tion related to the operation of the circuit (F80, P80, power and mill feed rate). THE BOND EFFICIENCY OF A GRINDING CIRCUIT In the plant: 1. Define the circuit for which the Bond Efficiency is to be determined. 2. Procure samples of the circuit feed and product. 3. Obtain the power draw of the size reduction equipment
EF5BM=[ P80+ ×P80] ( 3 ) The EF4 formula requires both the rod mill and ball mill work index (rod mill Wi is used to calculate the optimal feed size) and because this is a "singlestage ball mill" calculation, the F80 is actually the rod mill feed size (10,000 µm) from Table 1 and the P80 is the ball mill circuit product. The EF5 factor only applies below 75 µm to ball
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There is no doubt about the importance of Fred Bond's methodology [1,2,3,4,5] and its practical value in the field of comminution, not only in tumbling mills design and operation but also in the characterization of mineral raw materials grindability. The Third Law of Comminution, also known as the Bond's Law, is summarized in Equation (1) .
Product Size: All passing 6 mesh with 80% passing 20 mesh. Net power from pilot plant: KWH/ST. Mill, gear and pinion friction multiplier: Mill Power required at pinionshaft = (240 x x ) ÷ = 5440 Hp. Speed reducer efficiency: 98%. 5440 Hp ÷ = 5550 HP (required minimum motor output power).
reduction term of Bond's Equation. The engineers writing these reports may have been confused because the industry commonly uses units of kWh/t for both quantities, even though the two quantities refer to different things. It is incorrect to say, for example, "the ball mill work index is 13 kWh/t and the SAG mill SEC is 5 kWh/t,
implicitly modelled the impact of makeup balls diameter and discharge level on grate discharge mills' power. Bond published Equation 2 for overflow discharge ball mills. Furthermore, to calculate grate discharge mills' power, he proposed the multiplying factor of KWb = ( p)Cs( 2(910Cs))(
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A series of comminution tests was carried out to evaluate three multipass HPGR circuits and a jaw crusherball mill circuit. Combinations of HPGR units ( m and m diameter), jaw crushers and Bond ball mills were used to grind a 32 mm top size porphyry copper feed (BBWI = ) to a product P80 size of about 150 µm.
Bond Ball Mill Standard Test The procedure to carry out the Bond grindability test [1,18] is described below. The test is performed in the socalled Bond's standard ball mill, a laboratory mill 1200 1200, running at 70 rpm (BICO, San Francisco, CA, USA) with rounded inner edges and without lifters.
fred bond ball mill power draw equations T09:01:16+00:00 AMIT 135: Lesson 7 Ball Mills Circuits Mining Mill . Equations for mill sizes less than 381meters in diameter and greater than 381meters were proposed: t/h D 381 m Wet Ball Mill Power Draw (Bond) For wet ball mills, Bond expressed power draw as a function of the total mass ...
You need a twostage solution, first stage opencircuit mill and then second stage closedcircuit mill. First stage, will be broken into two parts as well, you use a Bond rod mill work index for the coarse component of the ore (+ mm) and the Bond ball mill work index for the fine component ( mm).
in a Bond ball mill for, 1, 2, 4, and 8 min. After each grinding cycle, the grinding product PSD is determined and returned to the mill for the subsequent grinding cycle.
factors with the threestage Bond equation gives this overall equation for grinding specific energy consumption. from a primary crusher product size, F80, to a ball mill cyclone overflow product size, P80. E=10Wi C. ( 1. 1. 10000 F 80 ) [. + 10Wi RM ( 21100 101000 )+10Wi ( P1 BM.
Austin's model, as has been mentioned, was not developed for ball mills but for SAG mills. Its over prediction of the power draw of 19% and high standard deviation (%) are perhaps ...
The failure of these rod mill and ball mill benchmark studies to validate either model led to the development of a "Third Theory" by Fred Bond Bond 1952. ... the mill power draw models are independent of the ore being processed (ore density matters, but feed and product sizes should not affect power draw if the mill is run properly). ...
Mike Daniel (2006) reports the measured input power to a laboratory ball mill apparatus is J/rev ( mWh/rev) versus 60 J/rev ( mWh/rev) in some of Fred Bond's discussions...
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Consultant at The Bond rod mill work index is a commonly used metric to describe ore grindability in the middle size classes, generally from 12 mm down to 1 mm. There are a couple ...
the form of Equation (3). The Jar Mill test favoured by gives a table of results of E and measured size x for a progressive batch grinding test; these results can be fitted as demonstrated in Figure 4. A series of Bond ball mill work index tests run at different closing mesh sizes can be fitted in almost the same way.
energy in ball mills for which the Bond equation was originally designed. The standard Bond grindability test . ... revolutions per minute which equates to a mill power draw of W.
(circular nomograph) Data (necessary): Feed size D and product size d f Given ore hardness (soft, medium or hard) Given capacity T (short ton/h) Result: The mill power draw P, which corresponds to a particular ballmill size DENVER SLIDE RULE (Photo) Determination of the ballmill dimensions (D x L) with the help of the Denver slide rule
Two Product Formula *** Three Product (bimetallic) Formula (Part 1) ***needs verify Three Product (bimetallic) Formula (Part 2) *** Ore specific gravity *** Pulp Density Relations *** Calculation of top size grinding media (Fred C. Bond) *** Calculation of top size grinding media AZZARONI's Formula *** Cyclone Design Calculator ***
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To apply it he de ned "Work Index" (W_i) for an ore as the speci c energy (kWh/tonne) required to reduce the ore from in nite grain size to 100 μm and he showed that for any ore the Work Index can be calculated from plant data and determined in a laboratory test.
P80 = 80% passing product size The constant in this equation is tensed the Bond Operating Work Index, Wio. Assuming Wio does not change as a function of the feed or product sire, and the ore itself has not changed, it is a direct measure of circuit efficiency, variations in circuit feed and product size taken into account.
Question: The Bond Work Index Equation is as follows: If the power draw on a ball mill is 2,750 kW, what is the Bond work index for the following charge: Throughput = 950 t h1 80 % passing size of the feed = 650 μm 80 % passing size of the output from the mill = 75 μm Sketch an approximation of the particle size distribution you might expect for the feed and
Many powerbased grinding models exist, and most operators are familiar with Fred Bond's "third theory". Bond's model is most commonly used to describe primary and secondary grinding to product ...
1745. 11:13:23. Alternative procedure to the Bond standard test is based on determining the grindability of an unknown ore by comparing it to the grindability behaviour of a reference ore. It can be performed in any laboratory ball mill, but it requires a reference sample ore for which wi is known.
Six tests were carefully performed with both mills using the same aggregate rock sample and with the same method of grindability testing based on Fred Bond's Ball Mill Grindability Work Index (BWi ...
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