FI68093B - EXHAUST FACTORY AT THE GENOM FLOTATION ELIMINATORY FORM OF THE FORMAT OF A PARTICULAR UPPER CONTAINER IN ENVIRONMENT - Google Patents

Abstract

A floatation tower for paper recovery has a set of cells one above the other, holding the fibrous paper paste, and into which water and compressed air are injected so that the impurities mix. with the bubbles to form a foam which can be removed separately. Water is admitted as a thin layer at the same time as the air to mix. with the liquid paste as it is circulated in a thin layer in a mixing chamber, passing it through and along the flow, controlling the thickness of the layer. Air is then admitted to skin off the foam and drive it into a collector vessel below, for recycling. By a similar process for each cell, ink, kaolin and fibres can be removed separately. The mixing chamber is conical, with a tangential lop entry.

Description

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c <«> 1W5 (51) Kv.lk. '/ lnt.CI.' D 21 C 5/02, B 03 D 1/00 3 UOMI - Fl NLAND (21) Patent application - Patentansöknlng 770953 (22) Application date - Ansökningsdag 30.0 j. ~ i ~ j (23) Start date - Giltighetsdag ^ 0 05 '} (41) Has become public - Blivlt offentlig 13-10.77 National Board of Patents and Registration (44) Date of publication of the publication | _? patent- och registersty reisers Ansökan utlagd och utl.skriften publicc-ad .0.0 (32) (33) (31) Pyydetty etuoikeus — Begärd priorec 12.04. / 6

Belgium-Belgien (BE) 0/166085 (/ 1) Sunds Defibrator Aktiebolag, Ssndhamnsgatan 81, S-10251 Stockholm,

Sweden s-Sver i ge (SE) (/ 2) Enar Valentin Hellberg, Brussels, Belgium-Belg ien (BE) (74) Oy Kolster Ab (54) Method and plant for the removal of contaminants in liquid particles by flotation - Förfarande och the elimination of genomic flotation is eliminated in the form of a fetal particle uptake and

The present invention relates to a method for removing impurities contained in a liquid as solid particles by flotation, which liquid contains at least one flotation agent, the air stream being sprayed into said liquid stream before the liquid enters the flotation cell to form air bubbles which disperse into the liquid. forming a foam full of these impurities which is removed from the surface of the liquid and, before the air and liquid are sprayed into the flotation cell, the liquid is circulated along the path in a thin layer to the mixing chamber while air is introduced into this liquid layer transversely to the liquid path .

2 68093

The above-mentioned flotation method for removing ink from pulp made from old papers is known, in which air is introduced directly to the bottom of the cell by suction by means of a propeller, whereby the propeller also serves to thoroughly mix and distribute the fiber suspension in the cell.

Directing the air directly into the mass undoubtedly makes it possible to adjust the pressure of the air and thus the diameter of the bubbles depending on the volume of the air, which in turn can be adjusted within certain limits. Although by increasing the volume of air it is possible to increase the pressure and thus increase the diameter of the air bubbles, on the other hand it is not possible to reduce the diameter of the bubbles while increasing the air flow, which in some cases may be necessary to separate certain impurities.

In fact, it has surprisingly been found that selective separation of impurities is possible by means of flotation by adjusting the dimensions of the bubbles and the volume of the air independently. Thus, for example, by removing inks from fibrous, pretreated pulp made from old papers, it is now possible to obtain different bubble dimensions for flotation of inks, for flotation of fillers such as kaolin or for flotation of fibers, after which they can be selectively separated.

In particular, the present invention relates to a method by means of which the dimensions of bubbles can be adjusted regardless of the volume of air mixed with the water to be purified.

The invention is characterized in that the thickness of the air layer is adjusted between the walls of two opposing parallel liquid flow passage chambers to increase or decrease the width of the interwall duct and thus increase or decrease the velocity of the fluid flow through the duct.

In addition, when the liquid is a fibrous suspension, such as paper pulp, it is found that forcing the pulp in the form of a thin layer to pass into a narrow chamber where it encounters split air sprayed transversely onto a thin liquid layer full of suspended fibers. cleansing effect.

When removing ink from pulp made from old papers, it has been found that the volume of air mixed into the pulp and the flow rate of the pulp in the mixing chamber affect the whiteness of the pulp and that by adjusting them, whiteness differences ranging from 57 to 66.6 ° can be obtained.

With these adjustments, it is possible to achieve efficient cleaning with the minimum amount of scrap.

According to another feature of the method, the length of the air passage into the liquid is adjustable.

Thus, the amount of air can be precisely adjusted with respect to the liquid layer passing through the mixing chamber.

According to another feature of the method, the air stream carries the foams with it to the hopper and the air is recovered for recirculation.

In the case of flotation in several cells, the mixture of air and liquid coming from the mixing chamber in each case is introduced into each chamber. This allows the dimensions of the bubbles to be adjusted in different ways from one cell to another, thereby selectively removing contaminants.

When the liquid contains fibers, the foams coming from the second chambers can be led to the liquid to be re-cleaned, which passes into the first flotation chamber, in order to reduce the loss of fibers.

The present invention also relates to a plant for removing impurities contained in a liquid as solid particles by flotation, which plant comprises at least one flotation cell, an inlet for liquid to be introduced into the cell, a mixing chamber through which liquid is introduced into the inlet and air is introduced to form bubbles therein. .

The invention is characterized in that the mixing chamber comprises opposite, parallel walls to form a liquid flow passage through the chamber, that at least one of the walls has through-holes or openings, that the aeration device 66095, respectively, to reduce and increase the width of the channel and thus to reduce or increase the velocity of the liquid stream passing through the channel in order to change the size of the bubbles formed and the inlet to provide a liquid flow to the beginning of the channel.

According to one feature of the invention, the mixing chamber is provided with a device for adjusting the distance between the parallel walls.

Other features and details of the invention will become apparent from the following description and the accompanying drawings, which show by way of example only an embodiment of the invention which is particularly suitable for removing ink from pulp made from old papers.

Fig. 1 is a schematic side view of a multilayer plant; 2 shows a horizontal section along the line II-II in Fig. 1, fig. 3 is an enlarged longitudinal vertical section of the mixing chamber, FIG. 4 shows a section along the line IV-IV in Fig. 3, FIG. 5 shows, on an enlarged scale, in vertical section, a first embodiment of the structure of the mixing chamber, FIG. 6 shows a section along Figures VI-VI, and FIG. 7 is a diagram showing whiteness!

In the present drawings, the same reference numerals denote serial parts.

The plant comprises four flotation cells 1, 2, 3, 4. These cells are annular and are arranged axially 1 apart so as to form four layers of a tower with several floors 5. It is clear that the number of floors of this tower can be more than four.

The defibered, chemically pretreated pulp in the form of a fiber suspension containing a blowing agent is fed by means of a pump 6 through a pipe 7 to the inlet of the cell 1, before which the suspension passes through the mixing chamber 8. This chamber has a narrow channel in which the fiber suspension circulates in a thin layer, while air is introduced transversely to the web of this layer 5 6 8 0 9 3 or along a part of the web through a pipe 6 connected to an air pressure source (not shown) in which vt · V is placed: t ~ iii 10.

The mixing chamber 8 is connected to the annular cell 1 by a tube 31 which leads tangentially to the large wall of the cell cylinder near its floor 5, so that the fiber suspension is rotated around the central tube 12 of the annular cell. The bubbles formed in the suspension adhere to the impurities and cause them to rise as foams to the surface. The foams are discharged out of the cell through the outlet 18 of the tube 12 partly due to the rotational movement of the suspension and partly due to the air flow generated above them. A vertical plate VJ placed above the surface of the pulp guides the foams to the outlet. The foams are collected in a funnel 13 surrounding the tube 12, from where they enter a water-filled retaining container. 37 The air flow required to remove the foams is led to the top of the cell via a tube 14 connected to a suction device ie fitted with a truncated cone above 16 for recirculation of the foam exhaust air. This tube is arranged concentrically in the central foam outlet tube 12 and is common to all overlapping cells. The foam exhaust air is introduced into the cell through the opening 17, from where it exits through the outlet 18, taking with it foams which, under the influence of gravity, fall into the hopper li iir.u :. exiting via pipe 16. The tube 16 extends into the adjacent canister 1> .., whereby it forms an upwardly tapering cone and is arranged towards the wider tube by recirculation of the foam exhaust air of this adjacent cell and other t> .unu, un 3, 4 forms. the parts form a cyclone and thus give oi.en iv.t doile centrifugal velocity, whereby e 'is drawn into this tube! m n is extracted by the action of the suction device 15, from which it is returned to the pipe 14 for re-use in the removal of foams.

In the cell 1, the partially cleaned pulp leaves it through a pipe 19 provided with a pump 20 by means of which the pressure can be increased. The tubes 19 extend into the mixing spindle of the next cell 14 located in the last curve of the tower. S iris uses the same method as in the first cell, and .ίλ continues in the other cells. These cells are fed with a continuous purity of pulp or water containing 6 68093 fibers, while the foams collected from these other cells are in turn recycled to the lower cell.

Foams containing waste material from the first and other cells can, of course, either be recycled or removed in each treatment step to a separate device, depending on the type of product for which the pulp is intended.

The plant also comprises a lid 40 which closes the last layer cell, an inspection window 41 allowing rapid emptying for cleaning purposes, a drain valve 42 for each cell, a flap 46 in a foam air tube, a floor 43 in a tube 12 to receive recycled waste, a tube 44 to cell 1, and to remove the approved mass of tube 45 to cell 2, which processes the most purified pulp.

Figures 3, 4 and 5, 6 show two embodiments of a mixing chamber.

In the embodiment according to Figures 3 and 4, the mixing chamber is rectangular in cross-section and comprises two parallel planar walls 21, 22 fixed to a parallelepiped-shaped body 23 and forming a channel between them connected to the pulp inlet and outlet pipes 7 and 11. wall 22 and is operated by a threaded body 24 guided in a threaded hole 26 located in a sleeve 27 connected to the upper adjacent wall of the parallelepiped body, the distance between the parallel walls being adjusted by the wheel 25 to determine the thickness of the mass revolution will be targeted. The wall 21 is provided with a membrane which ensures the tightness of the chamber. The wall 22, in turn, is a porous material, in this case porous glass, which allows air jets to enter the pulp layer passing through the chamber. The mixing chamber is preferably also provided with a plate 28, by means of which a part of the surface of the channels in the porous glass can be closed in order to adjust the air-permeable surface.

In the embodiment shown in Figures 5 and 6, the mixing chamber 8 is conical in shape and has two parallel

II

7 68093 full conical walls 29, 30 spaced apart to form a channel therebetween for mass. The pulp is fed into the chamber through a nozzle 31 which leads tangentially into the chamber through the wall 29 to cause the pulp to rotate, while the air blown through the ducts 47 in the inner wall 30 is received. The ducts 47 are connected to an air inlet duct 32 which is connected to a source of compressed air (not shown). The inner cone 30 is adapted to slide axially in the outer cone 29 to adjust the space between these walls and thus the thickness of the pulp layer. For this purpose, the inner cone, which may be rotating, is guided by a pipe 32, which at the same time forms an air supply pipe. A conical seal 33 fitted inside the cone 30 is attached to two rods 34 and 35 which slide in the end walls of the cone 30 and, if desired, allows part of the holes in the air distribution cone to be closed to adjust the surface allowing air to enter the mixing chamber. Because the airflow can be adjusted regardless of the mass flow rate, the cells can produce a type of bubble suitable for ink flotation, kaolin flotation. or flotation of the fibers to effect selective separation of these ingredients.

The use of a plant for removing ink from pulp has been explained above. It can also be used for other purposes, e.g. for cleaning ores or for purifying circulating water by foaming fibers. On the basis of laboratory experiments, it has been possible to draw a diagram showing the whiteness curves 48 and 49 of the pulp in Fig. 7, which are plotted for the ratio between the volume of air and the volume of the pulp and for the velocity of the pulp in the mixing chamber. The ratio of the air liter to the mass liter is marked in its abscissa, and the whiteness of the mass in degrees of Scan as the coordinate. Curve 48 shows the whiteness of the pulp at a pulp velocity of 4.23 meters / second, while curve 49 shows the whiteness of the pulp at a pulp velocity of 6.35 meters / second.

By adjusting the air-mass mixture and the mass velocity in the mixing chamber, whiteness differences ranging from 57 ° to 66.5 ° Scan are obtained. The experiments were performed on "magazine" type spent papers containing about 50% mechanical pulp of 8,68093, giving the original whiteness of the unprinted edges.

O

was 66.5 Scan.

Using the method according to the invention, the whiteness of printed parts containing about 2% of ink can be increased from 46 to 66.5 ° with a scan retention of 20 minutes, after 2.5 minutes the whiteness had already risen from 46 ° * 6 4, 5 ° reen Scan. By the best current conventional method, a 62.3 ° Scan was obtained on the same paper after 20 minutes of retention and about 54 Scan after 2.5 minutes.

It is clear that the invention is not limited exclusively to the embodiments shown and that various modifications may be made to the shape, adaptation and structure of some of the elements used to make it without departing from the scope of the invention, provided that these modifications do not conflict with the following claims.

Claims (10)

Method of Flotation To Eliminate Contaminants in the Form of Test Particles Contained in a Liquid Containing Ethereal Inston- tions to Cooling Fluids, Whereby an Air Stream Is Injected in a Stream of Liquid Before it enters at least on flotation coil thereon! säti: that air bubbles form soin lordein.s in the liquid, whitens stick to the impurities and rise to the surface during formation of foam which. is contemplated against the impurities and the son is diverted from the surface of the liquid, and before the air and the liquid are entrained in the flotation cell the liquid is circulated with you. can in a breathable tin shape in the form of a layer of saratidic acid is introduced into partial liquid layers in the cross-section of the web and along At least a portion of the bath, characterized in that the thickness of the air layer is adjusted between two opposite sides. to the chamber forming a flow passage for the liquid to increase or decrease the width of the passage thereon, and thereby the flow rate of the liquid through the passage, in order to reverse the size of the b ade adequately. A method according to the claim. 1, characterized in that the length of the air supply distance to the liquid so that shell 1 is treated is regulated. A method as claimed in claim 1, characterized in that an air stream is supplied at a low level at a level of the shaft in order to transfer delta to a vessel, in the event it is dropped to the bottom, under part that air toi: ·: 'is recovered for recycling. 4. Procedure according to. Claims 1-3, wherein a plurality of flotation cells are utilized, characterized in that a mixture of liquid and air from a mixture of cells in each cell is introduced. 5. A method as claimed in claim 4, characterized in that the foam from the unloaded cell is evacuated to a common vessel, while the streams of discharge-in-discharge discharge air are subjected to vacuum to circulate the streams. together with each other. Il 11 680 9 3 6. Available. e are: i. i - j pdn ^ -t ^ .navel 4 older 0 k '1 n n c - t o c! ·: a e enran; sd. other cells are recirculated: i t.lu; i \ d cokr sv sm pnnnere dm; ; ib '5 La f 1c La t1 onsce .; ! on. 7. d · d !. ng, gd.no d: act nn-Jelst flotation ο1: ίτι7 tiera fortoro-noaj-Ai '' · π · .o; ; - ': n: n g. No 72d ... ·. : on vakoko, viikon facility in anoi. o t · o - V mb rstono and f i a! a L,:. on nano 1 .i (id, ota .o 1 opp for a 11 n.oine .. J. L .n i. ... v va di: 1 p. 7. d: down'- n, a mixture shifts e (8) oonom: -: 7 7 ...,.: 0: -0.0: aas.1 · on 7 7 d .. i b. d3r at ..: tana fad;; .e · L dsoosa. käneneeekknad d.avav, at.tb la ndr. da; sk., amm a ro '8; Ι.ηηία c takes on resistance parallel to the road car (27,27,29. Ifö s 0, ··. Da, ·,; · η .rt: drn j. Ngsk anal for liquids gerom kanain aron., A · ...: .n ta, ioi nro tie: 3 of the walls have genongeendo pores and "ali" (2 7 '. Ase It · t. Tngsoraan esta ecoiums an air stream gonon, pores na for the b. Dn b \ q of babbloi in the fluid which flows genoui pass :; ien; ir; c> t äl le 'r.gsorgau (2 5; 3 2) for reiät lv movement of vänätten note: oob iron varttia',? to cleanse repo. increase maston; o ns e. odd,. ·: .. ·! Is igeoon v · 'i!: Y;. E: str ömme n's handy genorr. Passage »in end to change the sterics of the bubbles formed at least one in lepo a fluid stream to fit a s upstream end. 8. Laying in accordance with the requirements. Claim 7, can be c - ti o ά thereof, that is, firstly! the ningory (2 5; 3 2} is ir> r is said to be dn tadk n ;;;;, i. d: tt; 1 °, aj: n: d: o vd'ga itä son bnr i. .M.ot dd; p tnSo-ttive dtöi; oodi. 9. In egg n i ng en7j, g p-ondkiavet 8, k done took -n a j thereafter, aid. road bodies (27,20) at: konista ooh coaxielia, ooh one in at 2 Ido oun ;; ,,., r g.-o no n (d '2' as j. ie; lit. t elä td vi of απΉ.:;. 10. Anchorage. Act according to patent claim 9, characterized in that the inlet is arranged to provide a tangent to an IL heat flow passage. 11. Anla.gninc and:. 071 o'clock ten. r avo f 9 eli or if. k a n -n e t e c. <n a o thereof, that L bon .1 nnef at d, i: means for smiling da water stream.mmi. Port from pass age n at a no o 'high level which οίο · is higher than is expected to be the only enoni passages. 177, Audogr όος erddqt nänoc nv pa t en tk ra ven 9-10, kÄ n n e f o o k n n d <·. n; v. o dc: it contains organs for