Use of work index along with comminution circuit design the work index parameter is widely used in tracking mill performance. Kinetic grinding test approach to estimate the ball mill work. Bond ball mill grindability the sample was crushed to 100% passing 6 mesh 3. Mine 331 bond work index ii mine 331 bond work index test. Example of agsag ball mill circuit wio calculations 1 2 abstract optimum use of power in grinding, both in terms of grinding efficiency and use of installed capital, can have a large effect on. Guerrero, simulating the bond rod mill grindability. In this regard calculation of work index of limestone made by standard bond grindability test. Comminution testing jktech university of queensland.
Bond ball mill is a small universal laboratory mill used in calculating the grindability for practical calculations rhe size in microns which 80. Alternative approaches for determination of bond work index on. Bond work index is one of three different approaches that can be used to calculate the work index of. Pdf rapid determination of bond rodmill work index by. The fc bond ball mill is now ready for the next sample. Reference mineral granite of known weight and work index 15. The ball mill work index, wi kwhshort ton is calculated from the following equation bond 1961.
The work index is used when determining the size of the mill and grinding power required to produce the required ore throughput in a ball mill. Correction of bond ball mill work index test for closing. Oner 2000 have conducted a research of clinker and blast furnace slag mixture bond work index in different mass proportions. Pdf a quick method for bond work index approximate value. He found out that these values are always lower than the bond index obtained. A minimum of 8 kg of material crushed to nominally minus 10 mm is preferred. Calculate the standard circuit bond work index wistd for. The effect of circulating load and test sieve size on the. In this way, work index values are usually obtained for some specific grind size that characterizes the grinding operation to design or under evaluation. The above confirms that the design bwi for the primary ball mill is between 15 kwht and 18.
As will be shown later, for sizing the primary mill motor the bond method is used. 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. The grinding jar for the bond index rod mill is 12. For powerbased calculations the smc test also provides the comminution indices mia, mih and mic,which are routinely reported when a test is carried out see table 1 below.
According to the bond standard procedure, the work index is. This study was carried out in a standard bond ball mill 305 mm x 305 mm size. Bond work index value of these components mixtures is greater than the bond work in dex of harder components, clinker. Modeling, work index, miduk copper, control screen, bond ball mill. The bond ball mill is a small universal laboratory mill used in calculating the grindability of once a suitable grinding charge is prepared from one grade ofballs count and note the number diameter as shown in the work index equation 1. It can be used at mesh sizes from 65 to 200 mesh normally 100 mesh. Correlations for the grindability of the ball mill as a. Shahsavari, procedure for determination of bond ball work the grindability experiments was carried out on the four typical index in the commercial operations, min. Limestone bond ball mill work index pdf, sand making machine. Keywords autogenous grinding ag, ball mill, bond work index wi, comminution circuit, high pressure grinding rolls hpgrs, rod mill, semiautogenous grinding sag, specific energy w 4. Geometallurgical modelling of the collahuasi grinding circuit. Bond estimated the amount of wear in terms of kilograms per kwh based on the abrasion index, a. This standard grindability test simulates a closedcycle.
A bond ball mill work index test may be required for the design of a new mineral. Procedure for determination of ball bond work index in the. Bond work index determination of the bond work index of. Where, wioactis the actual operating bond work index kwht, w is the specific energy input kwht, p80 is the 80% passing size of product m, and f80 is the 80% passing size of circuit feed m. The bbmwi is then used in the design calculations of the new grinding circuit. 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. Request pdf procedure for determination of ball bond work index in the commercial operations the bond ball mill grindability test is run in a. Mine 331 bond work index ii mine 331 bond work index. Dwi and point load index is50 making it valuable in mineto mill studies as well. For overflow ball mills, the charge should not exceed 45% of the mill volume. 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. Geometallurgical estimation of comminution indices for. Using the bond work index to measure operating comminution.
According to the bond standard procedure, the work index is determined by simulating a dry grinding in a closed circuit in the bond ball mill to. Ball mill for determining bond ball mill work index 1 for the purists, there were two models in existence at the time. These equation application methods are used to process ball mill using a standard ball charge. This index is widely used in the mineral industry for comparing the resistance of different materials to ball milling, for estimating the energy required. Example of agsag ball mill circuit wio calculations. In recent, the brittleness testfriability value of bauxite, lizenithne, barite, marble. This study aims to develop a new approach toward estimating the bond ball mill work index bbwi by applying a series of kinetic grinding tests with bond standard mill.
The bond ball mill work index test is thought to be additive because of its units of energy. The simplified test method described in this paper is an alternative procedure to the ball mill grindability test. Bond work index formulaequation mineral processing. The mill rotates on rolls and its frequency is set to 70 rpm 1. Bond work index mill with standard ball mill charge.
According to the bond standard procedure, the work index is determined by simulating a dry grinding in a closed circuit in the bond ball mill to achieve 250% circulating load bond, 1949, 1952, 1961. F80 is the size in microns at which 80 percent of the new feed to ball mill passes. 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. Bond developed a relationship that can be used to determine the percent charge by volume as a function of the vertical height above the charge, he, and the radius of the mill, r, i. Bond ball mill work index test standard pdf simulating. Standard size ranges and the related bond work indexes feed size f 80. This raises the point that, in some cases, the bond ef4 oversize factor calculation is not suf cient to compensate.
It is commonly known that one must run the bond ball mill work index test such you pick a closing mesh to give a p80 close to desired grind size. The test is performed on a raw material approximately weighing 10 kg, which coarseness is 100% 3. Below describes in general terms the bond work index procedure used by a professional metallurgical testing laboratory. For any circuit, whether a crushing circuit, a rod mill, or a closed ball mill circuit, the work index always means the equivalent amount of energy to reduce one ton of the ore from a very large size to 100 um.
In their book process engineering of size reduction. Application of operating work indices in autogenous. 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 standard equation used by them for the ball mill work index bond work index is as follows. A quick method for bond work index approximate value determination. A method of c alculating autogenous semiautogenous grinding. Neither of these gave results that matched the observations of specific energy consumption from tumbling mills. Ball mill was employed to conduct the grinding test of seven.
Calculate the standard circuit bond work index wistd for the material being processed equation 3. Among all seven samples collected from the different faces of quarry, bond work index of limestone face4a results less than 20kwht, remaining 6 samples are marked as hard. Ball mill work index, bond index, grindability, ball grinding, ore testing. The purpose of this study to determine the effects of circulating load cl and test sieve size p. The bond ball mill work index test has been used for ore hardness characterization for more than 80 years. Determination of bond index of wasagu manganese ore in kebbi. The bonds standard ball mill is used to determine the work index value of differ ent samples the bond work index is defined as the kilowatthours per short ton required to break from infinite size to a product size of 80 passing 100 m if the breakage. 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 circuits. Bond s work index which is defined as the resistance of the material to grinding. Taguiam department of mining, metallurgical and materials engineering university of the philippines, diliman email protected abstract the bond work index refers to the measure of a materials hardness or resistance to crushing and grinding, and is numerically expressed as kilowatt hours per short ton. A method of c alculating autogenous semiautogenous. Determining the bond efficiency of industrial grinding circuits. A comparison of test procedures for estimating the bond ball. Procedure for determination of ball bond work index.
Determination of bond work index of lucky cement limestone. Kinetic grinding test approach to estimate the ball mill work index 343 the w i parameter is obtained from bond s ball mill grindability test bond, 1961. This test is performed according to the standard bond procedure which proposed model is presented in eq. Determine the feed 80% passing size f 80 and the weight percent 65 mesh. The work index is computed using the following empirical equation revised by bond in 1960, where the sieve opening. 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. The test requires calibration against the standard bond ball mill work index test to estimate the work index. The bond s standard ball mill is used to determine the work index value of differ ent samples. In mineral processing, industry comminution is an important process. Alternative approaches for determination of bond work.
It was developed by fred bond in 1952 and modified in 1961 jkmrc co. Ball mill was employed to conduct the grinding test of seven different samples. The bond ball mill grindability test is run in a laboratory until a circulating load of 250% is developed. Jan 01, 2009 a bond ball mill work index test is a standard test for determining the ball mill work index of a sample of ore. Kinetic grinding test approach to estimate the ball mill. Both procedures were conducted using a standard bond test mill. The bond grindability test has been widely used for predictions of ball and rod mill energy requirements and for selection of plant scale comminution equipment 5.
In conjunction with the bond ball mill work index they can be used to. An identical weight of wasagu manganese ore whose work index was to be determined was ground in the same ball mill under same condition as. It provides the bond ball mill work index which expresses the resistance of material to. The general size reduction equation is as follows morrell, 2004. Bond developed separate tests for the rod mill and the ball mill. A new approach to the calculation of work index and the. The ability to simulate the bond work index test also allows examination of truncated ball mill feed size distributions on the work index. Cite this article vladislav valerevich lvov and leonid sergeevich chitalov, comparison of the different ways of the ball bond work index determining. The rod mill work index rwi is used for particle size determination in a size range from 25 mm down to 2. This raises the point that, in some cases, the bond ef4 oversize factor calculation is.
Ball mill work index, bond index, grindability, ball grinding, ore testing, grinding energy consumption, physical and mechanical ore properties. The design bond work indices for the primary and secondary ball mills are 16. Laboratory equipment used by rivs for determining the bond work indexes. Determination of bond index of wasagu manganese ore in. Bond ball mill work index test standard pdf simulating the. Introduction the bond ball work index is widely used in the field of minerals processing as an indicator of ore grindability. It provides the bond ball mill work index which expresses. For grate discharge mills, the charge should occupy about 50% of the mill volume. The bond work index wi was calculated from the following equation eq. Graduated cylinder analyssete sieve shaker and screens procedure 1 do a screen analysis on about 250 grams of the assigned 6 mesh ore sample. The work index of a particular material is determined in the laboratory by conducting the standard bond grindability test. The bond work index is a constant characteristic related to the hardness of a specific ore type.
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