GB/T 5449-2015Determination of roga index of bituminous coal (English PDF)

1 Scope

This Standard specifies the method summary, instruments and equipment, test procedures, result expression, and method precision for determining the Roga index (R.I.) of bituminous coal. This Standard applies to bituminous coal.

2 Normative References

The following documents are indispensable to the application of this document. In terms of dated references, only the version with the specified date applies to this document. In terms of references without a specified date, the latest version (including all the modifications) is applicable to this document.

GB 474 Method for Preparation of Coal Sample

GB/T 483 General Rules for Analytical and Testing Methods of Coal

3 Method Summary

1 g of bituminous coal specimen and 5 g of Roga index-specific anthracite are thoroughly mixed and coked under specified conditions. The resulting coke residue is subjected to a drum test in a specific drum, and the Roga index is calculated based on the test results.

4 Instruments and Equipment

4.1 Drum test device. it consists of two drums, with a rotational speed of (50 ± 0.5) r/min. The drum has an inner diameter of 200 mm, a depth of 70 mm and a wall thickness of 3 mm. Two baffles, 180° apart, are riveted to the wall. The baffles are 70 mm long, 30 mm wide and 3 mm thick. The drum has a lid, which tightly fits with the drum to ensure its airtightness. Specifications and dimensions are shown in Figure 1.

4.7 Stirring wire. made of nickel-chromium wire with a diameter of 1.0 mm ~ 1.5 mm. Specifications and dimensions are shown in Figure 5.

4.8 Briquetting block. made of nickel-chromium steel, with a mass of 110 g ~ 115 g. Specifications and dimensions are shown in Figure 6.

4.9 Round hole sieve. with an aperture of 1 mm.

4.10 Flat shovel. 180 mm ~ 200 mm long, approximately 20 mm wide, 1.5 mm high, handle length 600 mm ~ 700 mm.

4.11 Dryer.

5 Roga index-specific Anthracite

Anthracite for Roga Index determination shall meet the following requirements.

---Ad is less than 4.00%;

---Vdaf is less than 7.00%;

---Particle size 0.3 mm ~ 0.4 mm;

---Sieve undersize is not greater than 7.0%.

6 Coal Sample

The coal sample used for the Roga Index determination test of bituminous coal shall be prepared in accordance with GB 474. The portion with a particle size of 0.1 mm ~ 0.2 mm shall account for more than 20% of the total coal sample. The coal sample shall be placed in a sealed container.

The time from sample preparation to testing shall not exceed 5 days.

7 Test Procedures

7.1 First, weigh-take 5.000 g ± 0.005 g of special anthracite coal, then weigh-take 1.000 g ± 0.005 g of the test coal sample and place them in the crucible.

7.2 Use a stirring wire to stir the mixture in the crucible for 2 minutes. The stirring method is as follows. tilt the crucible at approximately 45° and rotate it counterclockwise at approximately 15 r/min. Rotate the stirring wire clockwise at the same tilt angle at approximately 150 r per minute. During stirring, the ring of the stirring wire shall contact the arc part connecting the crucible wall and bottom. After approximately 1 minute and 45 seconds, continue stirring while gradually rotating the crucible and the stirring wire to a vertical position. After approximately 2 minutes, the stirring ends. During stirring, prevent the coal sample from splashing out.

NOTE: a mechanical device that achieves the same stirring effect may also be used.

7.3 After stirring, use a brush to gently brush off the coal powder from the crucible wall. Use a stirring wire to carefully level the mixture, ensuring that the layer along the crucible wall is slightly lower by 1 mm ~ 2 mm. This will allow the coal sample surface to be level after the briquetting block compacts the mixture.

7.4 Use tweezers to place the briquetting block in the center of the crucible, then place it under the pressure device. Gently lower the pressure rod and apply pressure for 30 seconds.

7.5 After pressure is applied, leave the briquetting block on the mixture and cover the crucible with a lid. Throughout the entire process, handle the crucible containing the sample with care to avoid impacts and vibrations.

7.6 Pre-heat the muffle furnace to approximately 850 °C. Open the furnace door and quickly move the crucible rack containing the crucible into the constant-temperature zone. Immediately close the furnace door and start timing; precisely heat for 15 minutes. After placing the crucible rack and crucible, it is required that the furnace temperature recovers to 850 °C ± 10 °C within 6 minutes, and then be maintained at 850 °C ± 10 °C. The heating time includes the temperature […]