hardgrove grindability index iron ore Hitlers
hardgrove grindability index iron ore. The resulting Hardgrove Grindability Index HGI provides a measure of energy required in a grinding process or a measure of yield for a given energy input A prepared 50g sample of No 16No 30 sieve size coal and eight 1in 254mm diameter polished steel grinding balls are placed in a stationary bowl having a machined circular track