DD298601A5 - INTERIOR CLADDING FOR TUBE BALL MILLS - Google Patents

Abstract

The invention relates to an inner lining for Rohrkugelmuehlen, which is suitable for crushing mineral, synthetic and Sekundaerrohstoffen or intermediate and end products. The inner lining for Rohrkugelmuehlen has radially encircling profiles whose cross-section has triangular shape with radii on the profile base and mountain and is characterized in dasz the center of the radius for the profiled ground in the radial plane of the mill (3) from the center of the other two Mahlplattenradien (4 and 5 ) is offset so that the profile ground in the direction of rotation of the mill at the running Mahlplattenende (6) up to maximum immersion depth (7) of the micro ball used (2) in the radially encircling profile increases {internal lining; Tube ball mills; Profiles, radially encircling; Triangular shape; Mahlplattenradien; Profiled ground, increasing; Immersion depth; Smallest ball}

Description

For this 2 pages drawings

Field of application of the invention

The invention relates to an inner lining for tubular ball mills, which is suitable for the comminution of mineral, synthetic and secondary raw materials or intermediate and end products.

Characteristic of the known state of the art

For inner linings of tubular mills, armor plate shapes that cause impact, shear or pressure effects are known. These include Hebeioisten-, step-, humpback, conical classification and Eckspiralpanzerungen and groove profiled inner linings (Schubert, H .: Preparation of solid mineral raw materials Bd. I, S · 147-157, VEB German publishing house for basic industry Leipzig 1976; Hoff I, K .: crushing and classifying machines, p 204-229, VEB German publishing house for basic industry Leipzig, 1985).

Grooved profiled inner linings according to the Austrian Patent AT-PS 283092 have the shape of a circular segment in the cross section of the radially circumferential grooves, wherein the radius corresponds predominantly to the largest grinding balls used. Since each smaller ball has only point contact with the refining plate and thus there is a reduced positive engagement between the balls and the refining plate, effective Wälzerkleinerungs- or Druckbeanspruchungseffekte not be achieved. To improve the crushing and maintenance conditions solutions are known for this profiling with transverse to the circumferential direction surveys or depressions (AT-PS 379762), different arrangement of grooves in the circumferential direction according to helices (AT-OE-309963), with varied land widths before transverse walls (AT-PS 373792), for dimensioning the groove and the distance (AT-PS 380410, AT-PS 380411) and used for highly wear-resistant material alloys (AT-PS 328834).

Furthermore, according to DD-WP 154425 and DD-WP 228957 inner linings are known which allow by radially encircling profiles with elliptical segment shape a two-point support certain Mahlkugelgrößen and thus effective Wälzorkleinerungseffekto and wear-and energy-intensive crushing, as it is known from previous inner linings suppress. A disadvantage of this solution is that due to the selected ellipse profile too small sickle-shaped Mahlspalt remains between Kugul and plate, this still decreases with progressive wear and thus this solution for the comminution of coarse particles (> 30mm) is unsuitable.

Furthermore, when using this profiling in conjunction with high-hardness iron-chromium-carbon alloys for the refining plates and balls in fine grinding agglomeration problems arise. Furthermore, an inner lining with radially encircling profiles whose cross-section triangular shape is provided with radii on the profile base and mountain, made of cast iron with nodular graphite and is used in all grinding spaces in a uniform geometry, known. The disadvantage of using this armor profiling in coarse grinding rooms is that the comminution of particles <5mm in the coarse grinding chamber superimposed fine grinding is insufficient and this situation unfavorable effect for subsequent effective grinding in the Feinmahlräumen.

Object of the invention

The aim of the invention is an inner lining for tubular ball mills, which is suitable for the comminution of mineral, synthetic and secondary raw materials and compared to the prior art has a low specific electrical energy requirements, and a low Mahlplatten- Mahlkugelverschleiß and.

Explanation of the essence of the invention

The invention has for its object to develop an inner lining for dry and wet-working tubular ball mills, for a simultaneous effective coarse and fine grinding in a process space of mineral, synthetic

and secondary raw materials or intermediate and end products is suitable. This object is achieved for an inner lining (1) with radially encircling profiles whose cross-section triangular shape with radii on the profile base and barbar, according to the invention achieved in that the center of the radius (3) for the profile base in the radial mill plane from the center of the other two Mahlplattenradien (4 and 5) is offset so that the profiled ground in the direction of rotation of the mill at the end of Mahlplattenende (6) up to the immersion depth (7) of the Kleinins' ball used (2) increases in the radially encircling profile. It is essential to the invention that a radius (8) is maintained at the base of the profile in the axial plane of the mill, whereby it increases with the direction of rotation of the inner lining (1) (from 9 to 6) or that the profiled ground in the axial plane of the grinding mill ends (9 ) merges into a trapezoidal shape from the triangular profiling with radius (8) at the end of the grinding plate end (10). By increasing dea profiled ground in the radial mill plane to the immersion depth (7) of the micro ball used (2) in the radially encircling profile is achieved that the grinding gap (11) under each resting on the profile mini ball (2) during the passage of the inner lining is narrowed to zero by the moving Mahlkugelschleppe of a certain output at the incoming Mahlplattenende (9) according to the figures 3 and 4, respectively. For each larger grinding ball remains at the outgoing end of the inner lining according to their immersion depth in the geometrically defined triangular profile a residual gap. A correspondingly large output gap under the overlying grinding balls at the tapered end of the inner lining is required to pull coarse Mahlgutpartikel under the rolling on the inner lining Mahlkugelschleppe and crush effectively. By narrowing the grinding gap in the direction of rotation of the mill to zero or to a greatly reduced residual gap at the outgoing end of the inner lining is achieved that the effective crushing of coarse particles is superimposed on an additional fine comminution by the very effective stress modes pressure and shear. It is essential that the grinding gap for the resting micro ball at the outgoing end of the inner lining narrows to zero, d. h., That this ball size only runs up on the bottom of the profile of the outgoing end of the inner lining and is not raised. This ensures that the entrainment of Mahlkugelschleppe remain minimal through the inner lining at the selected mill speed and thus the electrical energy requirements.

Advantages result from the inventive solution in the form of significantly improved Austragsfeinheiten from the process spaces of the tubular ball mills at the same throughput and specific electrical energy requirements. That is, at the specified target fineness for the different crushing tasks for tubular ball mills, z. As in dry cement or wet ore grinding significant increases in throughputs up to 20% and thus savings in specific electrical energy demand of the same magnitude are possible.

In wet ore radiation in single-chamber tubular ball mills with discharge chamber or overflow, where forcibly coarse and fine grinding takes place simultaneously in a process chamber, are by the general abandonment of the previously common strong cataract effect of the grinding balls drastic reductions in specific electrical energy demand and Mahlplatten- and Mahlkugelverschleiß reachable. The invention will be explained in more detail by means of exemplary embodiments.

embodiments

FIG. 1 shows an inner lining 1 in section in the radial mill plane in the profile valley, from which the rising profile ground in the direction of rotation of the tubular ball mill becomes apparent. The increase of the profile ground is achieved in that the center of the base radius 3 is offset from that of the other two Mahlplattenradien 4 and S. In Figure 2, the view of the end face of the inner lining at the approaching Mahlplattenende and in Figure 3, which is shown at the end of Mahlplattenende each with the resting micro ball 2 of the grinding ball filling used. Here, the center dea radius 3 is offset from that of the radii 4 and 5 so that the profiled ground in the radial mill level at the outgoing end of the inner lining, Figure 3, to the immersion depth 7 of the micro ball 2 used increases, d. H. that the micro ball runs on the running end of the inner lining of the profile base. Due to this structural design of the inner lining narrows at each mill revolution of the tubular ball mill, the grinding gap 11 under each resting micro ball from the initial value at the leading end, Figure 2, to zero, Figure 3, during the passage of the inner lining through the moving Mahlkugelschleppe.

When maintaining a radius 8 at the base of the profile in the axial plane of the mill, its value increases from the output in FIG. 2 to that shown in FIG. 3 by the increase in the profile ground in the radial mill plane to the insertion depth of the miniature sphere used. FIG. 4 shows the design of the profiled base of the inner lining at the end of the grinding table, when transition from a triangular profiling with radius 8 on the profiled ground at the leading end of the inner lining, FIG. 2, to trapezoidal profiling on the profiled bottom of the trailing end of the inner lining, FIG.

example 1 The inner lining is in the coarse grinding chamber of a continuous cement mill with 3.2m diameter and 15m Mahlbehnlänge

used. The grinding path length of the coarse grinding space is 3.75 m. For equipping the coarse grinding room are 480pcs.

Grinding plates of the inner lining required. In the grinding chamber, 40 tons of high-chromium-alloyed cast grinding balls with diameters from 100 mm to 60 mm in 10 mm increments

used.

The basic profiling of the radially encircling profiles consists of triangles with radii on the profile hill and ground, the

have isosceles triangles from the profile base from an opening angle of 90 °. The height of the triangles is 65% of the radius of the largest sphere used. The center of the radius 3 of the profiled ground in the radial plane of the mill is offset from that of the radii 4 and 5 such that the profiled ground at the trailing end of the inner lining according to FIGS

Immersion depth 7 of the grinding balls increases with 60mm. A radius 8 at the bottom of the profile in the axial mill plane is maintained,

wherein it increases in accordance with the figures 2 and 3 from the leading to the trailing end of the inner lining.

Example 2

The fine grinding of a lump size pre-reduced to <20 mm to particle sizes <90 μm is carried out in a wet-working single-chamber tubular ball mill with a discharge chamber with a diameter of 3.2 m. The ore contains up to 70% quartz and is therefore very abrasive. For complete digestion for downstream processing stages, the high target fineness with <90μιη is required. That is, both the crushing of the coarse particles and the fine grinding must be done effectively in a process space.

The interior lining according to the invention is used. For equipping the mill, 96 pieces of refining plates are required or the profiling is carried out on achsparaliei continuous grinding beam. The basic figure of the radially encircling profiles corresponds to that described in Example 1. The center of the radius 3 of the profiled ground in the radial mill plane is offset from that of the radii 4 and 5 so that the profiled ground at the end of the inner lining expires up to the immersion depth 7 of the grinding balls with 30mm diameter in the radially encircling profile according to figure. A polydisperse grinding ball filling consisting of grinding ball diameters from 100 mm to 30 mm grading with a mean ball diameter (= diameter = 50 mm) is used.

Claims (3)

1. Inner lining for tubular ball mills with radially encircling profiles whose cross-section has triangular shape with radii on the profile base and mountain, characterized in that the center of the radius for the profile base in the radial mill plane (3) from the center of the other two Mahlplattenradien (4 and 5 ) is offset so that the profiled ground in the direction of rotation of the mill at the running Mahlplattenende (6) to a maximum immersion depth (7) of the micro ball used (2) increases in the radially encircling profile. 2. Interior lining according to claim 1, characterized in that a radius at the profile base in the axial plane of the mill (8) is maintained, wherein it increases with the sense of rotation of the inner lining (1). 3. Inner lining according to claim 1, characterized in that the profiled ground in the axial mill level at the leading Mahlplattenende (9) of the triangular profiling with radius (8) at the running Mahlplattenende (10) into a trapezoidal shape.