AU2009101175A4 - Facing for mineral processing elements - Google Patents

Description

AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION Innovation Patent Applicant(s): BRADKEN RESOURCES PTY LIMITED Invention Title: FACING FOR MINERAL PROCESSING ELEMENTS The following statement is a full description of this invention, including the best method for performing it known to me/us: -2 FACING FOR MINERAL PROCESSING ELEMENTS Field of the Invention 5 The present invention relates to liners used in mineral processing equipment and more particularly is concerned with providing a wear resistant structure for a beam element to be used in gratings through which mineral ore falls and is broken to be passed into a hopper, chute 10 or other structure. These are typically called dump pockets where ore is transferred from haul trucks to the crushing circuit of a mine. The grizzly beams of the current invention are primarily used to protect the crushing and sizing equipment below the dump pocket from 15 excessive impact or oversize items. Background of the Invention The upper surface of such grizzly or ROM (run of 20 mine) beams is subject to impact and abrasion and therefore protection to provide long service life is required. The invention is concerned with new and useful alternatives compared with known arrangements. 25 Summary of the Invention The present invention provides an elongate beam for use in a grating for mineral processing; the beam having a structural support with an upper 30 surface onto which are secured a multiplicity of wear resistant block elements positioned along the edges of the surface and between which a series of cavities are provided; -3 whereby in use the cavities retain fine particles of mineral ore and the wear resistant blocks protect the beam from abrasion and impact forces from lumps of the mineral ore. 5 The size and positioning of the cavities may promote a known phenomena 'rock boxing'; thereby allowing ore to fall on ore which significantly reduces erosive wear. 10 In an embodiment, the bottom region of the cavities are faced with a wear resistant plate material. The block elements are advantageously of a white iron typically having about 15% chromium and about 3% 15 molybdenum, the block being vacuum brazed to a mild steel backing plate which in turn is adapted to be welded to the supporting structure of a suitable mild steel to provide structure strength in an economic manner. 20 When the bottom of each cavity is protected with a wear resistant plate, preferably a chromium carbide plate material is used and that material can be fusion bonded to a base material to facilitate the securing of the material to the base structure. 25 The plate material can be of a metallurgical structure based on AS2576-2355 or AS2576-2455. In these examples the metallurgical structure is primarily M 7

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3 carbides in a eutectic matrix of austenite and carbide. 30 However, other compositions can be used if so desired.

-4 Detailed Description of the Drawings By way of example only reference will be now made to the accompanying drawings of which: 5 Figure 1 is a perspective view of a beam for use in a grating for mineral ore processing; Figure 2 is a plan view of the beam of Figure 1; Figure 3 is a front view of the beam of Figure 1; Figure 4 is a bottom view of the beam of Figure 1; 10 Figure 5 is a side view of the beam of Figure 1; Figure 6 is the opposite side view of the beam of Figure 1; Figure 7 is an enlarged side view of a portion of the top wear resistant protection structure in the beam of 15 Figure 1; Figure 8 is a plan view of the structure of Figure 7; Figure 9 is a sectional end elevation taking along the line X-X of Figure 7; Figure 10 is a sectional end elevation taking along 20 the line Y-Y of Figure 7; and Figure 11 is a sectional side elevation taking along the line Z-Z of Figure 8. Description of Specific Embodiment 25 Figures 1 to 6 show in overview an embodiment of the invention being incorporated in a beam 10 which is adapted to be mounted with several beams in parallel to form a grating for a chute or container for receiving mineral 30 ore. Mineral ore is intended to be dumped on the grating and the lumps broken to pass between the beams and the embodiment illustrated has structure for protecting the top surface of the beam from wear.

- 5 The beam 10 has a box-section 12 with structural end portions 14 and 16 fabricated suitably from mild steel elements. At each end a mounting block 18 is provided for 5 engagement in a surrounding structure. The beam 10 has a top plate 20 on which the new protective arrangement to resist abrasion and impact forces is secured. Abrasion resistance is provided by mounting wear 10 resistant blocks 22 along the edges and ends of the beam with further blocks 23 providing transverse divisions whereby there are defined cavities 24 between the blocks 22 and 23. In each cavity a wear plate 26 is mounted, the wear plate having a thickness much less than the height of 15 the blocks and a small gap 28 is provided around each plate 26 to facilitate attachment by welding. Thus, fine particles of mineral become entrapped in the cavity and act to absorb impact forces from further 20 mineral dumped onto the top of the beam 10. The details of the wear block and wear plate structure can best be determined from Figures 7 to 11. 25 The wear plates 26 are preferably from chromium carbide composite cladding that is fusion-bonded to a base material and is highly abrasive resistant. Conveniently, the cladding is bonded to a mild steel base which can fixed, for example, by welding to the underlying structure 30 being top plate 20 of the beam 10. In a preferred embodiment, the plates 26 are of a grade to provide high abrasion and high impact resistance. The preferred grade has M 7

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3 carbides in a complex carbide austenite matrix, - 6 that material being treated to provide superior toughness with the formation of complex nodular carbides leading to a reduction in the size of the acicular M 7

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3 carbides and inter-carbide spacing. The product is based on 5 AS2576-2455. The blocks 22 and 23 are preferably from a composite material comprising a chromium-molybdenum abrasion resistant white iron casting metallurgically bonded to a 10 weldable mild steel backing plate 25. The hard chromium carbides are supported in a martensitic matrix. The mild steel backing plate is vacuum brazed to the white iron casting giving a true metallurgical bond. 15 In this embodiment, the main beam has side faces 28 of a suitable grade of chromium carbide composite cladding and economically the grade providing high abrasion resistance with moderate impact resistance is suitable. The preferred product is primarily M 7

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3 carbides in a 20 eutectic matrix of austenite and carbide and is based on AS2576-2355.

Claims (5)

1. An elongate beam for use in a grating for mineral processing; 5 the beam having a structural support with an upper surface onto which are secured a multiplicity of wear resistant block elements positioned along the edges of the surface and between which a series of cavities are provided; 10 whereby in use the cavities retain fine particles of mineral ore and the wear resistant blocks protect the beam from abrasion and impact forces from lumps of the mineral ore. is

2. An elongate beam in accordance with Claim 1, wherein the bottom region of the cavities are faced with a wear resistant chromium carbide plate material.

3. An elongate beam in accordance with Claim 2, wherein 20 the wear resistant plate is secured to the structure leaving a peripheral gap from adjacent wear resistant block elements.

4. An elongate beam in accordance with any one of the 25 preceding claims, wherein the block elements are of a white iron typically having about 15% chromium and about 3% molybdenum, the block being vacuum brazed to a mild steel backing plate which in turn is adapted to be welded to the supporting structure. 30

5. An elongate beam in accordance with any one of the preceding claims, wherein the sides of the beam are protected with a wear resistant chromium carbide plate -8 bonded to a base material to facilitate the securing of the material to the base structure.