What does a low Hardgrove grindability index indicate?
What does a low Hardgrove grindability index indicate?
Hardgrove Grindability Index (short HGI) is a measure for the grindability of coal. The smaller the HGI, the harder is coal texture and less grindable is the coal.
Which type of coals have the highest grindability index?
4. Which type of coals have the highest grindability index? Explanation: Grindability is the ease with which a coal can be grounded. The grindability index of pulverised coal is about 100.
What is grinder index?
A measure of the grindability of a material under specified grinding conditions, expressed in terms of volume of material removed per unit volume of wheel wear.
How do you calculate HGI of coal?
The HGI grindability value is calculated from the following formula: HGI = 13+6,93(50-m) The m value is the weight of oversize expressed in grams. The Hardgrove grindability index value is influenced by petrographic composition of coal.
What is HGI petcoke?
5.1 The HGI is used to predict the ranking of raw petroleum cokes or calcined petroleum cokes in industrial size mills used for crushing operations. The rankings are based on energy required and feed rate or both.
What is swelling index of coal?
The free-swelling index (FSI) is a measure of the increase in volume of coal when heated under specified conditions (ASTM D720; ISO 335). The FSI method is a small-scale test for obtaining information regarding the free-swelling properties of a coal.
What is HGI in Coke?
The Hardgrove Grindability Index (HGI) is a measure of coal’s resistance to crushing. SGS is a world leader in coal and coke testing services. …
What is grindability test?
A grindability test is a procedure that evaluates the resistance of a material to ball milling. This test is an effective way to calculate and compare the Bond Work Index (BW¡) of different ores. The higher the Bond Work Index, the more difficult it is to grind the material.
What do you mean by grindability of coal?
The grindability of a coal is a measure of its resistance to crushing. Two factors affecting grindability are the moisture and ash contents of a coal. In general, lignites and anthracites are more resistant to grinding than are bituminous coals.
What is caking index of coal?
The Caking Index, G, has been widely popularized and applied in coal geological exploration, production and utilization departments in China. The value of G characterizes the content of active component of coal, and is considered as a measure of the degree of reduction of coal.
What is the swelling index?
The swelling index is defined as the volume in ml taken up by the swelling of 1 g of herbal material under specified conditions. Its determination is based on the addition of water or a swelling agent as specified in the test procedure for each individual herbal material (either whole, cut or pulverized).
Why is the index of swelling determined?
Answer: The swelling index is used to determine the purity of oil or a particular material. For a particular oil the swelling index is constant. As a result of this is the swelling index is found alternate to the original material then there is some impurities present in that particular material.
Is the Hardgrove Grindability Index a unit or an index?
Hardgrove Grindability Index. Hardgrove Grindability Index (short HGI) is a measure for the grindability of coal. Grindability is an index, therefore it has no unit. The smaller the HGI, the harder is coal texture and less grindable is the coal.
Who are the authors of the Hardgrove index?
Bond Index & Hardgrove Grindability Index Tests for Biomass & Coal Author: Orla Williams, MEng CEng MCIBSE Co-Authors: Dr Carol Eastwick, Prof Ed Lester, Dr Donald Giddings, Mr Stephen Lormor (EDF Energy plc) Tuesday 16thSeptember 2014 BF2RA Status of Coal
Is there an index for the grindability of coal?
Hardgrove Grindability Index. Hardgrove Grindability Index (short HGI) is a measure for the grindability of coal. Grindability is an index, therefore it has no unit.
How is grindability determined in a sample mill?
Hardgrove Grindability Index (ASTM D409 Standard) Grindability is an important factor for the characteristic of the brittle raw materials by the design the mills. As grindability depends on many unknown factors, hardgrove grindability index (HGI) is determined empirically using a sample mill, according to the following procedure.
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