The essential grind CIM Sep the bond ball mill work index remains today as the only tool used for ball mill scaleup design for an only nominally not at all materially modified update on its use for industrial mill sizing see selection of rod mills ball mills pebble mills and regrind mills.
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.
MARC manufactures a wide range of laboratory ball rod mills and automated Bond rod ball mills (with wave liners) to suit most metallurgical laboratory applications Our range extends from small 6L jar type mills that are manually positioned on rollers to large 30L size mills.
Mill Type Tower Mills Engineering Design Number of Mills 6 Calculations Tonnage Rate t h 346 Mass Balance Bond Work Index Design kWh t 14 0 Engineering Design Solids Pulp Density 65 Engineering Design Feed Size F80 m 135 Engineering Design Product Size P80 m 20 Testwork Engineering Design Mill Ball Charge TBD Engineering Design.
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 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.
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 100 passing size of 3 35 mm Any screen size below 600 m can be used for the testwork depending on your requirements Bond Rod Mill Grindability Test.
Jan 15 2018 The Bond Ball Mill Work index (BBWi) is the industry standard procedure for assessing the grindability of ores The test involves conducting a locked cycle grinding test using Bond’s standard mill design The locked cycle test enables a batch process to emulate the grinding behaviour of a continuous mill with a 250 recirculating load.
Pressure grinding rolls (HPGR) products based on a Bond mill test procedure Multiple trade off studies have reported the performance of HPGR versus SAG milling with energy savings of between 11 and 32 per cent One factor that is often inconsistently defined in these studies is the change in the Bond Ball Work Index (BBWi).
Dec 12 2016 The basic parameters used in ball mill design (power calculations) rod mill or any tumbling mill sizing are material to be ground characteristics Bond Work Index.
In this regard calculation of work index of limestone made by standard Bond grindability test Ball mill was employed to conduct the grinding test of seven different samples Among all seven samples collected from the different faces of quarry Bond work index of limestone Face4A results less than 20kwh t remaining 6 samples are marked as hard.
Apr 07 2015 Following topics are mentioned Plant scale surveying and analysis of the results Material characterization tests standard bond work index and drop weight tests Grinding classification performance analysis of the cement raw material circuit Mathematical modelling of air swept ball mill Mathematical modelling of air classifier used in.
In terms of SAG power index SPI (for SAG grinding) and Bond Ball mill work index BWi (for ball mill grinding) A further measure the Minnovex crusher index Ci was also measured for use in the CEET program to determine SAG mill feed size (Kosick and Bennett 2001) The SPI values varied from 13 5 to 107 minutes with an average of 53 minutes.
Mill Type Overview Three types of mill design are common The Overflow Discharge mill is best suited for fine grinding to 75 – 106 microns The Diaphram or Grate Discharge mill keeps coarse particles within the mill for additional grinding and typically used for grinds to 150 – 250 microns The Center Periphery Discharge mill has feed reporting from both ends and the product discharges.
Measured and the Bond work index (BWI) is calculated as follows Where P1 is the aperture of the closing screen in microns and F 80 and P 80 are the 80 passing sizes of the test feed and product The world relies widely on the ball mill work index for the design and analysis of ball mill.
Mar 01 2001 TABLE 2 The Bond work index obtained from wet and dry Bond tests at various limiting screen sizes Limiting screen size Bond index obtained from wet Bond index obtained process from dry process Wiw Wiw x 1 3 Wid 212 14 5 150 11 7 15 2 15 5 106 16 8 75 13 5 17 6 17 7 53 15 7 20 4 19 3 Wet grinding required less power than dry grinding for.
Cycle test akin to the Bond Ball mill work index determination The first cycle starts with minus 6 mesh ore removed since it is believed that the fines content can fill most of the voids allowing little room for rock breakage and piston movement Without adequate piston.
Additionally while techniques like the Bond Work Index and scale up factors are useful for coarse grinding they can significantly underestimate grinding needs below 100 microns Similarly Tower Mill laboratory tests typically use much finer media than can be used in full scale operation and testwork is done in batch mode.
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 rod mill test gave RWilab of 14 5 kWh t −1 and a ball mill work index BWilab of 13 8 kWh t −1 Accepting that the rod mill work index applies to size reduction of the circuit feed down to the rod mill test product P 80 of 1050 m and that the ball mill work index applies from this size to the circuit product size calculate the.
Jul 31 2014 Wm = Wi ( 80P 10 80F 10 ) (1) where Wm is mill specific motor output power (kWh t) Wi is the Bond ball mill work index (kWh t) P80 is sieve size passing 80 of the mill product ( m) F80 is sieve size passing 80 of the mill feed ( m) The “efficiency factors” (Rowland 1975) modify equation 1 so that it caters for circuit.
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