GB/T 6730.6-2016 in English

Determination of metallic iron content in iron ore

Standard background and technological evolution

GB/T 6730.6-2016 replaces the old version of 1986. The main improvements include: the measurement range is extended to 0.150%~3.00%, the internal magnetic separation method is used to separate non-magnetic materials, and the joint precision test between laboratories is introduced.

Comparison of standard frameworks

Instruments and reagents

The required instruments include: glass culture dish, ferrite magnet and adjustable speed magnetic stirrer. As for reagents, ferric chloride solution and potassium dichromate standard titrant are mainly used.

Analysis steps

1. Sample decomposition:After magnetic separation, the sample is treated with ferric chloride-sodium acetate solution under electromagnetic stirring for 40 minutes, and the magnetic material is separated by filtration.
2. Titration analysis:Sulphuric acid and phosphorus mixed acid and indicator are added to the filtrate, and titrated with potassium dichromate standard titrant until the purple color is stable.
3. Blank test: Carry out a blank test along with the sample and calculate the volume of the titrant consumed to determine the metallic iron content.

Implementation suggestions

To ensure the accuracy of the results, it is recommended that:

• Inter-laboratory precision tests be conducted to verify the reliability of the method.
• Use standard samples to accept the analytical values to ensure that there is no significant difference between the results and the standard values.
• Round the results according to GB/T 8170, retaining two or three decimal places, depending on the content.