JPS62129162A - Apparatus and method for foam flotation - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides a method and apparatus for foaming separation (flotation separation);
More particularly, it relates to a method and apparatus for cleaning carbonaceous materials by foam separation.

BACKGROUND OF THE INVENTION Coal is an extremely valuable natural resource in the United States due to its relatively abundant reserves. It is estimated that the United States has more energy available in the form of coal than its natural resources of oil, natural gas, oil shells, and tar sands combined. Recent energy shortages, combined with the availability of abundant coal resources and continued uncertainty regarding the availability of crude oil, have made it urgent to develop ways to convert coal into a more efficient energy source. .

Considerable prior art methods for foam flotation separation of slurries of particulate matter involve introducing air into a liquid slurry of particulate matter, for example through a porous flotation machine bottom or through a hollow impeller shaft. It is based on a structure that creates surface bubbles. These prior art methods are fairly inefficient methods, especially when dealing with high concentrations of particulate matter.

Generally, these methods are insufficient to provide sufficient contact area between the particulate matter and the bubbling air.

As a result, a large amount of energy can be consumed for foam generation. Foam flotation methods that allow foam to rise in the slurry also tend to trap and entrain impurities such as ash in the foam slurry, thus reducing the resulting cleansed coal.
The resulting particulate product may contain more impurities than necessary.

Going into the details of the prior art, U.S. Patent No. 3,351,1
No. 99 discloses an apparatus for foam flotation having a flotation machine whose upper part is divided into a plurality of compartments by a partition wall. The flotation machine is shown as a rectangular or trapezoidal elongated trough with a sloped bottom from the point where the feed is introduced.

The foam is produced by four rotating paddles placed at the top of the flotation machine.
’ is removed by

U.S. Pat. No. 2,350,943 discloses a countercurrent foam flow flotation device in which foam flows from the end of the flotation device (tailings end) toward the feed end. Concomitantly, the tailings are forced to flow in a direction opposite to the foam flow and are discharged at the end opposite the slime (pulp) body. The apparatus is constructed in such a way that free flow and a common slime (pulp) level is maintained between the flotation machine units of the configuration, while at the same time the flotation machines are operably independent of each other. It consists of a plurality of independent flotation machines that are arranged to form multiple flotation machine units.

U.S. Patent No. 2,184,115 is interconnected;
Apparatus for flotation and concentration of ores consisting of a plurality of flotation machines capable of flowing concentrate from one flotation machine to another and counter-current flow of intermediates and tailings from one flotation machine to the other is disclosed. The intermediates and tailings pass through pipes connecting the various flotation machines.

Other patents disclosing foam flotation devices consisting of multiple flotation machines include U.S. Patent No. 4,399,028,953,7;
46.2073148.4,045,243.3,49
1,880.2.423,456.2,765,081
．． 4,184,967.2.983,377.2,68
No. 7,213 and No. 2,416,066 are included.

Other methods have been proposed and developed for preparing or cleaning coal from impurities such as ash and sulfur, either before or after burning the coal. U.S. Patent Nos. 4,304,573 and 4,412,84
The coal preparation method disclosed in No. 3 pulverizes raw coal into fine mesh size and then chemically treats it. According to this method, the chemically treated coal is then separated from ash and sulfur,
The cleaned or cleaned coal is then recovered from there.

More specifically, in the above-mentioned chemical surface treatment method, the coal is first cleaned from rocks, etc., and then about 48 to 30
Grind to a fine size of 0 mesh. The expanded surface of the crushed coal particles is then made hydrophobic and lipophilic by a polymerization reaction. Sulfur and mineral ash impurities present in the coal remain hydrophilic and are separated from the treated coal product in the water washing step. This process utilizes oil and water separation techniques, allowing the now hydrophobic coal particles to float in the harvest above the aqueous phase containing hydrophilic impurities.

For example, U.S. Pat. No. 4,3 (J 4,573 and
, 412,843, in which several independent flotation tanks are used in series for the coal washing circuit. The three-stage coal separation disclosed in these patents uses three flotation tanks and one scavenger tank. The suspended fraction of the slurry containing coal particles is reintroduced into the next flotation tank for staged cleaning. The tail fraction of the slurry, containing coal with some ash, is withdrawn from the bottom of the tank into a scavenger to recover the coal in a countercurrent flow. The rate of tailings withdrawal is regulated by a pump controlled by tank level sensors to prevent settling of solids into the piping between the individual tank units.

An improved apparatus for carrying out the aforementioned chemical coal washing process is disclosed in US Pat. No. 4,347,127.

This patent discloses that a primary spreading nozzle is located on a flotation tank for input slurry spreading and a recirculating spreading nozzle is located in a tank for settling material collection to redistribute particulate matter collected in a collection trough. Discloses a flotation device located on a water tank.

Although the chemical surface treatment flotation equipment described above gives excellent final product results, it is simpler and less expensive to construct.
, an improved device that reduces the overall control complexity required to operate the device is desirable.

<Object of the Invention> Therefore, the first object of the present invention is to obtain a foam flotation fraction of a slurry of particulate matter.
An object of the present invention is to provide an improved apparatus and method for disposing of wastewater. A second object of the present invention is to provide an improved apparatus and method for preparing coal by foam flotation separation of granular coal from its associated impurities such as ash and sulfur. A third object of the present invention is to provide a foam flotation separation of a slurry of particulate matter which is simpler, cheaper, more efficient and provides an improved yield of cleaning products. An object of the present invention is to provide a method and an apparatus for.

DETAILED DESCRIPTION OF THE EMBODIMENTS> The objects and features of the present invention for an apparatus and method for foam flotation separation may be understood by reference to the following detailed description of several embodiments thereof, taken in conjunction with the accompanying drawings. This will make it easier for those skilled in the art to understand.

In the accompanying drawings, identical (or similar) elements are consistently given the same reference number.

The apparatus and method of the present invention is suitable for the separation of a wide variety of solid-fluid streams by producing a solid-laden foam phase, and is applicable to the separation of many types of particulate matter. It is possible. Reference may be made to U.S. Pat. can.

According to the invention, a flotation tank, here a flotation machine (flo
-1aHo%6ell), are not independent of each other and are combined into one large tank with a sloping common bottom in hydraulic communication with the slurry of each flotation machine. .

With this arrangement, the collection and transport of coal-containing tailings in countercurrent flow into a scavenger tank is more efficient than with prior art methods, as shown in Figures 1-3. Instead of using separate piping and pumps between each tank, a common sloped bottom extends below all sorting compartments or flotation machines, as shown in FIGS. 1 and 3. A common bottom extending below all flotation machines slopes downwardly towards the point below where the input slurry enters the tank. Water input at the upper end of the sloped bottom provides a counterflow of tailings. This method of collecting the tailings, including some coal-containing particles, for recirculation into the scavenger tank results in both improved yield and reduced ash content in the final cleaned coal product. Furthermore, this configuration results in a simpler and less expensive flotation tank configuration in which only one liquid level sensor is used for all flotation machines in the tank.

In order to better understand the methods and apparatus disclosed herein, the present invention may be described with reference to the spherical coal preparation processes disclosed in, for example, U.S. Pat. Explain. Referring to the drawings in detail, FIG. 1 schematically shows a preferred embodiment of the invention having a flotation tank 5 consisting of three flotation machines filled with water up to level 6. The flotation tank 5 is of trapezoidal shape with the bottom sloping towards one end of the tank where the input slurry is fed.

In operation, a slurry of finely divided coal particles, along with impurities and additives and reagents, if desired, e.g. monomer compounds, chemical initiators, catalysts and a fluid hydrocarbon carrier, is added to the coal slurry feed, e.g. from a ball mill. It is first fed into the tank 7 and then sprayed into the flotation tank through at least one spray nozzle 8 located at a distance above the water level 6 in the tank 5 . In another embodiment, two or more primary nozzles can be used to spray the slurry and/or other desired components into the flotation machine in the flotation tank 5. Preferred types of dispensing nozzles for use herein include helical or helical open-flow dispensing nozzles, such as those disclosed in U.S. Pat. No. 4,514,291, incorporated herein by reference, or the Including U.S. Pat. No. 4,347,12
6 or 4,347,127.

The treated coal stream is pumped under pressure to the primary dispersion nozzle 8, where the shear forces generated break up the coal flocs.
ce-xla%t) The slurry is distributed as fine droplets so that the foam is violently injected into the contiguous ice mass of the flotation machine/161 and has a substantial amount of particulate matter suspended therein. 2 is created above the liquid surface, while other components of the slurry and small amounts of particulate matter settle to the bottom of the liquid bath.

The foam generated by the flotation machine/161 is transferred to the skimmer paddle 16.
This is shown in FIG. 2, which is a cross-sectional view of the device of FIG. 1 along line A--A. FIG. 2 is a cross-sectional view of flotator /161, but also shows similar cross-sectional views of flotation machines /162 and /163. As shown in FIG. 2, an upwardly sloping curved surface 18 extends from the water surface at the skimmer 16 to the collection chute 21 of the flotation machine to collect excess foam before discharging it into the chute foam collection tank 17. It also serves to remove moisture (contained) from the foam. Foam collection tank 1 from the first flotation machine
The foam discharged at 7 is pumped with water from the spray nozzle 40 to the flotation machine/i62 for further cleaning.
It is generally diluted and mixed before being sprayed through the spray nozzle 19 into the liquid level of the liquid. Flotation machine 42 (and flotation machine upper 3)
is similar to flotator 41 and the operations in flotator/2 (as well as flotator 43) are similar to those occurring in flotator 1. After treatment in flotator waste 2, the foam collected from flotator/162 into a foam collection tank similar to tank 17 is then pumped through primary nozzle 20 to the liquid level of flotator A3. The resulting clean coal foam is then dispersed into a further foam collection tank similar to tank 17.
It is removed for drying and final fuel blending. As is clear from the figure, the tailings from each flotation machine are
3, the fluid is removed in a hydraulically communicating inclined common bottom 110 of the flotation tank 5 in counterflow 10. Water is introduced into the inclined common bottom 11 at inlet 25 to maintain a controlled hydraulic flow therein, as shown in FIG.

In its upper part, the flotation tank 5 is divided into various flotation machines by partitions 30 and 31. The partitions 30 and 31 extend vertically into the tank, but do not extend completely to the bottom as shown, forming a common communicating bottom 11.

To explain one aspect of the present invention in more detail, a typical coal selector (flotation machine) according to the present invention is shown in FIG. As previously mentioned, FIG. 2 is a cross-sectional view of the flotation device 1 taken along the line A--A in FIG. 1. In this embodiment, a primary distribution nozzle 8 is positioned above the liquid bath of the flotation machine and distributes the input slurry of particulate matter through an aeration zone and into the liquid surface. This sparging operation creates a foam 2 above the liquid surface with substantial particulate matter suspended therein, while other components of the slurry and small amounts of particulate matter sink into the liquid surface. A collector trough 33 is arranged in the flotation machine below the primary dispersion nozzle 8 to collect the settling material. The collected material is then recycled to at least one recirculation dispersion nozzle 4 located in the vicinity of the primary dispersion nozzle 8 of the flotation machine. vertical baffle 1
5 is located between the primary and recirculation nozzles and serves to separate the material that settles from the spray from the respective nozzles. Foam 2 generated in the flotation machine is transferred to the skimmer paddle 1
6 through a chute 21 into a foam collection tank 17. The primary and recirculating distribution nozzles, 8 and 4, are preferably inclined from the vertical towards the direction in which the skimmer paddle 16 is moving to direct the foam stream along the liquid surface.

The foam pumped into tank 17 from the first flotator is diluted and mixed with water before being pumped and distributed into the liquid level of the second flotator for further cleaning. In the same manner, final (third) stage foam cleaning is performed in a flotator/163, after which the clean coal foam product is sent for drying and fuel blending. Figure 1-3 shows the tailings.
The foam is removed in a countercurrent flow 10, flowing in the opposite direction of the foam at the hydraulically communicating common bottom of the tanks, as shown therein.

Referring to FIG. 2, material that tends to settle into the slime (pulp) from the recirculating sparging is drawn off along the slanted bottom of the flotation machine 12 by a countercurrent 10 flowing through the common bottom 11.

Similarly, the substances that are not collected in the gutter 33 and have settled in the slime (pulp) from the primary dispersion are as shown in FIG.
It is drawn off along the flotation machine bottom 14 by the countercurrent 10 .

The slope angle used for flotation bottoms 12 and 14 is approximately 45' in certain embodiments. The angle of inclination of the common bottom 11 as shown in FIGS. 1 and 3 is approximately 50° in the same manner.

This geometry of the tank bottom is shown here only as an example and is not intended to limit different slopes to tanks of other sizes and shapes.

As shown in Figure 1, the use of level sensing controls with communication between flotation machines results in a simpler and less expensive system than systems with individual level controls for each tank in prior art configurations. Become. As shown in FIG. 1, the water flow velocity applied to the apparatus at position 25 is such that the flow of slime (pulp) from flotation waste 1 to genus 2 and backflow from 162 to 7163, i.e., in the direction of counterflow as disclosed. The liquid must be controlled to prevent liquid conversion, so that the slime (pulp) with a higher ash content in the separator 1 does not contaminate the slime (pulp) in the flotator A2. And the slime (pulp) in the flotation post rot 2 is the slime (pulp) in the flotation machine/163
do not contaminate. Furthermore, the velocity of the countercurrent at the tank bottom must be sufficient to prevent settling of the tailings in conduit 11.

According to the invention, therefore, the foam flotation device used comprises at least two and preferably three flotation machines arranged side by side with a common bottom in hydraulic communication below all the flotation machines. use. This configuration allows the use of one tank level control common to all flotation machines. A further controlled stream of water is introduced into the device to create a counter-flow pattern under the flotator, thereby transferring the higher ash content slime (pulp) in the first flotator to the second flotator. No contamination of slime (pulp) inside the machine. In the same way, the higher ash content slime (pulp) in the second flotation machine does not contaminate the slime (pulp) in the third flotation machine. The countercurrent flow must be sufficient to prevent tailings from settling at the bottom of the tank. The improved collection and transportation method of tailings for recirculation from the scavenger tank shown in FIG. 1 is more effective than previous methods.

Although several embodiments and variations of a method and apparatus for foam flotation separation of components of a slurry have been detailed herein, the teachings and disclosure of this invention will suggest many other embodiments and variations to those skilled in the art. It should be obvious. For example, although the drawings illustrate the use of three flotation machines, fewer or more flotation machines may be used depending on the particular purpose.

[Brief explanation of drawings]

FIG. 1 is a process diagram of the method of the invention and also a schematic diagram of the novel apparatus of the invention. FIG. 2 is a cross-sectional view of the method and apparatus of FIG. 1 taken along line A--A. FIG. 3 is a perspective view of the foam (foaming) flotation separation device of the present invention.

Claims (1)

[Claims] 1. (i) at least two flotation machines separated by a partition and having a common inclined bottom in communication for extracting tailings from each of the flotation machines; a flotation tank having a sloped bottom sloping downwardly toward the feed input end of the flotation tank; and (ii) a primary device for feeding slurry into the flotation machine. An apparatus for foam flotation separation of components of a slurry containing particulate matter to be separated, characterized in that the slurry feeding apparatus is arranged above the flotation machine. 2. The apparatus of claim 1, further comprising a device for recovering the floating fraction from the individual flotation machines. 3. The apparatus of claim 1, wherein at least one of said flotation machines includes a collector located in said flotation machine below said slurry feed device for collection of settled material. 4. Apparatus according to claim 1, characterized in that at least one recirculation feed device for refeeding settled material is located above the flotation machine and in the vicinity of the primary device for feeding slurry. 5. The device of claim 2, wherein the suspended fraction collection device includes at least one skimmer paddle. 6. at least three flotation machines, the flotation tanks being separated from each other by partitions and having a common inclined bottom in communication for extracting tailings from each of the flotation machines; An apparatus according to claim 1 having the following. 7. (i) a flotation tank having at least three flotation machines separated by partitions and having a common inclined bottom in communication for withdrawing tailings from each of the flotation machines; (ii) the slanted bottom is slanted downwardly toward the raw material input end of the flotation tank, and the slanted bottom is provided with an inlet member for introducing a liquid at the upper end of the slanted bottom; a primary device for feeding the flotation machine, the device for feeding the slurry being located above the flotation machine; (iii) a recirculation feeding device for refeeding the settled material; and (iv) a device for recovering a suspended fraction from the flotation machine. ,
An apparatus for foam flotation separation of components of a slurry containing particulate matter to be separated, characterized in that the device comprises: 8. In a method for foam flotation separation of components of a slurry containing particulate matter to be separated, (i) an input slurry of particulate matter is fed into a liquid bath of a first flotation machine and floated; (ii) creating a foam containing a substantial amount of particulate matter on the liquid surface, causing other components of the slurry and small amounts of particulate matter to settle into the liquid; (ii) on the liquid surface of the first flotator; The foam created is directed into a liquid bath of a second flotator to create a foam containing a substantial amount of suspended particulate matter on the liquid surface of the second flotator and other components of the slurry. and (iii) allowing the tailings fraction from the first flotation machine and the tailings fraction from the second flotation machine to settle into the first and second flotation machines. counter-current withdrawal in a common communicating bottom below the flotation machine, the common communicating bottom being inclined downwardly towards the direction in which the input slurry is fed in step (i); A foam flotation separation method for components of a slurry, the method comprising: 9. Collecting at least a portion of the settled material of the first flotator in a collector and recirculating it to the liquid bath of the first flotator, and foaming at least a portion of the recycled material onto the liquid surface; 9. The method according to claim 8, wherein the method is made to float as follows. 10. A patent claim in which the settled material of the second flotation machine is collected in a collector and recirculated to the liquid bath of the second flotation machine, and a portion of the recycled material is suspended as a foam on the surface of the liquid. The method according to item 8. 11. The foam created on the liquid surface of the second flotation machine is sent to a third flotation machine having a liquid bath, and the foam containing a substantial amount of floating particulate matter is transferred to the surface of the liquid bath. 9. A method according to claim 8 for producing. 12. further extracting tailings from the third flotation machine in countercurrents in a common communicating bottom below the first, second and third flotation machines;
12. The method of claim 11, wherein the common communicating bottom slopes downwardly in the direction in which the input slurry of step (i) is introduced. 13. The method of claim 12, wherein liquid is pumped into the upper end of the common communicating sloped bottom to create a controlled countercurrent flow of tailings. 14. The method of claim 12, wherein the foam on the liquid of the third flotation machine is collected.