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The crushing work index (CWi), estimated on the basis of the twinpendulum test, has been proposed by Fred Bond and accumulates a long track record in predicting the performance of crushing ...
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Fred Bond defined Work Index as "The comminution parameter which expresses the resistance of material to crushing and grinding. Numerically the Work Index is the kwh per short ton required to reduce the material from theoretically infinite feed size to 80 percent passing 100 microns." Wi and Wio both fit Fred Bond's definition for Work …
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The Bond crushing work index is a measure of material strength and is determined using a simple twin pendulum apparatus and a standard procedure. The Bond impact test attempts to emulate the crushing action that occurs inside the chamber of jaw, cone and gyratory crushers, where particles may not be broken in the first nipping cycle, …
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Bond (1947) defined the impact energy per unit of thickness C B by dividing the impact energy by the thickness of each particle w, so that (1) C B = 117 (1-cos ϕ) / w where ϕ is the angle, w is given in mm and C B in J/mm. From this and the material specific gravity ρ s (in g/cm 3) Bond proposed to estimate the crushing work index using the …
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Learn how to measure the crushability of rock samples using the Bond Impact Crushing Work Index test, a standard method based …
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This is or was used by to acquire the Impact (AKA Crushing) Work Index for sizing crushers. Use this in complement to the Bond Crushing Work Index Procedure. Another Summary Table of various Impact Work Index by Rock or Mineral Type (/metric tonne). Find a referential Rod Mill Work Index Table here.
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Also remember that the products from the SMC Test® can be re-used for Bond ball work index testing, the SMC Test® being effectively used as a feed preparation step for the Bond ball work index test. As a general …
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The Bond ball mill grindability test is run in a laboratory until a circulating load of 250% is developed. It provides the Bond Ball Mill Work Index which expresses the resistance of material to ball milling.This happens after 7–10 grinding cycles, which shows that the procedure is a lengthy and complex one and is therefore susceptible to …
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It is a well-known fact that the value of the Bond work index (wi) for a given ore varies along with the grinding size. In this study, a variability bysis is carried out with the Bond standard grindability tests on different critical metal ores (W, Ta), ranging from coarse grinding (rod mills) to fine grinding (ball mills). The relationship between wi and grinding …
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Rittinger's theory and law of the energy expended in crushing of rock is that the work of crushing is proportional to the reduction in diameter; or, as I have more fully expressed it: "The work …
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Therefore, this measure can be cheaply determined using other rock characteristics. In addition, the value of the BWi determines the energy required for crushing and milling (depends on the BWi type, e.g., crushing work index, Bond ball mill work index, and Bond rod mill work index), and this measure can be used to optimize …
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The crushing strength of an aggregate was determined by means of the so-called aggregate crushing index according to PN-B-06714-40 [19], analogous to the British method of determining aggregate crushing value (ACV) according to BS 812 [18], but with some differences. A specimen of aggregate in a steel cylinder with an internal diameter …
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Example Problem on Bonds Crushing Law and Work Index. What is the power required to crush 100 ton/h of limestone if 80 percent of the feed passes a 2-in. screen and 80 percent of the product a -in. screen. work index for limestone …
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This Grindability Test or Bond Ball Mill Work Index Procedure is used to determine the Bond Work Index of minus six mesh or finer feed ore samples. These equation application methods are used to process <1/2″ ore samples in a Ball Mill using a standard ball charge.. Below describes in general terms the Bond Work Index …
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The Bond work index is a measure of ore resistance to crushing and grinding and is determined using the Bond grindability test. Its value constitutes ore characteristic and is used for industrial ...
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The Bond' Crushing Work Index is common to calculate the power needed to crush rocks from a given F80 size to a resulted P80 product size. Bond's impact method comes from a double mirrored …
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It is a well-known fact that the value of the Bond work index (wi) for a given ore varies along with the grinding size. In this study, a variability bysis is carried out with the Bond standard ...
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FIGURE 4: BOND CRUSHING WORK INDEX v. UNCONFINED COMPRESSIVE STRENGTH (highlighting three rock types) Figure 4 displays Wi C and UCS values separated by the major rock types from a single African mine. The three rock types do show a mild correlation between crushing Work Index and UCS (R² values between 0.1 and …
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It is not recommended to use UCS as a proxy for the Bond crushing work index, or vice versa. If you insist on doing so, there are several potential regression equations above that you may choose ...
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The paper examines the determination of the bond work index (BWI) on finer samples and proposes an equation for the BWI on finer samples. The BWI is a method …
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The self-grinding work index is an extension of the concept of Bond work index. It generally refers to the work index calculated by using Bond's fracture theory on the principle of ore crushing energy consumption according to the W, F, and P data of a small or semi-industrial or industrial self-grinding test. In this kind of test, McPherson …
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Crushing and grindability are the parameters that characterize the resistance of raw materials to crushing. There are several procedures for determining the brittleness and grindability, and in practice, the most widely used methods are F. C. Bond (Bond, 1961). ... Kapur (1970) came to the conclusion that the estimation of the Bond index …
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Ore hardness can be estimated using commercially available standard techniques such as the SAG Power Index (SPI), Bond Work Index (BWI), and JK Drop Weight (JKDW) tests (Bailey et al., 2009 ...
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Learn what Bond's work index is and how it relates to mineral grindability, specific energy consumption and power models. Find out the differences between laboratory, operating …
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Bond's work index model of quantifying mineral grindability was born out of the desire for a better way of scaling up laboratory grindability test results to industrial-scale grinding mills (Lynch & Rowland, 2005). The Allis-Chalmers company (now ) collected a great deal of operating and laboratory data during the 1930s
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The Bond work index is a measure of ore resistance to crushing and grinding and is determined using the Bond grindability test. Its value constitutes ore characteristic and is used for industrial comminution plants designing. Determining the Bond work index value is quite complicated, timeconsuming and requires trained …
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Comminution efficiency can be expressed in three different ways. Theoretical Efficiency: actual energy consumed, in a comminution machine compared to the theoretical energy required to make the size reduction. Operating Efficiency: compares the operating work index, calculated from production comminution machinery operating …
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Generally Bond work index for mill dimensioning and controlling is measured by grinding a feed material of less than 3.36 mm (− 6 mesh) particle size under standardized conditions in a Bond's mill (Diameter × Length = 305 mm × 305 mm). Bond's method simulates closed-circuit grinding which is carried out in sections until the …
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2.3. Testing methods. The crushing index was determined in accordance with Pebble and crushed stone for construction (GB/T14685-2011) [29].Firstly, 3000 g of sample (M 1) was put into the determinator under pressure testing.Then test machine was started by the velocity of 1 kN per second until the load of 200 kN.Kept the load for 5 s, …
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The Bond low energy impact (crushing) work index test is specified to be performed on rock specimens between 50 mm and 75 mm in effective diameter. NQ-diameter drill core, frequently used in ...
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