GB/T 4699.4-2008Ferrochromium and silicochromium - Determination of carbon content - Infrared absorption method and gravimetric method (English PDF)

3.1 Principle

The sample is heated in a high frequency induction furnace combustion flow of oxygen, carbon dioxide generated by the oxygen contained in the measuring chamber to the infrared analyzer dioxide

Carbon absorption in a specific wavelength of infrared energy absorbed is proportional to its concentration can, according to the detector to accept the change in energy measured the amount of carbon.

3.2 Reagents and materials

3.2.1

acetone, the residue after evaporation, the carbon content is less than 0.0005%.

3.2.2

Magnesium perchlorate anhydrous particles.

3.2.3

asbestos caustic soda, granular.

3.2.4

glass wool.

3.2.5

tungsten particles, the amount of carbon is less than 0.002%, particle size of 0.8mm ~ 1.4mm.

3.2.6

tin particles, carbon content less than 0.002%, particle size 0.4mm ~ 0.8mm. If necessary, apply acetone (3.2.1) clean the surface and in the room

Warm and dry.

3.2.7

pure iron, carbon content less than 0.002%.

3.2.8

When oxygen purity of more than 99.95%, if other levels of oxygen to obtain a low and consistent blank, can also be used.

3.2.9

power source gas, nitrogen or compressed air, which contaminants (oil and water) content of less than 0.5%.

3.2.10

ceramic crucible diameter × height, 23mm × 23mm or 25mm × 25mm, and at more than 1200 °C high temperature furnace burning

4h or burned in oxygen burning to blank the lowest value.

3.2.11

crucible tongs.

3.3 instruments and equipment

3.3.1 Dingtan infrared absorption instrument (sensitivity of 1.0 × 10-6)

Its apparatus shown in Figure 1.