Modelling the specific grinding energy and ballmill scaleup ballmill scale up bonds law data. 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. For more information on the tests please see below. This standard grindability test simulates a closedcycle. Jktech laboratory services bond ball mill index test brmwi a bond ball mill index test bbmwi is a standard test for determining the ball mill work index of a sample of ore. You can find the sg of each mineral samples on the other table. Ball mill grindability test was conducted by standard practice using 100mesh 150 pm closing screens. It has been recognized that the grindability of an ore in a ball mill is a function of both feed and mill parameters. W bonds work index kwht p 80 particle diameter of product, 80% passing m f 80 particle diameter of feed, 80% passing m o the bonds work index of a material, which is commonly used in the british commonwealth as well as us, is determined in a standard laboratory ball mill but the test is cumbersome to perform.
Ball milling is a method used to break down the solids to smaller sizes or into a powder. The ability to simulate the bond work index test also allows examination of truncated ball mill feed size distributions on the work index. The work index of a particular material is determined in the laboratory by conducting the standard bond grindability test. The relationship between the ore hardness and iron content presented in figure 2 indicates that the samples with a higher magnetite content fe% are softer lower bond work index, suggesting that the magnetite in the ore may be. The full suite of bond comminution tests provide the ball mill work index bwi, the rod mill work index rwi, the crusher work index cwi and the abrasion index ai. The most widely used parameter to measure ore grindability is the bond work index, wi magdalimovic,1989.
The feed sample undergoes a wet screen analysis and a certain quantity, usually 0. Kinetic grinding test approach to estimate the ball mill. The geometry of a mill with conical ends is shown in figure 8. The type of ball inside of the mill is made of cast iron. 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. Why is the bond ball mill grindability test done the way. Pdf a quick method for bond work index approximate value. The rod mill work index rwi is used for particle size determination in a size range from 25 mm down to 2. Application of operating work indices in autogenous. Alabi oladunni oyelola, shehu aliyu yaro, binta hassan abstract in this study, the work index of wasagu manganese ore deposit in kebbi state of nigeria was determined using the modified bonds method of determining work index also known as berry and bruce method.
The ball mill is classified as an intermediate and fine grinder where the action of the grinding is based on impact and attrition. Kinetic grinding test approach to estimate the ball mill work. Determination of bond index of birnin gwari iron ore in nigeria bond. Reference mineral granite of known weight and work index 15. The bbmwi is a measure of the resistance of the material to crushing and grinding. Kinetic grinding test approach to estimate the ball mill work index 343 the w i parameter is obtained from bonds ball mill grindability test bond, 1961. To determine the energy required for crushing the given feed and thus obtain the work index for the same.
Engineering sustainability of mechanical recycling of. It provides the bond ball mill work index which expresses the resistance of material to. Relationships between comminution j energy and product size. Typical mill circuit represented by the bond ball mill test. Ball mill principle, advantage, disadvantage hindi youtube. The fc bond work index test ball mill was designed by f.
Testing method for ball mills outokumpu technology oyj. Marc manufactures a wide range of ball and rod mills to suit most metallurgical laboratory applications. The empirical formula to calculate bond mill work index bwi is presented in the equation 2. Bond for use in determining the bond index, a measure of grindability and power required for grinding applications. These equation application methods are used to process pdf available in physicochemical problems of mineral processing 531. In the second step of the testing method, the test is based on the bond ball mill. Wet ball mill power draw bond for wet ball mills, bond expressed power draw as a function of the total mass of media. Also determine the reduction ration and critical speed of the mill. This video was put together by joshua wright and aldo vasquerizo as a supplemental lecture for university of nevada reno. Dec 23, 20 sag semiautogenous grinding mill is an autogenous mill which uses grinding balls, it is similar to ball mill but has large diameter and short length. To analyze the results using the available theories. The bond ball mill work index is a measure of the resistance of the material to grinding in a ball mill.
Grinding solutions offers a range of bond work index testing from crushability and abrasion to ball and rod mills. See this useful summary table of bond work index by minerals. The ball mill is classified as an intermediate and fine grinder where. Hgi is a poor method of predicting grindability of biomass in vertical spindle mills. The procedure for the work index test bases the bwi value on the calculation of new fines generated in. Pdf a methodology to estimate ores work index values, using. Nov 27, 2018 in this video, we will show following things in hindi. 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. Because grindability is so widely used in mill design the assumption is often made that the method is valid without a sufficiently critical examination of the. The data samples were calculated on a cfrp which has a fiber. The bond ball mill work index test is thought to be additive because of its units of energy. A quick method for bond work index approximate value determination article pdf available in physicochemical problems of mineral processing 531. In this way, work index values are usually obtained for some specific grind size that characterizes the grinding operation to design or under evaluation. In this video, we will show following things in hindi.
The marcy expression is applicable for mill diameters between 1. To estimate the energy required for the grinding operation. May 18, 20 this video was put together by joshua wright and aldo vasquerizo as a supplemental lecture for university of nevada reno. It was developed by fred bond in 1952 and modified in 1961 jkmrc co. Using peripheral speed, the rotational speed can be determined. Pdf the effect of circulating load and test sieve size. Bonds law is often written in terms of the work index wi as. Determination of bond index of birnin gwari iron ore in. Our range extends from small 6l jartype mills that are manually positioned on rollers to large 30l size mills. The standard bond ball mill grindability test is a closed circuit dry grinding test with a 250% circulating load. Bond ball mill work index grindability tests youtube. 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.
Procedure for determination of ball bond work index in the. Investigation into the applicability of bond work index. A new approach to the calculation of work index and the. The test is performed on a raw material approximately weighing 10 kg, which coarseness is 100% 3. 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. Determination of the bond work index using an ordinary. Application of bond work index for calculating power required for closed milling circuit 9 4. The present work is an effort to show that the devia tion of the. Mill ball mill closed circuit crushing to 16 mm open circuit 8 dia. Milling rod ball mills including bond ball work grindability index.
To grind the coarse salt to a smaller size by using a ball mill and to obtain the particle size distribution of the initial and the sieved final mixture. 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. At least 15 to 20 kg sample material is required to simulate a closed grinding circuit in a ball or rod mill. Bond work index is being widely used to the estimate power required to grind materials. 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. The specific grinding energy w mill power draw p wt, where t the mill capacity mill dimensions from tables or charts. Ball mill principle, advantage, disadvantage hindi. These equation application methods are used to process ball mill using a standard ball charge below describes in general terms the bond work index procedure used by a professional metallurgical testing laboratory. A bond ball mill work index test is a standard test for determining the ball mill work index of a sample of ore. 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.
The bond work index is a measure of ore resistance to crushing and grinding. Investigation into the applicability of bond work index bwi. Bond quantified the rod mill power draw as a function of the work index, capacity, and a series of correction factors. This index is widely used in the mineral industry for comparing the resistance of different materials to ball milling, for estimating the energy required.
The test requires calibration against the standard bond ball mill work index test to estimate the work index. Determination of bond index of wasagu manganese ore in kebbi. Follow the provided icon link to download acrobat reader. A rotating drum causes friction and attrition between steel rods and ore particles. Bwi can predict the potential for mill choking of biomass in a tube and ball mill. Its value constitutes ore characteristic and is used for industrial comminution plants designing. Bonds approach consists of determining the ore hardness characteristics, or work index wi via standardized laboratory testwork. Determination of bond index of wasagu manganese ore in kebbi state, nigeria. The test requires calibration against the standard. Relationships between comminution j energy and product. Ball mill instruction manual pdf ball mill diagram sheet pdf the software to view and print adobe acrobat pdf is available for free from the adobe website. The total volume inside the mill is given by vm 4 d2 ml 1 2lc l l 1 dtdm 3 1 dtdm 8. This index is widely used in the mineral industry for comparing the resistance of different materials to ball milling, for estimating the energy required for grinding, and for ball mill scaleup.
We have all the laboratory and plant equipment you need to test or buildoperate your plant. This index is widely used in the mineral industry for comparing the resistance of different materials to ball milling, for estimating the energy required for grinding, and for ball mill. Its a topic of ball mill from pharmaceutics1 which will be asked in pharmacy exam so i made this ball mill in pharmacy topic in hindi for. According to the bond standard procedure, the work index is. If you have any questions, need advice, or need to conduct a metallurgical. Its a topic of ball mill from pharmaceutics1 which will be asked in pharmacy exam so i made this bal. Determining the bond work index value is quite complicated, timeconsuming and requires trained operating personnel and therefore is subjected to errors. These equation application methods are used to process bond work index by minerals. Generally, bond work index is a common method for selecting comminution equipment as well as estimation of grinding efficiency and calculating required power. The standard procedural outline of the test is stated in bond 1961.
Numerically, the work index is the energy required in kwht to reduce a given material from theoretically infinite feed size to 80% passing 100 microns. The second test, a bond work index determination, results in a specific energy value net hphrt from an empirical formula. The fc bond mills are used in laboratories throughout the world. The bond lowenergy impact test can be used to determine the crusher work index cwi, also known as the impact work index. The bond work index is a measure of ore resistance to crushing and grinding and is determined using the bond grindability test. This study was carried out in a standard bond ball mill 305 mm x 305 mm size. The product from the first step is then used for determination of the required ball mill energy for the secondary grinding stage to reach the target grinding size. It is a locked cycle test conducted in closed circuit with a laboratory screen. Numerically the work index is the energy required in kwhshort ton to. In all cases the min eral sample is crushed and screened to pass a predeter mined size 3. First, a jar mill grindability test requires a 5 lb. A quick method for bond work index approximate value determination. The bond ball mill grindability test is a lockedcycle laboratory grinding test. W is the work index measured in a laboratory ball mill kilowatthours per metric or short ton p 80 is the mill circuit product size in micrometers.
Pdf rapid determination of bond rodmill work index by. A new approach to the calculation of work index and the potential energy of a particulate material. We have a metallurgical test for every possible mineral type and treatment. 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 lockedcycle test where ground product is removed from test cycles and replaced by fresh feed. This test is performed according to the standard bond procedure which proposed model is presented in eq. It can be used to determine the grinding power required for a given throughput of material under ball mill grinding conditions. For grinding circuits where the feed to a ball mill is sent directly to the classifier and the cyclone underflow feeds the ball mill see figure 3. The bond ball mill grindability test is run in a laboratory until a circulating load of 250% is developed. This table of ball mill bond work index of minerals is a summary as tested on around the world sample. Pebble mill is used when product contamination by iron from steel balls must be avoided. In the current research, a simple, fast and accurate procedure is introduced to find the. It can be used at mesh sizes from 65 to 200 mesh normally 100 mesh. Why is the bond ball mill grindability test done the way it. A bond ball mill index test bbmwi is a standard test for determining the ball mill work index of a sample of ore.
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