Scope:

ASTM E248 covers the 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 of 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 used in ASTM E248 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 ASTM E248 test.

Data:

For ASTM E248, 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.

Conclusion:

ASTM E248 covers the procedure to determine the manganese in manganese ores by pyrophosphate complexed permanganate potentiometric titrimetry.