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 3.5 or 4 mm. The feed sample undergoes a wet screen analysis and a certain quantity, usually 0.5 -
· ih (HPGR ore work index) can be obtained from the SMC tests . These parameters can be further used to evaluate speciﬁc energy consumption in the Morrell model. 2.4. Bond Ball Work Index Test A grinding mill (F305 mm 305 mm) was used for the Bond ball mill work index test [18–21].
The Bond's standard ball mill is used to determine the work index value of differ ent samples. The Bond work index is defined as the kilowatt-hours per short ton required to break from infinite size to a product size of 80% passing 100 µm. If the breakage characteristics of a material remain constant over all size ranges, the calcul ated work
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 minor warming ...
The goal of this work is to create an equation to adjust a Bond ball mill work index from one P 80 basis to another. The proposed model consists of two components, the variable coefficient that is determined from a specific work index determination and a fixed exponent determined by a calibration procedure.
Mill diameter; Mineral density; Work Index. Bond estimated the amount of wear in terms of kilograms per kWh based on the abrasion index, A;, i.e., Wet Ball Mill = kg kWh = 0.16(A i-0.015) 0.33; Dry Ball Mill = kg / kWh = 0.023A i 0.5; Replacement Ball Size
C) for coarse rocks (75-50 mm), a rod mill work index (Wi RM) for intermediate sized particles (25-3 mm), and a ball mill work index (Wi BM) for small particles (<3 mm) (Ammtec, 2000). Laboratory testwork is required to determine these Work Indices, and each test requires carefully collected samples of rock that is representative of future mill ...
A ball mill also known as pebble mill or tumbling mill is a milling machine that consists of a hallow cylinder containing balls; mounted on a metallic frame such that it can be rotated along its longitudinal axis. The balls which could be of different diameter occupy 30 – 50 % of the mill volume and its size depends on the feed and mill size. ...
The Bond's Ball-Mill Work Index is a measure of the resistance of the material to grinding in a ball mill. This Index is widely used in the industry for comparing the resistance of different materials to ball milling, for estimating the energy required for grinding and for ball mill scale-up.
The aim of this study was to develop a new method for assessing the Bond work index in a ball mill (BBWI), which is based on a first order kinetics present in the Bond ball mill for grinding mineral raw materials (Austin et al., 1981; Ahmadi and Shahsavari, 2009). Theoretical basis of quick procedure
Ball Mills are generally used to grind material 1/4 inch and finer, down to the particle size of 20 to 75 microns. To achieve a reasonable efficiency with ball mills, they must be operated in a closed system, with oversize material continuously being recirculated back into the mill to be reduced.
Similar to a Comparative Work Index, this test is an open circuit dry batch grindability test run in the standard Bond Ball Mill for a set time. It can be used at mesh sizes from 65 to 200 mesh (normally 100 mesh). The test requires calibration against the standard Bond Ball Mill Work Index test to estimate the Work Index.
Oct 15, 2015· 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. •
The ball mill work index laboratory test is conducted by grinding an ore sample prepared to passing 3.36 mm (6 mesh) to product size in the range of 45-150 µm (325-100 mesh), thus determining the ball mill work index (Wi B or BWi). The work index calculations across a narrow size range are conducted using the appropriate laboratory work ...
Ball Mill Bond Work Index . 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 2006This index is widely used in the mineral industry for comparing the resistance of different materials to ball milling for estimating the energy required.
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 2.1 mm whereas Ball Mill Work Index (BWI) is used for the range from 2.1 mm down to 100 µm. Adjustment of grinding parameters:
The Bond low-energy impact crushing work index (more informally, the Bond crushing work index) is not as common as the Bond ball mill work index, and it is a notoriously noisy test.. The test is a 'per-specimen' test where individual specimens of prepared rock are hand-picked by the test operator and placed into the apparatus.
bond ball mill work index. Efficient Thickener. Efficient Thickener. Hydraulic Motor Driving Center Thickener. Hydraulic Motor Driving Center Thickener. Grid Type Ball Mill. Grid Type Ball Mill. Submerged Slurry Pump. Submerged Slurry Pump. Agitation Tank For Chemical Reagent.
As such, primary ball mills should be designed with the rod mill work index, and single-stage 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, amp Williams, 2006.
Laboratory Ball Mill For Bond Work Index Onemine Mining . The Bond ball mill work index is one of the most commonly used grindability tests in mining and is often referred to as the Bond work index The test is a 39lockedcycle39 test where ground product is removed from test cycles and replaced by fresh feed Read More Planetary Ball Mills 28428.
Jul 30, 2020· 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.
First, a Jar Mill grindability test requires a 5 lb. (2 kg) sample and produces a direct measured specific energy (net Hp-hr/t) to grind from the design feed size to the required product size. The second test, a Bond Work Index determination, results in a specific energy value …
The Bond ball mill work index is one of the most commonly used grindability tests in mining, and is often referred to as the Bond work index.. The test is a 'locked-cycle' test where ground product is removed from test cycles and replaced by fresh feed.
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. The simplified test method described in this paper, which is used at Anaconda Research Center to approximate the work index, is an alternative procedure to ...
work indices for the AG/SAG mill and ball mill can be re-organised as  and , where B'Wio and A'Wio are the corrected operating work indices and WAG/SAG, WBM are the respective power draw of AG/SAG and ball mills. Note that the ball mill operating work index is applied only on the portion that needs the additional grinding (Q2),
rod mill Work Index test for these purposes. Chose a o closing screen for the ball mill test one (standard square root of 2 series) mesh size coarser than the plant ball mill circuit P80. If between standard mesh sizes, the finer of the chose two. Results of Bond ball mill tests conducted with closing
However, in this situation the ball mill has to supply this energy and it has a different (higher) work index than the crusher (ie the ball mill is less energy efficient than a crusher and has to input more energy to do the same amount of size reduction). Hence from equation 7, to crush to the ball mill …