Work Index

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 …

Rock Crushing Theory and Formula using Kick …

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 …

How to use Bond Work Index to Measure Operating …

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 …

Compare and Understand Rod/Ball/Impact …

A new approach to the calculation of bond work index

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 …

[PDF] A quick method for Bond work index approximate …

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 …

Modified Bond Ball Mill Work Index Test

The Thirty-nine samples were submitted for the Crusher Index (Ci), SAG Power Index (SPI®), Standard Bond Ball Mill Work Index (BWI) and Modified Bond Ball Mill work Index (MBI) tests. The Ci, SPI® and Bond Wi values of these samples show a good indication of ore hardness variability within the ore body.

1 Comparison of measures of rock crushability

The Bond work index is used to calculate specific power consumption in crushing from Bond's law of comminution, given by ...

Crushing Work Index for PQ Core sample

The Bond crushing work index test is an inherently poor test and has been shown time and time again in Round Robin studies to have poor precision (repeatability). Angove and Dunne's paper on the subject gives results that show factors of over 2 in terms of reported work index values from the same sample from different labs. Coupled with the ...

Size Reduction, the Three Laws of Comminution, and the Bond Equation

Values of the Bond work index for common ores and minerals. Note that the each of the three energy-based empirical correlations involve two constants: ... Test work has indicated that by crushing the feed to 80% passing 5 mesh and grinding in a ball mill to 80% passing 400 mesh, recoveries will be satisfactory. Using the Bond equation, …

Crushing work index Calculation

A discussion thread about how to calculate the crushing work index (CWi) based on Bond equation and compare it with lab tests results. See the data, formulas, corrections, and …

Impact Work Index Procedure

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.

How to Calculate Grinding Mill Operating Efficiency

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 …

A new approach to the calculation of bond work index

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 …

Comparison of measures of rock crushability

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 ...

Prediction of Bond's work index from field measurable rock …

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 …

Bond Work Index (Energy equation)

BOND WORK INDEX. The Bond Work Index is a factor that measures the energy consumed in size reduction operation of the ore. The Bond's Work Index equation is: W=WI* (10/√P80 -10/√F80) where. W= the energy input (Work input) per ton, kwh/metric ton. WI= Work Index= specific energy per ton, kwh/metric ton (characterizes the ore)

Influence of crushing index on properties of recycled aggregates

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, …

Bond´s work index estimation using non-standard ball mills

BOND, F.C., 1961. Crushing and grinding calculations. Allis Chalmers Publications, No. 07R9235B. ... The Bond work index (BWI) is a well-known method used when selecting comminution equipment, to ...

A quick method for bond work index …

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 ...

BOND'S WORK INDEX: WHAT IT IS AND WHAT IT ISN'T

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 …

Impact of mechanical resistance of aggregate on properties …

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 …

Using the Bond work index to measure operating comminution …

Mining, Metallurgy & Exploration - Austin, L.G., Klimpel, R.R., and Luckie, P.T., 1984, Process Engineering of Size Reduction — Ball Milling, SME, Chapter 4, p.76 ...

A Statistical Comparison of Bond Ball Mill Grindability Work Index …

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 ...

A new approach to the calculation of bond work index

The Bond work index (BWI) is a well-known method used when selecting comminution equipment, to evaluate the grinding efficiency and to calculate the required grinding power. ... Bond, F.C., 1961. Crushing and grinding calculation part I and II. Brit. Chem. Eng. 6 (6 and 8). 378–385 & 543–548. Google Scholar. Chandar et al., 2016. R.K ...

BOND'S WORK INDEX: WHAT IT IS AND WHAT IT …

Bond's work index is one of the mostly widely used metrics of mineral grindability. In spite of its ubiquity, users are often not aware of the nuances of the work index family: what are its...

BOND'S WORK INDEX: WHAT IT IS AND WHAT IT ISN'T

The commonly used grindability tests included in the database are the Bond work indices for ball milling, rod milling and crushing; the drop weight test results A, b, A×b, DWi, Mia, Mic, Mih and ...

Impact work index prediction from continuum damage model …

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 …

Crushing in Mineral Processing

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 …

Using Rock Geomechanical Characteristics to Estimate Bond …

The Bond low-energy impact test, also named impact work index or Bond impact crushing work index, can measure the crushing work index (CWI) and describes …

A meaningful expression between bond work index, grindability index …

The friability value S 7 was measured by the brittleness test (Fig. 1), which gives a value for rock resistance to crushing due to repeated weight-drop (7) impacts.The brittleness test apparatus is designed to determine the grindability characteristics of Tauros limestones, which are used in cement production (Ozkahraman and Sirin, 1998).The …

Bond F.C., 1961. Crushing and Grinding Calculations

Title: Bond F.C., 1961. Crushing and Grinding Calculations.pdf Author: can Created Date: 4/2/2009 4:00:03 PM

Distribution of impact (crushing) work index for …

The traditional Bond work index proposed by F.C. Bond over 60 years ago is still today a useful tool for characterizing material crushability and grindability in the minerals industry.

Use of rock mechanical properties to predict the Bond crushing index

Table 1 Bond's index and crushing energy of the volcanic rocks (Malek, 1995) Rocks Bond's index (kW h/(short-ton)) Bond crushing energy (kJ/ton) Amphibole Biotite Diorite Granite 19.9 20.3 18.5 17.1 3080 3140 2860 2650 where rij and eij are six components of stress and strain.

Bond Crushing Law and Work Index Calculator …

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 …

Work Index

Work index is a material parameter that indicates the difficulty of ore crushing or grinding in mineral processing. Learn about the different types of work index, such as …