MXPA96004519A - Method and cell for floating mining - Google Patents

Abstract

Method and cell for separating and recovering valuable minerals from a mineral pulp in an aqueous medium, by floating the desired minerals in foam generated by adhesion of air bubbles to the desired mineral particles, which bring said particles to the surface where they are deposited. they hold in the form of foam, to be recovered, by passing the pulp in aqueous medium, through a sloping channel having a porous bottom wall, and to pass a current of air through said porous bottom wall, in order of creating bubbles in all its extension, and causing the adherence of air bubbles to the hydrophobic particles, as the pulp goes down, through said channel, to finally recover the desired minerals in the foam, separating them from the residue hydrophilic

Description

METHOD AND CELL FOR FLOATING MINERALS. BACKGROUND OF THE INVENTION. A. FIELD OF THE INVENTION. The present invention relates to a method and a cell for flotation of minerals in foam and, more specifically, to a method and a cell for separating and recovering desired minerals from a mineral pulp, by floating the desired minerals in foam generated by adhesion of air bubbles to the desired mineral particles, which bring said particles to the surface where they are held in the form of foam, to be recovered. B. DESCRIPTION OF THE RELATED ART. There are various methods and devices for the separation of valuable minerals, from a mineral pulp, which depend on the particular characteristics of the minerals that are to be separated. One of the most effective methods for the separation and recovery of valuable minerals, is the foam flotation process, which is based on making, in a generally aqueous medium, mineral particles with a surface that, by its nature or by modifications on its surface, it is water repellent, adhere to air bubbles injected into the medium, so that they bring the particles to the surface and hold them in foam form for their separation from the rest of the pulp. It is widely known that in order to achieve the flotation of a mineral, in addition to creating the appropriate surface conditions between the mineral particles and the liquid-air interface, it is fundamental that particle-bubble contact exists, which has been the main concern in the design of all flotation cells. One way to achieve this goal has been by means of a rigorous agitation of all the constituents of the pulp, which allows the particles to be kept in suspension so that they can be mixed with the air bubbles increasing the possibilities of contact. However, the conditions are very turbulent, causing a strong friction between the particles and bubbles, which causes the detachment of particles already adhered to the bubbles. In addition, since the bubbles travel in the same direction as the bubbles, it is necessary to give them long times to reach and affect the contact. In recent years, cells have been designed to eliminate the turbulent action of agitation, making the pulp of the descending ore and the rising air bubbles flow countercurrently, but this system still causes a lot of friction, mechanical drag and losses due to obstruction and they require delicate control equipment. However, they tend to increase the probability of particle-bubble contact and the friction is much less than in the agitation, achieving better results in most cases. In other models of cells, it has been tried to diminish these effects, using pulp-bubble mixers before the cells where particle-bubble adhesion occurs, and the mixer goes to the cell, which acts only as a separating medium, but no contact.

Based on the observations described, we sought to reduce the harmful effects on flotation caused by the same cells, increasing efficiency and reducing operating costs through an inventive concept that the pulp and bubbles travel in the same sense in a laminar flow. Devising conditions of minimum friction and turbulence, but with greater possibilities of contact, the applicant came to establish that these conditions would be reached in a flow of pulp that should pass through an air curtain. The air curtain would be formed by air bubbles rising up the bottom of a channel, through which the mineral pulp flows, so that the laminar flow would drag the bubbles in the same direction, considerably reducing friction, and the compact curtain of bubbles would increase the probability of particle-bubble contact. The basis of the new cell prototype in which it was intended to reach, mainly the reduction of operating costs and equalize or improve the efficiency of the separation with the current cells, is a channel that has a perforated or porous bottom wall, through which the air is injected, creating the air curtain, while the mineral pulp flows on the bottom of the channel, crossing the curtain, whereby the hydrophobic particles adhere to the bubbles and are carried to the surface where they float in a foam that moves in the same direction as the pulp, while that the hydrophilic particles pass through the air curtain and follow their natural flow to the discharge of the channel. The dimensions of the first prototype were determined based on a channel in its simplest form for the gravimetric concentration, to which a fixed box was attached to the bottom to act as an air chamber in which it would be injected the air continuously at a suitable pressure, while in the discharge two separators are placed, one for the concentrate that goes in the foam and the other for the "tailings". The size of the holes or the porosity of the bottom wall and its distribution can be determined based on the characteristics of the pulp, it being desirable that the holes or pores and their distribution be as small as possible. The flotation conditions were taken as a base on a mine that had been tested in conventional laboratory cells, and in which were established particle size, times, reactive dilutions, etc. Because the capacity of the canal was much greater than the capacity of the laboratory cell and to have bases of comparison, a circuit was designed for the flow of the products, which had to be recycled to give them the same times of floatation. To date, the following conclusions about the operation of the cell have been obtained. • The inclination of the cell is a function of the particle size.

• The air pressure is a function of the height or level of the pulp. • The cell has worked better with fine particles. • The smaller the holes or pores of the air supply, the better separations are obtained. • The speed of the pulp has been evaluated based on the precipitation of the solids and not on its influence on particle-bubble adhesion. • Several factors such as inclination, speed and air pressure influence the discharge of the foam. • The height of the pulp influences the speed of movement. All the factors and variables require a careful study, since all of them play an important role in the operation of the cell, so the influence of each of them will be a broad topic of study that should be evaluated individually, as well as global way with the other variables. SUMMARY OF THE INVENTION: It is therefore a principal objective of the present invention to provide a method for flotation of minerals in foam, to separate and recover valuable minerals from a mineral pulp, by passing a pulp in aqueous medium, through an inclined channel having a perforated or porous bottom wall, through which a stream of air is passed, which creates a curtain of bubbles in all its extension, in order to adhere air bubbles to the particles, as that the pulp is going down, through said channel.

It is also a principal object of the present invention to provide a method for flotation of minerals in foam, of the nature described above, wherein the pulp is passed through a curtain of air bubbles rising in the channel, through the which flows the pulp, so that the laminar flow drags the bubbles in the same direction, considerably reducing friction, increasing the probability of particle-bubble contact. It is still a principal objective of the present invention to provide a method for flotation of foam minerals, of the nature previously described, which presents greater probabilities in the treatment of fine particles. It is further a main objective of the present invention to provide a cell for flotation of minerals in foam, for separating and recovering valuable minerals from a mineral pulp, comprising an inclined channel having a perforated or porous bottom wall, through which is made to pass a stream of air, which creates a curtain of bubbles in all its extension, in order to adhere air bubbles to the particles, as the pulp goes down, through said channel. It is still a principal object of the present invention to provide a cell for flotation of foam minerals, of the nature previously described, which does not require mechanical agitation and therefore eliminates the turbulent action of agitation.

It is still a principal objective of the present invention to provide a cell for foam flotation of minerals, of the nature previously described, in which the maintenance and operation costs would be minimal and which does not require expensive control equipment. These and other objects and advantages of the present invention will be apparent to those skilled in the art from the following detailed description of the embodiments of the invention, which is provided in combination with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS. Figure 1 is a conventional perspective view of the cell for separating and recovering valuable minerals from a mineral pulp in an aqueous medium of the present invention; and Figure 2 is an exploded view of the cell illustrated in Figure 1, showing all its constituent parts. DESCRIPTION OF THE SPECIFIC PROCEDURES OF THE INVENTION. In its most general aspect, the method for separating and recovering valuable minerals from a mineral pulp in an aqueous medium, of the present invention, comprises passing the pulp in aqueous medium, through a downward inclined channel, having a porous background wall; passing a current of air through said porous bottom wall, by means of an air chamber connected to a source of pressurized air, which is coupled to the lower surface of the porous bottom wall, in order to create a curtain of air. bubbles in all their extension, to adhere air bubbles to the particles, as the pulp passes downwards, through said channel; and recover the hydrophobic mineral from the pulp, which floats like a foam, from the hydrophilic residues of the pulp. The separation and recovery of the minerals, in the foam, is normally carried out by overflowing in the upper part of a gate provided at the lower end of the channel, while the hydrophilic residues of the pulp are extracted through an outlet in the lower part of the gate.

The cell for separating and recovering valuable minerals from a mineral pulp in an aqueous medium, of the present invention, will be described below with reference to the specific embodiments thereof, illustrated in the accompanying figures, wherein the same numbers refer to the same parts of the figures, and comprises: a rectangular channel C inclined, having and having an upper end ES and a lower end El, consisting of two vertical side walls 1, 2, and a rear wall 3 at its end upper ES, having an inlet opening 4 to which a duct T coming from a reservoir D is connected to feed the pulp P that will run downwards, towards the lower end of the C channel; a porous bottom wall 10, of any suitable commercially available material, coupled to the lower part of the vertical side walls 1 and 2, and to the rear wall 3; an air chamber 20 coupled to the bottom surface of the porous bottom wall, which is constituted by two side walls 21, 22, a rear wall 23, a front wall 24 and a bottom wall 25, having the walls 21, 22 , 23 and 24 surrounding the chamber, a flange 26 at its upper part, for coupling to the porous bottom wall 10, by means of screws, rivets or the like, and an air inlet 27, in any of the walls of the chamber 20 , to which a source of pressurized air is coupled (not shown); and a gate 30 at the lower end of the channel 10, which has an upper overflow portion 31, to remove the foamed mineral F, and a lower opening 32, to which a conduit 33 is attached to remove the dense debris R of the pulp P. In a mode of the porous bottom wall 10, this may consist of a plate with extremely small perforations or extremely fine grooves, in order to create the air curtain along its entire length through which it will pass. Pasta. This perforated or slotted plate may also include, if desired, a layer of porous material on its upper or lower surface, to further reduce the sizes of the perforations or grooves. Likewise, it should be understood that the channel may adopt a "half-round" shape, with a "half-round" air chamber, or any other form that may be appropriate.

Therefore, it should be understood that the described and illustrated modalities are not restrictive of the invention and that they only serve to interpret their inventive concept, so that experts in the field may introduce changes in the design of the constituent parts of the invention that, however, they will be contained within the true spirit and scope of the invention which is claimed in the following claims. R E I V I N D I C A C I O N E S. 1. Method for separating and recovering valuable minerals from a mineral pulp in an aqueous medium, by floating the desired minerals in foam generated by adhesion of air bubbles to the desired mineral particles, which bring said particles to the surface where they are deposited. they hold in the form of foam, to be recovered, characterized in that it comprises passing the pulp in aqueous medium, through a sloping channel having a porous bottom wall; passing a current of air through said porous bottom wall, in order to create a curtain of bubbles in all its extension, to adhere air bubbles to the particles, as the pulp goes passing downwards, through said channel; and recover the particle of the desired mineral, from the foam, separating it from the residue of the pulp. 2. Method according to claim 1, characterized in that the porous bottom wall consists of a plate of porous material. 3. Method according to claim 1, characterized in that the porous bottom wall consists of a perforated or grooved plate. 4. The method according to claim 1, characterized in that the porous bottom wall, consists of a perforated or slotted plate, which has a porous layer on its upper or lower surface. 5. A cell for separating and recovering valuable minerals from a mineral pulp in an aqueous medium, by floating the desired minerals in foam generated by adhesion of air bubbles to the desired mineral particles, which bring said particles to the surface where they are held in the form of foam, to be recovered, characterized in that it comprises: a sloping channel having a porous bottom wall; and means for passing a stream of air through said porous bottom wall. The cell according to claim 5, characterized in that the inclined channel is rectangular and has an upper end and a lower end. The cell according to claim 5, characterized in that the inclined channel is rectangular and has a rear wall at its upper end, which has an inlet for the pulp. The cell according to claim 5, characterized in that the inclined channel is rectangular and has a gate at its lower end, for separating the hydrophilic residues, from the hydrophobic mineral in the foam. 9. The cell according to claim 5, characterized in that the inclined channel is semicircular or planar cross section. The cell according to claim 5, characterized in that the means for passing a current of air through the bottom wall n porous, consists of an air chamber coupled to the bottom surface of the porous bottom wall, to which a source of air under pressure is coupled.

Claims (1)

1. SUMMARY METHOD AND CELL FOR FLOATING MINERALS. Method and cell for separating and recovering valuable minerals from a mineral pulp in an aqueous medium, by floating the desired minerals in foam generated by adhesion of air bubbles to the desired mineral particles, which bring said particles to the surface where they are deposited. they hold in the form of foam, to be recovered, by passing the pulp in aqueous medium, through a sloping channel having a porous bottom wall, and passing a current of air through said porous bottom wall, in order to create bubbles in all its extension, and cause the adherence of air bubbles to the hydrophobic particles, as the pulp goes down, through said channel, to finally recover the desired minerals in the foam, separating them from the residue hydrophilic pulp.