3 Presentacion Kanta Roy - Acotec - Tega Industries

7/28/2019 3 Presentacion Kanta Roy - Acotec - Tega Industries

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OPTIMAL GRINDING SOLUTION

THROUGH LINER DESIGN

By B. K. Roy


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Tegas Glossary of SoftwareState of the art liner selectionand mill modeling software


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CASE STUDY: I

OPTIMIZATION OF AG MILL LINER(26X10)


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TARGET:Optimization of AG Mill power draw , mill throughput & Liner life.

Concerns: Mill Power Draw & throughput will remain same as existing (1800 Kw ) in

spite of that AG Mill has provision for higher capacity ( Available power2460 Kw).

Low liner life which is around 3000 hrs.

Ball path trajectory will not be better.


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Existing rubber shell liner.

Tega rubber lining keeping the profile same asexisting.

Hi-Lo : 250-460 YTS/250-250 YTS & P120.

Mill Effective diameter: 7419 mm.


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Existing Liner Profile:


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Power & Impact Spectra withExisting Liner :


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Visualization of charge motionwith Existing Liner:


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Proposed Tega rubber shell liner.

Solution for capacity improvement:

Tega rubber lining: 300-500 Lifters in alternate rows withmetal reinforced shell plate PM 140.Mill Effective diameter: 7515 mm.Power draw will be improved to 1985 Kw. ( Avg).No charge packing so improved charge motion & grinding.Capacity will improved by 9.3 %.


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Tega Liner Profile:


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Power & Impact Spectra with Existing Liner :


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Visualization of charge motion with

Existing Liner:


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Tega Rubber Liner for Optimum MillThroughput:

Benefits:

Power draw increased to 1980 Kw from 1800 Kw.

Capacity improve by 9.7%. Additional revenue generation due to112,000 tons of additional grinding/Mill.

Liner life will be 6000 Hrs +. So 1 shutdown/ Year as compared to 3 to4 shutdowns/ Year presently. Savings of production hour: 96hrs/Year/Mill.


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CASE STUDY-III

OPTIMAL GRINDING PERFORMANCE OF BALL MILLS ATPELLETIZATION PLANT-BRAZIL


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TO BE ABLE TO PROPOSE ALTERNATE

SELECTION IN BALL MILL LINERS FOR :

IMPROVED CAPACITY

IMPROVED LINER LIFE

OBJECTIVE


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BALL MILL: 5.2MX10.6M LG

ORE TYPE: IRON ORE TYPE OF DISCHARGE= OVERFLOW INSTALLED POWER = 4500W GRINDING MEDIA TOP SIZE = 30MM MILL SPEED = 12.9 RPM THROUGHPUT = 250-300 TPH FEED SIZE(K80) = 1.2MM PRODUCT SIZE(K80) = -45 MICRONS BOND WORK INDEX = 12 KWH/T

CHARGE VOLUME = 35% CIRCULATING LOAD= 200% POWER DRAW= 3500-3600 KW

OPERATING PARAMETER


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COMPARISON OF LINER PROFILE: 5M5B

TEGA SELECTION:( 40R) 140-110 BLS, P-50

EFFECTIVE DIAMETER WITH EXISTING LINERS = 4998.8MMEFFECTIVE DIAMETER WITH TEGA LINERS = 5072.0MM

EXTRA CAPACITY GENERATED BY TEGA LINERS = 3.8 %


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Advantage of TEGA design liners With time as the liners wear out, the bar and plate tends to

retain its profile shape as compared to the double wave design.Hence the level of productivity can be retained for a longer duration. In case of double wave profile, the edge of the linersonly wears out and hence the profile loses its shape with wear.

A representative sketch is shown below for reference. The

actual pattern of wear and its effect on capacity can beconfirmed with regular wear measurement plots to be taken atsite

Aluminum reinforced lifters are easy to install. This means lessdowntime during installation and replacement, resulting inincreased availability.

Leak proof fastening system reduces risk of flushing behindlining and eliminate leakage , resulting in better protection of mill body from corrosion.

TEGA liners are designed to utilize the maximum wearablerubber, providing better economy and minimum scrapgeneration.


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COMPARATIVE EVALUATION STUDY OF TEGA LINERS vsDOUBLE WAVE TYPE LINERS AT NIBRASCO- V

The following four parameters have been considered for evaluatingthe performance of the liners:

Throughput ( tons/hr)BLAINE ( specific surface area generated: cm2/gm)Specific energy consumption (kwh/t)The operating life of the liners will also have to be taken into

account.


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FOR EVALUATING THE PERFORMANCE WE HAVE TAKEN TWO APPROACHES .

APPROACH-I: One approach of evaluating the performance could becomparing the performance of the three mills at NIBRASCO V(5M5A,5M5B,5M5C) for the same given period of time. In doing so, the datafor the three mills for the period April 2006 to October 2006 have beencompared.

5M5A 5M5B 5M5C

MONTH-YEARTPH(t/h)

BLAINE(cm2/gm)

SPCIFICENERGYCONSUMPTION

TPH(t/h)

BLAINE(cm2/gm)


TPH(t/h)

BLAINE(cm2/gm)


APRIL-2OO6 271 1721 14.4 258 1688 16 262 1702 15.3

MAY-2OO6 248 1737 15.9 246 1756 16.2 246 1728 16

JUNE-2OO6 264 1735 14.5 264 1735 14.1 262 1710 15.2

JULY-2OO6 257 1684 15.1 262 1687 15.6 257 1632 15.5

AUGUST-2OO6 265 1720 14.8 273 1771 15.1 250 1669 16.5SEPT-2OO6 274 1706 14.3 285 1807 14.1 274 1725 14.8

OCT-2OO6 276 1655 14.1 312 1731 13.3 279 1728 13.9

AVERAGE265.

0 1708.3 14.7 271.4 1739.3 14.9 261.4 1699.1 15.3


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VARIATION OF BLAINE

1500

15501600

1650

1700

1750

1800

1850

APRIL-2OO6

MAY-2OO6

JUNE-2OO6

JULY-2OO6

AUGUST-2OO6

SEPT-2OO6

OCT-2OO6

MONTH (YEAR)

B L A I N E ( c m

2 / g m

)

5M5A 5M5B( TEGA ) 5M5C

VARIATION OF BLAINE

1500

15501600

1650

1700

1750

1800

1850

APRIL-2OO6

MAY-2OO6

JUNE-2OO6

JULY-2OO6

AUGUST-2OO6

SEPT-2OO6

OCT-2OO6

MONTH (YEAR)

B L A I N E ( c m

2 / g m

)

5M5A 5M5B( TEGA ) 5M5C

COMMENT: THE AVERAGE BLAINE NO (cm2/gm) MEASURED FOR 5M5B MILL WITH

TEGA DESIGN LINER 1.8% HIGHER THAN THAT OF 5M5A MILL AND 2.36% HIGHERTHAN THAT OF 5M5C MILL. THIS INDICATES THAT WITH TEGA DESIGN LINERS THEREIS MORE CASCADING EFFECT OF THE CHARGE, WHICH IS DESIRABLE FOR FINEGRINDING APPLICATION.


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APPROACH II : The second approach is comparing the performance of only 5M5BMill with Bar and Plate design (Tega) and Double wave type of liners. For this wehave considered the performance of the 5M5B Mill for the 1 st seven months ( i.e

April-2006 to Oct 2006) since the installation of new Bar and Plate design linersand corresponding 1 st seven months ( June 2005 to Dec 2005) since thepreviously installed double wave type of liner in the same 5M5B mill.

5M5B( TEGA DESIGN) 5M5B( DOUBLE WAVE DESIGN)

MONTH-SINCEINSTALLATION

TPH(t/h)

BLAINE(cm2/gm)

SPCIFIC ENERGYCONSUMPTION

TPH(t/h)

BLAINE(cm2/gm)

SPCIFIC ENERGYCONSUMPTION

MONTH 1 258 1688 16 261 1747 14.2

MONTH 2 246 1756 16.2 244 1740 15.8

MONTH 3 264 1735 14.1 271 1728 14.8

MONTH 4 262 1687 15.6 257 1722 15.6

MONTH 5 273 1771 15.1 278 1705 15.6

MONTH 6 285 1807 14.1 240 1859 16.8

MONTH 7 312 1731 13.3 252 1887 15.9

AVERAGE 271.4 1739.3 14.9 257.6 1769.7 15.5


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COMPARISON OF TPH

0

50

100

150

200

250

300

350

1 2 3 4 5 6 7

MONTHS( FROM DATE OF INSTALLATION)

T P H ( T / H R )

5M5B(TEGA) 5M5B (DOUBLE WAVE)

COMPARISON OF TPH

0

50

100

150

200

250

300

350

1 2 3 4 5 6 7


T P H ( T / H R )

5M5B(TEGA) 5M5B (DOUBLE WAVE)

COMMENTS : THE AVERAGE THROUGHPUT (T/Hr) OF 5M5B MILL WITH TEGADESIGN BAR AND PLATE DESIGN IS 5.35% HIGHER THAN WITH DOUBLE WAVETYPE LINERS.


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COMPARISON OF BLAINE

155016001650170017501800185019001950

MONTH1

MONTH2

MONTH3

MONTH4

MONTH5

MONTH6

MONTH7

MONTH

B L A I N E ( C M 2 / G M )

TEGA DESIGN DOUBLE WAVE DEGIGN

COMPARISON OF BLAINE

155016001650170017501800185019001950

MONTH1

MONTH2

MONTH3

MONTH4

MONTH5

MONTH6

MONTH7

MONTH

B L A I N E ( C M 2 / G M )

TEGA DESIGN DOUBLE WAVE DEGIGN

COMMENT: THE AVERAGE BLAINE MEASURED WITH BAR AND PLATE DESIGN IS 1.7%LOWER THAN THAT WITH DOUBLE WAVE LINERS.


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COMPARISON OF SPECIFIC POWER CONSUMPTION

0

2

4

68

10

12

14

16

18

1 2 3 4 5 6 7


S P E C I F I C P O W E R C O N S U M P T I O N (

K W H / T )

5M5B(TEGA) 5M5B(DOUBLE WAVE)

COMPARISON OF SPECIFIC POWER CONSUMPTION

0

2

4

68

10

12

14

16

18

1 2 3 4 5 6 7


S P E C I F I C P O W E R C O N S U M P T I O N (

K W H / T )

5M5B(TEGA) 5M5B(DOUBLE WAVE)

COMMENTS: THE AVERAGE SPECIFIC ENERGY CONSUMPTION ( kwh/t)WITH DOUBLE WAVE TYPE OF LINER IS 4.0% HIGHERTHAN THAT OFBAR AND PLATE DESIGN.


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COMMENTS:

Approach-II is more representative in nature for comparing theperformance if there has not been any appreciable change in the orecharacteristics since the last double wave type of liners were installed in5M5B in May 2005.

FROM THE ANALYSIS IN APPROACH-II, THE FOLLOWING HAVE BEEN OBSERVED:

THROUGHPUT ( TONS/ HOUR): TEGA DESIGN BAR AND PLATE DESIGN HAS 5.35% HIGHER PRODUCTIVITY THAN DOUBLE WAVE TYPE LINERS.

BLAINE (cm2/ gm): THE AVERAGE BLAINE FOR TEGA BAR ANDPLATE DESIGN IS MARGINALLY LOWER (1.7%) THAN DOUBLE WAVE TYPE LINERS. BUT THE BLAINE HAS BEEN IMPROVING OVER THE

PAST MONTHS AND AT PRESENT IT IS BETTER THAN ANY OTHER MILLS AT NIBRASCO V.SPECIFIC ENERGY CONSUMPTION (kwh/t): THE AVERAGE SPECIFIC

ENERGY CONSUMPTION WITH TEGA BAR AND PLATE DESIGN IS 4.0%LESS THAN THAT WITH DOUBLE WAVE TYPE DESIGN LINERS.


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IMPLICATIONS:WITH 5.35 % HIGHER PRODUCTIVITY, TEGA DESIGN LINERS WILL MEAN:0.0535X257.5X24X30X12 = 119026 TONS (APPROX) OF EXTRAPRODUCTION PER ANNUM FOR 5M5B MILL.THIS HIGHER PRODUCTIVITY HAS BEEN ACHIEVED WITH 4.0% LOWERSPECIFIC ENERGY CONSUMPTION. THIS IN EFFECT MEANS ENERGYSAVINGS TO THE TUNE OF 1.40 MILLION kwhr APPROX (UNITS)!! PER

ANNUM PER MILL.COST/ FININCIAL IMPLICATIONS:

AT THE PRESENT PRICE LEVEL OF USD110/ TON FOR PELLETS, THISWOULD IMPLY ADDITIONAL REVENUE GENERATION OF USD 13.0 MILLION

AND SIMULTANEOUSLY COST SAVING, ON ACCOUNT OF LOWER ENERGYCONSUMPTION, TO THE TUNE OF USD175800 APPROXIMATELY. (Assumingcost of energy at 12.5 cents /unit ).THE ABOVE DATA IS FOR A SINGLE MILL. HENCE THE POTENTIALBENEFITS (ADDITIONAL REVENUE GENERATION + COST SAVING), CANBE HUGE CONSIDERING THE FACT THAT CVRD HAS 16 GRINDING MILLS

AT VITORIA PELLETIZATION PLANT.


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CASE IV:Performance of Primary Ball Mill liners at

concentrator in South Africa


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Performance of Primary Ball Mill liners

Problems reported:

After three months of operation with very low ball

charge(18%-14%), some surface cracks or fissures were foundin some of the shell lifters.

Breakage of quite a lot of grinding media was also observedduring the initial run of the liners.

Peening of grate plates.


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Design data for the liner selection: Mill Diameter: 5.18M. Mill Length: 8.4M. Mill speed: 75% critical. Mill circuit: Closed. Aperture size of classifier screen:0.6mm. % recirculation load:? Fresh Feed rate: 177MTPH; Motor Rating: 3600KW F80: 100mm P80: 140 micron.

BWI: 17.49 Total Charge volume:32% (max) & 24% (min) Maximum size of Ball: 80mm


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With 18% charge volume & present liner:


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With 24% charge volume with Tega liner


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Root Cause analysis for the high liner wear & ball breakage:

Greatly accelerated liner wear due to high-energy impacts on the liner.This can reduce liner life from a year to less than a few months under theseexcessive stresses, especially when worn to partial thickness.

Ball fracture from the high velocity impacts directly onto steel an impulseforce which many balls cannot withstand. This results in a loss of top-sizegrinding media and reduced milling efficiency, plus increased ball additioncosts.

Due to low charge level, there was ball breakage & the broken balls werenot culled out. During liner & charge motion interaction, these broken balledges caused that type of wear in a few lifters which were in the zone of broken ball concentration.


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Performance of Primary Ball Mill


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Root Cause of Grate Opening:

Inclined Grate subject to ball impact.

Low & tapered charge level leading to very less cushionagainst metal to metal impact.

Flow of comparatively ductile material of the grate underrepetitive ball impacts causing reduction of the width of the slots.


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Proposed solution:

Actual flow rate of feed , recirculation load & % solids to be measuredfrom site to come to the actual open area requirement in the grate.

If possible, charge level to go unto 24% minimum.

As EGL is not very important here due to the mill being oversized,Change of the grate from inclined to straight disposition is solicitedalong with the change the pulp lifters accordingly.

Since, low charge level is the fate of the operation, grate should be of metal only to accommodate the required open area.


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Thank You..

..

Gracias..

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