Hardness: The hardness of a material determines the crushing force needed and the type of crusher that is suitable. Crushing of the harder materials may require the use of the compression crushers, while the softer materials can be processed by the impact or roller crushers.
Only relatively small quantities of sample are required and can be re-used to conduct Bond ball work index tests. ... b and ta as well as the JK crusher model's t10-Ecs matrix, all of which are generated as part of …
The metal Bond ball mill is 30.5 cm inside diameter and. 30.5 cm inside length, with rounded corners. It is smooth except for the door hole used for charging. The grinding charge consists of 285 iron or steel balls (43 @ 36.8 mm diameter, 67 @ 29.7 mm diameter, 10 @. 25.4 mm diameter, 71 @ 19.1 mm diameter, and 94 @.
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.
When selecting the proper Roll Crusher for an application, you must fully consider all the components of the crushing process. There are numerous factors to be considered, such as: Material to be crushed. Feed size. Product size. Ratio of reduction. Capacity. Compressive strength. Moisture content.
MDPI May 19,2015.Another dimension is given by the scale of the test,ranging from pilot scale testing down to testing.load test,indirect tensile strength test,and hardness tests.Samples.Bond defined a crushing work index (in kWh t) by:. Hardness Archives Page 2 of 2 Mineral Processing & Metallurgy Apr 6,2018.A Mineral Hardness Kit is …
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.
of the primary crusher product is required for subsequent laboratory hardness characterization. 7.2 From the Laboratory The Morrell method uses hardness parameters obtained from the SMC Test® (SMC Testing Pty Ltd., 2015; Annex A) and the Bond Ball Mill Work Index Test (GMG, 2016a). The sampling and surveying guideline (GMG, 2016b) …
The work indices are important for determination of crushing energy requirements and the abrasion index is important for estimating equipment metal wear and grinding media consumption. The hardness according to Mohs scale of Gibbsitic and Boehmitic bauxites are typically 1–3, while it ranges from 6½–7 for Diasporic bauxites [ 3 ].
A Processing Machinery Laboratory test indicates the limestone has an impact value of 10.8 ft-lb/in. and a specific gravity of 2.60. The Work Index is, therefore, 10.7 (see Reference I above). MATERIAL: Limestone WORK INDEX —10.7 CRUSHER: 42-65 Primary gyratory Open Side Setting: 5″; Eccentric Throw: 1″ Recommended …
1. Calculate the Actual Operating Bond Work Index of the grinding circuit. • Estimate the F80 and P80. • Calculate the work or specific energy input from the size reduction …
work index in a more common lab mill, such as the Denver lab mill (Fig. 2), is investigated. Experimental Equipment and ore samples. A jaw crusher, a roll crusher, a series of DIN sieves and sample dividers were used to prepare the ore samples. A 305- by 305-mm (12- by 12-in.) standard Bond mill, a 305- by I 27-mm (12- by 5-in.) Denver
The Work Index is actually the total work input in kwhr/short ton required to reduce from theoretically infinite particle size to 80% passing 100 microns, or to approximately 67% passing 200 mesh. Knowing the Work Index, one has but to apply the proper given equation to determine the power input required.
The model has the benefit of retaining the variability in hardness that is built into a database of work indexes, while using Hukki's specific energy approach to adjust for P80.
Here, 3 models gave almost same R 2 value, but as the previous prediction equations are in the form of linear, here also linear model is considered. The prediction equation is as follows: (26) BWI = 0.34 RHN − 6.61 where, BWI = Bond's work index (kWh/sh. ton), and RHN = Rebound hardness number. Table 12.
It is a well-known fact that the value of the Bond work index (wi) for a given ore varies along with the grinding size. In this study, a variability bysis is carried out with the Bond standard grindability tests on different critical metal ores (W, Ta), ranging from coarse grinding (rod mills) to fine grinding (ball mills). The relationship between wi and grinding …
Commentary on the apparatus of the Bond rod mill Work Index by Alex Doll December, 2015 alex.doll@sagmilling The Bond "Third Theory" of comminution was originally divided into three size classes reflecting the varieties of comminution equipment common during the time period when Bond (and his collaborators) were gathering the …
imperfect and ore hardness can vary with size, grindability tests are designed to best represent the size reduction of the industrial equipment analysed. For that reason, it is preferable to design a primary ball mill from a rod mill work index rather than a ball mill index, because the industrial mill will operate over a coarser size reduction
This Table of Ball Mill Bond Work Index of Minerals is a summary as tested on 'around the world sample'. You can find the SG of each mineral samples on the other …
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 …
Abstract and Figures. 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 ...
Most cone crushers have a feed opening size of 5-14", so material that's larger than the maximum size allowable will need a first stage of crushing before they can be fed into a cone crusher. Final Product Isn't Uniform. Cone crushers do an excellent job of providing finished material that's relatively homogenous.
granite, feldspar and quartz were tested for hardness, abrasion, compressive strength and modulus of elasticity and the bond work index of these samples were estimated. The value of Bond work index of the above samples has shown a variation from 10.8 kwh ton-1 for bauxite (high abrasion value and low compressive strength) to 20.4 kwh ton- 1
and hardness parameters including: xBond Ball Mill Work Index (WiBM) xJK Drop Weight (modified and full test) parameters This paper focuses on throughput estimation and is a continuation of works discussed in McCaffery et al (2006). Several approaches have been used to develop the current throughput estimation model. This
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 …
The single most common reason for an increase or drop in the production of fines is the WORK INDEX of the ore. If you remember, the work index of the ore is a method of measuring the degree of hardness. As the ore becomes harder the fracture lines in the rock become cleaner or sharper with less crumbling of the face and edges of the …
The selection or sizing of a crusher is much helped by measuring the rock's hardness during engineering. ... The Work Index for rod and ball mills can be determined from laboratory tests and, as demonstrated by Rowland, the relationship gives us a reasonably accurate tool for the design of rotary grinding mill circuits. ... The procedure ...
A cone crusher might produce aggregates with a flakiness index of less than 10%, meaning over 90% of the output material has a cubical shape, which is desirable in construction materials. High Reduction Ratio : Cone crushers can achieve a higher reduction ratio than many other types of crushers, often between 6:1 and 8:1, and …
The crusher has a feed opening gap of 25 mm, a stroke of 4.9 mm, a cone angle of 44o (in relation to horizontal) and a mantle length of 150 mm. A constant closed-side setting of 7.6 mm was used in ...
The paper by Angove & Dunne (1997) reports a standard deviation in crushing work index tests across laboratories as 4.5. The laboratory CWi value of 27.4 (metric) is almost within 4.5 units of the 22.4 value I calculated, so what you are observing is probably the natural variation in the crushing test.
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 …
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. Although considered an ...
A quick procedure with two grinding cycles for the determination of the Bond. work index approximate value is exactly the same as in the first two grinding cycles of. the standard Bond test and ...
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 pendulum impact crusher test on <76mm but >51mm (3″ and 2″) square rock pieces.
The Bond Low-Energy Impact test can be used to determine the Crusher Work index (CWi), also known as the Impact Work Index. ... 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 …
The Bond crushing work index test procedure is not terribly well described, and different laboratories have different procedures that can result in different results (by up to -50% +). I am not aware of the calibration of the test being checked in over 50 years, so it is impossible to say which procedure is "correct".
