This standard specifies the principle, reagents and materials, apparatus, coal sample preparation, instrument calibration, determination procedures, result calculation, method precision and test report for determining the grindability (HGI) index of coal using the Hardgrove Method (hereinafter referred to as "Hardgrove").
This standard is applicable to soft coal and hard coal.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB 474 Method for Preparation of Coal Sample
GB/T 483 General Rules for Analytical and Testing Methods of Coal
GB/T 6003.1 Test Sieves — Technical Requirements and Testing — Part 1: Test Sieves of Metal Wire Cloth
GB/T 19494.2 Mechanical Sampling of Coal — Part 2: Method for Sample Preparation
3 Principle
Coal sample with a certain size range and mass grinded by Hardgrove grindability machine, and sieved under specified conditions; weigh the mass of coal sample on the sieve; the mass of sieved coal sample can be obtained from the mass of coal sample before grinded subtracts the mass of coal sample on the sieve; Hardgrove grindability index of coal may be looked up from a calibration chart prepared from standard reference material, or from the calculation of simple linear regression equation.
Before the determination of grindability index of coal, Hardgrove grindability test machine shall be calibrated with standard reference material for Hardgrove grindability index of coal.
