Although it was developed nearly 50 years ago, Bond's method is still useful for calculating necessary mill sizes and power consumption for ball and rod mills. This paper discusses the basic development of the Bond method, the determination of the efficiency correction factors based on mill dimensions and feed characteristics, and the application of the results to designing grinding circuits.
Ball Mills or Rod Mills in a complete range of sizes up to 10′ diameter x 20′ long, offer features of operation and convertibility to meet your exact needs. They may be used for pulverizing and either wet or dry grinding systems. ... The parameter Wi, known as the work index of the ore, is obtained from batch bench tests first devised by ...
The next two examples are for rod mill ball mill circuits. Figure 2 shows a conventional rod millball mill circuit. The data for this circuit and Wi0 calculations are: Rod mill size x (′ x 16′ diameter inside shell ′ ′ rods) Ball mill size x (″ x 16′ diameter inside shell ′)
Abstract The Frederick C. Bond has several grinding indices (ball, rod, abrasion), one of which has been a significant guide for ball mills. The Bond ball mill work index is an expression of the material's resistance to ground and a measure of the grinding efficiency.
To calculate the Bond work index ( Wi) in a standard laboratory scale rodmill, Bond derived the following equation: (1) W i = 62 P i G i 10 P 10 F kw h sh t where F is 80% passing size of original feed, P is 80% passing size of circuit product and Pi is the testsieve size in μm [1].
Rod Mill Design Calculations. EF1 Dry Grinding for the same range of work, dry grinding requires times as much power as wet grinding. EF2 Open Circuit Grinding when grinding in open circuit ball mills, the amount of extra power required, compared to closed circuit ball milling, is a function of the degree of control required ...
index in a ball mill (B BWI), which is based on a first order k inetics present in the Bond ball mill for grinding mineral raw materials (Austin et al., 1981; Ahmadi and Shahsavari, 2009).
W is the work index measured in a laboratory ball mill (kilowatthours per metric or short ton) ... Rod mills are less common than ball mills for grinding minerals. The rods used in the mill, usually a highcarbon steel, can vary in both the length and the diameter. However, the smaller the rods, the larger is the total surface area and hence ...
A quick method for Bond work index approximate value determination. D. Todorović Maja Trumić L. Andric V. Milošević Milan Trumić. Materials Science. 2016. 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 ...
10 mm), the crushing work index SWI is applicable; for medium size particles (from 100 mm to 2100 μm) — rod milling work index RWI; for finer particles — ball milling work index BWI (Table). These indexes are readily obtained using the specialpurpose laboratory equipment (Fig. 1). Finding the total specific energy consumption
mill. As such, primary ball mills should be designed with the rod mill work index, and singlestage ball mills should be with both the rod mill and ball mill indices. This is because it is common to observe a difference (sometimes significant) between the rod mill and ball mill index values for a given ore type (McKen, Verret, Williams, 2006). On
Bond Ball/Rod Mill Work Index. Bond ball mill work index (BBMWI) test is a standard test used to measure the ball mill work, which is calculated in accordance with the procedure proposed by the Bond [21]. The BBMWI determines how much energy is needed to grind a sample of ore in a ball mill [22].
Ball Mill Work Index has been widely used for ball mill sizing, and is also utilized in computer simulation. BOND ROD MILL GRINDABILITY TEST The Bond Rod Mill Grindability Test is also performed according to the original Bond procedure. It requires 15 kg of minus ½ mesh material that is preferably prepared at the testing facility. The Bond Rod ...
2019 Armstrong 3 for wet rod mill grinding ... An original procedure chart is proposed for choos ing the determination method of the Bond Ball Mill Work Index for various initial ...
Unrelated 'entertaining' image. The specification for the apparatus to determining a "Bond" rod mill work index is first described in Bond Maxton (1943). It states that the apparatus is a tumbling rod mill to be operated in a locked cycle test at a fixed circulating load. The geometry of the grinding chamber is described as: mill ...
[Show full abstract] different characteristics of rod mill and ball mill, solving the grinding problem of difficult attrition bauxite. Compared with the traditional onestage grinding, the power ...
Rowland,, 1978, "Determination and use of operating work indices in controlled grinding circuitsA 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 predefined 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 stagecrushed to 100% passing size of < mm.
standard Bond crushing, and rod mill work indices, abrasion indices and by Dawson for Bond Ball Mill Work Index tests using crushed feed, and Standard Autogenous Grinding Design (SAGDesign) Tests, patented by Outokumpu. (See reference 8 below). The comparison of these results gives context to how the various measurements relate to each
Ball and Rod Mills. JeanPaul Duroudier, in Size Reduction of Divided Solids, 2016. Performance. Rod mills are used in an open circuit between crushing and the ball mill. They often operate in wet and where the pulp contains up to 50% solid by mass. ... Bond had used short tons to determine work index. To convert to metric tons the factor ...
A screen analysis down to 3 mesh is also made. Bond Impact, grindability tests, and abrasion index tests are also run on the sample. Rod mill grindability tests for Work Index are run at 10 or 14 mesh, and ball mill Work Index tests are run at the desired grind if finer than 28 mesh.
However, Bond Work Indeces are related to the type of equipment to be used (rod mill, ball mill, SAG uses Drop Ball parameterKwhr/m3, so it is more complex than just specific energy consumption ...
In this paper, systematic errors encountered in a rod mill Bond Work Index determination related to the weight and size distribution of the sample are first estimated experimentally. The first type is shown to be relatively small, whereas the second can be as high as 3 kWh/t when the feed size F 80 is finer than mm. A phenomenological basis ...
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 mm, as required for the Bond Ball Mill Work Index test feed.
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The ball mill work index laboratory test is conducted by grinding an ore sample prepared to 100% passing mm to product size in the range of 45150 µm, thus determining the ball mill w i .
use a rod mill F80 of 16,000 µm and a rod mill P80 of 1,000 µm. Note that—in order for no correction factor for ball mill product fineness to apply—the ball mill circuit P80 should be no less than approximately 70 µm (Bond, 1962). This Bond Efficiency determination should not be applied to cir
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. The test is a closedcircuit dry grindability test performed in a standard rod mill.
There are three variants of this test; crushing work index, rod mill work index, and ball mill work index [2]. In this review, only the ball mill work index will be discussed, since ball mills are the only equipment of the three that are capable of significant degrees of fine grinding. The ball mill standard grindability test utilises a ...
The work index Wi was defined by F. Bond as the specific energy (kWh/ton) required to reduce a particulate material from infinite grain size to 100 microns. ... tory rod mill and the semi ...
using a novel ring mill, a laboratory ball mill, a labora tory rod mill and the semi continuous process using the same rod mill as described below. In all cases the min eral sample is crushed and screened to pass a predeter mined size or 4 mm. The feed sample undergoes a wet screen analysis and a certain quantity, usually
Rod mills generate small amounts of fines, as fine particles typically accumulate in the space between rods without enduring comminution [2]. Effective grinding of this material occurs in the ball mill compartment, generating finer fragmentation. The Bond Rod Mill Work Index (BRMWI) test was only possible for Blend 5 (Table 2) due to excessive
The Bond Index conforming rod charge consists of: 6 rods of " diameter and 21" length 2 rods of " diameter and 21" length The grinding jar for the Bond Index Rod Mill is 12″ x 24″ in size and has a waveshaped design.
Key words: Comminution, Bond work index, Grinding, Crushing, Ball mills, Rod Mills. Theoretical efficiency
Introduction. A 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 ...
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