In practice, it is possible to find materials of non-standard size that are finer than 3.327 mm.in this work, a procedure for the calculation of the bond work index is suggested for cases when the bond crushing tests by pressure and impact, trans aime, vol 169, 1947, pp bond rod mill grindability test. the test determines the bond rod mill work index which is used with bonds third theory of comminution to calculate net power requirements when sizing ball mills. various correction factors may have to be applied.
ball mill wio, bwio 8.6 circuit wio, owio 14.6 bond ball mill work index, bwi, kwht 13.4 bond rod mill work index, rwi, kwht 18.1 table example of agsag ball mill circuit wio calculations abstract optimum use of power in grinding, both in terms of grinding efficiency and use of installed capital, can have a large effect on bond test wis rod mill: ball mill: 9.5 kwht.8 kwht bond standard circuit work index: assume the rod mill work index of 9.5 applies from the actual rod mill feed sizeof 19,300 to a rod
jan 15, 2018 this is typically quantified based on bond ball work index tests of hpgr products, which generally report a significantly lower bbwi value than for the hpgr feed the implications for the equipment sizing of the downstream ball mills can for the simplified bond method, an approximate work index may be determined by running a batch dry-grinding test. the test was performed using a cm diameter tumbling ball mill with material hold-up of about 10%, media loading of about 25% and a unit interstitial filling. two kilograms of the mm lignite samples were ball-milled for
the aim of this study was to develop a new method for assessing the bond work index in a ball mill which is based on a first order kinetics present in the bond ball mill for grinding mineral raw materials theoretical basis of quick proceduremill ball mill closed circuit crushing to mm open circuit dia. rod mill to mm closed circuit dia. ball mill to um the ore test work index circuit operating work index the standard bond circuit coarse ore bins fine ore bins screen crushing screen classification rod mill ball mill this IS the reference basis for all work
the grinding jar for the bond index rod mill is in size and has a wave-shaped design. At least to kg sample material is required to simulate a closed grinding circuit in a ball or rod mill. the rod mill work index is used for particle size determination in a size range from mm down to 2.1 mm whereas ball mill work Wi bond work index wibm bond ball mill test work index wic bond impact crushing test work index size coarser than the plant ball mill circuit If choos-ing between two standard mesh sizes, choose the finer dicted by the bond designscale-up method for the
the bond work index refers to the measure of the materials hardness or resistance to crushing and grinding, and is numerically expressed as the kilowatt hours per short ton required to reduce the material from theoretically infinite feed size to 80% passing 100 .m. It is calculated using the equation below: 4.45 number, size and mass of each ball size depends on mill load and whether or not the media is being added as the initial charge. for the initial chargin of a mill, coghill and devaney defined the ball size as a function of the top size of the feed, i.e 0.40 dB ball size feed size
dec 12, 2016 ball mill power calculation example. wet grinding ball mill in closed circuit is to be fed 100 tph of a material with a work index of and a size distribution of 80% passing inch (6350 the method is used to size a cement ball mill. efficiency correction factors are applied with the bond equation. the method is valid both for clinker grinding and for raw materials grinding. this method only gives a rough and initial idea for sizing a cement ball mill.
computer simulation of product size distribution of a laboratory ball mill. particulate science and technology 2011, comparison of the bond method for sizing wet tumbling ball mills with a sizemass balance simulation model. powder technology 1983, drop weight index and the coarse ore grinding index test data from the bond ball mill work index test is used to calculate the fine grinding index the ia and ib indices are used to calculate specific energy for the coarse and fine components of the total grinding specific energy at the pinion
the article presents the review, studies and classification of the existing methods of the bond ball mill work index determination. the scope of the analysis embraces the methods of aksani and nmez, todorovi, berry and bruce, horst and bassarear, ahmadi, kapur, gharehgheshlagh, lewis, magdalinovich, karra, smith and lee, armstrong, as well jktech and aminpro approaches.please find below two calculators for sizing mills using the bond and rowland methods: ball mill sizing: calculator for ball mill in a single stage circuit. rod ball mill sizing: calculator for rod mill as first stage of the circuit and ball mill as second stage of the circuit.
the grindability of an ore in the process of mineral dressing can be determined by use of the bond work index this index is determined on a laboratory-scale using a bond ball-mill and by however, if the sample is to be prepared by cutting with a diamond saw as little as is normally sufficient. also remember that the products from the smc test can be re-used for bond ball work index testing, the smc test being effectively used as a feed preparation step for the bond ball work index test.
figure rod millball mill work index ratio unconfined compressive strength 100 200 300 400 ucs 0.5 1.5 wirmwibm siddall et al identified the ratio of bond rod mill work index and ball mill work index as being indicative of an ores compentency. figure plots this ratio versus ucs; no trend is apparent 2005), the smc test drop weight test index the sag power index and bond ball mill work index provide unquestionable margin of design safety in the plant however, this approach does not consider the inherent
cycle test akin to the bond ball mill work index determination. the first cycle starts with minus 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 jan 14, 2021 size of 152 mm to 80% passing 1.7 mm, and a simple adjustment procedure in case the sag product size needed to be adjusted. bond rod and ball mill work indices are readily converted to pinion energy for rod and ball mills but not for sag mills. reproducibility, while not studied in this paper is clearly a part of the meaningfulness of the data
ore sample will be tested in a standard bond ball mill grindability test with a closing screen size chosen so the test product closely matches the survey product depending on the plant configuration, it may be possible to also collect this raw ore sample without shutting down any grinding mills.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 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.
can be determined using the data generated by a conventional bond ball mill work index test ic. and ih. values are also provided as a standard output from a smc test the general size reduction equation is as follows where bond index ball mill rod mill Bt 100 Xl retsch. the grinding jar for the bond index rod mill is in size and has a waveshaped design at least to 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 mm down to mm whereas ball mill work
the mill power is 22.5 watts, calculated by fi- nally the product is wet screened to find the size 2.4. rod mill semi continuous process the same mill is used for the semi continuous grinding tests which is similar to the bond test but with the exist- ing mill of known power. after time the mill product isthe proposed model correlates the specific grinding energy, the clinker work index and the specific surface of a cement produced through fine-grinding in ball mills.
jul 31, 2014 the following modified bond equation was proposed for crushing Wc cP Wi where: Wc is energy consumed for clinker crushing Wi is bond ball mill work index Pc -is sieve size passing 80% of the clinker after crushing Fc is sieve size passing 80% of the clinker before