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Calculate a Mill’s Operating Work Index Grate Discharge mills will not face this issue C This value represents the Volumetric Fractional Filling of the Voids in between the balls by the retained slurry in the mill charge As defined this value should never exceed 100 but in some cases – particularly in Grate Discharge Mills – it could be lower
The Bonds standard ball mill is used to determine the work index value of differ ent samples The Bond work index is defined as the kilowatthours per short ton required to break from infinite size to a product size of 80 passing 100 µm
Bond Work Indicies obtained from bench scale crushability and grindability tests or from pilot plant tests are used in the Bond Equation to determine the energy required to produce the required size reduction in comminution circuits The Bond Equation as found in reference 5 is W 10Wip05 – 10Wip05 Where W kwh per short ton
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
Figure 1 Uniaxial compression test machine 3 STANDARD BOND TESTS The Bonds standard ball mill is used to determine the work index value of differ ent samples The Bond work index is defined as the kilowatthours per short ton required to break from infinite size to a
According to the Bond standard procedure the work index is determined by simulating a dry grinding in a closed circuit in the Bond ball mill to achieve 250 circulating load Bond 1949 1952 1961 The test is performed on a raw material approximately weighing 10 kg which coarseness is 100 3327 mm
The mill rotates on rolls and its frequency is set to 70 RPM corresponding to 85 of the critical frequency The mill power is 225 Watts calculated by 6 Fi P nally the product is wet screened to find the size d80 24 Rod Mill Semi Continuous Process The same mill is used for the semi continuous grinding
The basic parameters used in ball mill design power calculations rod mill or any tumbling mill sizing are material to be ground characteristics Bond Work Index bulk density specific density desired mill tonnage capacity DTPH operating solids or pulp density feed size as F80 and maximum ‘chunk size’ product size as P80 and maximum and
The ball ﬁ mill work index is con rmed at 16 kWht The operating ﬁ work index though is in the range of 21 kWht to 25 kWht showing high inefﬁ ciency This raises the point that in some cases the Bond EF4 oversize factor calculation is not suf cient to compensate ﬁ for the milling inef ciencies that arise
The standard Bond Ball Mill Work Index test procedure is firstly to stage crush the feed to minus 335mm and size a representative sample The test then involves a series of batch grinds in a standard Bond mill A Bond mill is 0305m by 0305m with rounded corners a smooth lining and runs at 70rpm The charge consists of 285 balls weighing a
The Bond crushing work index test sometimes called the impact work index test is noisy and the difference you observed is perfectly reasonable The paper by Angove Dunne 1997 reports a standard deviation in crushing work index tests across laboratories as 45
Apr 14 2019 · The Bond Index Calculator is based on source data from the US Treasury and translates yield curves into returns that mirror a realworld index methodology It does this by modeling the full maturity range of the desired bond index fund and calculating both the coupon payments and price appreciation of each rung on the ladder
W is the work index measured in a laboratory ball mill kilowatthours per metric or short ton P 80 is the mill circuit product size in micrometers F 80 is the mill circuit feed size in micrometers Rod mill A rotating drum causes friction and attrition between steel rods and ore particles
The basic parameters used in ball mill design power calculations rod mill or any tumbling mill sizing are material to be ground characteristics Bond Work Index bulk density specific
The standard equation used by them for the ball mill work index Bond work index is as follows Bond proposed equation 1 to calculate work which how to calculate crusher work index « iron ore crusher The work index Bond 1952 is the work input in kilowatt hours per ton required to
2 the operating work index Wio of an existing grinding circuit can be calculated given known mill power draw throughput feed and product size distributions kWht 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
In the present work equations were also derived giving zthe ballmill power drawP as a function of its dimensions internal mill diameter D and length L zthe ballmill power drawP as a function of the feed D f mm and the product size d mm the Bond work index w i
Ball Mill Power Calculation Example A wet grinding ball mill in closed circuit is to be fed 100 TPH of a material with a work index of 15 and a size distribution of 80 passing ¼ inch 6350
fine ore work index kWhtonne P 1 closing screen size in microns Gbp net grams of screen undersize per mill revolution p 80 80 passing size of the product in microns f 80 80 passing size of the feed in microns Note that the Bond ball work index test
Question The Ore Fed To A Rod Mill Has A Bond Work Index Of 175 KWht1 The P80 Of Feed To The Mill Is 425 Cm And The P80 Of The Product From The Mill Is 0185mm Calculate The Work Required To Grind The Ore To The Product Size As Well As The Reduction Ratio
The grindingproduct size P in a Bond ball mill which is given by the aperture size which passes 80 of the grinding product as a function of the aperture size of the test screen P k can be expressed by the formula P P k K 2
Sep 06 2019 · How to Calculate Bond Total Return A corporation issues a bond to raise money to run a business Government entities issue bonds to fund capital projects such as a new highway The bond issuer is the debtor and a bond investor is the
Mar 29 2019 · A bond is a debt security that pays a fixed amount of interest until maturity When a bond matures the principal amount of the bond is returned to the bondholder Many investors calculate the present value of a bond The present value ie the discounted
Oct 18 2019 · Mill Levy The mill levy is the assessed property tax rate used by local governments and other jurisdictions to raise revenue in order to cover annual expenses The mill levy is calculated by
To calculate the KICKs and Rittingers coefficients following formulas can be used − with the limits of Bonds range upper d BU 50 mm and lower d BL 005 mm
Decisionmaking on selection of SAG mills increasingly uses the methods of sizing the milling power based on laboratory tests on grindability of minerals This article considers one of such methods allowing determination of mill characteristics based on the Bond work
Sep 10 2019 · An example of a bond would work something like this The issuing entity lets say a corporation such as Ford Motor Company is offering bonds that pay 7 percent interest for 30 years The bond investor decides she wants to buy a 10000 bond She sends the 10000 to Ford and receives a bond certificate in return