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.

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 ...

2018-3-23 · You can also review the step-by-step Bond Work Index Test Procedure I posted here. See thisuseful summaryTable of Bond Work Index by Minerals. For any circuit, whether a crushing circuit, a rod mill, or a closed ball mill circuit, the Work Index …

1998-11-1 · Rowland, C.A., 1978, "Determination and use of operating work indices in controlled grinding circuits–A proposed concept," Mill Operator''s Conference and Exhibit, Northwestern Branch, Australasian Institution of Mining and Metallurgy, Mt. Isa, Queensland Australia, June.

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.

The Marcy expression is applicable for mill diameters between 1.52 to 4.1meters. Using peripheral speed, the rotational speed can be determined. Bond quantified the rod mill power draw as a function of the Work Index, capacity, and a series …

2015-6-6 · 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 …

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 ...

submitted to the Bond ball mill work index test The number of SAG mill revolutions required to grind the material to a P 80 of 1.7 mm is used to predict AG/SAG specific energy using quation 4 Correction E The Bond equation is used to calculate ball mill specific energy from T …

2019-2-24 · Equation (11.2) is a statement of Kick''s Law. ... In Bond''s 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. ... It includes ball mills, in which the material to be ...

2017-5-26 · 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)

2013-12-24 · 2.2. Ball Mill Batch Process The mill dimensions, (D × L), are 0.204 × 0.158 m and it is loaded with 6.5 kg steel balls between 25 and 32 mm in diameter. The mill rotates on rolls and its frequency is set to 70 RPM (1.667 Hertz) corresponding to 85% of the critical frequency. The mill power is P = 16.2 Watts,

2018-11-15 · WORK INDEX •Work Index, Wi, is the gross energy requirement in kilowatt hour per ton of feed (kWh/ton of feed) to reduce a very large particle to such a size that 80% of the product will pass through a 10micrometer, or 0.1 mm screen. •If Dp is in mm, 𝑊𝑖=𝐾 1 𝐷𝑝𝑝 𝐾 = 0.1𝑊𝑖=0.3162𝑊𝑖 I =0.3162𝑊𝑖 1

The work performed included analysis of operating performance data from 49 mills and included extensive determinations of the Bond Abrasion Index for different ore types. For an improved understanding, the wear rate constant is directly related to the grinding media consumption rate expressed in grams of steel per kWh drawn by the mill…

2017-10-19 · The grinding balls diameter determined by the Bond formula has a recommendatory character and serves as a starting point for calculating the necessary proportion grinding media feeding a new mill. More precisely adjust the ball load in the mill …

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.

2018-10-24 · The Work Index is a fitted coefficient to Bond''s equation given in the picture above. The work index can either be measured in the laboratory (the Bond ball mill work index determination is a ...

Bond Tests SGS. 2 days ago Bond F C Crushing Tests by Pressure and Impact Trans AIME Vol 169 1947 pp 58 66 Bond Rod Mill Grindability Test The test determines the Bond Rod Mill Work Index which is used with Bond s Third Theory of Comminution to calculate net power requirements when sizing ball mills Various correction factors may have to be applied.

2021-8-26 · 1 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.

Bond Index Ball Mill / Rod Mill BT 100 XL - RETSCH 18 Apr 2018 ... (8) is suitable for determining the work index at various product sizes from one ball mill grindability test made at product size Po.

1989-1-1 · The Bond work index, W i, as an indicator of the grindability of raw materials is not a material constant but rather it changes with change of size of the grinding product.Therefore, in practice we can expect some difficulties and errors when the energy consumption is determined according to this formula in the case when, for a given size of grinding product, the value of the work index …

2020-3-22 · The Bond rod mill work index is not as common as the Bond ball mill work index, and there are two different variations on the mill apparatus.The SAGMILLING models expect a mill with a "wave liner", and is not compatible with mills using "smooth liners".

Bond Work Index Procedure and Method

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,