GB/T 1573-2018Determination of the thermal stability of coal (English PDF)

1 Scope

This Standard specifies the method summary, apparatus, samples, determination procedures, result expression, method precision and test report for the determination of thermal stability of coal. This Standard applies to lignite, anthracite and non-caking bitumite.

2 Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition dated applies to this document. For undated references, the latest edition of the referenced documents (including all amendments) applies to this document.

GB/T 474, Method for preparation of coal sample

GB/T 483, General rules for analytical and testing methods of coal

3 Terms and definitions

For the purposes of this document, the following terms and definitions and those defined in GB/T 483 apply.

6 Sample

Prepare about 2 kg of air-dried coal sample of particle size 6 mm ~ 13 mm in accordance with GB/T 474; carefully screen out the coal sample of particle size less than 6 mm; divide into two after mixing up.

7 Determination procedures

7.1 Use crucibles to take 500 cm³ of coal sample from two shares of coal sample respectively; weigh (accurate to 0.02 g) and make the difference in the masses of the two coal samples not greater than 1 g. Place each coal sample into 5 crucibles; put on the crucible cover and place the crucibles on the crucible holder. For the repeated determination of each sample, it shall not be heated in the same furnace.

7.2 Rapidly put the crucible holder holding crucibles into the constant-temperature zone of the muffle furnace which has been heated to 900°C; shut the furnace door; adjust the furnace temperature to 850°C, to heat the samples for 30 min at the temperature exactly. After the crucibles and crucible holder are in place, it is required that the furnace temperature is recovered to (850 ± 15)°C within 8 min; maintain it at (850 ± 15)°C after this. Or else, the test is void. The heating time includes the temperature recovery time.

7.3 Take the crucibles from the muffle furnace; cool to room temperature; immediately weigh the total mass of each share of residual coke (accurate to 0.02 g).

7.4 Overlap the screens of mesh sizes 6 mm and 3 mm and bottom tray on the sieve shaker; pour one share of residual coke weighed into the 6 mm screen; put on the sieve cover and fix it.

7.5 Start the sieve shaker for screening for 10 min.

7.6 Weigh respectively the masses (accurate to 0.02 g) of all grades of residual coke of particle size 6 mm, 3 mm ~ 6 mm and less than 3 mm. Compare the total of the masses of residual coke of all particle sizes and the total mass of residual coke before screening, and the difference between the two shall not exceed ± 1 g, or else, the test is void.

8 Expression of results

8.1 The index of thermal stability and the auxiliary index of thermal stability of coal are calculated in accordance with Formulas (1) ~ (3). […]