SU1270945A2 - Air-lift pneumatic flotation machine - Google Patents

Abstract

one.

Description

1 The invention relates to the field of froth flotation in combination with separation and can be used; enrichment of minerals 1x II regeneration of sludge water containing fine classes and granular miner. You are in the range of the density of the original feed. According to the main auth. No. 971483 1 | Aeronautical & Pneumatic Alotation Machine, consisting of one or several chambers, including a pulp-discharge pocket with an adjustable gate, a bath, vertical non-partitions, parallel bath axes forming the counter-current flotation compartments with peaks and distant bases, equipped with tubular aerators and foams, and the airlift chamber - straight-through compartment, equipped with a pulp divider 4 guiding canopies, a pulpoSO3 with a shower mixer, made in the form of a chamber with vertical partitions, emitting slurry pipelines, collectors forming a trapezoidal trench, a vertical plate installed along the axis of the trough, tubular aerators forming parallel V-shaped rows, facing upward, water-air distribution device made in the form of a triangular prism Mbi with crevices covered with elastic plates, and the countercurrent and direct precision compartments are connected by bypass devices, made in the form of nozzles, telling the bases of the countercurrent flotation compartments to the airlift slurry lines - E p of winding compartments, and provided with rotary valves installed in the branch pipes with said actuator for rotation, dampers. In the well-known aerolift-pneumatic flotation machine, the upper level of the sides of the airlift chamber is located below the upper edges of the partitions, which delimit the aeration zones and non-aeration zones of countercurrent Φ: 1 outlets about half the width of the airlift chamber. Since the level of the pulp carrying on its surface the submerged and foam layers for unloading is maintained in the mashshna chambers with the help of a gate in the pulp discharge pocket above the partitions delimiting 5 zones of aeral or non-aeration zones at 10-30 mm, 10–30 mm The release of aerated pulp from the airlift is carried out under a sub-layer formed in the flotation units. Consequently, both in the airlift and in the flotation unit, the formation of the foam layer is carried out at the expense of flotation complexes formed in the internal volume of the pulp. At the same time, the limiting size of the material enriched in the machine is determined by the weight of the particles that can be lifted into the foam layer in the composition of the flotation complexes from the internal volume of the pulp. In terms of specific productivity, the aerolift-pneumatic flotation machine exceeds the achieved level in comparison with the best flotation machines in mass production by 1.5 times, but it is inferior in terms of this indicator to the foam separation apparatus, since the process of froth separation has a shorter time duration in comparison with the flotation process from the internal volume of the pulp. In addition, in a known machine, the supply of aerated pulp with an airlift to the internal volume of the pulp, stifling countercurrent compartments, and the subsequent distribution of pulp flows in accordance with the hydrodynamics provided for in the prototype, is only possible provided that the specific weight of the aerated pulp produced by the airlift is greater the specific gravity of aerated pulp filling the aeration zones of the countercurrent compartments on the top of the upper edges of the airlift chamber. The difference in specific weights is due to the difference in the saturation of dispersed pulp air, which fills the straight airlift compartment and the countercurrent flotation compartments, taking into account that the specific gravity of the aerated pulp is inversely proportional to the air content. The need to comply with the reduced aeration of the pulp in the airlift containing pulp with the maximum participation of floated minerals leads to a decrease in production from a given performance to which the machine is tuned, it is possible to change the flow direction of the aerated pulp based on the following.

When the unregulated reduction of the load on the machine takes place, the air consumption remains unchanged, and the aeration of the pulp in the airlift accordingly increases in proportion to the decrease in its volume flow.

At the same time, in flotation sections with constant air flow, the aeration of the pulp decreases in proportion to the decrease in the flow of pulp entering the counter-flow compartments in a smaller quantity, both by reducing the overall load on the machine and by increasing the yield of frothy product from the airlift with increasing pulp aeration in him.

The decrease in aeration of the pulp in the counter-current compartments is due to the fact that, in proportion to the reduction in the volume flow of the pulp, the speed of the downward flow slowing down the ascent of air bubbles decreases. Accordingly, as the rate of ascent of air bubbles increases, the air content in the pulp volume filling the flotation unit decreases.

If, as a result of a change in the load on the machine, the aeration of the pulp in the airlift exceeds the aeration of the pulp located in the flotation compartments at the edges of the airlift chamber, then the pulp filling the countercurrent compartment and having a greater proportion due to the reduced aeration displacing the pulp coming out of the airlift, overflowing into the chamber through its sides, and the stream of pulp having increased aeration and a smaller specific gravity will rise along the axis of the airlift with a narrow stream to the level of foamy layer, producing its destabilization and destruction. At the same time, the technological performance of the machine will decrease.

The purpose of the invention is to increase the machine's productivity by reducing the destruction of the foam layer.

visors installed along the outer walls of the ram compartment with 3a3OpaNm and the possibility of vertical and horizontal movement, and V-shaped fairings installed on the outer walls of the rammer compartment and facing an angle towards the counter-current compartment, the width of which is equal to the maximum gap, the tops of the walls of the continuous compartment are installed at the same level with the tops of the partitions that delimit the aeration and non-aeration zones of the counter-current compartments, and the tops of the curvilinear visors placed under the direct-flow compartment at a height of 50-350 mm, equal to the thickness of the foam layer.

FIG. 1 shows a transverse

0 a cross section of a flow-pneumatic flotation machine; in fig. 2 - the same, side view.

The machine has one or more

5 cameras installed at the same level or cascade.

Each chamber consists of a deep rectangular bath 1, divided by vertical partitions 2 into a continuous flotation compartment 3,

0 located along the axis of the bath 1, and two countercurrent flotation compartments 4 placed between the sides of the bath 1 and partitions 2, a pulp and air mixer 5 placed under the base of the straight flotation compartment 3, curvilinear visors 6 with gaps 7, fairings 8, a pulp outlet pocket 9 and bypass devices consisting of pipes 10, butterfly valves 11 with actuators 12.

The linear flotation compartment 3 is made in the form of an air-lift and includes a rectangular chamber placed

5 between the partitions 2y along the axis of the bath 1, the pulp and air mixer 5 containing pulp-receiving pipes 13, vertical partitions 14 forming the pulpups located along

0 sides of the airlift base and having outlet slots 15, manifolds 16 forming a trapezoidal chute, located along the base along the axis of the airlift, vertical supporting plate 17, perforated tubes 18, fixed V-shaped upwardly on the plate 17 and fittings mounted on inclined walls 16 collectors in three rows in a staggered order (bottom row, with an interval close to the diameter of the pipe, and two upper rows with an interval of three times larger). The manifolds 16 and the perforated tubes 18 constitute an AeroShaft aerator. A pulpodel 19 is installed above the airlift with guiding visors 20. An air distribution bubbling device is installed by the aelift aerator, made in the form of a triangular prism 24 having a slit 22 over the base along the sides of the slit, closed with soft rubber valves 23 and fresh 24 of air. In the countercurrent flotation compartments 4, located on the sides 25 of bath 1, aerators are installed consisting of collectors 26 and perforated tubes 27 installed in three rows in a checkerboard pattern (the bottom of the SRI is at intervals close to the tube diameter , and the two upper rows — with an interval that is three times larger. Aerators have a slope from airlift to the sides of bath 1 from O to 15. Aerator collectors adjacent to V9HNA I board are located in niches formed by the expansion of the bath at the bottom. manifolds and sides of the bath in channels formed niches 28 for outlets ska remnants of profiled pulp from aeration zone: Expansion of the upper part of bath 1 is separated by vertical partitions 14, which delimit aeration and non-aeration zones, tell each other through gaps 29. Bottoms of countercurrent flotation compartments 4 are made in the form of four truncated truncated pyramids 30 having windows 31 To discharge the chamber waste, in the end part of the bath 1, a pulp-discharge pocket 32 with an adjustable gate is connected, which communicates with the window MJ5 31. The foam 1 is installed on the bath 33. The capacities of the pyramidal bottoms 30 are opposite GOVERNMENTAL compartments communicate with co-current airlift-compartment via overflow device. Pre-prepared pulp by contacting with reagents through pipelines with a hydrostatic head of the water column, approximately equal to the height of the machine chamber, enters the slurry pipes of the airlift chamber and through the outlet slots 15 under the vertical partitions 14 evenly distributed along the entire length from the two sides of the airlift base . In the flotation of pulp with a high content of thin classes, a reduced density of the initial feed is preferred. In order to avoid creating overpressure in the continuous flotation cell, the machine is filled with pulp with open nozzles 10, which is done by turning the flaps 11 to a vertical position. After the chambers of the machine are filled with pulp, the nozzles 10 overlap with flaps 1 1. At the same time, air is supplied to the aerators of the machine under a pressure of up to 2 kg / cm, passing through the collectors 16 and 26 and the aerator tubes 18 and 27 and saturating the slurry that fills the airlift flotation compartment-chamber bounded by partitions 2 and the counter-current flotation compartments 4 finely dispersed air. A hydrostatic pressure differential is created between the columns of the non-aerated pulp that fills the pipelines and the aerated filling airlift chamber. Under the influence of the hydrostatic pressure difference, the airlift continuously receives the initial power and delivers aerated pulp evenly distributed by the pulper 19 with guiding goats 20 in countercurrent flotation compartments 4. Unlike the prototype, the flow of air into the airlift increases to the limit located at the verge of turning up pulp flow in the airlift chamber to foam. The specific volume flow rate of dispersed air per unit volume flow rate of pulp required for foaming depends on many factors (nutritional density, its sieve composition, floatability of enriched minerals, used reagents, etc.) and is determined experimentally and, for example, when flocking coal with ash and coal. А15% and pulp density of 100-150 g / l within (1.5-2): 1. A three-fold arrangement of the perforated tubes 18 in the airlift tori allows such a specific air flow rate at a high machine productivity. In the process of raising the foamed pulp flow in the continuous flotation compartment of the airlift chamber bounded by partitions 2, the aeroflocs intensively form due to the thin classes due to the intensive mixing of the air-pulp mixture into the aerator area and close proximity to the aerator planes, and at the expense of granular minerals in the process of their rise in conditions of continuous contact with air bubbles in a foaming upflow. At the same time, the intensification of the formation of flotation complexes containing coarse-grained minerals is also due to the longer duration of their stay in the aerated volume of the motor compartment due to the lower rate of their rise by the upward flow due to the greater weight. In addition, the flotation efficiency in the in-line compartment increases due to the release of the smallest air bubbles from the solution, which is due to a change in hydrostatic pressure when the depth of the airlift chamber reaches 3-4 m. In countercurrent flotation compartments, the level of pulp maintains 4 The partitions 2 and partitions 14 are 10-30 mm by means of a gate installed in the pulp discharge pocket 32. Continuous aeration of the pulp pillars filling the counter-compartments 4 is formed and continuously maintained layer and submerged layer located on the surface of the pulp mirror over partitions 2 and 14 below the upper edges of the visors 6. Foamed pulp containing float complexes, part of free air bubbles and liquid layers with rock non-floated minerals, as well as a small part of floatable minerals that are not attached to the air bubbles are discharged from the aero-lift chamber into the pulp and drain chamber formed by the visors 6, the fairings 8 and the upper part of the partitions 2 from their top to the horizontal plane passing Res angles V-shaped fairing B. pulporassloechnoy chamber upflow velocity is reduced by I5-35% increase in flow area, respectively. At the same time, in the upper part of the chamber, the upward flow is transformed into horizontal, the separation of foamed pulp with accumulation of flotation complexes with reduced fluid content in the form of interlayers and non-floating minerals in the upper layers of the foam, the content of fluid and non-floating minerals in the lower layers. compared with the share participation of these components in the internal volume of foamed pulshl in the internal volume of foamed pulp in the airlift chamber, i.e. source of nutrition. The top layer of foam from the pulp layer chamber is poured over the edges of curved peaks 6 onto a previously created and continuously maintained foam layer on the surface of the pulp mirror in countercurrent flotation compartments 4. The formation of a foam layer on the pulp surface in compartments 4 is provided by aeration of the descending pulp flow in countercurrent compartments 4 dispersed air issued by perforated tubes 27.. Since the velocity of the ascending stream in the pulp layer chamber is two to three times higher than the deposition rate of minerals in the foam layer, the bulk of the floated minerals, including those with fixed air bubbles of insufficient lift, for their withdrawal into the foam layer from the internal volume of the pulp, as well as free minerals, is fed to the foam layer in compartment 4. The specific gravity of foam coming from the pulp layer chamber is equal to or close in value to the specific weight of the froth layer in flotation compartments 4. Therefore, when foam is supplied to Well, there is no destruction of the foam layer, which allows to increase the specific loads, to produce flotation followed by separation of liquid pulps and to increase the grain size of enriched minerals by 2-3 times compared with the usual flotation size, since the probability of retaining coarse minerals in the foam layer is somewhat times greater than the likelihood of their discharge into the foam layer from the internal gaps of the pulp object under conditions of turbulent flows and centrifugal forces causing the destruction of flotation complexes.

The lower layer with a high content of liquid and non-flooded minerals is poured through the sides of the airlift chamber with partitions 2, then through adjustable gaps 7 is brought into the internal volume of the pulp in compartments 4 and is directed obkatkatm 6 inclined downward in the direction of unloading chamber waste through the canals 28. At the same time, the fairings 8 prevent the dispersed air delivered by the tubes 27 from entering the gaps 7 and direct the upward flow of air bubbles obliquely upward.

During the mutual intersection of the soil, an intensive aeration of the pulp occurs through the gaps 7, which provides for the flotation of useful minerals contained in it in small quantities.

The intensity of the flow of liquid pulp passing through the gaps 7 is determined by the difference in the specific gravities of aerated pulp filling the countercurrent flotation compartments 4 and the gaps 7. When a stable foam is created in the airlift chamber, which is possible in the case of high density and high content of floated minerals in the original feed , the release of liquid from foam interlayers and non-floated minerals may be insignificant and the entire volume of the initial feed will be fed to compartments 4 on the foam layer in the form of foam. At the same time, the pulp flow through gaps 7 will be equal to yul: or close to it. In this case, the gaps 7 in the main part will be filled with liquid, and in the upper part - foam, forming a hydraulic lock with a total hydrostatic pressure equal to hydrostatic pressure of the column height

aerated pulp in the compartments 4 in the area of the pulp bed chamber. When the initial feed density changes, the content of floatable minerals and other factors that reduce foam stability, the intensity of the flow of pulp through the gaps 7 increases in order of self-regulation, which is a positive quality of the proposed technical solution.

However, the volume flow rate of the pulp through the gaps 7 also depends on

the size of the gaps, which are determined and established during the development of the optimal mode, taking into account the peculiarities of the technology of the processed mineral raw materials, specific loads, the density of the original feed, etc.

Since the level of the pulp in the compartments 4 is maintained above the partitions 14, and the proportion of non-aerated

the pulp filling the non-aerating zones between the partitions 14 and the sides of the bath 1, is greater than the specific gravity of the aerated pulp filling the compartments 4, then in the non-aerating zones

They form downward flows causing continuous overflow of pulp from compartments 4 and the creation of horizontal flows near the surface of the pulp mirror from compartment 3 to the sides.

baths 1. Horizontal pulp fluxes transport froth onto the surface by gravity for unloading.

Changing the intensity of gravity transport of the foam layer through the aeration zones of the counter-current compartments 4 by changing the height of the overflow through the partitions 14 to the non-aeration zone, changing the air flow in the aerators of the counter-flow compartments, as well as the inclination angle of the aerators in the compartments 4, can be used to control the output, density and quality foam product in a wide range. Moreover, the higher the density of the original feed and the higher the content of thin classes, the lower should be the speed of transporting the foam layer to unloading.

In the process of transporting the foam layer, foam separation of the initial feed produced in the form of foam onto the foam layer occurs, and the secondary concentration of the floating minerals in the foam layer due to sludge. The foamy product, which is largely devoid of the liquid that carried the non-floated minerals, is discharged as foam the final product. Pouring pulp into the non-aerating zone through partitions 14 contains a small amount of floatable minerals, mainly precipitated from the foam layer, and is close in composition to chamber waste, is discharged through gaps 29 into the lower aeration zone of the countercurrent flotation units 4 for control flotation.

The fluid that is drained from the interlayer of the foam layer and the minerals that are not transplanted and part of the floating mines falling out of the foam layer form a descending stream of pulp in the upper aeration zone of the countercurrent compartments 4, having a height equal to the height of the partition 14.

The speed of the downward flow in the upper aeration zone compared to the upstream flow rate in the airlift decreases in proportion to the flow area and the decrease in pulp flow due to the removal of part of the load in the foam product using foam separation and transporting the top layer of pulp through the aeration zone and gaps 29 into the lower aeration zone, located between the gaps 29 and aerators with perforated pipes 27.

The low speed of the descending flow in the upper aeration zone, especially in the section from the top of the partitions 2 and 14 to the fairings 8, and the weak turbulence of the flows create favorable conditions for separating the grain of the floatable minerals into the froth layer during the aeration of the pulp with dispersed air supplied through collectors 26 and perforated tube No. 27 of aerators of countercurrent flotation compartments 4.

The remains of the profiled pulp from the upper aeration zones enter the lower aeration zones and, combined with the pulp flows transported through the non-aeration zones and gaps 29, are subjected to control flotation.

Aeration rises into the foam layer, and when the aerators consisting of collectors 26 and perforated tubes 27 are installed at an angle of up to 15 °, proflotted pulp is installed, the passage above the aerators to the sides of the bath 1 is discharged through the channels 28 under the aerators.

Transportation of residual profluated pulp over the aerators to the sides of bath 1 is due to the presence of a hydrostatic pressure differential in the area of aerators of countercurrent flotation units 4 between the greater height of the column of non-aerated pulp at the edges of the bath 1.

Under the influence of the hydrostatic pressure difference, a slight upward flow of pulp between the perforated tubes 27 is created, contributing to the earlier detachment of air bubbles from the tubes and thereby increasing its dispersity, preventing solid particles from falling through the aerators creating conditions above the dispersant tubes that are identical to the boiling layer , and reinforcing the flow over the pyramidal bottoms, thereby eliminating solid precipitates on the bottom.

From the tank of the pyramidal bottoms 30 through the windows 31 the proflotted pulp enters the pulp-discharge pocket 32 with adjustable piber, and from the pocket 32 as an initial feed - into the next chamber or into the waste from the final chamber.

The bypass devices, consisting of nozzles 10, butterfly valves 11 and actuators 12, are designed to provide intracameral circulation of the pulp when the initial supply is interrupted for a short time or the volume flow is reduced below the set minimum.

The machine works as follows.

When the initial power supply is cut off (its volumetric flow is lower than the set minimum), the signal from the flow sensor, for example, of the capacitive type, activates the actuators 12 to turn the flaps 11 into the open position. After opening the nozzles 10, the pulp from the tanks of the pyramidal bottoms 30 under the influence of the difference in hydrostatic pressures flows through

the nozzles 10 and the pulp lines of the chamber are transferred to the pulp mixer of the airliner, and the foamed pulp issued by the airlift to the pulp-separation chamber, where foam is distributed, overflows through the visor 6, is fed to the inside of the foam layer, and the liquid and Predominantly non-floated minerals through the gaps 7 enter the inside of the foam. pulp compartments 4 countercurrent flotation.

After the initial power supply is resumed according to the signal from the pulp flow sensor, the butterfly valves 11 are turned on by means of actuators 12 to the closed position and the machine continues to operate without a circulatory load in a constant manner without supervision intervention.

At the same time, the bypass devices ensure the work of the unit and with the operational load, depending on the requirements of the technology, for example, the floatability of the minerals is difficult, the high content of coarse-grained minerals in the internal volume of the pulp and chamber waste falling out of the foam layer. In this case, the machine will operate according to a scheme identical to the one proposed for the case with the arrival of a load less than the set mi1mmuma.

This feature enhances the versatility of the machine and the breadth of its use.

The air distribution device is intended for sparging before starting the machine, working on heavy dense pulps, or flooding it as a result of a disturbance of the reactant mode, emergency shutdown of air supply, continued supply of power, etc.

The order of the start of the spammed machine is as follows.

Through one of the pipes 24, equipped with valves and a check valve, fresh water is fed into the triangular prism 2I under pressure. After increasing the pressure in the reservoir of the prism 21 to the magnitude of the hydrostatic pressure surplus of the pulp column in the airlift and the sediment resistance in its bottom tank, the valves 23 open and water flows through the slots 22 under pressure to the base of the airlift, loosened sediment.

Air is then supplied through the other, nozzle 24. Air outlet, along the same path as the water, produces intense pulp bubbling. During the bubbling period, the flap 11 in the by-pass nozzle, ah 10, must be placed in a vertical position, i.e. bypass devices are open.

After the restoration of normal intracameral circulation of the pulp, the supply of water and air through the nozzles 24 is stopped, and the machine operates according to a constant scheme.

The specific productivity of the proposed machine and the extraction of the useful component due to the involvement of small particles in the flotation process are higher than in the known.