correlation between the abrasion valueX2 and work index Wi is found to be Wi -1.8 Ln X2 11.5 with correlation coefficient of 0.80. KEYWORDS Bond work index Mechanical properties of rocks Grinding energy- Crushing resistance 1- INTRODUCTION Comminution in a mineral processing plant, or mill, involves a sequence of crushi ng
2 The Bond work index refers to the measure of the materials hardness or resistance to crushing and grinding, and is numerically expressed as the kilowatt hours per short ton required to reduce the material from theoretically infinite feed size to 80 passing 100 .m. 2 It is calculated using the equation below W i
Two of the most popular methods for estimating grinding energy requirements are the Bond operating work index OWi and the Morrell specific comminution energy method. Both relate the comminution energy to the reduction in the 80 th percent passing size of the feed and product streams F 80 and P 80 .
Dec 12, 2016 If P is less than 80 passing 70 microns, power consumption will be. Ball Mill Power Calculation Example. A wet grinding ball mill in closed circuit is to be fed 100 TPH of a material with a work ...
The work index covering grinding in tumbling mills of coarse sizes is labelled M. ia. The work index covering grinding of fine particles is labelled M. ib Morrell, 2008. M. ia. values are provided as a standard output from a SMC Test Morrell, 2004. a whilst M. ib. values can be determined using the data generated by a conventional Bond ...
Jul 30, 2020 The Bond Rod Mill Work Index is a measure of the resistance of the material to grinding in a rod mill. It can be used to determine the grinding power required for a given throughput of material under rod mill grinding conditions. It is a locked cycle test conducted in closed circuit with a laboratory screen.
The Bond Work Index is material specific and is obtained from laboratory crushing tests on the feed material. Hard and brittle materials have a work index in the range 4 10 4 8 10 4 Jkg. Bonds law holds reasonably well for a variety of materials undergoing coarse, medium
analysis is given in the table below. The power required to crush this material is 500 kW of this 20kW is needed to operate the empty mill. The feed rate is at 150 tonhr. Calculate the power required for the second operation using a Rittingers Law b Kicks law Mesh x 1 x 2 34 2.1 -
Oct 05, 2006 For crushing, the Unconfined Compressive Strength UCS provides a guide. Units are MPa. For ball milling you need the Bond Ball Mill Work Index. Units are kWht. Knowing the Bond Work Index and the feed and product sizes you can calculate the power input required.
Jul 31, 2014 The following modified Bond equation was proposed for crushing Magdalinovic, 1990 Wc cP A Wi cP 10 - cF 10 8 where Wc - is energy consumed for clinker crushing kWht, Wi - is Bond ball mill work index kWht, Pc -is sieve size passing 80 of the clinker after crushing m, Fc - is sieve size passing 80 of the clinker before ...
It is desired to crush 10 tonhr of iron ore hematite. The size of the feed is such that 80 passes a 72.6 mm screen, and 80 of product a 3.175mm screen. Calculate the gross power requirement for wet grinding and dry grinding. Work index of Hematite is 12.68 Ans 17.96kW
the thicker panel has to be processed, it is required for crushing in small sizes using a jaw crusher. The CFRP plates of 25mm thickness were used before passing the mill and the desired size after passing the mill was 0.045mm of thickness. Figure 2. Application of Bond work index for calculating power
allis chalmers grinding mills - Gulin Machinery. The Third Theory of Grinding, published by Fred C. Bond of Allis Chalmers in 1952, for calculating crusher and grinding mill power requirements permits.Mar 16, 2012 grinding quartz and copper ore in a laboratory ball mill, there has ..
2.1.9 Crushing Power The required crushing power is a function of Bond work index, capacity and the reduction ratio. Adopting Gupta and Yan 5 the power is given by, P Q.R d.w i where Q crushing capacity, Rd reduction ratio x 1 x 2 and wi work index. In this work Q
Current estimates of grinding power requirements used for equipment sizing are indirect indications often based on industrial experience or scaled up from laboratory tests. Work indices Bond, Hardgrove, Kick, Von Rittinger, Hukki, et. al. are also indirect and empirical equations that calculate the energy needed to
Throughout the batch grinding tests, the power draw of the mill was measured using a purpose built power meter to facilitate the calculation of specific grinding energy. Results Table I shows the Bond ball mill work index obtained for the ore samples as well as the iron and silica content in concentrate and tail after LIMS. The concentrate weight
Power used for grinding P kW 14 W 2. Determine the critical speed of the ball mill. n c 1.472 Hz 3. Study the particle size distribution for the product and represent it by differential and cumulative analysis. Graph 3 The peak shows that the desired size of product is obtained in high quantity than as compared to others. Also around the peak the fraction of particles close to the ...
Conventional primary grinding technology . uses a semi- or fully autogenous mill and the accepted small scale test to determine the specific energy requirement is the SAG Power Index, SPI test. Ore samples are typically prepared for SPI testing as part of any design or forecasting study using CEET technology. This preparation requires crushing a
Grinding is a very inefficient process and it is important to use energy as efficiently as possible. A three theories depend upon the basic assumption that the energy required to produce a change dL in a particle of a typical size dimension L is a simple power function of L - . where dE is the differential energy required
Definition of Specific Energy Requirements and Efficient Design of a Grinding Circuit Simulation of Mill Sizing and Prediction of Mill Feed Rates by DJBs Millpower2000 Bond Work Index-based Methodology, Matching the Mill Drive to the Mill for Effective Operating Capability to the
The Morrell Method for grinding mills is based on predicting the specific energy at the pinion shaft. To adjust the power draw measured at the motor input to power at the pinion a 6.5 correction was made. In the case of crushers the Morrell Method relates to motor input power less no-load power net power.
The abrasive grains are properly mixed with is a suitable bond, which acts as a holder when the wheel in use. The grinding wheel may be manufactured in one piece or of segments of oppressive blocks build up into a solid wheel. These wheels are available in different shapes mounted on a different form of Machines for a particular type of work.
Mar 13, 2015 Bonds theory 22. 1. Bonds work index is the work required to reduce unit weight from a theoretical infinite size to 80 passing 100 m. 2. This theory is useful for rough mill sizing. 3. The work index is useful for comparing efficiency of milling operations 23. Kicks Theory 24.
Size reduction by crushing has a size limitation for the final products. If further reduction is required, below 5- 20mm, grinding processes should be used. Grinding is a powdering or pulverizing process using the rock mechanical forces of impaction and attrition. The two main objectives for a grinding process are
Bond has suggested a law intermediate between Rittingers and Kicks laws, by putting p 32 in the general equation Writing C 5Ei then Bond terms Ei the work index, and expresses it as the amount of energy required to reduce unit mass of material from an infinite particle size to a size L2 of 100 m, that is q . 7.
Jan 01, 2016 The impact crushing strength of rocks so determined is used to calculate the Bond crushing work index using the expression ... A standard Bond laboratory ball mill test was commissioned to estimate the grinding power requirements in the design of an alumina refinery. The size analysis of the R.O.M. ore after preliminary screening was Size mm ...
Bond Work Index relationship has been noted to apply down to approximately 70 m, and perhaps no finer , without making qualifications. Calculations First, calculate the actual Operating Work Index, WloACT-, of the grinding circuit. Estimate the 80 passing sizes of circuit feed and product, F80 and P80, in microns
Morrell recon gured the Bonds Third Theory formula to cause extra power requirements to be inputed. This technique incorporates the material speci c gravity SG. The AGSAG speci c energy values produced using this method are susceptible to higher values of crushing and rod mill work indices.
Drop Weight Index DWi and the coarse ore grinding index M ia. Test data from the Bond ball mill work index test is used to calculate the fine grinding index M ib. The M ia and M ib indices are used to calculate specific energy for the coarse W a and fine W b components of the total grinding specific energy at the pinion W
expressed in appropriate units. In Bonds equation, if L is expressed in microns, this defines E i and Bond calls this the Work Index. The greatest use of these equations is in making comparisons between power requirements for various degrees of reduction. EXAMPLE 11.1. Grinding of sugar
W 10Wi .5 .5 1 1 P F, where W work input, kwhton Wi work index for the specific rock type, kwhton P 80 passing size of the product F 80 passing size of the feed One reason for using Bonds third theory is that work index Wi has been measured and reported for many rocks.
Effect of core diameter on the Bond impact crushing work index test The Bond low energy impact crushing work index test is specified to be performed on rock specimens between 50
Ball Mill DesignPower Calculation. The basic parameters used in ball mill design power calculations, rod mill or any tumbling mill sizing are material to be ground, characteristics, Bond Work Index, bulk density, specific density, desired mill tonnage capacity DTPH, operating solids or pulp density, feed size as F80 and maximum chunk size, product size as P80 and maximum and ...
SAMPLING REQUIREMENTS Information Gained Preliminary drill core for resource definition and split for bond work indices Whole core for Autogenous Media Competency Index, Impact crusher work indices and fracture frequency Bulk Sample , large diameter drill core, open pit or
Abstract The Bond work index is a measure of ore resistance to crushing and grinding and is determined using the Bond grindability test. Its value