Mill Ball Mill Closed circuit crushing to 16 mm Open circuit 8' dia. rod mill to 1 mm Closed circuit 8' dia. ball mill to P80 um The ore Test Work Index = Circuit Operating Work Index 9 The Standard Bond Circuit Coarse Ore Bins Fine Ore Bins Screen Crushing Screen Classification Rod Mill Ball Mill THIS IS THE REFERENCE BASIS FOR ALL WORK ...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 …

1.. IntroductionA Bond Ball Mill Work Index test is a standard test for determining the ball mill work index of a sample of ore. It was developed by Fred Bond in 1952 and modified in 1961 (JKMRC CO., 2006).This index is widely used in the mineral industry for comparing the resistance of different materials to ball milling, for estimating the energy required for grinding, …...Numerically, the work index is the energy required in kwh/t to reduce a given material from theoretically infinite feed size to 80% passing 100 microns. The work index of a particular material is determined in the laboratory by conducting the standard Bond grindability test. Bond developed separate tests for the rod mill and the ball mill.

A Bond ball mill work index is then performed on the mill product for the design of SAG-ball mill circuits. This is important because it was found that there was a 1–1.5 kWh/t higher ball mill work index if the –3.35 mm ball mill test feed size is obtained by SAG mill grinding compared with crushing...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 recovery was in the order of 50–60%. Furthermore it may be observed that the Bond ball mill work indices for the ore (Wi) varies from 14.6 to 20.9 kWh/t.

The Bond Index conforming rod charge consists of: 6 rods of 1.25" diameter and 21" length. 2 rods of 1.75" diameter and 21" length. The grinding jar for the Bond Index Rod Mill is 12″ x 24″ in size and has a wave-shaped design. At least 15 to 20 kg sample material is required to simulate a closed grinding circuit in a ball or rod mill...This is accomplished by the standardization of mill dimensions, tumbling speed, grinding ball charge weight and distribution, sample ore charge weight in the mill and operating practice. The results of this investigation reveal that the Bond work index grindability values may differ substantially with different standard Bond ball mills.

Bond ball mill work index C Wi Bond crusher work index D HPGR roll diameter (m) E sp net specific energy consumption (kWh/t) F HPGR hydraulic pressing force (kN) F 80 particle size at which 80% of particles pass in feed F SP 2HPGR specific pressing force (N/mm ) L HPGR roll length (m) ṁ or m-dot HPGR specific throughput constant (ts/hm3)...Correction of Bond Ball Mill Work Index Test for Closing Mesh Sizes It is commonly known that one must run the Bond ball mill work index test such you pick a closing mesh to give a P80 close to desired grind size.

The ability to simulate the Bond work index test also allows examination of truncated ball mill feed size distributions on the work index. For grinding circuits where the feed to a ball mill is sent directly to the classifier and the cyclone underflow feeds the ball mill (see Figure 3.10), a question arises as to whether this practice will alter the ball mill work index (BW i) of the material ...Relationship between the Bond work index (w i ) and the ore hardness designated by Denver Source publication Modelling the specific grinding energy and ball mill scale-up india final

21 CONCLUSIONS Continued In the present work, equations were also derived, giving: zthe ball-mill power drawP as a function of its dimensions: internal mill diameter D and length L, zthe ball-mill power drawP as a function of the feed D f (mm) and the product size d (mm), the Bond work index w i (kWh/short ton) and the mill throughput T (short ton/h), zthe ball …...Work Index Ball Mill. Bond Work Index Ball Mill Calculation Design And Safety The grinding jar for the bond index rod mill is 12 x 24 in size and has a waveshaped design at least 15 to 20 kg sample material is required to simulate a closed grinding circuit in a ball or rod mill the rod mill work index rwi is used for particle size determination in a size range from 25 mm down to 21 …

is the ball mill grindability. When F is the size in microns which 80 per cent Of the new ball mill feed passes, P is the microns which 80 per cent of the last cycle sieve undersize product passes, and PI is the .opening in microns of the sieve size tested, then the ball mill wortk index Wi is calculated from the following revised (1960) equation...A Bond Ball Mill Work Index may also be used in the simulation and optimisation of existing mill(s) and the associated grinding circuit(s). Sample requirements: A minimum of 8 kg of material crushed to nominally minus 10 mm is preferred. JKTech would stage crush the sample to minus 3.35 mm, as required for the Bond Ball Mill Work Index test feed.

The Bond grindability testing procedure has been standardized to obtain the same grindability values, i.e., Bond work index (BWi), on the same ore when tests are performed in different laboratories or by different operators. This is accomplished by the standardization of mill dimensions, tumbling speed, grinding-ball charge weight and distribution, sample charge …...An alternative mill ball charge is proposed that closely approximates Bond's original total ball mass, number of balls and ball surface area. Results of 30 Bond Work index tests of six pure materials (calcite, magnesite, labradorite (feldspar), quartz, andalusite and glass) using closing screen apertures (P 1) values of 500, 250, 125, 90 and 63 ...

Safety is a prime consideration for all Alsto equipment and the Bond Index Ball Mill is supplied equipped with acoustic enclosure. The ball mill is designed to …...JK Bond Ball Mill Test Since its introduction in the 1960s, the Bond Ball Mill Work Index (BBMWi) parameter has been extensively used in predicting ball mill power draw. Use of Work Index Along with comminution circuit design the work index parameter is widely used in tracking mill performance. Due to the age and lack of controls for the test,

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 Work Index calculated from the testing can be used in the design and analysis of ball mill circuits. The test requires a minimum of 10kg of sample that has been stage-crushed to passing size of <3.35 mm...SMC Data Processing. The results from conducting the SMC Test® are used to determine the drop-weight index (DWi) which is a measure of the strength of the rock as well as the comminution indices Mia, Mih and Mic. In conjunction with the Bond ball mill work index they can be used to accurately predict the overall specific energy requirements of ...

RETSCH is the world leading manufacturer of laboratory ball mills and offers the perfect product for each application. The High Energy Ball Mill E max and MM 500 were developed for grinding with the highest energy input. The innovative design of both, the mills and the grinding jars, allows for continuous grinding down to the nano range in the shortest amount of time - with only …...Predicting Mill Feed Specific Energy from Bond Ball Mill Work Index Tests at Olympic Dam Y Li1, V Liebezeit2, K Ehrig3, M Smith4, B Pewkliang5 and E Macmillan6 1. MAusIMM, Senior Geometallurgist, BHP Olympic Dam, Adelaide, South Australia 5000. Email: [email protected] 2. Senior Geometallurgist, BHP Olympic Dam, Adelaide, South Australia …

Bond Work Index (BWI) & Hardgrove Grindability Index (HGI) tests for biomass & coal. • BWI can predict the potential for mill choking of biomass in a tube and ball mill. • HGI is a poor method of predicting grindability of biomass in vertical spindle mills. • Pellets should be composed of pre-densified particles close to the target size. •...rod mill work index has not been de ned as yet. The ball fi mill work index is con rmed at 16 kWh/t. The operating fi work index, though, is in the range of 21 kWh/t to 25 kWh/t showing high ineffi ciency. This raises the point that, in some cases, the Bond EF4 oversize factor calculation is not suf cient to compensate fi

FIGURE 8: ROD MILL/BALL MILL WORK INDEX RATIO v. UNCONFINED COMPRESSIVE STRENGTH 100 200 300 400 UCS (MPa) 0 0.5 1 1.5 2 WiRM/WiBM (metric) Siddall et al (1996) identified the ratio of Bond rod mill Work Index and ball mill Work Index as being indicative of an ore's compentency. Figure 8 plots this ratio versus UCS; no trend is apparent ...Ball Mills Steel Ball Mills & Lined Ball Mills. Particle size reduction of materials in a ball mill with the presence of metallic balls or other media dates back to the late 1800's. The basic construction of a ball mill is a cylindrical container with journals at its axis.