• Author / Uploaded
• Osterlin Mayhua Capcha

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EXAMPLE 22 – Comminution

1 2 3 4 5 6 7 8 9 10 11

NO SEC SCR CRJ CVB SCR CRC SCR CRC MLB SMP CYH

FLOWSHEET DATA OPR UNIT PROCESS IS1 IS2 IS3 IS4 IS5 IS6 INV OS1 OS2 OS3 OS4 OS5 OS6 COMMINUTION 0 0 0 0 0 0 0 0 0 0 0 0 0 GRIZZLY 1 0 0 0 0 0 0 2 3 0 0 0 0 JAW 3 0 0 0 0 0 0 4 0 0 0 0 0 CONVEYOR 2 4 0 0 0 0 0 5 0 0 0 0 0 DOUBLE DECK 5 0 0 0 0 0 0 6 7 8 0 0 0 CONE 7 8 0 0 0 0 0 9 0 0 0 0 0 DOUBLE DECK 6 9 13 0 0 0 0 10 11 12 0 0 0 CONE 11 12 0 0 0 0 0 13 0 0 0 0 0 BALL MILL 10 14 18 0 0 0 0 15 0 0 0 0 0 15 16 0 0 0 0 0 17 0 0 0 0 0 CYCLONE 17 0 0 0 0 0 0 19 18 0 0 0 0

Cummulative Fraction Passing Data 17.00 IN 12.00 IN 8.48 IN 6.00 IN 4.24 IN 3.00 IN 2.12 IN 1.50 IN 1.05 IN 0.742 IN 0.525 IN 0.371 IN

1.0 0.98 0.85 0.68 0.48 0.37 0.26 0.20 0.14 0.11 0.08 0.06

3 TY 2000 TY

0.04 0.00001

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COMMINUTION EXAMPLE The design of the circuit is to achieve a product of 110 microns. Process Data The components required are SiO2 (Quartz) Solid and H2O aqueous. Stream 1 - The Feed flowrate is 400 mt/hr and contains 95% solids. Stream 14 - Ball mill make-up water. Initially estimated as 10 mt/hr. This flowrate will be adjusted by a percent solids controller, PSC, on the ball mill unit operation, maintaining 68% solids. Stream 16 - Cyclone make-up water. Initially estimated as 10 mt/hr. This flowrate will be adjusted by a percent solids controller to maintain 55% solids. Percent Solids Controls CN ID 1001 MLB 68% Solids 1002 CYH 55% Solids User Created Objects Scaler Name ID USMLBRATIO MLB L-WR

OP 9 11

SN 14 16

PS 0.68 0.55

Value 1.25

Then click the Ball Mill unit operation with the Edit Object Data Tool & in the Controls CtA field enter USMLBRATIO„(IL+0)÷ID IL is the Ball Mill Length Inside Liners

ID is the Ball Mill Diameter Inside Liners

Now add the following Stream Graphic Boxes, remembering there is already an EXAMPLE in the List window of the Stream Graphics Boxes and this is Box number 1. Stream Graphic Boxes - Add the following Stream Graphics Boxes. Box No 2 Box No 3 BX Outputs Cyclone CW 6 L1 SN SN F1 S S L2 SI Mt/Hr SI Mt/Hr F2 SI VCWT S SI VCWT S L3 LI Mt/Hr LI Mt/Hr F3 LI VCWT S LI VCWT S L4 % Solids % Solids F4 100 ×VPCS S 100 ×VPCS S L5 P80 P80 F5 VP80 S VP80 S L6 No CYH F6 'NO' VFLS u11 L7 Dia CYH INCHES F7 'DC' VFLS u11 L8 CYH PRESS F8 'PR' VFLS u11 L9 % CIRC LOAD F9 100×(SI VCWT s18)÷SI VCWT s19 All Streams Except 15 & 19

Stream 19

Box No 4 Ball Mill 6 SN S SI Mt/Hr SI VCWT S LI Mt/Hr LI VCWT S % Solids 100 ×VPCS S P80 VP80 S No. MLBs 'NO' VFLS u9 DIA INSIDE LINERS 'ID' VFLS u9 Length INSIDE LINERS 'IL' VFLS u9 MLB L TO W RATIO USMLBRATIO Stream 15

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From the results it will be noticed the cyclone overflow did not meet the requirements of 80% passing 110 microns. A feedback controller will now be applied to adjust the cyclone feed stream percent solids to achieve the required micron size. Feedback Control CN 1003

OP 11

NO 10

SN 0

OV 0.55

LV 0.5

HV 0.6

VF VP80 s19 110

SP 1

SL ID Control % Solids so P80=110

The Feedback Controller above will adjust the Percent Solids Controller 1002 until a P80 of 110 microns is achieved in stream 19. Percent Solids Control For the Feedback Control to adjust the Percent Solids Control the following changes must be made to the Percent Solids Control 1002. The PS variable in PSC controller 1002 should be change to; VCTL 1003 The model may be calculated again. The feedback controller adjusts the percent solids of the cyclone feed until the desired product size of 110 microns is achieved in stream 19. Unit Operation Data All of the Input Data for the Unit Operations can be found on the diagram. How The Flowsheet Is Calculated. 1. Calculate the Current Section. 2. After Calculating select to Edit the Ball Mill and then select the Dimensions Window. The Ball Mill is setup initially with Calculation Option 2 - P80. The variable P8 is set at 110 microns which is our target and the Diameter Of The Inside Liners, ID, is set at 15.5 feet. After Calculating METSIM will predict the Inside Liners Length, IL. In this example 39.45928869 feet. 15.5 x 39.5 is too long for a Ball Mill so we go to the to the Ball Mill Window of the Unit Operation data and change the Number of Ball Mills, NO, to 2. Now Calculate just the Ball Mill. Then go back to the Dimensions Window in the Ball Mill Unit Operation Data and look at the value for IL. It should now be 19.72964435. The Mill Ratio for this is 1.375 = 15.5 x 19.75. So to set METSIM to use this size change the CO option to 1-Bond Inside Length so that METSIM will now use the IL in the Calculation instead of the P8, P80, value. Next Calculate the Flowsheet. Notice in the results that 10 Cyclones were predicted but the P80 value was a little low at 104 microns. A feedback controller will now be applied to adjust the cyclone feed stream percent solids to achieve the required micron size. Feedback Control CN 1003

OP 11

NO 10

SN 0

OV 0.55

LV 0.5

HV 0.6

VF VP80 s19

SP 110

SL 1

ID Control % Solids so P80=110

The Feedback Controller above will adjust the Percent Solids Controller 1002 until a P80 of 110 microns is achieved in stream 19.

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Percent Solids Control For the Feedback Control to adjust the Percent Solids Control the following changes must be made to the Percent Solids Control 1002. The PS variable in PSC controller 1002 should be change to; VCTL 1003 The model may be calculated again. The feedback controller adjusts the percent solids of the cyclone feed until the desired product size of 110 microns is achieved in stream 19. The Cyclone achieves 110 microns in stream 19 but only 9 Cyclones have been predicted. As an equal number of Cyclones are required for 2 Ball Mills it will be necessary to change the IL . Set the IL variable in the Ball Mill to 19.5 and Calculate. Still only 9 Cyclones predicted so set the IL variable in the Ball Mill to 19.25 and Calculate. Now METSIM Predicts 10 Cyclones at a pressure inside our range for the Cyclone. RESULTS NO. STREAM MT/HR-SI MT/HR-LI MT/HR-TC ---+--+--------+--------+-------1 1 380.000 20.000 400.000 2 2 242.449 12.760 255.210 3 3 137.551 7.240 144.790 4 4 137.551 7.240 144.790 5 5 380.000 20.000 400.000 6 6 126.013 6.632 132.645 7 7 111.292 5.857 117.149 8 8 142.695 7.510 150.206 9 9 253.987 13.368 267.355 10 10 380.000 20.000 400.000 11 11 172.922 9.101 182.023 12 12 243.849 12.834 256.683 13 13 416.771 21.935 438.706 14 14 0.000 237.547 237.547 15 15 2253.630 1060.532 3314.162 16 16 0.000 708.939 708.939 17 17 2253.630 1769.471 4023.101 18 18 1875.364 803.725 2679.089 19 19 378.267 965.746 1344.013

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Comminution Example SCREEN SIZE ANALYSIS

---------------SCREENS MICRON ---------------12.0 IN 304800 8.48 IN 215392 6.00 IN 152400 4.24 IN 107696 3.00 IN 76200 2.12 IN 53848 1.50 IN 38100 1.05 IN 26670 .742 IN 18847 .525 IN 13335 .371 IN 9423 3 TY 6730 4 TY 4760 6 TY 3360 8 TY 2380 10 TY 1680 14 TY 1190 20 TY 841 28 TY 595 35 TY 420 48 TY 297 65 TY 210 100 TY 149 150 TY 105 200 TY 74 270 TY 53 400 TY 37 600 TY 26 800 TY 19 1200 TY 13 1600 TY 9 2000 TY 7

STREAM NO. 1 1 P80= 194554 -------------------MT/HR % RET % PAS -------------------7.600 2.000 98.00 49.400 13.000 85.00 64.600 17.000 68.00 76.000 20.000 48.00 41.800 11.000 37.00 41.800 11.000 26.00 22.800 6.000 20.00 22.800 6.000 14.00 11.400 3.000 11.00 11.400 3.000 8.00 7.601 2.000 6.00 7.599 2.000 4.00 0.765 0.201 3.80 0.769 0.202 3.60 0.761 0.200 3.40 0.769 0.202 3.19 0.761 0.200 2.99 0.766 0.202 2.79 0.764 0.201 2.59 0.769 0.202 2.39 0.765 0.201 2.19 0.765 0.201 1.99 0.758 0.199 1.79 0.773 0.203 1.58 0.772 0.203 1.38 0.737 0.194 1.19 0.793 0.209 0.98 0.779 0.205 0.77 0.692 0.182 0.59 0.838 0.220 0.37 0.812 0.214 0.16 0.593 0.156 0.00

STREAM NO. 10 10 P80= 9941 -------------------MT/HR % RET % PAS -------------------0.00 0.000 100.00 0.00 0.000 100.00 0.00 0.000 100.00 0.00 0.000 100.00 0.00 0.000 100.00 0.00 0.000 100.00 0.00 0.000 100.00 0.00 0.000 100.00 0.00 0.000 100.00 0.00 0.000 100.00 89.86 23.647 76.35 103.46 27.226 49.13 58.59 15.419 33.71 29.65 7.803 25.91 15.30 4.027 21.88 11.84 3.115 18.76 10.60 2.790 15.97 9.45 2.487 13.49 8.36 2.201 11.29 7.36 1.936 9.35 6.41 1.688 7.66 5.55 1.460 6.20 4.74 1.248 4.96 4.04 1.062 3.89 3.39 0.891 3.00 2.77 0.729 2.27 2.32 0.611 1.66 1.87 0.493 1.17 1.43 0.376 0.79 1.28 0.338 0.46 1.04 0.274 0.18 0.69 0.181 0.00

STREAM NO. 15 15 P80= 795 -------------------MT/HR % RET % PAS -------------------0.00 0.000 100.00 0.00 0.000 100.00 0.00 0.000 100.00 0.00 0.000 100.00 0.00 0.000 100.00 0.00 0.000 100.00 0.00 0.000 100.00 0.00 0.000 100.00 0.00 0.000 100.00 0.00 0.000 100.00 0.00 0.000 100.00 10.13 0.449 99.55 24.05 1.067 98.48 39.46 1.751 96.73 56.95 2.527 94.21 76.42 3.391 90.81 97.06 4.307 86.51 122.33 5.428 81.08 150.57 6.681 74.40 185.24 8.220 66.18 223.51 9.918 56.26 261.41 11.600 44.66 243.15 10.789 33.87 177.24 7.864 26.01 131.00 5.813 20.19 99.19 4.402 15.79 85.27 3.784 12.01 66.12 2.934 9.07 46.66 2.071 7.00 43.65 1.937 5.07 31.85 1.413 3.65 82.35 3.654 0.00

---------------SCREENS MICRON ---------------3 TY 6730 4 TY 4760 6 TY 3360 8 TY 2380 10 TY 1680 14 TY 1190 20 TY 841 28 TY 595 35 TY 420 48 TY 297 65 TY 210 100 TY 149 150 TY 105 200 TY 74 270 TY 53 400 TY 37 600 TY 26 800 TY 19 1200 TY 13 1600 TY 9 2000 TY 7

STREAM NO. 17 17 P80= 795 -------------------MT/HR % RET % PAS -------------------10.13 0.449 99.55 24.05 1.067 98.48 39.46 1.751 96.73 56.95 2.527 94.21 76.42 3.391 90.81 97.06 4.307 86.51 122.33 5.428 81.08 150.57 6.681 74.40 185.24 8.220 66.18 223.51 9.918 56.26 261.41 11.600 44.66 243.15 10.789 33.87 177.24 7.864 26.01 131.00 5.813 20.19 99.19 4.402 15.79 85.27 3.784 12.01 66.12 2.934 9.07 46.66 2.071 7.00 43.65 1.937 5.07 31.85 1.413 3.65 82.35 3.654 0.00

STREAM NO. 18 18 P80= 973 -------------------MT/HR % RET % PAS -------------------10.13 0.540 99.46 24.05 1.282 98.18 39.46 2.104 96.07 56.95 3.037 93.04 76.42 4.075 88.96 97.06 5.175 83.79 122.33 6.523 77.26 150.57 8.029 69.23 185.24 9.877 59.36 223.37 11.911 47.45 257.76 13.744 33.70 217.14 11.579 22.12 124.36 6.631 15.49 74.08 3.950 11.54 50.31 2.683 8.86 41.09 2.191 6.67 31.06 1.656 5.01 21.65 1.154 3.86 20.10 1.072 2.78 14.59 0.778 2.01 37.64 2.007 0.00

STREAM NO. 19 19 P80= 110 -------------------MT/HR % RET % PAS -------------------0.000 0.000 100.00 0.000 0.000 100.00 0.000 0.000 100.00 0.000 0.000 100.00 0.000 0.000 100.00 0.000 0.000 100.00 0.000 0.000 100.00 0.000 0.000 100.00 0.001 0.000 100.00 0.136 0.036 99.96 3.655 0.966 99.00 26.011 6.876 92.12 52.878 13.979 78.14 56.919 15.047 63.09 48.886 12.924 50.17 44.182 11.680 38.49 35.055 9.267 29.22 25.015 6.613 22.61 23.552 6.226 16.38 17.257 4.562 11.82 44.719 11.822 0.00

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