What is the importance of the the bond work index in mineral processing?
What is the importance of the the bond work index in mineral processing?
Bond work index (Wi) can be considered as one of the most important affecting factors in the design of grinding systems which express on the value of energy (kwh) consumed per ton of the ground ore.
What is the meaning of work index?
‘Work Index’ is the amount of energy required to do this work. It is a measurement of how hard the rock is and an expression of the resistance that a material has to crusher. It shows for example, that their is more energy required to crush Basalt then Iron Ore.
What is the significance of a large work index of an ore sample?
The index gives the energy required to reduce a limit weight of material from a theoretical infinite size to 80% passing 100μm. We should note that the higher the value of the work index, the more difficult it is to grind the material.
What is Bond index in Limestone?
limestone : andesite = 25 : 75, limestone : andesite = 50 : 50, limestone : andesite = 75 : 25.
What is the unit of work index?
If the measured power for the operating work index is given as kilowatt -hour per metric ton (kWh/t), then the calculated work index is power per metric ton. For closed-circuit grinding, F is the feed to the circuit before adding the circulating load, and P is the product after removing the circulating load.
What is P80 and F80?
F80 is the 80% passing size of the circuit feed, and P80 is the 80% passing size of the circuit product, in microns. For example, a grinding circuit is processing 450 t/h (of dry feed) with a mill drawing 3,150 kW (at the pinion).
What is the work index for sandstone?
5 show that dolerite has the highest Crushability Work Index (CWI) of 37 KWh/t followed by conglomerate, sandstone and phyllite with values; 36.7 KWh/t, 32.8 KWh/t and 30.6 KWh/t respectively.
What is the work index of gypsum rock?
Table of Bond Work Index by Minerals
| Source 1 | Source 5 | |
|---|---|---|
| Granite | 16.6 | 11.0 |
| Graphite | 48.0 | |
| Gravel | 17.7 | |
| Gypsum rock | 7.4 | 7.0 |
What is work index in size reduction?
‘Work Index’ is to measuring energy in size reduction what the ‘meter’ is to measuring distance. It is a standard measure that brings all size reduction circuits onto a common basis for comparison. It starts with Bond’s Work Index equation: W is the work (energy) input per ton.
What is crushing in mineral processing?
Crushing is the first step of mineral processing where the ore/rocks from the mine site is fed into the mechanical equipment in order to reduce the size of masses for subsequent usage by liberating the valuable mineral from the gangue.
What is the Bond Work Index?
The Bond work index is a parameter which represents a measure of an ore resistance to grinding. micrometers in size. According to the Bond standard procedure, the work index is determined by simulating a dry grinding in a closed circuit in the Bond ball mill to achieve 250% circulating load (Bond, 1949, 1952, 1961).
What is the Bond ball mill work Index?
The Bond Ball Mill Work Index (BBWi) test is carried out in a standardised ball mill with a pre-defined media and ore charge. The test requires a minimum of 10kg of sample that has been stage-crushed to 100% passing size of <3.35 mm. Any screen size below 600µm can be used for the testwork depending on your requirements.
What is the work index of a bond grinding machine?
Based on these observations, Bond and until the establishment of stable recircul ating load (Maxson et al., 1933). resistance to grinding. Numerically, the work index represents the energy ( kWh/sht) micrometer s in size. According to the Bond standard procedure, the work index is achieve 250% circulating load (Bond, 1949, 1952, 1961).
How are the work index calculations conducted?
The work index calculations across a narrow size range are conducted using the appropriate laboratory work index determination for the material size of interest, or by chaining individual work index calculations using multiple laboratory work index determinations across a wide range of particle size.
