RU2015731C1 - Pneumatic floatation machine - Google Patents

Abstract

FIELD: mechanical engineering. SUBSTANCE: machine has a vertical cylindrical column, a pulp load device, a chamber product unload device, a telescopic pipe located along the axis of an apparatus and an air inlet device. Moreover, the machine has an inclined partition, a conical distributor and aerators. The column is made from two chambers. The cross section area of the upper chamber is larger than that of the lower chamber. The aerators are positioned above the inclined partition, the conical distributor and under the edge of the telescopic pipe. The upper chamber has a foam spraying device, and the load and unload devices are positioned in the lower chamber above and below the inclined partition respectively. EFFECT: improved structure. 2 cl, 1 dwg

Description

 The invention relates to the beneficiation of minerals and can be used in the beneficiation of coal, mining raw materials, and non-ferrous metal ores.

 It is known that pneumatic column flotation machines have shown their advantages, especially when enriching finely dispersed mineral raw materials.

 To increase the efficiency of enrichment of both fine and large mineral particles in recent years, a number of column machines have been proposed in which the pulp is aerated with a water-air or pulp-air mixture obtained outside the flotation chamber by ejecting air with a stream of water with a foaming agent at a pressure of 170-330 kPa.

 The disadvantage of these devices is the high consumption of compressed air for pulp aeration, as well as the need for many additional structural elements to increase the uniform distribution of aeration over the column section, such as pipes of various lengths, perforated plates, a set of concentric, radial and annular barriers.

 The closest in technical essence and the achieved results is a pneumatic flotation machine comprising a cylindrical chamber for separating foam and chamber products, having an annular threshold and an external annular chute for collecting the foam product. The bottom of the chamber is made inclined and in its lower part there is an unloading device for the chamber product. A central stilling pipe enters the chamber through an inclined bottom, in the lower part of which an aerator is located in the center, through which a pulp-air mixture is supplied. To adjust the height of the foam layer, the distance between the upper edge of the stilling pipe and the level of the annular threshold can be changed using a telescopic device on the central pipe.

 A disadvantage of the known device is the high energy consumption for ejection of air during the generation of the pulp-air mixture and the relatively low activity of flotation of large and hard-to-float particles in the chamber of the machine due to the lack of additional aeration.

 The aim of the invention is to increase the specific productivity of the machine by improving the flotation of mineral particles of a wide range of particle sizes.

 This goal is achieved by the fact that in the pneumatic flotation machine column type mounted inclined partition separating the flotation compartment from the loading device. The column is made in height of two chambers, while the cross-sectional area of the upper chamber is larger than the cross-sectional area of the lower chamber.

 Along the axis of the apparatus is a telescopic pipe for power supply with a bell in the loading device, designed for airlift loading of pulp. Opposite the bell is a device for introducing transport air. In the upper chamber, under the upper edge of the telescopic tube, pneumatic type aerators are placed in an annular manner near the inner wall of the housing. Aerators are mounted above a cone-shaped pulp feed distributor.

 The lower chamber is equipped with aerators in cross section above the unloading device.

 A foam irrigation device is installed in the upper chamber.

 Comparative analysis with the prototype shows that the proposed device differs from the known one in that the pneumatic flotation machine is equipped with an inclined partition, a cone-shaped distributor and aerators, the column is made of two chambers, while the cross-sectional area of the upper chamber is larger than the cross-sectional area of the lower chamber, the aerators are located above the inclined partition , cone-shaped distributor and under the upper edge of the telescopic pipe. In addition, in the prototype there are no such signs as the presence of devices for irrigation of foam, and the loading device for the pulp and the unloading device for the chamber product are located in the lower chamber, respectively, lower and higher than the inclined partition.

 This allows us to conclude that the proposed device meets the criterion of "novelty."

 It is known to use airlifts in flotation machines, for example, where the airlift serves as the only aeration device. The water-air mixture before the spout from the airlift is a coarse system.

 Further dispersion of the air plugs occurs when they hit the baffle plate and cascade spout into the side compartments of the camera.

 The machines did not find wide industrial application, mainly because of the difficulty in controlling the hydrodynamics of the flotation process in them. As a rule, in such machines, a plug mode of movement of a two-phase mixture and irregular aeration of the pulp are inevitable.

 In machines created in recent years, airlift is most often used for transporting pulp in order to create an alternation of countercurrent and direct-flow movement of pulp and air.

 In the proposed machine, the airlift is used as a pulp elevator, but at the same time, it is also preliminarily partially (15-20%) saturated with air, i.e. activation, conditioning immediately before the flotation process.

 Although some of the other distinguishing features of the proposed solution have also been previously used in other known solutions, the new set of essential features in the proposed solution gives a new effect, which is confirmed by the explanations following the description of the operation of the device.

 The drawing shows a flotation machine, a General view in section. Vertical column 1 consists of two cylindrical chambers: lower 2 smaller diameter and upper 3 with a larger cross-sectional area. A telescopic pipe 4 of the airlift loading is placed on the axis of the apparatus, ending at the bottom with a bell 5, against which an air inlet device is installed at the lower point of the column body. In the upper chamber 3 above the airlift loading pipe 4, a cone-shaped distributor 6 of the pulp-air mixture is movably mounted, together with the pipe. Below the edge of the airlift pipe 4 at the inner wall of the upper chamber 3 are mounted aerators 7 pneumatic type; a part of similar aerators 7 is also mounted above the cone-shaped distributor 6. The upper chamber 3 is equipped with a device for irrigation of foam 8 and an annular groove 9 for collecting the latter.

 The device operates as follows. The pulp treated with reagents is fed through the loading pipe 11 under the bell 5 of the airlift pipe 4, from where it is transported from below to the upper chamber 3 of the column 1. In the airlift pipe 4, the formation of a pulp-air mixture and partial saturation of the pulp with air (activation). The depth of entry of the pulp-air mixture is regulated by an airlift pipe 4, arranged telescopically. The pulp-air mixture ejected from the airlift 4 using a cone distributor 6 is distributed evenly over the cross section of the chamber 3 in the form of upward flows. In this “suspended” state, the pre-aerated pulp interacts with air bubbles generated by pneumatic aerators 7 located annularly at the inner wall of the chamber 3 and above the cone distributor 6. The formed flotation complexes in the foam layer are washed with water using an irrigation device 8, which improves separation hydrophobic and mechanically entrained hydrophilic particles. A hydrophobic material with foam enters the annular foam trough 9 and is removed as a concentrate, and hydrophilic and less hydrophobic particles are lowered into the bottom chamber 2 for doflotation. Here, they additionally interact with air bubbles generated by aerators 13. Hydrophobic particles entering the doflotation zone form flotation complexes and are removed with foam into the concentrate, and hydrophilic particles into the chamber product discharged through pipe 12.

 Comparison of the proposed machine with the prototype allows us to conclude that the new technical solution makes it possible to increase the flotation activity of mineral particles of a wide range of particle sizes. In the prototype machine, pulp aeration is carried out once - in the aerator located in the lower part of the column, and then the pulp-air mixture formed in the aerator is fed into the central stilling pipe and then into the chamber where the separated particles are separated from the foam layer. Those particles that could not stay on air bubbles in conditions of significant turbulence (mainly large, as well as less hydrophobic particles) do not get into the foam and are removed with the chamber product, which leads to a decrease in the specific productivity of the machine.

 In the proposed machine, pulp aeration is carried out in three stages (in three zones). Primary aeration of 15-20% of the total required air volume occurs during airlift pulp rise. This aeration is not sufficient for flotation, but activates it. Active flotation is carried out in the upper chamber of the machine during the interaction of air bubbles generated by pneumatic aerators with mineral particles of the pulp. And, finally, additional aeration of the pulp in the lower chamber allows to float large and less hydrophobic particles deposited from the upper chamber.

 Other design features of the proposed machine contribute to the creation of optimal flotation conditions in the upper and lower chambers. Significant expansion of the upper chamber compared to the airlift pipe allows to minimize the centrifugal velocity of the pulp and air torch and to achieve a "suspended" state of the pulp during its aeration from below. The conical distributor also contributes to this. Due to the fact that the lower chamber has a smaller diameter than the upper one, the flotation conditions that are optimal with respect to pulp density are maintained.

 All the features of the proposed pneumatic flotation machine listed in comparison with the prototype provide an increase in the flotation efficiency of mineral particles in a wide range of particle sizes, which increases the specific productivity of the machine.

Claims (2)

 1. PNEUMATIC FLOTATION MACHINE, including a vertical cylindrical column, a loading device for pulp, an unloading device for a chamber product, a telescopic pipe located on the axis of the apparatus and an air inlet device, characterized in that, in order to increase the specific productivity of the machine by improving the flotation of mineral particles of a wide range of sizes, the machine is equipped with an inclined partition, a cone-shaped distributor and aerators, the column is made of two chambers, while the cross-sectional area of the upper chamber is larger than the cross-sectional area of the lower chamber, the aerators are placed above an inclined partition, a cone-shaped distributor and under the upper edge of the telescopic pipe.  2. The machine according to claim 1, characterized in that the upper chamber is equipped with a device for irrigation of foam, and the loading device for the pulp and the unloading device for the chamber product are located in the lower chamber, respectively, lower and higher than the inclined partition.

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