JPS6235821B2 - - Google Patents

Description

Claim 1: An outer shell 8 and opposite ends 10 with central feed and discharge openings 2, 3 for feeding and discharging material;
A plurality of rows of end liner members 12, 15 are provided at opposite ends of the mill, with each end liner member 12 in the radially innermost row having a plurality of radially extending ribs 19, 20, Forms the basis of supply of 21,
said radial ribs 19, 20, 21 on the end liner members 12 of the radially innermost row form a continuation of additional radial ribs on the end liner members 15 of the adjacent row; Additionally, an end liner member 12
a head portion 25 at the radially inner end of the radially innermost row of said end liner members 12 radially inwardly of the upper plurality of radial ribs 19, 20, 21; 25 is a dry self-growing mill characterized in that it projects beyond the radial ribs 19, 20, and 21 in the axial direction.

2. A mill according to claim 1, wherein the central feed and discharge openings 2, 3 are provided at opposite ends of the mill.
a row of low profile internal head liner members 12 adjacent to the row, and a row of external head liner members 15 radially outwardly of said row of internal head liner members 12.
and the radial direction 23 on the external head liner member 15 is
the radial ribs 19, 20, 2 on the inner head liner member 12;
1 from the radially outermost end of the inner head liner member 12 to the inner head liner member 12.
A mill characterized in that it extends over part of the length of and forms a continuation of the ribs 23 on said external head liner member 15.

3. A mill according to claim 2, wherein each external head liner member 15 is substantially groove-shaped in cross-section, and each adjacent pair of sides of said external head liner member 15 has one rib 23,23. A mill characterized by working together to achieve results.

4. In the mill according to claim 3, a rib 1 is provided adjacent to each side of each internal head liner member 12.
9, 21, said ribs cooperating with ribs 19, 21 of adjacent inner head liner members 12 to define a continuous portion of said ribs 23, 23 formed by adjacent sides of each pair of said outer head liner members 15. A mill characterized by what it does.

5. A mill according to claim 4, further comprising a further rib 20 on each of the internal head liner members 12 intermediate the spaced apart ribs 19, 21, which rib is connected to the pair of external head liner members 15. A mill, characterized in that it forms a continuous part of one of said ribs 23, 23, which are separated by adjacent sides.

6. The mill of claim 5 further comprising a rib extension 24 on each said internal head liner member 12, said rib extension 24 aligned with said other rib 20 on said internal head liner member 12. extends radially inwardly beyond the ribs 19, 21, and the height of the rib extension 24 is greater than the ribs 19, 21.
A mill characterized in that it is somewhat smaller than the height of 20, 21.

7. The mill according to claim 2, wherein the head member 25 is integral with the internal head liner member 12.

8. A mill as claimed in claim 1 further comprising a row of internal head cap liner members 31 adjacent the central feed and discharge openings 2, 3 of the mill, said internal head cap liner members 31 The radially innermost row of the end liner members 30 includes a stepped flange 38 that engages a corresponding step 39 on the row of internal head cap liner members 31; A mill characterized in that the plurality of radial ribs 36 on the radially innermost row of the end liner member 30 are common.

9. The mill of claim 1, wherein: a row of central head liner members 32 located radially outwardly from said radially innermost row of end liner members 30; and said row of central head liner members 32. an external head liner member 33 located radially outwardly from
, each of the central head liner member 32 and the outer head liner member 33 including the ribs 34, 35 extending the entire length thereof, and the ribs 3 on the radially innermost row of the end liner members 30;
A mill characterized in that it forms six continuous parts.

10. The mill of claim 9, wherein there are two of said ribs 36, 34 on each of said inner head liner member 30 and center head liner member 32, and one of said ribs 35 is on each said outer head liner member. A mill characterized by being on 33.

11. In the mill according to claim 1, a plurality of outer shell liner members 40 covering the mill outer shell 8,
44, each said outer shell liner member 40,4
4 includes at least one longitudinally extending lifter bar 41, 43 formed as an integral part thereof.

12. The mill of claim 11, wherein there are two lifter rods 43 formed as an integral part of each of the outer shell liner members 44; A mill characterized in that it extends along the edge and cooperates with a lifter bar 43 of an adjacent shell liner member 44 to lift the material during rotation of the mill.

13. The mill according to claim 12, wherein the lifter rods 4 at each end of each of the outer shell liner members 44
3 to the height of the lifter rod 43 approximately.
A mill characterized by being within the range of 1.8 to 5.5.

14. The mill of claim 11, wherein each said shell liner member comprises an intermediate section 44 and two individual end sections 45 at opposite ends thereof, said end sections 45 mutually extending. A mill characterized in that it is identical and includes a lifter bar 46 thereon, forming a continuous part of the lifter bar 43 on said intermediate section 44.

15. The mill according to claim 14, wherein the number of intermediate sections 44 is twice the number of end sections 45, and said end sections 45 have a width twice that of said intermediate sections 44. , each said intermediate section 44 has said lifter bar 43 at each end thereof.
each said end section 45 includes a lifter bar extension 46 on its end of the same thickness and spacing as the outermost lifter bar 43 of each pair of center sections 44; said end section 4 corresponding to two widths of the rod 43;
A mill characterized in that one lifter rod extension 47 on each of said end sections 45 intermediate the ends of 5 forms a continuation of adjacent lifter rods 43 on each pair of intermediate sections 44.

16 In the mill according to claim 11,
A mill further comprising individual corner liners 50 between the respective end liner members 12, 15 and said shell liner members 40, 44 to protect the shell 8 therein.

17. The mill of claim 11, wherein each said shell liner member 40 is formed with one lifter bar 41 as an integral part, and said lifter bar 41 on an adjacent shell liner member 40 is formed as an integral part. A mill characterized in that the ratio of the spacing between is approximately within the range of 2.3 to 5.5.

BACKGROUND OF THE INVENTION This invention relates generally to mill liners, and more particularly to improvements in liner construction for dry autogenous mills.

During the processing of raw iron ore and other such materials, the mined raw ore is fed to a mill where it is crushed and ground before passing through a classifier which separates the material according to size. One type of mill commonly used for this purpose is a dry autogenous or self-grinding mill. Both the shell and the ends of such a mill are fully lined to protect the shell from wear and to aid in the crushing and grinding operations within the mill.

In the past, a common type of shell liner consisted of a series of circumferentially spaced, longitudinally extending lifting rails with separate ledges therebetween to protect the shell between the rails. The ends of the mill were also lined with radially inner and outer rows of wedge-shaped baffle liner members and one or more rows of ring liner members between the outer rows of baffle liner members and the shell ends.

Deflector liner members or elements are keyed into the mill to aid in crushing and comminution operations.
It was designed to have an effect. However, in practice, the axial thickness of the deflector liner member was quite large, which unduly limited the width of the ore curtain, and the working volume of the mill was also adversely affected, resulting in reduced mill performance. . Also, because of the thickness of deflector liner members, foundry operations are required to cast such liner members as two-piece constructions or as hollow-centered constructions to ensure homogeneous metallurgy, with mill end began to show evidence of premature wear, even though they were not always adequately protected by the liner members and resulted in high scrub losses for liner member removal and replacement. Additionally, such liner members are quite heavy, making their handling difficult, which greatly increases the time required to replace liner members, and the amount of Scrappross is also significantly higher, both of which add to the overall maintenance cost of the mill. It has increased significantly.

For large mills, it was previously believed that in order to obtain the desired throughput tonnage of the mill it was necessary to provide for peripheral discharge of material from the mill by sloping the grid at the mill discharge end. However, in practice it has been found that gratings are not very effective in obtaining the desired ambient emissions and such gratings are subject to excessive wear.

SUMMARY OF THE INVENTION It is a primary object of the present invention to provide an improved mill liner design that significantly improves mill performance without significantly changing the final milled product structure compared to mills with conventional baffle liners. be.

Another objective is to provide a liner design that improves mill throughput without sacrificing grinding efficiency.

Yet another object is to provide a liner design in which liner weight and scrub loss are substantially reduced and liner wear is reduced, thereby substantially reducing overall maintenance costs for the mill.

Another object is to provide a liner design of the type described which provides better mill end protection.

Another object is to provide a liner design that requires less time to replace due to lower weight and simpler liner patterns than conventional liner designs.

Another object is to provide a liner design that eliminates ambient emissions from large mills without adversely affecting mill throughput tonnage.

These and other objects of the present invention provide a low profile end liner at the mill ends incorporating radial ribs of suitable height to greatly improve mill performance without sacrificing milling efficiency. This can be achieved by using Such new end liner designs not only provide adequate protection to the mill ends, but also substantially reduce liner wear per ton of ore crushed and require less replacement time compared to conventional liner designs. Less due to lower weight. Also, to simplify maintenance and reduce scrub losses, lifter rods for the shell liner elements are formed as an integral part of the shell liner. Furthermore, in large mills, where peripheral discharge is eliminated, the shell liner member is preferably made in a three-piece design, i.e., consisting of an intermediate section and two identical end sections, thus forming two end sections. Allows the middle section, which is most subject to wear, to be replaced without having to be replaced.

To the accomplishment of the above and related objects, the present invention includes the features hereinafter fully described and particularly pointed out in the claims. While the following description and accompanying drawings illustrate in detail certain embodiments of the invention, they are merely illustrative of some of the various techniques in accordance with the principles of the invention.

[Brief explanation of the drawing]

FIG. 1 is a side elevation view of a typical dry autogenous mill incorporating the liner design of the present invention; FIG. 2 is a side elevation view of line 2--
Figure 3 is an enlarged partial cross-sectional view of the mill taken on the plane of Figure 2 showing the interior of the mill lined with one embodiment of the liner design of the present invention;
Figure 4 is an enlarged exploded perspective view of several individual components, including the end liner, of the embodiment of Figures 2 and 3; Figure 5 is taken from the right edge of Figure 3; An enlarged partial end elevation view of some of the shell liner elements seen; FIG. 6 is an enlarged partial cross-sectional view of the mill of FIG. 1 similar to FIG. What is shown: Figure 7 is a partial perspective view of a portion of the liner gauge of Figure 6, looking from inside the mill to the left; Figure 8 is a partial perspective view of a portion of the modified end liner design of Figures 6 and 7; FIG. 9 is an enlarged partial end elevation view of several center sections forming part of the shell liner design of the embodiment of FIGS. 6 and 7; FIG.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1, there is shown a mill 1, preferably of the dry autogenous type, into which raw ore mined is conveyed through a central feed side 2 and crushed into the desired form. It is ground to size and then carried out of the mill on the discharge side 3 opposite the feed side by an air stream which passes continuously through the supply conduit 4 and the discharge conduit 5 at each end of the mill.

The rate of product feed into the mill is usually controlled by a sound level control device to raise or lower the sound level within the mill as desired. Changes in the product level within the mill will affect the power draw of the mill, and matching the maximum power draw to sound conditions can provide the best throughput to the mill. Mill throughput can also be controlled by adjusting air flow. Air passing through the mill carries particulates out of the mill, and the air velocity controls or determines the roughness of the material exiting the mill.

Both the shell 8 and the ends 10 of the mill are fully lined as is customary to protect the interior of the mill from wear and to aid in the crushing and grinding operations within the mill. However, instead of using conventional wedge-shaped serpentine liner members at the mill ends, low profile liner elements are used. It has been found that thick internal baffle liner members at opposite ends of the mill unduly limit the width of the ore curtain defined by the axial spacing a between internal liner members 12 at opposite ends of the mill adjacent central opening 14. Ta. Material falls through the central opening as it is carried upwardly by the shell and end liners 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 greater the resistance to airflow through the mill.
And the opposite relationship also holds true. Additionally, it has been found that slightly increasing the distance between the internal liner members 12 on the feed and discharge sides of the mill improves the performance of the mill. However, if the increase becomes too large, an excessively high pressure drop will occur, which will adversely affect product removal from the mill, which will not only reduce the grinding speed of the mill even though the mill's power draw is high. Wear of the liner on the discharge side of the mill will also be accelerated due to particulate formation and racing against the liner.

In actual practice, for example, the mill performance of a 6.4 m diameter mill shown in Figures 2 and 3 is substantially improved for mills using conventional deflector liner elements up to 104.14 cm, and The pressure drop and liner wear of the inner end liner member 12
The distance a between the internal liner members 12 on the feed and discharge sides of the mill is reduced by reducing the thickness b from 41.28 cm to 25.40 cm.
It was found that this can be avoided by increasing the
Similarly, mill performance of substantially larger mills, such as the 10.52 m diameter mill shown in FIGS. Thickness from 57.15cm
It has been found that this can be avoided by increasing the distance a' between the internal end liner members on the feed and discharge sides of the mill by decreasing it to 38.10 cm. Such further reduction in liner thickness will result in unduly high pressure drops and
High mill power draws not only reduce the milling speed, but also result in accelerated liner wear on the discharge side of the mill due to the particulates formed and running against the liner.

Also, the conventional external wedge deflector liner member has the most significant effect on mill power draft;
It was also found that it plays an important role in the grinding performance of the mill. For example, it has been found that if external deflector liner members are replaced with low profile liner members, these allow the mill to extract even more power. At the same time, if only a smooth plate outer liner member is used instead of an external deflector liner member, the grinding efficiency will be very poor and the grinding will be insufficient to produce an impact grinding action and the grinding for discharge from the mill. It was found that there was insufficient total lifting action to expose the material to the air flow.

Radial ribs are incorporated into the end liner members to increase the grinding efficiency of the mill. It was found that the rib height has a direct effect on the grinding efficiency of the mill. Therefore, if the rib height is too low, the total lifting action will be insufficient, resulting in not only a reduced grinding speed but also excessive abrasive grinding, which will cause the liner to be crushed by the ore running towards the lights. Fine particles and severe wear occur on the discharge side. For the same reason,
If the rib height is too large, the throughput of the mill will be adversely affected and the ribs will not be cleaned, thus having the effect of shortening the overall length of the mill. The actual size of the rock being crushed in the mill also influences the preferred height of the ribs.

In the actual test, approximately 16.51cm on a 10.52m mill.
Using a low profile end liner member with a rib height of 300 mm not only allows the mill to extract the required power, but the mill also has a lower profile than a mill of the same size but with a conventional full deflector liner member. It was found to have consistently excellent performance. It has also been found that the preferred rib height for a low profile end liner member on a 6.4 m mill is approximately 10.16 cm.

The use of low profile end liners with radial ribs has the advantage of reducing the number of end liner members, making maintenance easier and reducing scrub loss. In intermediate size mills, such as 6.4 m mills, a single row of low profile internal head liner members 12 of the type shown in FIGS. 2 and 3 may be substituted for both the conventional internal and external deflector liner members. A single row of external head liner members 15 can be used in place of both internal and external conventional ring liner members.

Each of the individual external headliner elements 15 preferably has a substantially groove-shaped cross section, with the width of each element increasing progressively with increasing radial distance from the axial center of the mill as shown in FIGS. Each of the individual internal head liner elements 12 also preferably has three spaced apart radial rib elements 19, 20, 21 which extend for a portion of their length from the radially outermost end thereof and The spacing and height substantially correspond to and are a continuation of the radial ribs 23 on the external head liner element 15. Side ribs 1 on internal head liner elements 12
9, 21 also have approximately the same width as the ribs 23 on the outer head liner elements 15, but the intermediate ribs 20 on the inner head liner elements have two adjacent ribs 20 on each pair of outer head liner elements cooperating with each inner liner element 12. It is approximately twice the width corresponding to the width of the rib 23. Also, the intermediate rib 20 on each of the internal head liner elements preferably has two side ribs 19, 21.
, in which case the height of the rib extension 24 is somewhat smaller. Each internal head liner element 12 has a head portion 25 at its radially inner end.
This part ends with radial ribs 19, 20, 2
1 and 23 to limit the width of the ore curtain as described above and also to protect the radial ribs from undue wear. The profile of the end liner is preferably the same on both the feed and discharge sides of the mill, so that the mill lining is symmetrical as shown, increasing liner life, especially for external head liners on the discharge side of the mill. The lifespan of the member 15 is increased.

In larger size mills, such as 10.52 m mills, the conventional internal deflector liner members are preferably replaced with an internal head base 31 and cap 31 arrangement, and the conventional external deflector and internal and external ring liner members are replaced by the sixth It replaces central and external head liner members 32, 33 as shown in FIGS. Each central head liner element 32 preferably includes two circumferentially spaced radial ribs 34 extending the entire length thereof, while the outer head liner elements 33
each has a single radial rib 35, and two such external headliner elements provide a continuation of each central headliner element. Each inner head base liner element 30 preferably includes a pair of radial ribs 36 extending a portion of its length from its radially outer end and defining a continuous portion of the central and outer liner element ribs. The radially interior portion of each internal head base liner element has a stepped flange 38 which engages a corresponding step 39 on each internal head cap liner element 31. Preferably, there are two such internal head cap liner elements 30 for each internal head cap liner element 31, each such internal head cap liner element also pivoting on a radial rib on each of the various end liner elements. radial ribs to limit the width of the ore curtain and protect the radial ribs in the manner described above.

Such a reduction in the number of end liner rows is possible because new low profile end liner designs have lower weight. This allows for the casting of long end liner elements while eliminating the handling problems associated with conventional end liners during liner replacement caused by their excessive weight.

The shell liner elements are separated from the end liner elements and, like conventional shell liners, extend in a series of circumferentially spaced longitudinally spaced locations, preferably within an optimum range of lifter spacing and height ratios. Including frying stick. However, in order to simplify maintenance and reduce scratch loss, the shell liner design of the present invention has been changed from the original separate rail and ledge design to one in which the lifting bar is an integral part of the shell liner member. . Thus, for example, in a mill of intermediate dimensions,
Each shell liner element 40 preferably has a second, third, fifth
Although shown includes a single axially extending lifter bar 41 formed as an integral part adjacent one end of the shell liner element, in larger mill sizes two such axially extending lifter bars 43 are preferred. are formed as an integral part of each shell liner element 44 extending along each end thereof as shown in FIGS.

Furthermore, due to the length of large size mills, each shell liner element for large mills is desirably comprised of three pieces: a middle section corresponding to the shell liner element 44 previously described, and two identical end sections. section 45
Consisting of Each end section 45 has an axial length that is less than each intermediate section 44 so that such end section is twice the circumferential width of each intermediate section and is the outermost of the central sections of each pair. It has at its end an axially extending lifter rod 46 having the same thickness and spacing as the lifter rods 43. The end sections also desirably include a central lifter bar 47 corresponding to the width of the adjacent lifter bars 43 of each pair of intermediate sections, effectively providing a contiguous portion of the lifter bars of two such intermediate sections. The advantages of forming the outer shell liner element in a three-piece design are:
This is intended to enable the intermediate section, which receives most of the wear, to be replaced more frequently than the end sections.

Conventional internal shell designs for large mill sizes also usually include a grate at the discharge end of the shell to provide for some ambient discharge from the mill. In the past, such ambient discharge was considered necessary for large size mills to obtain the desired tonnage throughput. However, in practice it has been found that gratings are not very effective in obtaining the desired ambient emissions and such gratings are subject to excessive wear. Furthermore, it has been found that with the new liner design of the present invention, ambient emissions are eliminated, thus eliminating the problems associated therewith and without adversely impacting mill throughput tonnage.

Although the spacing and height of the shell liner lifters may vary within a certain range, for a 6.4 m mill, the spacing s between adjacent lifters 41 is preferably approximately 34.14 cm, so that when newly installed the lifters The height h is approximately
14.61cm, and thus when newly installed,
The ratio of length s to height h shown in FIG. 5 is approximately 2.3. Further, such shell liner members are preferably replaced after the ratio increases to about 5.5 due to lifter wear. For a 10.52 mm mill, the spacing s' between lifters 43 at each end of the shell liner member is preferably approximately 44.32 cm, and the maximum height h' when newly installed is approximately 24.13 cm. , when new, the ratio of length s' to height h' as shown in Figure 9 is approximately
1.8, and the liner member is preferably replaced after the ratio increases to about 5.5, also due to wear.

Separate corner liners 50 are also preferably used for the second and sixth
It is provided between the respective outer end liner and outer shell liner members of both illustrated embodiments to protect the outer shell therein. This is very important. This is because the outer shell is very expensive.

From the foregoing, the various liner designs of the present invention, particularly with low profile end liner members incorporating radial ribs of appropriate height, maximize mill volume while
It will be apparent that this provides sufficient lift to utilize the entire mill diameter for grinding operations. In actual testing, using such a new liner design,
It has been found that the throughput of the mill is increased by as much as 9-20% over a mill with conventional dual row deflector liner members without sacrificing grinding efficiency. Additionally, this new liner design reduces liner weight and scratch loss, resulting in a 25% reduction in liner wear, eases liner handling during handling, reduces overall mill maintenance costs, and reduces liner end and The outer shell was now better protected.

Although the present invention has been illustrated and described with reference to certain preferred embodiments, it will be apparent that equivalent alterations and modifications may be made to others skilled in the art upon reading and understanding this specification, and the present invention contemplates , including all modifications, are limited only by the scope of the claims.