EP1193342A1 - Column flotation device - Google Patents

Abstract

The flotation system (10a), to separate a suspension into fractions which are rich and poor has a suspension inflow (22) into the separation tank column (28) which gives a central and vertical main flow (30). Blades (32) are arranged radially outside the main flow. To give a fraction with a low matter content, a flow is directed outwards and at a downwards angle to a collection zone (18), into a ring collection channel (34) for the fraction which has a low material content. The separation tank has a circular or polygonal cross section. Or it has a general funnel shape, with an upwards expanding cross section. A further assembly of blades, stacked over each other, forms a cascade structure radially outside the collection channel. The collection channel is between the downstream edges of the initial blades and the upstream edges of the second set of blades. Inflow openings are at the lower end of the collection channel, for the introduction of chemicals and/or bubble fluid mixtures. A filtration zone (40) is radially outside the collection channel, to hold filtration particles of active carbon. The system has a filtrate outlet and a filter material outlet, where the filtration particles move in a counter flow to the filtrate flow in the filtration zone to the regeneration unit (44) at the opposite end, and are recirculated as regenerated particles. A number of blade flotation units and/or filtration units are assembled in an array outwards and in succession. Separate outlets are between them, to take off different fractions. Two or three blade flotation units are deployed as shells, radially outwards, with two or three filtration units outside a flotation unit. The blades have the shape of a closed conical ring, at a pitch angle of 10-40 degrees to the horizontal, and preferably 20-30 degrees . In the direction of the flow of the low-content fraction, the blades have a length which is 1-4 times the width of the main flow channel defined by the inner edges of the blades. The gap between the blades increases upwards from below. At least part of the blades is corrugated. At least part of the blades is a multilayer honeycomb structure, with two outer layers and linking structures between them, preferably forming passage flow channels between the outer layers. At least part of the blades is a micro-porous membrane, and at least a part of the blades forms a curvature. The suspension inflow has a channel for the incoming suspension into the flotation assembly, with a radial outlet system to give an outflow in a radial direction, covered by a central passage preferably covered by a conical dome, so that the suspension flows centrally into the flotation tank. The radial unit has a horizontal beating plate (26), to deflect the suspension flow radially, The radial unit has a number of radial outflows (24) in a discrete array round the circumference. A take-off unit (16) for the fraction with a high content of matter is over the separation tank, with a passage aligned with the main flow. It has at least one impeller system to pass the rich fraction through a reject outlet, using a rotating conveyor screw or spatial paddles (56) in a horizontal channel (52). The flotation action is non-selective, using a pressure relief flotation with a bubble flow at the suspension inlet. Or the flotation is selective, with a feed of chemical additives at the suspension flow inlet.

Description

The invention relates to a flotation device for separation of substances or mixtures of substances from suspensions for Formation of at least one substance-rich and low-substance fraction with a columnar separation tank that has a suspension inlet below as well as several obliquely arranged one above the other arranged slats, a first exit for the low-cloth Fraction and a second one arranged in the upper area Output for the high-content fraction includes.

Such a flotation device is from the publication "Wochenblatt für Papierfabrikation", 1998, Issue 13, page 660 known. Such an arrangement has compared to conventional Flotation arrangements with essentially horizontal Suspension flow the advantage of a much lower Space requirements for the installation, whereas the necessary for it significantly greater height is usually not critical. at In this arrangement, a suspension flows along the outer walls a cylindrical container upwards, the Clear water between several spaced separating cones radially enters and exits into a central collecting line can be. A disadvantage of this known arrangement however, is that the clear water flow an increasing due to the direction of flow Experiences flow velocity, which actually causes the particles flowing at the top have a tendency to getting carried away. This reduces the efficiency of the Material separation. Another disadvantage is that consecutive Separation processes, be it flotation processes or coupling of flotation and filtration processes requires separate installation of separate assemblies that then be closed in a row.

Other column flotation devices are from the US 5467876 and US 5294003 known.

Proceeding from this, the object of the invention is to create a generic flotation device, which avoids the disadvantages mentioned above and in particular through an effective separation of the desired substances in the suspension in a low-substance and a substance-rich fraction. In addition, the arrangement is also said to be compact enable functional series connection of several isolators.

This object is achieved by the specified in claim 1 Features resolved. There are advantageous further developments from the subclaims.

The main advantages of the invention are that by arranging the vertical flow radially upwards and the arrangement of the fins radially outside the main flow the flow of the lean fraction is directed radially outwards and is slowing down, which is a better separation of the particles. Another advantage is that the low-fraction on the outer circumference, that is, collected behind the downstream edges of the fins , which means that additional separation stages are required with a small footprint can be provided, be it as additional flotation or as filtration levels. Through a targeted cascade Sequence of several separation levels, especially flotation levels different principles, (pressure relief and physical selection procedures) can be several Fractions of different substance contents are generated. The associated additional space requirement in the radial direction is relatively small.

Most conveniently, the separation tank has a circular cross-section. However, other cross-sectional shapes are also required possible, especially a polygonal, especially triangular or square cross section.

The separation tank is usually cylindrical his. If there is a large accumulation due to technical reasons of the substance-rich fraction in the upper area can be a funnel-like or conical design of the main flow channel, that is, a radial reset of those further up Front slat edges should be appropriate.

According to an advantageous development of the invention is radial at least one further arrangement outside the collecting duct several second slats provided one above the other arranged in cascade, with the collecting channel between the downstream edges of the former and the upstream edges of the second fins is formed. This arrangement enables an improved separation of the suspension and in particular the derivation of a first sub-fraction after the first flotation step and the derivation of the Residual fraction after the second flotation step.

Inlet openings are preferably at the lower end of the collecting duct for the introduction of chemicals and / or Bubble fluid mixtures provided a selective (in particular by means of collective adsorption or hydrophobization) and / or a non-selective flotation principle for use bring to.

Alternatively or additionally, according to another advantageous Formation of the invention outside the collecting channel one of them loaded with filtration particles Filtration room provided. This is a separation of substances on the filtration principle possible what only one has very little additional radial space. there a particularly effective filtration can be achieved if a filtrate outlet and a filter material outlet are provided are, the filtration particles in countercurrent to the filtrate walk through the filtration room and thereby for regeneration removable and at the opposite end in regenerated Condition can be fed again.

In all the embodiments described above can advantageously between the individual flotation and / or filtration stages separate outlets to remove different ones Parliamentary groups.

According to another advantageous embodiment of the invention the lamellae in the form of closed conical rings. A special one there is good separation of the fractions if the Slats an angle of inclination to the horizontal of 10 ° -40 °, preferably have 20 ° -30 °. It is also advantageous if the length of the lamellae in the direction of flow of the lean fabrics Fraction is 1 to 4 times the width of the through the inner edges of the fins delimited main flow channel. The distance between adjacent slats can be from below increase towards the top to accommodate the different flow and consistency ratios in the lower and upper range separation tank.

At least some of the slats can expediently be used be wavy, the waves in the circumferential direction run, so that this does not affect the flow the low-fraction fraction is connected. This training has the advantage of a considerably higher rigidity of the slats.

A particularly advantageous development of the invention provides before that at least part of the slats as a multilayer, preferably honeycomb structure with two outer layers and in between arranged connection structures is formed, wherein preferably continuous flow channels between the Outer layers are formed. This results in an essential higher strength of the slats.

Another development of the invention provides that the suspension inlet comprises a feed line with a radial outlet device to generate an outflow in radial direction and this is connected from one to one centric passage, preferably conical dome is covered so that the suspension is centered over the passage enters the separation tank. In this way, one favorable introduction of the suspension into the lower area of the Separation tanks causes.

Fig. 1:

eine schematische Längsschnittansicht durch eine erste Ausführungsform der Erfindung mit einer Flotations- und einer Filtrationstufe;

Fig. 2:

eine schematische Längsschnittansicht durch eine zweite Ausführungsform der Erfindung mit zwei aufeinanderfolgenden Flotationsstufen;

Fig. 3:

schematisch zwei alternative Formen für die Lamellen; und

Fig. 4:

schematisch eine Anordnung mit drei aufeinanderfolgenden Flotationsschritten.

The invention is further explained below with reference to the accompanying drawings. It shows:

Fig. 1:

is a schematic longitudinal sectional view through a first embodiment of the invention with a flotation and a filtration stage;

Fig. 2:

a schematic longitudinal sectional view through a second embodiment of the invention with two successive flotation stages;

Fig. 3:

schematically two alternative shapes for the slats; and

Fig. 4:

schematically an arrangement with three successive flotation steps.

In Figure 1, a first embodiment of the invention is shown schematically in axial longitudinal section, thus a flotation device 10a. In terms of component groups, this essentially comprises an inflow unit 12, a material separation unit 14, a discharge unit 16 for the substance-rich fraction and a first collecting area 18 for the substance-poor fraction. A second collection area 20 for solid particles is also provided.

In the inflow unit 12 leads a feed line 22 for the suspension to be separated, which in the embodiment shown lead into a plurality of separate or an annular outlet 24 which are provided with baffle plates 26 . In the feed line 22 or the area of the outlets 24 there is preferably a feed line (not shown) for a liquid containing gas bubbles for non-selective flotation and / or chemical substances for selective flotation.

The material separation unit 14 is essentially formed by a cylindrical separation tank 28 , in the central area of which a vertical main flow channel 30 is formed, which extends from the inflow unit 12 to the discharge unit 16

leads. Radially outside of the main flow channel 30 , a number of axially spaced lamellae 32 are provided one above the other, which are annularly conical and define between them a radially outward and obliquely downward flow for the lean fraction towards the first collecting area 18 . This annular first collecting area 18 , which is formed between the wall of the separation tank 28 and the downstream edges of the fins 32 , leads to a collecting space 34 arranged above the uppermost fin 32 for a first low-fraction, in which a first collecting tube 36 for this first low-material fraction Group is provided.

A simple one-stage embodiment of the invention would get along with the assemblies shown so far, the first header tube 36 in such a simple embodiment not necessarily being provided at the top but also elsewhere, for example at the bottom.

The embodiment shown in Figure 1 includes in addition to previously discussed flotation - a filtration stage that will now be described.

Radially outside concentrically the wall of the separation tank 28 , a filter outer wall 38 is provided at a certain distance, so that an annular, essentially cylindrical filter space 40 is formed between the two. The filter space is filled with a filter material, preferably sand of a certain consistency or other filter substances such as activated carbon or mixtures thereof.

This filter chamber 40 comprises in its upper end region a second collecting pipe 42 for a second low-fraction, which is obtained after a flotation and a subsequent filtration step. Above the filter space 40 there is a filter material regeneration unit 44 ( not shown in more detail), which has the task of cleaning or regenerating filter material and conveying the regenerated filter material into the filter space 40 . The filter material passes through the filter space 40 and arrives in a discharge channel 46, from where it is fed back to the filter material regeneration unit 44 via the schematically indicated line 48 in the used state. The filter material regeneration unit 44 comprises at least one discharge line 47 for a second substance-rich fraction, which is produced by the material separation on the filter material located in the filter space 40 when it is regenerated.

The filter chamber 40 is connected via one or more connection openings 50 to the first collecting area 18 , via which the fraction enters the filter area that has already passed through the flotation area and is not discharged via the first collecting pipe 36 .

The discharge unit 16 essentially consists of a widening collecting channel 52 for the substance-rich fraction, which leads to one or more collecting channels or pipes 54 . In order to better convey the material-rich, mostly sludge-shaped fraction from the collecting channel 52 into the collecting channel 54 , one or more conveying devices 56 , shown as rotating paddle arrangements, are provided.

Below the material separation unit 14, preferably functionally combined with the inflow unit 12 , a collecting device 58 is provided for the sedimentation of heavy particles, which opens into a sediment outlet 60 .

Now the operation of this first embodiment further illustrated the invention.

Via the feed line 20 , a suspension flows, to which chemical substances and / or gas bubbles can be added, to the outlets 24 and is deflected by means of the baffle plates 26 in such a way that when entering the inflow unit 12 , a horizontal flow initially occurs, which occurs when entering the main flow channel 30 changes into a radial main flow. This process is supported by the conical shape of the lowest lamella 32 . The type of generation and the location of the introduction of gas bubbles or the number and size of the bubbles determine the type of flotation (pressure relaxation or dispersion flotation).

The desired substances from the suspension separate under the action of the supplied gas bubbles and / or chemical substances on the way up into a substance-rich fraction flowing upwards and a substance-poor fraction flowing radially through the lamellae 32 . The material-rich fraction, which is usually sludge-shaped, can be discharged via the collecting troughs 54 after collection in the discharge unit by means of the conveying devices 56 . This substance-rich fraction can either contain undesirable substances such as ash or ink particles, in the recycling of waste paper (is then usually referred to as reject fraction) or else valuable substances, for example in the extraction of ore or minerals.

The fraction of poorer material branched off radially from the main flow in the main flow channel 30 reaches the first collecting area 18 after flowing through the annular spaces formed between the fins 32 . If - unlike in the embodiment shown in FIG. 1 - no further filtration process follows - this is the desired low-fraction which is removed via the first collecting pipe 36 .

If, however, a more effective material separation is desired at least for a part of the fraction located in the first collecting area 18 , this partial fraction flows through the connection openings 50 into the filter space 40 and from there in the vertical direction upwards, in counterflow to the filter material flow, which is from top to bottom runs. A second low-fraction can then be removed via the second collecting pipe 42 , from which the filtered substances are removed compared to the fraction that can be discharged via the first collecting pipe 36 , which in turn are removed from the system via the discharge line 47 . The filter material circulates between the filter space 40 and the filter material regeneration unit 44 . The heavy particles obtained during the separation, for example iron parts, fall into the sedimant collecting device 58 and then into the sediment outlet 60 .

FIG. 2 shows an alternative embodiment of the invention in the form of a flotation device 10b , which differs from the embodiment according to FIG. 1 in that two flotation stages are arranged one behind the other. The same reference numerals designate the same components. To avoid repetition, reference is made to the above description insofar as it relates to the first flotation step.

The embodiment of FIG. 2 differs from that of FIG. 1 in that a second group of fins 62 is arranged radially outside the first collecting area 18 , radially outside of which a third collecting area 64 is provided. Although in the embodiment shown the first slats 32 and the second slats 62 have the same distances and inclinations, it is not necessary. Rather, the number, shape, inclination, etc. of the second slats 62 can be selected independently of that of the first slats 32 depending on the specific conditions.

In this embodiment, a feed pipe 66 is provided at the lower end of the first annular collecting area 18 , via which a liquid or chemical substances mixed with gas bubbles are supplied in order to achieve certain flotation conditions in the first collecting area 18 .

Arranged above the third collecting area 64 is a third collecting pipe 68 for collecting a second low-fraction, which, in contrast to the fraction that can be removed via the first collecting pipe 36, is further freed of substances to be separated.

Insofar as collector pipes 36, 42, 68 are referred to in this context, any form of collector device is intended to be understood. In particular, it can also be a matter of a plurality of tubes or openings which are provided in walls and only open into collecting tubes outside the wall.

FIGS. 3a and 3b show two shapes for slats 32, 62 , which are useful instead of simple flat shapes. 3a shows a honeycomb-like structure with two outer surfaces 70a and 70b , between which connecting struts 72 are provided, the gray areas being intended to represent shadows. The cavities formed between adjacent connecting struts 72 preferably form continuous lines via which part of the flow can also take place. FIG. 3b shows a wave-like configuration of the fins 32, 62 , the direction of flow being indicated by an arrow, that is to say parallel to the wavefront.

An arrangement of three successive flotation stages is shown schematically in FIG. 4, which would look similar to the embodiment of FIG. 2, except that 64 further lamellae would be radially outside the third collecting area. The central axis a, not shown in FIGS. 1 and 2, shows that one side is not shown completely here. Outside of the third collecting area 64 , further slats 74 of a further flotation stage are provided in this embodiment, which preferably have a different distance between adjacent slats. A fourth collecting space 76, which is only schematically indicated, is then provided radially outside of the lamellae 74 for an even lower-fraction.

Claims (32)

Flotation device for separating substances or mixtures of substances from suspensions to form at least one substance-rich and low-substance fraction with a column-like separation tank, which has a suspension inlet at the bottom and several slanted slats arranged one above the other, a first outlet for the lean fraction and a second outlet arranged in the upper area comprises the fraction rich in material, characterized in that the suspension inlet effects a central, vertically directed main flow, the lamellae being arranged radially outside the main flow and for the lean fraction causing an outward and obliquely downward flow, and radially outside the lamellae a ring-like Collection channel for the low-fraction is formed. Flotation device according to claim 1, characterized in that the separation tank has a circular or polygonal cross section. Flotation device according to claim 1, characterized in that the separation tank is funnel-shaped with a cross-section widening towards the top. Flotation device according to one of the preceding claims, characterized in that at least one further arrangement of a plurality of second slats provided one above the other is arranged in a cascade manner radially outside the collecting duct, the collecting duct being formed between the downstream edges of the first-mentioned slats and the upstream edges of the second slats. Flotation device according to Claim 4, characterized in that inflow openings are provided at the lower end of the collecting duct for the introduction of chemicals and / or bubble fluid mixtures. Flotation device according to one of the preceding claims, characterized in that radially outside of the collecting channel there is provided a filtration space filled by the latter and filled with filtration particles. Flotation device according to claim 6, characterized in that a filtrate outlet and a filter material outlet are provided, the filtration particles migrating through the filtration space in countercurrent to the filtrate stream and being removable for regeneration and being able to be supplied again in the regenerated state at the opposite end. Flotation device according to one or more of claims 4 to 7, characterized in that a plurality of lamella flotation arrangements according to one of claims 1 to 3 and / or filtration arrangements according to claim 6 are arranged concentrically to one another. Flotation device according to claim 8, characterized in that separate outlets are provided between the individual flotation and / or filtration stages for removing different fractions. Flotation device according to claim 8, characterized in that two or three lamella flotation arrangements are arranged in a shell-like manner concentrically to one another. Flotation device according to claim 8, characterized in that two or three filtration arrangements are provided radially outside a lamella flotation arrangement. Flotation device according to one of the preceding claims, characterized in that the lamellae have the shape of closed conical rings. Flotation device according to one of the preceding claims, characterized in that the lamellae have an angle of inclination to the horizontal of 10 ° -40 °. Flotation device according to claim 13, characterized in that the lamellae have an angle of inclination to the horizontal of 20 ° -30 °. Flotation device according to one of the preceding claims, characterized in that the length of the lamellae in the flow direction of the low-fraction is 1 to 4 times as large as the width of the main flow channel delimited by the inner edges of the lamellae. Flotation device according to one of the preceding claims, characterized in that the distance between adjacent lamellae increases from bottom to top. Flotation device according to one of the preceding claims, characterized in that at least some of the lamellae are of wavy design. Flotation device according to one of the preceding claims, characterized in that at least some of the lamellae are designed as a multilayer structure with two outer layers and connecting structures arranged between them. Flotation device according to claim 18, characterized in that at least part of the lamellae is designed as a honeycomb structure. Flotation device according to claim 18, characterized in that continuous flow channels are formed between the outer layers. Flotation device according to one of the preceding claims, characterized in that at least part of the lamellae are designed as a microporous membrane. Flotation device according to one of the preceding claims, characterized in that at least some of the lamellae are curved. Flotation device according to claim 1, characterized in that the suspension inlet comprises a feed line which is connected to a radial outlet device for generating an outflow in the radial direction and which is covered by a dome provided with a central passage, so that the suspension is centered over the passage in enters the separation tank. Flotation device according to Claim 23, characterized in that the radial outlet device comprises a horizontal baffle plate in order to deflect the suspension flowing against it in the radial direction. Flotation device according to claim 23, characterized in that the radial outlet device comprises a plurality of discrete radially directed outlet openings distributed over the circumference. Flotation device according to claim 1, characterized in that a removal unit for the substance-rich fraction is provided above the separation tank, which comprises a central passage for the substance-rich fraction which is essentially flush with the main flow and at least one conveying device in order to feed the substance-rich fraction to a reject outlet. Flotation device according to claim 26, characterized in that the conveying device comprises a rotating screw conveyor. Flotation device according to claim 26, characterized in that the conveying device comprises at least one essentially horizontally extending channel with rotating clearing paddles. Flotation device according to one of the preceding claims, characterized in that it is set up for non-selective flotation. Flotation device according to claim 29, characterized in that the flotation is designed as a pressure relief flotation and in the area of the suspension inlet there is an inlet for a gas-bubble-displaced liquid. Flotation device according to one of the preceding claims, characterized in that it is set up for selective flotation. Flotation device according to claim 31, characterized in that an inlet for chemical additives is provided in the area of the suspension inlet.

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