FI115447B - Flotation plant and method - Google Patents

Abstract

The invention relates to a flotation arrangement (1, 15) for flotating minerals or the like from slurries containing these particles, said flotation arrangement comprising a flotation cell (3) including edges (2) and a bottm (10), and a mixing mechanism arranged in the flotation cell, elements for feeding air inot the cell and elements for feeding material to be flotated into the cell and for removing the flotated material out of the cell, so that in connection with the top edge (4) of the flotation cell (3) there is arranged at least one support element (6, 14) for facilitating the discharge of the foam layer (5) and for supporting the foam layer (5). In addition, the invention relates to a method for flotating minerals or the like from slurries containing these particles by means of a flotation arrangement (1, 15), said flotation arrangement comprising a flotation cell (3) including edges (2) and a bottom (10), and a mixing mechanism arranged in the flotation cell, elements for feeding air into the cell and elements for feeding material to be flotated into the cell and for removing the flotated material out of the cell, so that the foam layer (5) is supported and its removal is facilitated by at least one support element (6, 14) arranged in connection with the top edge (4) of the flotation cell (3).

Description

j '115447 FOAMING EQUIPMENT AND METHOD i

The invention relates to a flotation apparatus as defined in the preamble of the independent claims and to a method for flotation of minerals or the like from slurries containing these particles.

The flotation machine used to recover valuable components such as metal concentrates usually includes a flotation cell having an inlet for feeding slurry to the cell and an outlet 10 for non-foamable material to be removed from the flotation cell.

The flotation cells may be single, series or parallel connected mixing vessels. They can be rectangular or cylindrical, lying or upright. The air required to form the foam is fed through a hollow rotatable shaft which is connected to a mixing member which mixes the slurry to maintain the slurry in the suspension state. As the mixer rotates, air is supplied to the slurry and air bubbles are dispersed in the slurry. The cell may also be pneumatic, in which the air ··· is supplied to the cell via special means without mechanical mixing.

'··· * In addition, the flotation cell is supplied with reagents that are adhered to the slurry: : 20 to the surface of recoverable value particles. Reagents do '; · '* Value particles become hydrophobic and thus promote the attachment of value particles to air bubbles. As the value particles attach to the air bubbles, the value particles begin to rise up toward and form the free upper surface of the flotation cell. . stable foam mattress. Value particles continue to rise out of the foam layer • *

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! ./ 25 cells for drainage channels. In a so-called reverse flotation, the worthless ingredient is hydrophobic, so that in the flotation process, the valuable substance is not foamed.

.v Nowadays more use has been made of vertical cells, which are still 30 cylindrical and normally flat. One frequently encountered difficulty is that mineral particles already adhered to the gas bubbles are not retrieved from the flotation cell because the currents formed in the cell, and in particular on its surface and top 115447 2, are misdirected or too weak, i.e. unable to move foamed gas bubbles out of the cell. Often flotation cells need to be placed many in succession to achieve the desired result. From a practical point of view, the result of obtaining foam 5 to the discharge ridges requires a sufficiently thick layer of foam which depends on the mineral to be foamed and the stage of the foaming process. Usually a relatively thick layer of foam is required for a good result in getting the foam to the drainage channels.

10 If the viscosity of the slurry is high, not much air can be dispersed in it because the air bubbles grow too large and interfere with the foam intake over the edge of the cell. In this case, the foam layer, when the slurry surface is low in the cell, receives support from the cell edges and is well formed, but due to the small amount of air it is difficult to get it out of the cell. There is not enough air to lift 15 layers of foam out of the cell. Especially low-content ores, such as precious metals, often have the problem that the foam mattress at the top of the cell collapses because the slurry edge is too long compared to the required concentrate production. Again, foam mattresses that are heavily loaded can '·· * become so heavy that it is almost impossible to remove them into the drainage lanes and 20 foam mattresses can collapse completely. When the foam collapses, at least some of the '·· * mineral particles return to the sludge. A new air bubble is then needed to re-raise the mineral particle into the foam layer. This reduces the rate of flotation, low air efficiency and,. excess air mechanically lifts more worthless minerals into the foam

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25 and substances.

F-patent 78628 discloses a flotation machine in which a downwardly tapering wedge-shaped or conical .v foam mattress for adjusting the volume and / or area of the foam is installed. By means of the adjusting member ': 30 the foam mattress becomes thick and, at the same time, the foam is directed upwardly towards the walls of the frothing machine and the discharge chutes connected to the walls.

I 115447 3

From Fl patent 88268, a foaming machine is known in which a slurry space, substantially below the foam bed formed in the foaming machine, is provided with at least one control member so that the free surface area of the foaming machine substantially at least below the foam bed Hereby, the rate of foam formation by air bubbles containing mineral particles can be increased because the volume flow rate per unit area of air bubbles containing mineral particles increases as the free space decreases. In addition to increasing the rate of foam formation, the invention seeks to accelerate the recovery of foam from the foam mattress 10 from the flotation cell. However, the apparatuses of the above solutions take up space over the entire volume of the cell and do not appear to contain a sufficiently inexpensive solution to support the foam mattress and facilitate dispensing.

The object of the present invention is to provide a novel solution which avoids the disadvantages of the prior art. In particular, it is an object of the invention to facilitate the continuous extraction of the foam from the flotation cell, wherein at least one ... support element for facilitating the release of the foam layer and supporting the foam layer is provided at the top of the foam cell.

:: 20 '··· * The invention is characterized by what the independent claims; ”· Is indicated in the character sections. Other embodiments of the invention are characterized by what is stated in the other claims.

* · 25 Significant advantages are achieved by the apparatus and method of the invention! The foaming apparatus of the invention for foaming minerals or the like from slurries containing these particles comprises a flotation cell having edges and a bottom and a .v mixing mechanism disposed in the flotation cell. Further, the flotation apparatus comprises means for introducing air into the cell and means for feeding the foamable material into the cell and removing it from the flotation cell. To support the foam layer and facilitate its dispensing from the cell, at least one support element is provided at the top of the cell 115447 4 t. Depending on the concentrate to be processed and the size of the cell, the required number of support elements is required. The support element may be formed of one part or may be composed of many parts.

The support element may be formed from the edge of the cell or may be a separate part to be attached to the edge 5. The shape of the support element is preferably serrated, wavy or the like. The support element facilitates the continuous dispensing of mineral foam from the cell to the discharge chutes. In particular, foaming of low-content ores is facilitated, whereby the slurry edge is too long in relation to the required concentrate production, and foaming becomes more difficult due to foam collapse.

In addition, flotation of ores is particularly facilitated where, due to the high viscosity of the slurry, not much air can be dispersed in the slurry. In this case, due to the small amount of air, the foam does not rise over the edges, although the foam layer is well formed with support at the edges of the cell. For the foam to successfully protrude from the honeycomb, the foam edge must have only a limited length for a given 15 concentrate production. The support element according to the invention then assists in retaining the already formed foam layer in the pile and outputting the cell.

Certain concentrate production in flotation successfully also requires a certain slurry edge length in the cell. Excessive slurry edges, such as low-content ores, may result in •:: 20 collapse of the foam layer. By using a saw blade, wavy or similar support element; ··, a suitable foam edge length is seen at the top of the flotation cell to successfully remove the foam from the cell.

··· 'The support element allows the foam edge to be adjusted to the desired length. , for concentrate production. In this case, the length of the foam edge will change continuously from zero to · 25 to 100% of the length of the slurry edge when the slurry surface “! *” Underneath the foam is raised. The support element can be used to find a suitable slurry surface height * »that corresponds to the optimum ether edge length. When the length of the optimum ether edge is reached, the flotation process proceeds without breaks, which are often due to the foam collapsing. The solution according to the invention is easy to implement and inexpensive. By saving on possible process interruptions already at one cell, the flotation maintained by the entire cell series is facilitated.

I 115447 5

The invention will now be described in detail with reference to the accompanying drawings.

Figure 1 Equipment according to the invention 5 Figure 2 Equipment according to another embodiment of the invention

Figs. 1 and 2 show the flotation apparatuses 1 and 15 according to various embodiments of the invention. In the flotation apparatus 1 shown in Fig. 1, the support element 6 has a serrated shape. Fig. 2 shows another embodiment of the invention according to which the support element 14 has the shape! 10 wavy. In the flotation cell 3 with edges 2 and the bottom 10 is treated slurry 13 which is guided to the cell 3 from below. The figures do not show the mixing mechanism inside the flotation cell, nor the devices for introducing air into the cell, since it too is inside the cell. As air is added, as foaming proceeds, a foam layer 5 is formed on the surface of the slurry layer 13, the formation of which, as the foam layer 5 rises in the cell 3, is supported by the support elements 6 and 14 of the invention. to the upper edge 4 using fastening means, for example bolts. By means of the support elements 6 and 14, the change of the foam edge length 7 as the slurry surface 11 20 rises is monitored and adapted to the desired concentrate production. The length of the foam edge ·, · changes continuously from zero to 100% of the slurry edge length 8 as the slurry surface 11 is raised. When a suitable foam edge length 7 is obtained by means of a serrated or corrugated support element, a suitable slurry surface height 9 corresponding to the optimum ether edge length can be found. By knowing the length of the optimum ether edge 25, it is facilitated by the continuous discharge of the foam from the cell 3 to the outlet ridges 12 adjacent to the upper edge 4.

It will be apparent to one skilled in the art that various embodiments of the invention are not limited to the examples above, but may vary within the scope of the appended claims.

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Claims (12)

A flotation plant (1,15) for flotation of minerals or the like from sludge containing these particles, said flotation plant comprising a flotation cell (3) with edges (2) and a bottom (10) and a stirring mechanism arranged in the flotation cell, supplying devices of air to the cell and means for feeding the material to be flotated into and out of the flotation cell, characterized in that at least one support element (6,14) which facilitates removal of the foam layer (5) and supports the foam layer (5) has been arranged in connection therewith. to the flotation cell (3) Upper edge (4). Flotation system according to claim 1, characterized in that the support element (6,14) consists of a part. in Flotation system according to claim 1, characterized in that the support element (6,14) consists of several parts. Flotation system according to claims 1-3, characterized in that the supporting element (6.14) forms part of the edge (2) of the cell (3). : · 1 20 Flotation system according to claims 1-3, characterized in that the supporting element (6,14) consists of a separate part which can be attached to the cell; / (3) side (2). ♦ · • », 25 Flotation system according to any of the preceding claims, characterized in that the supporting element (6) is substantially serrated. * » Flotation system according to claims 1-5, characterized in that the support element (14) is substantially road-shaped. :; 30 Flotation system according to any of the preceding claims, characterized in that a change in the length of the foam bed edge (7) steplessly from noil to one hundred percent of the length of the sludge edge (8) can be observed when raising the sludge surface (11). Flotation system according to any one of the preceding claims, characterized in that the suitable height (9) of the sludge surface corresponding to the length of the optimal sludge edge can be searched by means of the support means (6,14). A method for flotation of minerals or the like from sludge containing these particles with a flotation plant (1,15) comprising a flotation cell (3) with edges (2) and a bottom (10), a stirring mechanism arranged in the flotation cell, devices for supplying air into the cell and means for supplying the material to be flotated into and out of the flotation cell, characterized in that the foam layer (5) is supported and removal thereof is facilitated by at least one supporting element (6,14) arranged in connection with it. flotation cell (3) Upper edge (4). 11. A method according to claim 10, characterized in that the length (7) of the foam bed edge is continuously changed from noil to one hundred percent of the length of the sludge edge (8) when the sludge surface (11) is increased. : 20 A process according to claims 10-11, characterized in that the sludge surface; · [Suitable height (9) corresponding to the length of the optimal sludge edge is searched for; / using the support element (6.14). • ·> · <»1 · I