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WORK INDEX •Work Index, Wi, is the gross energy requirement in kilowatt hour per ton of feed (kWh/ton of feed) to reduce a very large particle to such a size that 80% of the product will pass through a 10micrometer, or 0.1 mm screen. •If Dp is in mm, 𝑊𝑖=𝐾 1 𝐷𝑝𝑝 𝐾 = 0.1𝑊𝑖=0.3162𝑊𝑖 I =0.3162𝑊𝑖 1
For overflow ball mills, the charge should not exceed 45% of the mill volume . For grate discharge mills, the charge should occupy about 50% of the mill volume . 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.e.,
This paper presents the breakage properties of five different porous materials based on a kinetic model, which was commonly used in the cement industry. For this purpose, firstly, standard Bond's grindability tests were made for five porous samples. Secondly, eight different mono-size fractions were ground between 1.7 mm and 0.106 mm formed by a V2 sieve series.
The Bond work index is one of the most useful and interesting parameters used in designing grinding equipment. However, it must be obtained under restrained conditions, especially in regards to the Bond standard lab mill. The main objective of this study is to show how this index can be obtained using a Denver ball mill, which is present in most mineral …
Work Index values (crushing, rod mill and ball mill). Data from 11 mines located around the world is analysed for correlations between UCS and various Wi values. Introduction Need to accurately predict future mine and mill production rates requires a knowledge of ore grindability well in advance of when ore are actually mined.
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. The simplified test method described in this paper is an alternative procedure to the ball mill grindability test.
A Bond Ball Mill Work Index may also be used in the simulation and optimisation of existing mill(s) and the associated grinding circuit(s). Sample requirements: A minimum of 8 kg of material crushed to nominally minus 10 mm is preferred. JKTech would stage crush the sample to minus 3.35 mm, as required for the Bond Ball Mill Work Index test feed.
After which, the ore was grinded in a ball mill until a 250% circulating load was achieved. The Bond work index was then calculated to be equal to 41.38 kWh/tone. I. Introduction Comminution is the process of reducing particle size by breaking, crushing and grinding until the valuable minerals are minute enough and can be isolated by such ...
The power predictions for ball mills typically use the following form of the Bond equation: here • E is the energy (kilowatt-hours per metric or short ton) • Wi is the work index measured in a laboratory ball mill (kilowatt-hours per metric or short ton) • P80 is the mill circuit product size in micrometers • F80 is the mill circuit ...
characterisation of an iron ore resource is critical to effective project evaluation, process design, risk management and project execution. ... • Bond rod mill work index test • Bond ball mill work index test • Minnovex MODBOND grindability test • …
Starting from the first-order grinding kinetics defined by means of the Bond ball mill, this paper discusses a simplified procedure for a rapid determination of the work index by just two grinding tests. The applicability of the simplified procedure has been proved on samples of copper and Iron ores that are located in Iran.
The grindability of an ore in the process of mineral dressing can be determined by use of the Bond work index (Wi). This index is determined on a laboratory-scale using a Bond ball-mill and by ...
Work Index Ball Mill. Cone Ball Mill. QHQM Lab Ball Mill . XMB Ball and Rod Miller. XFG Lab Flotation Machine. Lab Continuous Flotation Machine ... like gold, tungsten, tin, tantalum, iron, manganese, chrome, titanium, bismuth and lead whose size ranges from 2-0.037mm, also to pyrite whose size ranges from 4-0.037mm；Changing its grooves ...
Practical 1: Title: Ball Milling Objective: 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. Introduction: 'Ball milling is a method used to break down the solids to smaller sizes or into a powder. A…
Ball mills are progressively used to grind the ores for particle size reduction and to liberate valuable minerals from the ores. The grinding of ore is a highly energy-intensive process [1,2,3,4].In this process, the size of the particle obtained depends on the energy consumption of …
Table I shows the Bond ball mill work index obtained for the ore samples as well as the iron and silica content in concentrate and tail after LIMS. The concentrate weight recovery was in the order of 50–60%. Furthermore it may be observed that the Bond ball mill work indices for the ore (Wi) varies from 14.6 to 20.9 kWh/t.
In iron ore beneficiation plant, we should study its grinding work index according to its own ore characteristics and formulate a better set of grinding process parameters. Classification efficiency is a key factor affecting the operating efficiency of the mill. 2.Magnetic Separation Operation
Source 4: Tenova Bateman mills (AG/SAG, Rod, Ball Mills) Source 5: Doering international Source 6: SME handbook of mineral processing, N.L Weiss Editor, NY 1985. Bond Work Index Tester
2. Wear and tear in wet crushing is more than that in dry crushing of materials. 3. Size enlargement (opposite of size reduction) is not a mechanical operation. 4. A 'dust catcher' is simply an enlargement in a pipeline which permits the solids to settle down due to reduction in velocity of the dust laden gas. Correct.
Grinding is a process of reduction of lumps to powder depending on the requirement of particle size and particle shape. The present investigation involves the identify the physical properties of th...
A method of grinding a mineral-containing ore, which includes grinding the mineral-containing ore in a primary milling process and thereafter fine grinding the mineral-containing ore in a secondary ball-mill. A composite grinding medium comprising a mixture of steel balls and pebbles is used in the secondary ball-mill. The pebbles have an average size which is …
The ball mill work index laboratory test is conducted by grinding an ore sample prepared to passing 3.36 mm (6 mesh) to product size in the range of 45-150 µm (325-100 mesh), thus determining the ball mill work index ( WiB or BWi ).
There is a copper ore with a flow of 500 short tons / h, whose Work Index is 18.6 kw.h / short ton, and a density of 3.02 g / cm3. Below are data of a part of the Process (Grinding and Flotation Plants): Grinding plant It has: A rod mill with a diameter of 3.35 m and a length of 6.70 m, the length of the bars being 6.55 m.
Comparison of ore hardness measurements for grinding mill design … and by Dawson Metallurgical Laboratories, Inc. for Bond Ball Mill Work Index tests using … » More detailed grindability index iron ore – Crusher South Africa
This reduces the need for product to recirculate within the ball mill, lowering the consumption of grinding media and reducing iron oxide contamination they can introduce. As ore grades are declining globally, we need to process more. HPGRs can process the increasing volumes of ore effectively, making the mines more profitable.
The work index is computed using the following empirical equation revised by Bond in 1960, where the sieve opening at which the test is made, (microns) 358 (2) Gb Bond's standard ball mill grindability, net grams p of ball mill product passing sieve size P 1 produced per mill revolution.
Work Index For Iron Ball Mill Bond work index an overview sciencedirect topics the ball mill work index laboratory test is conducted by grinding an ore sample prepared to 100 passing 336 mm 6 mesh to product size in the range of 45150 m 325100 mesh thus determining the ball mill work index .
Ball Mill Wio, BWio 8.6 Circuit Wio, OWio 14.6 Bond Ball Mill Work Index, BWi, kWh/t 13.4 Bond Rod Mill Work Index, RWi, kWh/t 18.1 Table 1. Example of AG/SAG 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 Bond Work Index (BWI or W i) is defined as the calculated specific energy (kW h/t) applied in reducing material of infinite particle size to 80% passing 100 μm . The higher the value for W i, the more energy is required to grind a material in a ball mill, .
For mineral processing project, after blasting, crushing and screening system is always the first stage to reduce the big raw ore lumps to proper small particle size for following mill grinding system. Normally to reduce the big ore lumps to small …
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