US2290892A - Wet magnetic separation - Google Patents

Description

"July 28, 1942'. A. L. .1. QUENEAU WET MAGNETIC SEPARATIQN `Filed Nov. 15,` 1940 l l I July 28, 1942.

A. L. J. QUENEAU wET MAGNETIC SEPARATION 2 Sheets-Sheet 2 Filed Nov. l15, 1940 Patented July 28,1942

UNITED STATES PATENT GFFICE WET MAGNETIC SEPARATION Augustin Leon Jean Queneau, Peapack, J. Application November 15, 1940, semi No. 365,837-

' s claims. 101.2094214) trating is eiected by the wet magnetic separation of the feebly magnetic vmineral from the relatively nonmagnetic material. However, the principles of the invention may be applied whenever the magnetic concentrates obtained by the wet magnetic separation method from a mixture of relatively magnetic and-nonmagnetic particles include such a high percentage of the nonmagnetic particles as torender the separation -im practical, it being obvious, however," that this problem is more troublesome. when the relatively magnetic particles are of lowv magnetic permeability.

A speciiicexample of a wet magnetic separator constructed to operate in accordance with the invention is illustrated by the accompanying drawings, the various `gures being as follows:

Figure 1 is a top view. Figure 2 is a vertical-section on the line lI-II in Figure l1; and l Figure 3 is an enlarged a detail.

More specically, these drawings show opposed poles i magnetically energized by solenoids 2 and provided with revolving pole pieces 3 working in line with the magnetic iield about horizontal section oi horizontal axes and provided with radial extensions 4. There is a gap between the extensions I of the respective pole pieces 3, but except for .this the magnetic circuit is closed by a yoke 5, the

arrangement of the entire magnetic system being such as to produce a concentrated magnetic ileld lbetween the opposing extensions of the respective revolving pole pieces, this iield varying from a maximum when the extensions are substantially horizontal to a minimum when the extensions are *substantially vertical.

Avertical separator box i extends down between the extensions I of the revolving pole pieces 3, this box .having .arcuate recesses 6* in which-the pole pieces vwith their extensions work,

this arrangement permitting a relatively small trates-collecting chambers Il. box B is open and is provided with an overflow |2, the wet pulp being introduced at a 'rate replate-S, and ,side outlets l leading to concen- The top of the specting the rate of ilow permitted by the orifice plate 9, to build up a head in the box '6 to the i extent permittedby the position of the overflow In operation, assuming the wet pulp to be in the box 6 at a level dictated by the overflow I2,

downward revolution of the pole pieces 3 eiected in the case of the illustrated machine by'driving the shaft I 3 working the pole pieces 3' through a gear train I4, causes the relatively magnetic material to be drawn transversely outwardly from the pulp stream owing through the gorge between the recesses 6' and dropped oppositely outwardly,.t he tailings continuing to ow downwardly so as to eventually leave by way of the oriflce plate 9. It is to be understood that this separation of the magnetic concentrates is efi fected by reason of the concentrated magnetic In the operation of this separator and of other wet magnetic separators of an equivalent type, a problem is presented in that too high a percentage of the relatively nonmagnetic material separates from the pulp stream along with the relatively magnetic particles into the concentrates now. -Efforts have been made to exclude gap between the extensions 4 and permitting the attainment of amagneti'cv neld of the proper concentration to work on feebly magnetic material such as hematite. A wet pulp of the ore or other mixture to be concentrated is'introduced to the top of the box 6 by way of an inlet 1, the

bottom of the box below the magnetic rleld having a central outlet 8 through which the tailings constantly now under the control ot an orince the nonmagnetic particles by introducing liquid to either the collecting chamber Il or the lower portions ofthe box 6 inside the baiiies l5, for the purpose of creating counterflows of liquid leaving the spaces between the tops of the baiiles I5 and the recesses 6" of the box, it thus being necessary forthe concentrates'to ow'against this liquid counterow. The idea is that this will exclude the relatively nonmagnetic particles so that more will be carried away with the tailings, as they should be. This practice has not' met with success.

The present invention is characterized in that the liquid columns coniined by the collecting chambers Il and all other portions of the equipment up to the spaces between the tops of the bames I5 and the box recesses 6*, are maintained static in the sense that no withdrawal of either liquid or concentrates is permitted which will produce an exiting flow, nor is any additional liquid introduced in the manner lust previously discussed. However, the oriiice plate `8 remains so that there is a gravitational pulp flow through the gorge of the box 8 with the static liquid columns to either side of this pulp flow and communicating with the latter by way of the spaces between the baille tops and the box recesses,

these spaces being hereinafter considered as entrances to the static liquid columns.

Now, when thepole pieces are revolved while the pulp is flowing through the box gorge under the iniiuence of the head dictated by the'overiiow l2, magnetic concentrates are separated in the form of iiows traveling through the entrances to the static liquid columns, the concentrates flows displacing the liquid, rendering the static columns dynamic and producing counterfiows out from the entrances which, being restricted, function as orices and most eiiectively exclude nonmagnetic particles since the liquid counterilows opposing the entrance of the concentrates iiows to the previously static columns are of exactly balanced volume respecting the concentrates ilows. Furthermore, by properly restricting the size of the entrances, as by adjusting the heights of the bailies l5, the areas of the entrances to the otherwise static columns can be correlated to the entering concentrates flows so that the liquidcounterilows and the concentrates flows have -the same velocities. x v

It might be mentioned at this point that the battles I5 are removable so that they can be substituted by others of diiierent heights, and their positions are adjustable horizontally as indicated by the broken lines in the drawings, the lower portion ofthe box 6 being. provided with a series of grooves |55 for receiving the bailies. The exact heights and horizontal position ,of the banles Al5 can'be determined only by experience, their adjustment being but one of the many variables that can be adjusted in the case of the separator disclosed herein.

' 'I'he other variables mentioned above include the pulp density, which is determined by the provportioning of the liquid and the ground ore or other mixture of materials: the velocity of the iiowing pulp through the box gorge, which is determinable by the size of the orifice in the oriiice plate 9; the speed of the downwardly and transversely outwardly revolving magnetic field which is determined by the revolving speed of the pole pieces 3; the correlation between the moving speed of the pulp as compared to the revolving sneed oi' the magnetic iield; and the concentration of the magnetic iield. which'is determined by the current in the solenoids 2 and the size of the magnetic gap between which the pulp flows. These/'are in addition tothe adjustment of the horizontal positioning of the baffles I5 and their P concentrates that'havecollected. from the bottoms' of the collecting chambers Il'. In accordthe counterflows being ejected from the entrances into the pulp flows so las to travel' with the tailings, and the incoming concentrates iiow.

With the above in mind, the exits to the collecting chambers Il are in the form of rotating box valves I6 emptying through pipes I6n into liquid in tanks I1 from which the concentrates are ultimately removed by bucket conveyors i8 of the continuous type. Liquid is constantly introduced `into tanks I1 by way of pipes I9, the liquid constantly overflowing through overflows 20 and the liquid levels thereby being maintained in the tanks I1. With this arrangement, rotation of one of the boxes of one of the valves I6 which'is filled with concentrates causes these concentrates to dump through the pipe I6* into the liquid in the tank l1, the liquid rising and filling this box so that when it is ultimately returned to a concentrates receiving position it is filled with liquid which is displaced into the collecting chamber with which the valve is in connection.- In this Way the two liquid columns on either side of the tailing ow are maintained under static conditions except for the liquid movement caused through displacement by the entering concentrates flow.l

Experience has shown that once the various l variables are set, the magnetic concentrates separate from the pulp with a much lower percentage of nonmagnetic particles of material which properly belong in the tailings than can possibly be attained' when the counter ows are created bythe constant introduction of liquid. regardless of what care is taken in regulating this introduction. However, itl is conceivable that some of the. advantages of this invention might beattained by carefully balancing the introduction of liquid as compared to the entering concentrates flow to provide a balanced counterflow for -these concentrates. In practical workthis balancing is impossible except by rendering static the columns of liquid into which the magnetic concentrates fall and permitting the counterfiows to be caused solely by the concentrates displacing the liquid in these otherwise.

static columns.

I claim:

1. A wet magnetic separation method including producing a gravitationally iiowing column of a mixture of relatively magnetic and nonmaglnetic particles in liquid, producing a static co1- umn of liquid with an opening transversely communicating with said fiowing column, magnetically drawing a magnetic concentrates flow from said flowing column through said opening into said static column and rendering said static column dynamic solely by allowing said concentrates flow to gravitationally displace liquid therefrom into said flowingr column through said opening, thereby causing said concentrates flow to enter said opening through a liquid counteriiow in substantial volumetric balance therewith, the size of said opening and the volume of said concentrates ii'ow being correlated to cause said counteriiow to exclude tailingsv from said concentrates flow through said opening.

ance'with' the invention, this is done so that as bers, whereby tol preserve thel balance between' 2. A wet magnetic separation method including producing a gravitationally 'flowing column of a mixture of relatively'magnetic and nonmagnetic particles in liquid, producing a static column of liquid with an opening transversely communicating with said flowing column, magnetically drawing a'magnetic concentrates ow from' said flowing column through said opening into said-static columnv and rendering said static column dynamic solely by allowing said concentrates ow to gravitationally displace liquid therefrom into said fiowing column through said opening; thereby causing said concentrates flow to enter said opening through a liquid counterflow in substantial volumetric balance therewith,

the size of said opening and the volume of saidl concentrates flow being correlated to cause said counterflow to exclude tailings from saidconcentrates ow through said opening, collected concentrates being removed from the second gravtationally owing columnfof said pulp, prof ducing column, creatinga concentrated magnetic Iield that repeatedly cuts said owing column transversely and revolves downwardly through said opening while reducing in force, thereby drawnamed liquid column while simultaneously subing concentrates of said mineral through' said opening into Athe second named column and prosaid opening by v ducing a counteriiow through displacement action, the second column being rendered dynamic solely by said displacement,y maintaining said opening at a size causingfsaid ccunterilow to have a velocity excluding tailingsof said material therefrom and removing concentrates from the second named column while-1 simultaneously adding equal volumes of liquid.

AUGUSTIN LEON JEAN QUENEAU.

a static column oi liquid with an opening transversely communicating with said flowing

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