point is determined potentiometrically.

 Figure 1: Potentiometric titration apparatus

Specimen size:

A sample weighing 0.30 to 0.40 g is taken for the test.

Data:

The percentage of manganese is calculated as follows,

Where,

A = KMnO₄ solution required for titration of the

sample, mL

B = normality of the KMnO₄ solution, and

C = sample used, g.