Hardgrove grindability index. [ ′här‚grōv ‚grīn·də′bil·əd·ē ‚in‚deks] (engineering) The relative grindability of ores and minerals in comparison with standard coal, chosen as 100 grindability, as determined by a miniature ballring pulverizer. Also known as Hardgrove number.
The Hardgrove grindability test and test machinery are designed and developed to characterize the relative grindability of coals. The Hardgrove grindability index represents a composite physicomechanical property of the coal, embracing a number of specific properties such as hardness, strength, tenacity and fracture, and is a function primarily of coal rank and secondarily of coal type.
HARDGROVE GRINDABILITY INDEX MACHINE ( HGI ) Measures the Coal resistance in milling and crushing The Hardgrove Grindability Index Machine allows many different types of coal users to determine how coal will perform in milling machines, allowing engineers to estimate grinding power and throughput capacities. (HGI) is
· The Hardgrove Grindability Index was developed in the 1930s from experimental work by R. Hardgrove to determine the relative difficulty of reducing various coals to a particle size required for ...
Foaming index, which is the measurement of gas capturing potential of the slag, is calculated from the height and gas flow rate. Viscosity and surface tension, which are the key properties for the foaming index, are calculated by Urbain's model and additive method, respectively.
Hardgrove Index Mills. one of them is the hardgrove index, associated mainly with vertical spindle mills and the other is bonds grindabilityssociated with tumbling mills prasherj987onds grindability can be empirically related to the energy required for comminution and thus is.
The Hardgrove Grindability Index is calculated on four splits (or portions), two each taken from the two reserved cans. The results are averaged to give the index for the entire lot. Cans of standard reference sample are shipped to customers upon request, along with a questionnaire designed by ASTM to obtain data on the quality of the sample.
of the slag. The earliest models used the basicity (%CaO/ %SiO 2) or basicity indices where different weights were given to different basic oxides ( CaO, MgO, or FeO). The most widely used parameter is the ratio of NBO to tetragonal ions (NBO/T), which is calculated using Equation . NBO/T is a measure of the depolymerization of the slag ...
Hardgrove Grindability Tester measures relative ease of pulverization of coals compared to standard coals in accordance with ASTM D409 Hardgrove Machine resulting Hardgrove Grindability Index (HGI) provides a measure of the energy required in a grinding process or a measure of yield for given energy input.
Hardgrove index is one of the tests applied in coal preparation plants to determine the grindability of coal. This test method is a simple, fast and efficient method and is widely used because it is reproducible under laboratory conditions. High Hardgrove index values indie that coal is easy to grind, while small Hardgrove index values ...
· HGI in Coal or the Hardgrove Grindability Index Testing of coal is used to determine the ease with which coal can be ground up into smaller particles. When coal is in large pieces, it is burnt less efficiently. In industry, energy can be more easily obtained .
· Re: Hardgrove Grindability Index 09/23/2010 6:02 AM Indeed, ball and race type mills are not designed for products with a HGI much lower than 50 (some suppliers decline responsibility if such coal is grinded in their mills): since mechanical pressure is applied with the balls, if the product is too hard to grind, there won't be enough product between the ball and the lower rotating race.
ISO 5074:2015 specifies the method for determining the grindability index of hard coal using the Hardgrove machine. It also specifies the procedure for calibrating the test machine and for preparing the standard reference coal samples. NOTE In this International Standard, the term "hard coal" is used as an indiion of maturity or rank in the ...
· Dear Experts, I am working in Bulk handling equipment company one of our client specfiion given hardgrove index for designing the bucket wheel cutting force. I am not able to understand how hardgrove index no convert in cutting resistance of material. The material is coal having density T/ please give me reply if you have.
2 Slag Activity Index Clause 6 Table 2 Vibration machine with timer cube mould fitting assembly 12000 ± 400 vibration per min. Compressive Strength machine Poking Rod, Petroleum Jelly Proving ring with all accessories suitable for calibration of CST machine Tachometer Cube Moulds × .
Hardgrove Grindability Index (HGI) 45 – 70: Nominal Topsize: 50 mm: IDT: Min 1,200 °C in a reducing atmosphere: Chlorine (DB) % Max: Fluorine (DB) 200µg/g Max: Phosphorous (DB) % Max: Mercury (DB) µg/g Max: Arsenic (DB) 80µg/g Max: Size restriction