EP0046753B1 - Dry autogenous mill - Google Patents

Dry autogenous mill Download PDF

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Publication number
EP0046753B1
EP0046753B1 EP80901675A EP80901675A EP0046753B1 EP 0046753 B1 EP0046753 B1 EP 0046753B1 EP 80901675 A EP80901675 A EP 80901675A EP 80901675 A EP80901675 A EP 80901675A EP 0046753 B1 EP0046753 B1 EP 0046753B1
Authority
EP
European Patent Office
Prior art keywords
mill
liner members
members
shell
liner
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP80901675A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0046753A1 (en
EP0046753A4 (en
Inventor
Colin D. Jardine
Sooit Chong
Rodney H. Coles
Stephen Hebb
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
MA Hanna Co
Original Assignee
MA Hanna Co
Hanna Mining Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by MA Hanna Co, Hanna Mining Co filed Critical MA Hanna Co
Publication of EP0046753A1 publication Critical patent/EP0046753A1/en
Publication of EP0046753A4 publication Critical patent/EP0046753A4/en
Application granted granted Critical
Publication of EP0046753B1 publication Critical patent/EP0046753B1/en
Expired legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C17/00—Disintegrating by tumbling mills, i.e. mills having a container charged with the material to be disintegrated with or without special disintegrating members such as pebbles or balls
    • B02C17/18—Details
    • B02C17/22—Lining for containers

Definitions

  • This invention relates to a dry autogenous mill.
  • the mined crude ore is fed to a mill where it is broken up and ground before passing through a classifier where the material is separated according to size.
  • a mill commonly used for this purpose is a dry autogenous or self-grinding mill. Both the shell and ends of such a mill are completely lined to protect the shell against wear and assist in the crushing and grinding action in the mill.
  • a common type of shell liner consisted of a series of circumferentially spaced longitudinally extending lifting rails, with separate lug members therebetween to protect the shell between the rails.
  • the ends of the mill were also lined with radial inner and outer rows of wedge-shape deflector liner members and one or more rows of ring liner members between the outer row of deflector liner members and the ends of the shell.
  • GB-A-632 532 discloses a material reduction mill which includes a shell and opposite ends having central feed and discharge openings therein through which the material is fed into the mill and subsequently discharged therefrom, a plurality of rows of end liners covering the mill ends and said liners having radial ribs for obtaining a lifting action of the material within the mill during the grinding operation.
  • the deflector liner member or elements were designed to provide a keying action in the mill to assist in the crushing and grind action.
  • the width of the ore curtain was unduly restricted, and the operating volume of the mill was also adversely affected resulting in reduced mill performance.
  • foundry practices required that such liner members be cast either in two pieces or with hollow centres to insure homogeneous metallurgy, whereby the mill ends were not always adequately protected by the liner members and began to show evidence of premature wear, despite high scrap loss on removal and replacement of the liner members.
  • such liner members were quite heavy, making them difficult to handle, which greatly increased the time required to change the liner members, and the amount of scrap loss was also substantial, both of which substantially added to the overall maintenance cost for the mills.
  • a dry autogenous mill construction including a shell and opposite ends having central feed and discharge openings therein through which material is fed into the mill and subsequently discharged therefrom, a plurality of rows of end liners covering said mill ends, said end liners including radially extending ribs for obtaining a lifting action of the material within the mill during the grinding operation, characterised in that head portions are provided at the radial inner ends of the end liner members in the radial innermost row adjacent said central feed and discharge openings which protrude axially beyond said radially extending ribs to protect said ribs against undue wear and restrict the axial spacing between the ends of said mill through which the material falls as the material is carried upwardly during rotation of the mill, each of said end liner members in such radial innermost row providing a common base for a plurality of said radial ribs which form a continuation of the radial ribs on the end liner members in another of said rows.
  • Such new end liner design not only provides adequate protection to the mill ends, but also substantially decreases the liner consumption per ton of ore ground, and requires less time for change-out due to their lower weight, as compared to the conventional liner design.
  • the lifter bars for the shell liner elements are formed as an integral part of the shell liners.
  • the shell liner members are preferably made of a three piece design, a middle section and two identical end sections, thus permitting the middle section which bears most of the wear to be replaced without having to replace the two end sections.
  • a mill 1 preferably of the dry autogenous type to which the mined crude ore is conveyed through a centre feed side 2 and broken up and ground to the desired size before being carried out of the mill at the discharge side 3 opposite the feed side 2 by the air flow which continuously passes through feed and discharge conduits 4, 5 at opposite ends of the mill.
  • the feed rate of the product to the mill 1 is normally governed by sound level controllers to raise or lower the level in the mill as required.
  • the change in the product level within the mill is reflected in the power draw of the mill, and by keying the maximum power draw to the sonic conditions, the best throughput can be realized for the mill.
  • the mill throughput can also be controlled by regulating air flow.
  • the air passing through the mill 1 carries the fines out of the mill, with the air velocity controlling or determining the coarseness of the material coming out of the mill.
  • the air entering the mill is also normally heated to remove moisture from the ore.
  • both the shell 8 and ends 10 of the mill 1 are completely lined, as is conventional practice.
  • low profile liner elements are used. It was found that the previous thicker inner deflector liner members on both ends of the mill unduly restricted the width of the ore curtain defined by the axial spacing a between the inner liner members 12 at opposite ends of the mill adjacent the central opening 14 therein through which the material falls as it is carried upwardly by the shell and end liner members as the mill rotates.
  • the width a of the ore curtain has a direct effect on the pressure drop across the mill. That is, the wider the ore curtain, the more resistance there is to air flow through the mill 1 and vice versa. Moreover, it was found that some increase in the distance between the inner liner members 12 on the feed and discharge sides of the mill will improve mill performance. However, too much of an increase may result in an excessive high pressure drop, adversely affecting the product removal from the mill 1, in which event not only will the grinding rate of the mill 1 be reduced despite higher mill power drawn, but the liner wear on the discharge side of the mill will also be accelerated due to fines build-up and racing against the liners.
  • the mill performance for example, of a 6.4 meter (m.) diameter mill, depicted in Figs. 2 and 3, was substantially improved while avoiding excessive pressure drop across the mill and wear on the liner by reducing the thickness b of the inner end liner members 12 from 41.28 centimeters (cm.) to 25.40 cm. so as to increase the distance a between the inner liner members 12 at the feed and discharge sides of the mill from the original 72.39 cm. in the case of a mill with conventional deflector liner members to 104.14 cm.
  • the mill performance of a substantially larger mill for example, a 10.52 m. diameter mill such as depicted in Figs.
  • the conventional outer wedge-shape deflector liner members have the most significant effect on mill power draft, and also played an important role in the grinding performance of the mill. It was found, for example, that if the outer deflector liner members are replaced with low profile liner members, they will allow the mill to draw more power. At the same time, it was found that if only smooth plate outer liner members are used in place of the outer deflector liner members, the grinding efficiency is very poor in that there is insufficient overall lifting action to generate the impact grinding action and to expose the ground material to the air stream for discharge from the mill.
  • radial ribs are incorporated on the end liner members.
  • the height of the ribs was found to have a direct effect on the grinding efficiency of the mill.
  • the rib height is too low, there will be insufficient overall lifting action, as a result of which not only will the grinding rate be low, but there will be excessive attrition grinding that produces fines and severe wear on the discharge side of the liner from ore racing against it.
  • the height of the ribs is too great, it will adversely affect the mill throughput, in that the ribs will not clean off thus in effect shortening the overall length of the mill.
  • the actual size of rock being crushed within the mill will also have an effect on the preferred height of the ribs.
  • low profile end liners with radial ribs also has the advantage that the number of rows of end liner members may be reduced to further simplify maintenance and reduce scrap losses.
  • a single row of low profile inner head liner members 12 of the type shown in Figs. 2 and 3 may be used in place of both the conventional inner and outer deflector liner members, and a single row of outer head liner members 15 may be used in place of both the inner and outer conventional ring liner members.
  • Each of the individual outer head liner elements 15 is desirably substantially channel-shape in cross-section with the width of each element progressively increasing as the radial distance from the axial centre of the mill increases as shown in Figs. 3 and 4.
  • each of the individual inner head liner elements 12 preferably has three spaced-apart radial rib elements 19, 20, 21 thereon extending from the radial outermost end for a portion of the length thereof, with their spacing and height substantially corresponding to that of the radial ribs 23 on the outer head liner elements 15 to provide a continuation thereof.
  • the side ribs 19,21 on the inner head liner elements 12 are also approximately the same width as the ribs 23 on the outer head liner elements 15, whereas the intermediate rib 20 on the inner head liner elements is approximately twice such width to correspond in width to the two adjacent ribs 23 of each pair of outer head liner elements associated with each inner liner element 12. Also, the intermediate rib 20 on each of the inner head liner elements 12 desirably extends radially inwardly beyond the two side ribs 19, 21 thereon with the height of the rib extension 24 being somewhat less.
  • Each inner head liner element 12 terminates in a head portion 25 at the radial inner end thereof which protrudes axially beyond the radial ribs 19, 20, 21 and 23 to restrict the width of the ore curtain as aforesaid and also to protect the radial ribs against undue wear.
  • the end liner configuration is preferably the same at both the feed and discharge sides of the mill so that the mill lining is symmetrical as shown to enhance the life of the liner and particularly the outer head liner members 1-5 on the discharge side of the mill.
  • the conventional inner deflector liner members are preferably replaced by an inner head base 30 and cap 31 arrangement, and the conventional outer deflector and inner and outer ring liner members are replaced by centre and outer head liner members 32 and 33 such as shown in Figs. 6-8.
  • Each centre head liner element 32 desirably includes two circumferentially spaced radial ribs 34 extending the entire length thereof, whereas each of the outer head liner elements 33 has a single radial rib 35 thereon with two such outer head liner elements providing a continuation of each centre head liner element.
  • each inner head base liner element 30 desirably includes a pair of radial ribs 36 extending from the radial outer end thereof for a portion of its length providing a continuation of the centre and outer liner element ribs, and the radial inner end of each inner head base liner element has a stepped flange 38 which is engaged by a corresponding step 39 on each inner head cap liner element 31.
  • each shell liner element 40 desirably includes a single axially extending lifter bar 41 formed as an integral part thereof adjacent one end of the shell liner element as shown in Figs. 2, 3 and 5, whereas for the larger mill sizes, two such axially extending lifter bars 43 are desirably formed as an integral part of each shell liner element 44 extending along each end thereof as shown in Figs. 6, 7 and 9.
  • each shell liner element for the-larger mills desirably consists of three pieces, a middle section corresponding to the shell liner element 44 previously described, and two identical end sections 45. Because each end section 45 is axially much shorter than each middle section 44, such end sections may be twice as wide in the circumferential direction as each middle section, with axially extending lifter bars 46 on the ends thereof of the same thickness and spacing as the outermost lifter bars 43 of each pair of center sections. Also, each end section desirably includes a center lifter bar 47 equivalent in width to the adjacent lifter bars 43 of each pair of middle sections to provide in effect a continuation of the lifter bars of two of such middle sections.
  • the advantage in making the shell liner elements of a three piece design is that it permits the middle sections which bear most of the wear to be replaced more frequently than the end sections.
  • the conventional shell liner design forthe larger mill sizes also normally includes a grate at the discharge end of the shell to provide for some peripheral discharge from the mill.
  • peripheral discharge was thought necessary in order to obtain the desired tonnage throughput forthe larger size mills.
  • the grate was not very effective in obtaining the desired peripheral discharge, and such grate was also subject to excessive wear.
  • the peripheral discharge could be eliminated thus eliminating the problems associated therewith, and without adversely affecting the tonnage throughput of the mill.
  • the spacing and height of the shell liner lifters may vary within a certain range, for the 6.4 m. mill, the spacing s between adjacent lifters 41 is preferably approximately 34.14 cm., and the height h of the lifters when newly installed is approximately 14.61 cm., thus providing a length s to height h ratio schematically shown in Fig. 5 of approximately 2.3 when newly installed. Moreover, such shell liner members are preferably replaced after the ratio has increased due to the wearing down of the lifters to about 5.5. In the case of the 10.52 m. mill, the spacing s' between the lifters 43 at each end of the shell liner members is desirably approximately 44.32 cm. and the maximum height h' is approximately 24.13 cm. when newly installed to provide a length s' to height h' ratio as depicted in Fig. 9 of .approximately 1.8 when new, and the liner members are preferably replaced after the ratio has similarly increased due to wear to about 5.5.
  • Separate corner liners 50 are also desirably provided between the respective outer end liner and shell liner members of both the Figs. 2 and 6 embodiments to protect the shell thereat, which is very important, since to replace the shell is very expensive.

Landscapes

  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Crushing And Grinding (AREA)
EP80901675A 1980-02-27 1980-02-27 Dry autogenous mill Expired EP0046753B1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US1980/000198 WO1981002396A1 (en) 1980-02-27 1980-02-27 Mill liner for dry autogenous mills

Publications (3)

Publication Number Publication Date
EP0046753A1 EP0046753A1 (en) 1982-03-10
EP0046753A4 EP0046753A4 (en) 1984-04-04
EP0046753B1 true EP0046753B1 (en) 1986-07-23

Family

ID=22154217

Family Applications (1)

Application Number Title Priority Date Filing Date
EP80901675A Expired EP0046753B1 (en) 1980-02-27 1980-02-27 Dry autogenous mill

Country Status (7)

Country Link
EP (1) EP0046753B1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
JP (1) JPS6235821B2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
AU (1) AU537248B2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
DE (1) DE3071664D1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
IN (1) IN155356B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
WO (1) WO1981002396A1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
ZA (1) ZA81680B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02201037A (ja) * 1989-01-31 1990-08-09 Mitsubishi Motors Corp エンジン出力制御装置
EA021505B1 (ru) * 2008-04-01 2015-07-30 Уиэр Минералз Острейлиа Лтд. Лифтер в сборе для барабанной мельницы и способ его модернизации
CN102836763A (zh) * 2011-06-25 2012-12-26 顾开明 一种带加强筋的磨头衬板
CN105605336A (zh) * 2014-11-12 2016-05-25 盐城市雷击环保科技有限公司 一种环氧玻璃丝缠绕管
CN110252471B (zh) * 2019-06-22 2023-09-29 内蒙古尾得选矿科技有限公司 一种伴石自动嵌衬自磨机

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB632532A (en) * 1947-05-16 1949-11-28 Weston David Material reduction mills
US2566103A (en) * 1947-11-05 1951-08-28 Weston David Liners for material crushing and grinding mills
US3211387A (en) * 1962-09-17 1965-10-12 Koppers Co Inc Grinding mill lining and control of the wear thereof
US3404846A (en) * 1962-10-09 1968-10-08 Nordberg Manufacturing Co Autogenous grinding mill
US3469795A (en) * 1966-02-25 1969-09-30 Aerofall Mills Inc Material reduction mill
US4172560A (en) * 1978-03-13 1979-10-30 Vermillion Equipment & Supply Co., Inc. Replaceable liner for the discharge assembly of a rotary grinding mill or the like

Also Published As

Publication number Publication date
AU6722281A (en) 1981-09-03
EP0046753A1 (en) 1982-03-10
EP0046753A4 (en) 1984-04-04
ZA81680B (en) 1982-02-24
DE3071664D1 (en) 1986-08-28
WO1981002396A1 (en) 1981-09-03
AU537248B2 (en) 1984-06-14
IN155356B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1985-01-19
JPS57500184A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1982-02-04
JPS6235821B2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1987-08-04

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