DE1269071B - Vacuum flotation process and device - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. α .:

B03d

German class: Ic- 7/10

Number: 1269 071

File number: P 12 69 071.0-24

Filing date: June 8, 1966

Open date: May 30, 1968

The invention relates to a multi-stage vacuum flotation process and a corresponding one Flotation device under vacuum.

In the area of so-called vacuum flotation are the Elmore vacuum process and the related one Basic device according to British patent 17 816 from 1904. With this device are amazing results were achieved over half a century ago.

It is known that liquids such as. B. water, substantial amounts of gases such. B. air, can solve. The amount of dissolved gas increases roughly steadily with increasing pressure, but decreases with increasing temperature. At a pressure of 760 mm of mercury, 11 water dissolves 29.2 cm »air at ⁰ ° C, but only 17.1 cm» at 25 ° C. When the pressure is doubled, the specified amount of gas also doubles.

It is also known that after a drop in pressure or under vacuum, the gas from an ao Solution preferably on unsaturated surfaces, such as B. mineral surfaces that at least are partially covered by organic collector reagents, settles. This well-known phenomenon becomes the selective separation by flotation under vacuum or partial vacuum.

It is also known that in practical flotation processes from the liquid under negative air pressure excreted gas for optimal foaming and excretion of the floatables Ingredients are insufficient. To establish adaptability and simple means of To get control of the flotation process under vacuum, it is necessary to add additional gas to the to introduce conditioned mass or pulp. As soon as this is done, the flotation process is in the desired position Extent under control.

The most important basic processes of the flotation process under vacuum are:

Vacuum flotation process and device

Setting and maintaining a vacuum in a closed flotation cell;

Introduction of feed turbidity into the cell;

Adjusting the level of the pulp to a constant level in the cell;

Introduction of additional gas into the lower part of the cell from an external source is at a higher pressure than that present in said flotation cell;

Dividing the additional gas into fine bubbles;

Applicant:

Outokumpu Oy, Helsinki

Representative:

Dipl.-Ing. R. Schomerus, patent attorney,

3000 Hanover, Theaterstr. 2

Named as inventor:

Risto Tapani Hukki, Otaniemi (Finland)

Claimed priority:

Great Britain June 14, 1965 (25 097)

Downward direction of the turbidity flow, so that a countercurrent to the rising bubbles is created;

Collecting the floatables above the level of the feed opening in an upward direction rising foam column;

Discharge of the foam product and

Discharge of the non-floating components below the entry level of the additional Gas.

A pretreatment of the suspension to be processed serves on the one hand to change the surfaces of the mineral or minerals by making them floatable with suitable chemicals, while the other minerals are made water-usable, while on the other hand gas, normally Air in which liquid is dissolved. The methods used and the quantities required on the flotation reagents, such as. B. collectors, frothers and modifiers are those skilled in the art known. They are therefore not explained further in the description.

809 557/146

The basic device for the above-described flotation process mainly comprises

a non-mechanical flotation cell;

Means for setting and maintaining a vacuum in the cell;

Means for introducing the sludge in a predetermined amount per unit time;

Means for creating a constant level of mirrors in the cell;

Means for introducing additional gas into the lower part of the pulp with predetermined Amount per unit of time;

Means for dividing the additional gas into fine bubbles;

Devices for the downward direction of the turbidity flow opposite to the upward direction of bubbles;

in the flotation cell, a column-like upwardly directed chamber above the level of the feed opening;

Devices for collecting and discharging the concentrated products;

below the level of the feed opening a downwardly directed conduit for collecting the non-floatables Components and

Means for discharging these constituents as residue product.

A selection is available for setting and maintaining the desired vacuum in the separation chamber of suitable vacuum pumps available.

The introduction of the aerated slurry into the flotation cell is controlled by injection in a horizontal direction Direction made or the slurry is lifted by suction from a point located below the feed opening.

Additional gas is drawn from the atmospheric air or at a predetermined rate from an external source of air under pressure via suitable nozzles, bubble generators and porous or perforated Manifold made of suitable material is inserted in the lower part of the cell. The introduction a pressurized air-water mixture through an injector is used to produce a finely divided Air-water mixture is particularly suitable. The introduction of a pressurized air-turbidity mixture is also possible.

The basic device can also contain one or more cyclones for the foam product, which are between the vacuum pump and the flotation cell are arranged. In the said cyclone system there is a separation most of the concentrate ingredients and accompanying liquid from that Carrier gas caused by foam destruction. The separated concentrate mass is through one of the above described similar arrangement discharged. The already of most of the solids and the gas stream freed from the associated liquid is sucked off by the vacuum pump. Any Solid substances that have passed through the cyclone system can be known behind the vacuum pump through Facilities are removed.

It is also already known that flotation processes are interconnected under vacuum can. Such an interconnection consists of a series of arranged on the same plane Elmore basic units; the result is a series of concentrates of various levels and finishes obtain. According to another previously known principle, the flotation can also be carried out within a single vacuum device.

The vacuum flotation process according to this invention consists of groups of individual processes

ίο to separate the floatable components from non floatable components in a system under vacuum with the help of gas bubbles that partially be formed by the excretion of gas dissolved in the liquid and partly by distribution a gas distributed from the outside into the liquid in a predetermined amount can be produced, such that the foam product is higher from a given flotation stage in one cell to a following one lying and higher quality concentrates supplying stage in a separate cell with the flow of the evacuated gas is conveyed, while the residue product of the latter operation through Gravity is returned to the previous work stage, which is on a lower level.

The flotation device according to this invention consists essentially of groups of basic elements, which are connected to a multi-level closed circle system under common or partial vacuum are and additional facilities for foam destruction between the flotation cells and the vacuum pump to remove most of the solid matter and liquid from the carrier gas exhibit.

Details of the present invention are based on the embodiments shown in the drawings explained in more detail. It shows

A b b. 1 shows a schematic vertical cross section through a base unit,
A b b. 2 a side view of a somewhat modified embodiment of the flotation device,

A b b. 3 a side view of a further embodiment,

A b b. 4 is a schematic vertical side view of a device arrangement of a multi-stage closed Circular system with several basic flotation units.

According to A b b. 1 is a basic unit, a closed conditioning and ventilation container 1 upstream, which is equipped with a propeller 2. For introducing the pulp under pressure the container 1 is provided with an inlet pipe 3 and for the introduction of likewise under pressure standing gas in a similar manner with a pipe 4, the cross section of which is adjustable by a valve 5.

The transfer of the pulp from the conditioning tank takes place through the pressure difference via an inlet line 6, the passage of which through a Valve 7 is controllable.

The main part of a flotation cell 8 consists of a cylindrical inlet part 9, a cylindrical foam chamber 10 and a conical bottom part 11. A section 12 is attached to the bottom part 11, with one or more injection nozzles 13 for the introduction of additional gas, an emergency discharge pipe 14 Valve 15 and a washing water inlet pipe 16 with valve 17 is provided. The bottom part 11 is also provided with an open suction discharge tube 18, which is from an open

5 6

Tube 19 is surrounded by a larger diameter. nozzles 13 in the lower part of the in the container 8

The tubes 18 and 19 result in a very simple removal of the pulp originating from the gas introduced

Carrying and overflow system, which is the mirror of the turbidity foam in the foam chamber 10. In this

holds in the cell 8 at a predetermined level. The Chamber will find further rearrangements of the Tip of the tube 18 can be height-adjustable 5 particles instead. The floatable particles rise with it

be trained. For draining the coarsest sand- the foam upwards while the particles of

Part of the pipe is 18 with an opening 20 containing other minerals that are carried along by the foam

see, which can be closed by a plug 21. again in the areas between the bubbles

In the example shown, there is also a downward slide under existing liquid films. These

Pressurized gas with also pressurized ίο downward movement can be achieved by spraying the

sensitive water through injection nozzles 13 draws foam are supported with a washing solution,

leads. The liquid, which sinks in countercurrent, carries

The continuously operating discharge device for the undesired particles continues with it. The Er-

the non-floatable outflow has another result is a concentrate of very high quality,

cylindrical bottom part 22 with a long 15 The concentrate flows into the collecting container 27

vertical discharge pipe 23 is connected. over and is loaded with carrier gas in the cyclone 30

The length of the pipe is conveyed to that in the device where the foam is destroyed. The concentrate

adapted to the prevailing vacuum. The lower reaches in a continuous stream over the

End of the pipe 23 forms a water seal with pipe 31 in the container 32, from which it finally

an open vessel 24, which is discharged with an overflow weir 20 via a weir 33, during the

25 is provided. The turbidity contained in the vessel 24 is removed from the apparatus via the vacuum side and the column of sludge in the tube 23 forms the one that is pulled out.

liquid completion of the unit. The residue product is discharged via the parallel The upper part of the container 8 is furthermore provided with a hydraulic arrangement, which is provided with the pipe 23, the cover 26, which encloses the container 24 and the weir 25, and also with a Foam collecting device The level of the slurry in the cell 8 is through the 27, an open pressure equalization pipe 28 and a simple overflow arrangement according to A b b. 1 on con-line 29, which leads to a cyclone 30. Maintained at a constant height. The larger proportion of the return discharge of the foam concentrate is used a level can through the opening 20, which is through the further parallel hydraulic closure. This 30 valve 21 is closed, pulled out, consists of an outlet pipe 31, a container 32 In the device according to A b b. 2 flows the concentration weir 33 and an overflow weir 33. A conduit 34 extends over the upper edge of the part 10 and is collected in connecting the cyclone 30 with any suitable scrubber 35 surrounding the part 10. Vacuum source (not shown). In the washer 35, the product flows through the other accessories not shown in A b b. 1 is shown 35 gravity along the inclined floor 35, z. B. vacuum gauges, pressure downwards and enters the outlet pipe 31. The gauges, vacuum and pressure equalization tank, cyclone 30 mainly prevents an overflow the air, an accidental foaming of the system,
pointer for the level of the level of the sludge and 40 The mode of operation of the device according to A b b. 3 Devices for controlling the level of the slurry differs from the already described da pumps, washing water spraying systems for overflow, in that there is no overflow for the foam pre-spraying of the foam column, devices at hand that control the height of the foam level of washing or dilution water etc. Container 8 regulates. The foam developed and enclose. Those skilled in the art are familiar with the solid particles entrained in the foam. long, as shown, into the cyclone 30, where the device according to A b b. 2 differs from concentrate from the carrier gas, as already explained, which is essentially separated in the following.

borrowed points: the container 8 is with a concentration to flotation processes under vacuum at higher

Tratswäscher 35 provided, which run on the outside of the 50 temperatures, the conditioning

Foam chamber 10 is attached. The scrubber 35 and flotation units with heating elements

is directly connected to the discharge pipe 31, can be of any suitable design,

while the line 29 from the top of the lid Any number of those previously described

26 goes out. Basic units can be different closed with respect to A b b. 3, the container 8 does not have 55 systems to be combined. Mainly

Overflow for the foam product. Instead, such systems carry out flotation processes

with a conical hood 36 and a cylindrical one which the foam product of a given

Equipped foam chamber 37, through which the Kon-Flotationstufe to a following, higher lying

centrate reaches the cyclone 30 via the line 29. that enters with the flow of the evacuated gas

The basic device according to A b b. 1 works as follows: 60 produces higher grade concentrate, while the

The residue product from the last operation, pretreated with reagents and under pressure

Pre-aerated pulp flows out of the conditioning by gravity to the first process, the on

device 1 is executed via inlet 6 with a steady flow, a lower level, back-

which is set via the valve 7, enters the flotation.

tion cell 8. Gas separation and the formation of the 65 die in A b b. 4 illustrated multi-level

Bubble nuclei attached to the collector-covered particle closed circulation system has five separate ones

take place immediately. Aided by the upward flotation cells 38, 39, 40, 41 and 42 on, all

rising bubbles emerging from the injection under a common or partial vacuum

stand. The cells 38 and 39 represent prefoamer units, while the cell 40 is a main flotation unit and the cells 41 and 42 serve as post-foaming units.

From the conditioning device 1 are led into the units 38 and 39 inlet pipes 6, which are equipped with valves 7, as in A b b. 1 shown are equipped.

To create the closed circuit system, the following connections are made between provided for the flotation cells:

Lines 43 and 44 for conveying pre-concentrates from the units 38 and 39 into the Main flotation unit 40;

Lines 45 and 46 for draining the residues from the main flotation into the pre-units 38 and 39 or

Lines 47 and 48 for discharging the residues from units 38 and 39 into the Post-foaming units 41 and 42 as feed material and

Lines 49 and 50 for conveying the post-concentrate from the post-units 41 and 42 in the pre-units 38 and 39.

Vacuum lines that connect two flotation cells on different levels, at the same time provide the flow paths for conveying the foam product from a unit lower height to a unit of higher height.

For gravity return of the residues from a higher level unit to a unit At the lower level, the flow arrangement is basically the same as that shown in Fig. 1. The only The main difference is that the outlet pipe 23 is essentially horizontal here Lines, such as B. 45, 46, 47 and 48, is replaced, the discharges 22 with the corresponding introduction part 9 connect. In other respects, the multi-stage closed rebreather consists of already described means.

The multi-stage closed circuit flotation system according to A b b. 4 works as follows:

The pretreated and pre-aerated feed pulp is at a desired pulp concentration and at a desired temperature by the existing pressure difference of one or more Conditioning containers 1, which are on a lower level, via inlet pipes 6 and valves 7 in the Pre-expansion units 38 and 39 drawn, in which the separation into pre-concentrate and corresponding residue products, as already described, takes place. In the present case, the lines 43 and 44 drawn preconcentrates are combined in the main flotation cell 40. The concentrate is over the line 29 is drawn into the cyclone 30, where the concentrate is removed from the foam by destroying the the latter is separated. Due to the force of gravity, residue pulp flows out of the cell 40 via lines 45 and 46 into the pre-expander cells 38 and 39. Residue pulps flow out of the due to the force of gravity Units 38 and 39 via lines 47 and 48 into the post-foamer cells 41 and 42. The concentrates these units are dragged to the corresponding upstream units at a higher level. The final outflows of the post-foamer cells are discharged via pipes 23. Extra gas is introduced into each basic unit, as already explained.

Obviously, there are many ways of composing, all of which are devices work under a common vacuum or partial vacuum. Mainly, flotation cells can be assembled according to the following principles will:

The vacuum connections to the pre-expander cell, which receives the conditioned raw task, at the same time form the line for transferring the foam product from the pre-expander cell into a main flotation cell, which is stored on a higher level, while the one discharging the residues from the higher cell Lines form a return for the residue product of the higher stage into the pre-expander cell;

the pipes from the bottom of the pre-expander cell conduct the corresponding residue product to a post-foaming cell located on a lower level, while the vacuum lines leading to the post-foaming cell also lines for the foam product from the post-expansion cell into the pre-expansion cell form;

or the vacuum lines leading to the pre-expander cell also form a line for the transport of the foam product from the pre-foaming cell to the post-foaming cell, which is stored on a higher level, while that on the bottom part of the main flotation cell attached drains form a return line for the residues into the pre-expander cell; and

the discharge lines attached to the bottom part of the pre-expander cell simultaneously form a conduit for the corresponding residues to a post-foamer, which is on a lower Level is stored, while the vacuum lines that lead to the post-foamer cell, too a line for conveying the foam product from the post-foaming cell to the Form pre-expander cell.

Other than those in A b b. 4 vacuum lines between units inserted where they are needed. The lines can of course with valves for control the flow rate can be equipped in any size.

As a special example it is mentioned that in the case of a low-grade copper ore, of which only one small amount of concentrate can be separated, a final main flotation unit removes the concentrates z. B. can assume six identical pre-units, which are stored around them on a lower level. On the other hand, a similar post-foaming unit can also be used on one for each pre-unit in contrast, be provided lower level. For a high quality iron ore of which a high one Percentage concentrate can be obtained, forms a graduated combination of a main flotation, a pre-foaming unit and a post-foaming unit, each of a similar size, the basic group. It is that It will be apparent to those skilled in the art that many other combinations may be appropriate.

The method and the apparatus described in this invention can be used in principle for any Separation by flotation can be used by conventional flotation processes and in conventional open mechanical flotation units are feasible. Additionally, they can be used for Concentrations of very finely divided particles are used where the conventional Funds were either barely sufficient or completely failed. It is clear that further treatment of many concentrates produced in the conventional flotation plants end products of very improved Quality, with or without size reduction of the particles.

Claims (6)

Patent claims: 1. Vacuum flotation process, consisting of groups of individual processes for separating the floatables of non-floatables in a vacuum System with the help of gas bubbles, which are partly due to the excretion of dissolved in the liquid Gas can be formed and partly by distributing an externally into the liquid in a predetermined amount of distributed gas are produced, characterized in that the foam product from a given flotation stage in one cell to a following, higher lying and higher quality concentrates delivering stage in a separate cell with the electricity of the evacuated gas is conveyed, while the residue product of the latter operation is returned by gravity to the previous work stage, which on a lower level. 2. Flotation device for the vacuum flotation process according to claim 1, characterized by Connections of several individual basic flotation cells with a common vacuum device, such that the lead to the pre-expander cells (38, 39) fed with the feed sludge Vacuum lines (43, 44) at the same time for conveying the foam products from the pre-expander cells (38, 39) serve to the main flotation cell (40) lying on a higher level, while the discharge lines (45, 46) arranged on the bottom part of the main flotation cell Form recirculation for the residue product of this cell in the pre-expander cells. 3. flotation device for the flotation process according to claim 1, characterized by compounds several individual basic cells under a common vacuum, in such a way that the bottom part of the pre-expander cells arranged discharge lines (47, 48) at the same time feeds of the residue products of the pre-foamer cells to post-foamer cells (41, 42), which are lower are arranged, while the vacuum lines leading to the post-foamer cells (49, 50) also as lines for conveying the foam product from the post-foaming cells (41, 42) serve to the pre-expander cells (38, 39). 4. flotation device for the flotation process according to claim 1, characterized by compounds several individual basic cells (38 to 42) under a common vacuum, such as that the vacuum lines (43, 44) leading to the pre-expander cells (38, 39) simultaneously Lines for supplying the foam products from the pre-expander cells to a higher one Form the main flotation cell (40), while those arranged on the bottom part of the main flotation cell Discharge lines (45, 46) simultaneously deliver the corresponding residue product to the pre-expander cells (38, 39), and the lines arranged on the bottom part of the pre-expander cells (47, 48) Guides for the pre-foamer residues to the lower-lying post-foamer cells (41, 42), while the vacuum lines (49, 50) also lines for the transport of the foam products from the post-foamer cells to the Form pre-expander cells. 5. Flotation device according to one of claims 2 to 4, characterized in that one or several cyclones (30) for foam destruction between the uppermost flotation cell or cells of the Vacuum device are arranged. 6. Flotation device according to one of claims 2 to 5, characterized by one of the flotation cell associated heating device. Considered publications:
German Patent No. 336 771;
British Patent Nos. 206 869, 633 776. 1 sheet of drawings 809 557/146 5. 68 © Bundesdruckerei Berlin