AU606506B2 - Column flotation sparger removal - Google Patents

Description

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il l- i r NWEALTH OF AUSTRA AO FORM PATENTS ACT 1952 COMPLETE SPEC IF CAT TO N FOR OFFICE USE: Class Int.Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority: Related Art: Uame of Applicant: Address of Applicant: Actual Inventor: MOUNT ISA MINES LIMITED Mount Isa Operations, Mt. Isa, Queensland 4825, Australia John Martin Eisenmenger Address for Service: SHELSTON WATERS, 55 Clarence Street, Sydney Complete Specification for the Invention entitled: "COLUMN FLOTATION SPARGER REMOVAL" The following statement is a full description of this invention, including the best method of performing it known to u 1 Complete of PI 7248 dated 15th March, 1988 W ;Jt SHELSTON WATERS PATENT ATTORNE

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CLARENCE STREET. SYDNEY |j AUSTRALIA j Cables; 'Valid' Sydney Telex: 24422 This invention relates to apparatus for use in a column flotation process.

Flotation is a method of mineral separation used for the concentration of metallic minerals and based on the affinity of properly prepared mineral surfaces for air bubbles. In froth flotation, a froth is formed by introducing air into a pulp of finely divided ore and water containing a frothing agent. Those materials that have an affinity for air bubbles rise to the surface in froth and are thus removed from those that are completely wetted. Froth flotation is typically conducted in a cell provided with a plurality of sparger tubes disposed near the lower end and having means for introducing feed above the sparger outlets. The cell is typically provided with a number of vertically extending baffles and with an overflow lip over which concentrate-bearing froth flows to effect separation.

The spargers typically comprise an array of tubes extending through the side walls of the column towards a vertical mid-plane of the column. From time to time, the spargers require removal for cleaning or other maintenance. In some designs, each tube is separately i flange mounted or the tubes may be disposed on a removable manifold to facilitate removal. In another design, sparger tubes enter the column via a hinged and sealed door which may be swung open to give access to the tubes. More commonly the sparger is mounted to a removable lower-portion of the column which may be I -2disconnected from the upper portion when access to the tubes is needed. Needless to say, in any event, the column must be emptied prior to sparger maintenance or removal. This operation necessarily results in material losses as well as extending the down time of the plant during sparger cleaning.

An object of the present invention is to provide flotation apparatus having sparger arrangements which avoid or at least ameliorate some of the disadvantages of prior art. A further object is to Sprovide a sparger which is readily accessible for 9r It cleaning and which reduces the down time involved when

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r. C A further object of the present invention is to provide a sparger arrangement having improved efficiency.

According to one aspect the invention consists in a flotation apparatus comprising a column, a sparger adapted to be raised or lowered within the column, and guide means effective to prevent rotation of the sparger about the column axis while being raised or lowered.

Although it is not essential, the column may in a preferred embodiment be generally cylindrical.

In preferred embodiments, the guide means includes a hollow rail and air is supplied to a sparger assembly via a hose which extends within the rail and is connected to the lower side of the sparger assembly. Also for preference, the sparger assembly comprises a plurality of radially extending tubes, communicating with a circular -3-

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77^ i i., manifold.

A preferred embodiment of the invention will now be described by way of example only with reference to the accompanying drawings wherein Figure 1 shows a vertical cross-section through a flotation column according to the invention. Figure 2 shows a portion of the columnar figure 1 in a plan view looking down from above. Figure 3 shows an embodiment of a sparger for use in the invention in side elevation. Figure 4 shows the sparger of Figure 3 in. plan. Figure 5 shows a general view of a plurality of flotation tanks according to the invention.

Cr, v With reference to Figures 1 and 2 there is shown a flotation column 1 of generally cylindrical shape and closed at the lower end by a conical closure 2. Column 1 is open at its upper end. Guide rails 3 and 4 on diametrically opposite sides of the interior of column 1 extend from the lower edge of the cylindrical portion to the top of the column. A sparger assembly 20 hereinafter more particularly described with reference to Figures 3 and 4 is situated within column 1 and has sparger arms 21 extending radially from a central manifold 22 which is provided on its upper surface with cable attachment means 23 and at its lower edge is connected with a flexible air hose 5. Guide rail 4 is hollow or is a "U"-shaped channel and air hose 5 extends from outside column 1 within guide rail 4 to below the sparger and then is connected to sparger manifold 22. Sparger assembly has guide arms 24 extending radially outwardly and at an

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1 rJ ii A_ *1 angle to the horizontal. Guide arms 24 terminate in guides 25 which are adapted to slidingly engage and co-operate with guide rails 4 and 3. When the sparger assembly is raised or lowered by means of a winch cable attached to the manifold at 23, the sparger assembly slides upwardly or downwardly on the guide rails without axial rotation. When the sparger assembly is raised the air hose accumulates beneath it within the tank and consequently there is no problem of handling the hose or of drainage from the hose.

As is shown in Figure 5, a plurality of tanks 1 may be mounted side by side on a frame 30, the tanks being provided at the upper end with an overhead monorail 31 on which a trolley mounted winch may be supported, whereby the spargers may be raised or lowered as required.

The preferred embodiment of a sparger assembly is shown in Figures 3 and 4 and comprises a central manifold 22 of cylindrical construction which communicates via radially extending arms with a circular manifold 26 and a 20 lower circular manifold 27. The upper and lower circular manifolds have radially outwardly extending sparger tubes 28 and 29 respectively. The upper and lower circular manifolds 26, 27 are in communication with each other at equi-angularly spaced vertical manifolds 33.

The upper and lower sparger assemblies are off-set, being rotated one with respect to the other.

Although the sparger assembly illustrated in Figures 3 and 4 is preferred, other assemblies in which the

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ii i! 1 sparger tubes are arranged in a wagon wheel shape or in a spiral shape or in a spiral nebula shape are also suitable.

The flotation apparatus herein described permits the sparger assembly to be readily removed from the top opening of the column without need to empty the column.

Surprisingly, the column works efficiently without vertical baffles, given the excellent air distribution from the sparger. However, if desired, vertical baffles may be mounted to the sparger assembly. Other guide z t r means may be used to prevent rotation of the sparger P assembly during raising and lowering.

ji As will be apparent to those skilled in the art from the teaching hereof, the invention may be embodied in other forms and may be manufactured using any suitable materials without departing from the scope of the inventive concept herein described.

Claims (6)

1. A flotation apparatus comprising a column, a sparger adapted to be raised or lowered within the column, and guide means effective to prevent rotation of the sparger about the column axis while being raised or lowered.

2. A flotation apparatus in accordance with claim 1 wherein the guide means includes a hollow rail.

3. A flotation apparatus in accordance with claim 2 wherein air is supplied to a sparger assembly via a hose which extends within the rail. S,

4. A flotation apparatus in accordance with claim 2 wherein the rail is connected to the lower side of the sparger assembly.

A flotation apparatus in accordance with claim 3 wherein the sparger assembly comprises a plurality of radially extending tubes, communicating with a circular manifold.

6. A flotation apparatus substantially in accordance with Claim 1 with reference to the examples. DATED this 8th day of March 1989 MOUNT ISA MINES LIMITED i Attorney: IAN T. ERNST Fellow Institute of Patent Attorneys of Australia of SHELSTON WATERS