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FM 306: SIZE REDUCTION AND SIEVING OBJECTIVE •To grind the given limestone material to a smaller size using a ball mill and to obtain the size distribution of the initial and the final mixture by sieving. •To estimate the energy required for the grinding operation. •To analyze the results using the available theories. INTRODUCTION
The work index (Wi) is calculated in a laboratoryscale ball mill with Bond equation. The Bond work index has been widely used in designing fullscale mills but the Bond test is rather complex, lengthy susceptible to procedural errors and this is why attempts have been made to abbreviate and simplify Bond test procedure (Weiss, 1985). 2.
using the Bond equation (1961). For every Bond Rod Mill Work Index test carried out at JKTech, a standard report is issued. The report details the Bond test procedure method, and presents the results including F80, P80, Grindability and Work Index. Further interpretation of .
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 CenterPeriphery Discharge mill has feed reporting from both ends and the product discharges ...
The mill product can either be finished size ready for processing, or an intermediate size ready for final grinding in a rod mill, ball mill or pebble mill. AG/SAG mills can accomplish the same size reduction work as two or three stages of crushing and screening, a rod mill, and some or all of the work of a ball mill.
Bond''s original work on establishing the energy for size reduction was established in a m (8 foot) internal diameter wet grinding overflow type ball mill. Doubt is now expressed whether the derived empirical equation is applicable to high pressure roller crushers where .
Feb 18, 2019· Calculation of top size grinding media (Fred C. Bond) Calculation of top size grinding media AZZARONI''s Formula I attach Fred Bond''s first empirical equation for sizing grinding .
used in conjunction with other Bond Work Indices (CWi, RWi, BWi) to determine power requirements using Bond''s Third Law of Comminution. Barratt and Millpower 2000 Barratt (1986) proposed the use of an empirical formula for predicting SAG power involving the use of a combination of Bond work indices over a range of sizes from F 80 to a defined P
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. These equation application methods are used to process <1/2″ ore samples in a Ball Mill using a standard ball charge. Below describes in general terms the Bond Work Index Procedure used by a Professional Metallurgical Testing Laboratory.
Dec 18, 2013· It can be seen that in the regime in which the Bond equation is valid, energy use increases exponentially as product size decreases with constant feed size, with an exponent of (approximately) − For P80s finer than 75 μm, the Levin test, a modified Bond ball mill work index test, may be used to predict grinding performance.
FM 306: SIZE REDUCTION AND SIEVING Introduction: ... (Bond''s Law) (7) Note that the definition of particle size in Bonds law is different: D80 = Particle size such that 80% by weight of the sample is smaller than it. ... Dry Grinding work index is times wet grinding index. Open circuit work index is
Sep 04, 2016· Two worked examples are considered to illustrate the computation of energy consumption in comminution using Kick''s, Rittinger''s and Bond''s laws. The worked examples on open as well as close ...
2 MODELLING THE SPECIFIC GRINDING ENERGY AND BALLMILL SCALEUP Ballmill scale up (Bond''s Law)Data: zBond work index w i zFeed D f and product d size (both 80% cumulative passing) Result: The specific grinding energy w Mill power draw P = wT, where T the mill capacity Mill dimensions (from Tables or charts)
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; madi and Shsavari, 2009). Theoretical basis of quick procedure
Definition, objectives of size reduction and size separation, factors affecting size reduction, laws governing energy and power requirements of mills including ball mill, hammer mill, fluid energy mill etc., sieve analysis, standards of sieves, size separation equipment shaking and vibrating screens, gyratory screens, cyclone separator, air separator, bag filters, cottrell precipitator ...
Bond''s model is most commonly used to describe primary and secondary grinding to product sizes above, for example, 100 µm. Operators sometimes use Bond''s equation to describe grinding in situations where it is not appropriate, such as fine grinding below 50 µm. ... Can I use BWi Bond Work Index to Size a Regrind Mill: Fine Grinding ...
size reduction circuits (Charles, 1957). However Bond''s Third Law can be reasonably applied to the range in which ball/rod mills operate in. In spite of the empirical basis of Bond''s theory, it is the most widely used method for the sizing of ball/rod mills and has become more likely a standard. The general form of Bond''s equation is as ...
Bond Rod Mill Grindability Test. The test determines the Bond Rod Mill Work Index which is used with Bond''s Third Theory of Comminution to calculate net power requirements when sizing ball mills*. Various correction factors may have to be applied. The test is a closedcircuit dry grindability test performed in a standard rod mill.
Bond''s equation was developed for the purpose of designing conventional crushing and grinding circuits (crushrodball mill or crushball mill). ... Bond ball mill work index test is used to ...
W = Bond''s work index (kWh/t) P 80 = particle diameter of product, 80% passing (µm) F 80 = particle diameter of feed, 80% passing (µm) o The Bond''s 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.
Morrell recon gured the Bond''s Third Theory formula to cause extra power requirements to be fi inputed. This technique incorporates the material speci c gravity (SG). The AG/SAG specifi c fi energy values produced using this method are susceptible to higher values of crushing and rod mill work .
Energy and temperature analysis in grinding Rowel, Morganl, A. Batakol T. Jin2 I School of Engineering, Liverpool John Moores University, UK 2 CranJield University, UK Abstract Energy consumption and dissipation are discussed, leading into a thermal model for grinding.
Oct 24, 2018· People are mistaking the operating work index for the specific energy consumption of an operating mill or circuit. First, let''s define what the specific energy consumption is. ... Bond''s equation ...
The mill power is = Watts, calculated by (6). Fi P nally the product is wet screened to find the size d80. 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 .
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