AU754833B2

AU754833B2 - Ore screening panel

Info

Publication number: AU754833B2
Application number: AU18459/00A
Authority: AU
Inventors: Jeff Zubovich
Original assignee: Screenex Australia Pty Ltd
Current assignee: Sandvik Rock Processing Australia Pty Ltd
Priority date: 1999-02-22
Filing date: 2000-02-21
Publication date: 2002-11-28
Anticipated expiration: 2020-02-21
Also published as: AU1845900A

Description

AUSTRALIA

Patents Act

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Application Number: Lodgement Date: 2 1 s t February 2000 Applicant :Richardson Pacific Limited' 0 Invention Title: Ore Screening Panel 0 0* 0 .0b.

40.4 The following statement is a full description of this invention, including the best method of performing it known to the applicant.

*0 a 0* 0 00 Ore Screening Panel This invention relates to improvements in ore screening panels used in the separation and grading of materials in the mining and quarrying industries.

Background to the invention Australian patent 482212 proposed a modular screening panel system for ore screening decks which is now widely used by the mining industry and replaced the earlier screening cloths, and large wire screening frames. The screening panels were all of the same size [eg. 300mm] and made of reinforced S" "polyurethane. The panels are adapted to be secured to an underlying support frame using dependent spigots which are a force fit into corresponding apertures 15.. in the support frame. Patent 517319 provided an alternative method of securing S:•i the panels to the frame using a pin expanded fastening concept.

These screens are used for a variety of purposes including heavy media recovery from ore streams which require separation by gravity. The ores that are treated in this way include coal, iron and diamonds. In heavy media recovery, the media S 20 typically magnetite or ferro-silicones is recovered on wash screens after the ore separation [gravity] step. Difficulty has been encountered in this separating step to achieve adequate recovery of the heavy media. One means used is to use 0. wash water sprayed over the ore particles as they pass over the screen deck. To improve the recovery rate, weirs or barriers have been placed on the screen deck under the wash water sprays to slow down the flow of the ore and increase agitation to promote separation. One conventional arrangement is to have two wedged shape solid surface panels on either side of a screening panel to restrict flow and increase agitation. Patent application 16555/97 claims to be an improvement over this method by providing a specialized screening panel which sprays wash water upwardly to increase agitation and media separation.

It is an object of this invention to provide a device for improving the recovery of heavy media.

Brief description of the invention To this end the present invention provides a heavy media recovery panel for use in screening decks which consists of a panel having a leading edge a trailing edge and two side edges and a surface extending between all four edges and being inclined from the leading to the trailing edge such that the depth of trailing edge is greater than the depth of the leading edge.

By providing a depression in the screening surface the ore and the wash water accumulates in the depression and due to the inclined surface and the momentum of the ore particles the agitation is sufficient to effectively separate the ore from the heavy media typically, ferrosilicones or magnetite and recover them as part of the wash water which passes through the apertures in the screen S" panels.

It is preferred that the surface of the panel parallel to the trailing edge is flat; that is parallel to the screen deck which itself is level with the surface of the 4 edges of the heavy media recovery panel. It is also preferred that small apertures be provided in the surface section adjacent the trailing edge which is the lowest portion of the surface of the recovery panel. These drainage apertures allow recovery of the heavy media separated during the agitation in the panel.

The heavy media recovery panel is preferably of the same external size and material as the other panels in the washing/dewatering section of the screen deck. Panels are generally 300mm square or 600x300 mm and made from a hard grade of polyurethane.

Detailed Description of the Invention A preferred embodiment of the invention is illustrated in the drawings in which; figure 1 is a schematic side view of the screen deck; figure 2 is a plan view of the heavy media recovery panel of this invention; and figure 3 is a side sectional view of the panel of figure 2.

As shown in figure 1 the ore 1 from the flotation tank travels in the direction of the arrow over a screen deck 2 composed of polyurethane screening panels of the type disclosed in patents 482212 and 517319. The aperture sizes are chosen to be suitable for dewatering and recovery of magnetite or ferro-silicones which form the heavy media. Wash liquid, usually water, is sprayed from nozzles [not shown] located above the screen deck 2.

The heavy media recovery panel 3 has a leading edge 4 a trailing wall 5 and two side edges 6. Dependent spigots 7 are provided on side edges 6 to fasten the panel to the screen deck support frame. These spigots can be of the type described in patent 482212 or 517319.

The surface of the panel extending between the edges comprises a first inclined portion 8 which slopes downwardly from the leading edge 4 toward the trailing wall 5 and a second flat section 9 which extends between the sides 6 adjacent the trailing wall 5. The portion 9 is provided with small dewatering apertures 10 to allow drainage of the heavy media to be recovered.

0io The panel of this invention is suitable for use in any heavy media recovery screening applications relating to ores such as diamonds, coal or iron ore. The particles will have heavy media such as magnetite or ferrosilicone attached to them as they flow down the screen deck. As the ore and wash water enter the 15 depression formed by the sides 6, the trailing wall 5 and the surfaces 8 and 9 15 they tumble down the inclined surface 8. The volume of ore slurry passing over the screen deck maintains the tumbling action in the section above surface 9 so that the agitation that occurs there is sufficient to separate a substantial proportion of the magnetite or ferro-silicone from the coal or iron. The ore particles after agitation in the recovery panel continue along the surface of the 20 screen deck. The separated magnetite and ferro-silicon are entrained in the wash water and are drained out through the apertures 10 in the surface 9 or are .i drained out through the dewatering apertures in the screening panels S.downstream of the heavy media recovery panel 3.

From the above description it can be seen that this invention provides an inexpensive and cost effective means of improving the recovery of heavy media.

Claims

1. A heavy media recovery panel for use in screening decks which consists of a panel having a leading edge, a trailing edge and two side edges and a surface extending between all four edges inclined from the leading to the trailing edge such that the depth of trailing edge is greater than the depth of the leading edge to form a media recovery depression and dewatering apertures are located in said depression adjacent said trailing edge.

2. A panel as claimed in claim 1 in which there is a substantially flat surface between the inclined surface and the trailing wall of the panel.

3. A panel as claimed in claim 2 wherein the substantially flat surface contains said dewatering apertures. fe**: 0. g* *a. 0