GB/T 2565-2014Determination of grindability index of coal -- Hardgrove method (English PDF)

5074.1994 Hard Coal - Determination of Hardgrove grindability index.

As compared with ISO 5074.1994, this standard has some structural changes,

AND Appendix A provides the clause number comparison between this

standard and ISO 5074.1994.

There are technical differences between this standard and ISO 5074.1994,

and the terms involved in these differences have been indicated by a vertical

single line (︱) in the blank position on the outside margin. AND Appendix B

provides the list of the corresponding technical differences and their causes.

This standard was proposed by China Coal Industry Association.

This standard shall be under the jurisdiction of the National Coal

Standardization Technical Committee (SAC/TC 42).

The drafting organizations of this standard. Coal Science Research Institute -

Detection and Research Branch, Shenhua Sales Group Co., Ltd.

6.5 As for the prepared 0.63 mm ~ 1.25 mm coal sample, CONDUCT air drying

using the air drying method as specified in GB 474; after reaching to the air

drying state, FOLLOW Chapter 8 to conduct determination.

7.1 USE the Hardgrove grindability index standard substance of the coal to

calibrate the Hardgrove tester at least once every year using the methods as

specified in Appendix C.

7.2 In case of changing the operators and instruments, renewing or repairing

the equipment (including the test sieve), OR having doubt of the determination

results, it shall use the Hardgrove grindability index standard substance of the

coal to conduct calibration.

8.1 Test RUN the Hardgrove tester to check whether it is normal, AND the

tester shall be able to automatically stop running after (60 ± 0.25) r; CHECK

the surface of the 0.071 mm sieve and REPLACE it if it is loosened.

8.2 USE the short hair brush to thoroughly clean the grinding bowl, grinding

ring and steel ball, and MAKE the steel ball distribute into the groove of the

grinding bowl as evenly as possible.

8.3 MIX the 0.63 mm ~ 1.25 mm coal samples evenly; USE the riffle to reduce

8.4 WEIGH (50 ± 0.01) g of the coal sample (m) which had been removed of

coal powder, accurate t 0.01 g. POUR the coal powder evenly into the grinding

bowl; FLATTEN its surface; USE the short hair brush to clear the coal sample

falling onto the steel ball and the grinding bowl projections to the steel ball

surroundings; when the cross groove of the grinding ring is basically in line

with the cross head at the lower end of the main shaft direction, PLACE the

grinding ring in the grinding bowl.

Appendix C

(Normative)

Calibration of Hardgrove tester

C.1 USE the 4 Hardgrove grindability index standard substance of coal to

calibrate the Hardgrove tester, and MAKE the calibration diagram or

CALCULATE the unary linear regression equation parameters.

C.1.1 USE the Hardgrove tester to be calibrated to conduct determination of

the 4 Hardgrove grindability index standard substance of coals, with each

Hardgrove grindability index standard substance of coal being repeatedly

determined for 4 times; CALCULATE the mass of the substance passing

through the 0.071 mm sieve; CALCULATE four times of the arithmetic mean of

the mass of the substance passing through the 0.071 mm sieve.

C.1.2 On the rectangular coordinate system drawing, USE the arithmetic mean

of the mass of the substance passing through the 0.071 mm sieve as

determined four times as the ordinate AND the corresponding Hardgrove

grindability index standard substance as the abscissa to draw the test data of

the Hardgrove grindability index standard substance of the coal based on the

least square method. The resulting line is the calibration chart of the Hardgrove

tester (sieve, etc.)...

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