Jun 12, 2012· An "Index of Work Satisfaction form" would be a form used in a survey intended to assess the satisfaction of a work force and to develop a numerical index to describe their aggregate level of ...
correlation between the abrasion value(X2) and work index (Wi) is found to be Wi = -1.8 Ln (X2) + 11.5 with correlation coefficient of 0.80. KEYWORDS: Bond work index ± Mechanical properties of rocks ± Grinding energy- Crushing resistance 1- INTRODUCTION Comminution in a mineral processing plant, or mill, involves a sequence of crushi ng
Bond Work Index. In the 1930s through early 1950s, Bond developed a new theory of comminution that introduced an index, called the 'Bond Work Index', which relates power consumption in crushing and grinding to the feed and product size distribution. His theory and index were introduced in a widely cited 1952 journal article.
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The Bond work index, W i, as an indicator of the grindability of raw materials is not a material constant but rather it changes with change of size of the grinding product.Therefore, in practice we can expect some difficulties and errors when the energy consumption is determined according to this formula in the case when, for a given size of grinding product, the value of the work index …
TO DETERMINE WORK INDEX FOR HIGH PRESSURE . GRINDING ROLLS . ABSTRACT. The use of High Pressure Grinding Rolls is gaining significant interest as a replacement for SAG milling in the . comminution of hard rock ores because of the potential for reduced costs in terms of energy and grinding ball consumption.
This was based on the Work Index concept. From this concept came two equations: (a) the equation to determine the Work Index from Bond grindability tests, and (b) the Bond equation, which uses the Work Index to determine the energy needed for grinding.
Hardgrove Grindability Index (short HGI) is a measure for the grindability of coal. Grindability is an index, therefore it has no unit. The smaller the HGI, the harder is coal texture and less grindable is the coal. Grindability is an important factor for the design a coal mill.
Bond Grinding Circuit Efficiency Meeting of Bond Efficiency Guideline Working Group of the Global Mining and Standards Group Salt lake City, 2014 Based on Presentation to the 2008 Meeting of SME, by C.A. Rowland, Jr. and R.E. McIvor. Bond Grinding Circuit Efficiency • The Bond Work Index equation • Ore test WI • Circuit operating WI
The work index covering grinding in tumbling mills of coarse sizes is labelled M ia. The work index covering grinding of fine particles is labelled M ib (Morrell, 2008). M ia values are provided as a standard output from a SMC Test® (Morrell, 2004a) whilst M ib values can be determined using the data generated by a conventional Bond ball mill ...
Abstract: The Bond work index is a measure of ore resistance to crushing and grinding and is determined using the Bond grindability test. Its value constitutes ore characteristic and is used for industrial comminution plants designing. Determining the Bond work index …
Oct 15, 2015· The Hardgrove Grindability Index (HGI) test is based on Rittinger’s theory that “the work done in grinding is proportional to the new surface produced” , . The index varies from 20 to 110, with a lower HGI indicating a coal is harder to grind and more energy will be required to reach the required degree of fineness.
Vol.8, No.9 Alternative Approaches for Determination of Bond Work Index 733 Where H is the Hardgrove index and mH is the mass (in gm) of the particles smaller than 74 µm. The mean of two to three parallel measurements are to be considered.
The Bond work index is a measure of ore resistance to crushing and grinding and is determined using the Bond grindability test. Its value constitutes ore characteristic and is used for industrial ...
grinding circuit efficiency. Bond Work Index efficiency has been widely used by industry, but until now without concise standard methods, or a formal guideline, for doing so. The Bond Efficiency SubCommittee of - the Industrial Comminution Efficiency work group of GMSG has
Bond work index studies were carried out for the BHQ and BHJ ores with different product fineness in order to evaluate the energy requirements in fine grinding. A higher Bond work index …
The Bond Ball Mill Work Index is a measure of the resistance of the material to grinding in a ball mill. It can be used to determine the grinding power required for a given throughput of material under ball mill grinding conditions. It is a 'locked cycle' test conducted in closed circuit with a laboratory screen.
Test conducted on a Bond Index testing mill (Bico-Braun, USA) 700ml of sample milled for 100 revolutions. New number of revolutions is calculated to produce fines equal to 1/3.5 of the total charge of the mill. The Bond Work Index W i expresses the resistance of the material to grinding to a …
Bond Work Index Tests. Grinding Solutions offers a range of Bond Work Index Testing from crushability and abrasion to ball and rod mills. For more information on the tests please see below: Bond Low Energy Impact Test. The Bond Low-Energy Impact test can be used to determine the Crusher Work index (CWi), also known as the Impact Work Index.
Generally, Bond work index is a common method for selecting comminution equipment as well as estimation of grinding efficiency and calculating required power. In the current research, a simple, fast and accurate procedure is introduced to find the
A Bond Rod Mill Index Test (BRMWI) is a standard test for determining the Rod Mill Work Index of a sample of ore. The BRMWI is a measure of the resistance of the material to crushing and grinding. It can be used to determine the grinding power required for a given throughput of material under rod mill grinding consitions. JKTech Pty Ltd
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.
At least 15 to 20 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 25 mm down to 2.1 mm whereas Ball Mill Work Index (BWI) is used for the range from 2.1 mm down to 100 µm. Adjustment of grinding parameters:
nent n using conventional grinding procedures. The same calculation can be used to calculate the true value of . W. i. and attribute a potential energy state to a material at any size. Keywords: Work Index, Potential Energy, Grinding . 1. Introduction . The size-energy relationship is generally expressed by the following Equation (1), 1,2 21 11 ...
standard Bond crushing, and rod mill work indices, abrasion indices and by Dawson for Bond Ball Mill Work Index tests using crushed feed, and Standard Autogenous Grinding Design (SAGDesign) Tests, patented by Outokumpu. (See reference 8 below). The comparison of these results gives context to how the various measurements relate to each
It was obvious that d80 was decreased with increasing grinding time and decreasing work index, but the effect of grinding time on d80 was more at lower values of work index rather than higher values. Also, the feed size of ore had no effect on the interaction effect of grinding time and work index at desired levels. 3.4.
A mill is a device that breaks solid materials into smaller pieces by grinding, crushing, or cutting. Such comminution is an important unit operation in many processes.There are many different types of mills and many types of materials processed in them. Historically mills were powered by hand (e.g., via a hand crank), working animal (e.g., horse mill), wind or water ().
Comminution. Grinding Solutions offers an extensive range of comminution services, ranging from SAG mill testing to fine and ultrafine grinding. Tests range from industry standards, such as Bond Work Index Testing, to cutting-edge techniques such as pulp chemistry monitoring, to help optimise comminution circuits.
2 MODELLING THE SPECIFIC GRINDING ENERGY AND BALL-MILL SCALEUP Ball-mill 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 operating work index (Wio) of an existing grinding circuit can be calculated, given known mill power draw, throughput, feed and product size distributions. kWh/t = Power applied per ton of feed to the grinding unit Wi = The standard Bond work index of the ore P 80 = The 80% cumulative passing size of the product in microns F 80