DE10029537C1 - Mineral loose material sampling method uses separation grid, turbine and cyclone for separation of successive material quantities to provide X-ray fluorescence sample - Google Patents

Abstract

The sampling method uses a separation grid (11) for removal of a relatively small quantity of material particles from the loose material stream, with the movement direction of the separated particles altered via an impact plate (28), or by an energy stream or an electrical field, with subsequent separation out of a second and a third partial quantity via a turbine and a cyclone. The largest particles are pulverized and combined with the remaining particles for providing an analysis sample for an X-ray fluorescence analysis device. An Independent claim for a mineral loose material sampling device is also included.

Description

The invention relates to a method and a device for taking samples from moving mineral bulk materials.

Methods and devices for taking dust-like samples from mineral bulk goods have become known, for example, from EP 0 331 903 A2, DE 38 06 677 A1 and DE 195 23 075 C1. This state of the art Common to technology is that it is exclusively about procedures and Devices for taking dust-like samples. The condition this is because the mineral to be sampled has a dusty consistency can.

A method has become known in particular from EP 0 331 903 A2, from which the four following method steps can be taken, according to which:

• - From a bulk material flow, a subset through a pipe over the limited opening of the tube is removed,
• - the direction of movement of the particles in the tube after removal will be changed,
• - With the help of a device from the first subset a second Subset is suctioned off and then
• - From this second subset on the corresponding device third subset is suctioned off.

The requirements for a dusty consistency of the mineral to be sampled however, they are not always available without restrictions. They fail or do not lead satisfactory results for minerals, where for example the to sampling lignite contains high levels of salt. The same is true where siderite, Iron carbonate FeCO3, which contains lignite. In both cases this leads Burning such lignite to make the ash doughy. The batter Ash then forms agglomerates weighing several tons, which adhere to the  Separate the boiler wall. From a certain size, these can be No longer hold agglomerates on the boiler wall and fall down. You can great damage to the boiler.

The presence of salt and iron compounds in the sample to be sampled However, mineral can only be detected if the bulk material flow Particles can be removed that have a grain size whose Diameter is greater than 10 mm. Particles of this size are significantly larger as dust particles.

This results in the object of the present invention, which is already apparent from the To further develop methods and devices known in the art, that the presence of sodium and iron compounds within one mineral bulk goods, especially raw lignite, with sufficient Security can be demonstrated.

This object is achieved by a method having the features of patent claim 1 solved.

It is particularly beneficial if you have the direction of movement of particles that branched off from the falling bulk flow, changes. So that will avoided that too large a proportion of dust-like particles from the branched amount is sucked. With the change in the direction of movement, especially the larger particles, it is guaranteed that their share in the aspirated amount is sufficient to the critical sodium and To be able to analyze iron compounds.

Use gravity or to change the direction of movement Inertia of the particles. In the former case the kinetic energy of the falling particles to bounce off a fixed resistance to them to be able to suction. In the second case, the particles come from outside with energy acts, whereby they change their direction of movement.  

With the help of a cyclone, the extracted partial quantity becomes a partial quantity deposited, which has a particularly high proportion of large particles.

The aim is to take the sample continuously. For this Basically there are two suction pipes parallel to each other, each with its own cyclone intended. These are operated one after the other, i. H. first is about that first suction tube and the first cyclone a first sample and then over the second Suction tube and the second cyclone taken a second sample, whereupon the Withdrawal cycle repeated. After the rough separation, the coarse particles separated are brought together to form a continuous stream, crushed, and fed to the measuring device already mentioned.

However, it can also be advantageous to open up the coarse particles before comminution Sieve grain sizes smaller than 10 mm. The screening then takes place before the Crush the particles in a grinder or crusher. The intermediary a screening level depends on the type and the respective state of the sampling mineral.

A device for performing the method has the in claim 3 specified features.

The grid divider consists of a plurality of parallel and im mutual spacing arranged straight bars, each one have approximately trapezoidal cross-section, the two facing each other parallel sides of the trapezoid run horizontally by the wider side above is arranged. For a better understanding of the following explanations stated that the term "top" and the term "bottom" are each horizontal Define the location of objects that are spaced vertically from each other.  

The wide, upper side of the trapezoidal cross-section of the bars is straight or arched. The two oblique, tapering downwards Sides of the trapezoid, which represents the cross section of the bars each a concave shape. This way, at the entry of the grating divider sharp edges are formed, which are intended to particles, which are only slight are larger than the mutual lateral spacing of the bars, initially slow down and then under the force of the subsequent bulk material flow to press through the grid divider.

The bars are firmly connected to a shaft in a way that that they can be replaced if necessary. The shaft has is a square, round or oval cross section and its wall usually closed, but it can also have openings, especially in its lower area, where bulk particles are not extracted be returned to the rest of the bulk material flow.

As an organ to change the direction of movement of particles that make up the lattice divider have passed, a baffle plate is suitable, which is in the shaft at a distance arranged below the grating at an angle to the horizontal is. The angle of inclination of the baffle can be changeable and adjustable. The The inclination of the baffle plate depends on the mineral to be sampled and its current state, d. H. dry or moist.

Particles that were first slowed down by the grid divider and then pressed through the grating divider, come under in free fall increasing speed on the inclined baffle plate. When it hits They jump upwards on the baffle plate and change their way in this way Direction of movement. After changing the direction of movement pulled them into the mouth of a suction pipe. With the help of the baffle plate avoided that predominantly fine, d. H. dusty particles be sucked in. The inclination of the baffle plate also prevent that  Form caking on the baffle plate, especially when it is wet Bulk goods is to be feared.

Instead of a baffle plate, the particles falling through the grating divider can also be subjected to an air or liquid flow from the side. Even in such a case, they change their direction of movement and it is ensures that as many of the larger particles as possible are extracted. Next A possible lateral flow against the particles can also change the direction of movement of the larger particles using an electric field take place, which is built up inside the shaft.

The mouth of the intake manifold is to enlarge the inlet cross-section beveled at the top. It is also advantageous if the mouth of the suction pipe is on or is horizontally pivoted in the wall of the shaft. It is for that required, a suitable joint and a suitable drive on the wall to install the shaft, with the help of which the mouth of the suction pipe is horizontal can be pivoted.

The components of the device for removing from described so far Samples from a bulk flow are all within the funnel one Transfer station arranged where the mineral bulk in free fall from a first conveyor belt is handed over to a second. Appropriate Transfer points are, for example, also in the state mentioned at the beginning Technology shown.

Parallel to the first suction pipe and the first cyclone is a second suction pipe and a second cyclone for coarse separation and one turbine each. The A fine separation is connected downstream of the upper exit of the cyclones can also be acted upon by the turbine with the induced draft. Are optional one of the two suction pipes and the downstream separators, as well as the Turbines can be operated. The operation is carried out discontinuously one after the other by one suction pipe is operated while the other is at rest. As soon as one  sufficient amount of coarse grain has been deposited in the first cyclone is on the second intake manifold is switched over and the deposition cycle is repeated. Finally, the two coarse deposits are brought together and theirs Particles fed to a crusher. The crusher crushes the particles Grain sizes of less than 3 mm in diameter, making them suitable for the following Measurement in the measuring device have the optimal size.

In special cases, the rough discharge of both cyclones can be provided first dose and then pass through a sieve. The sieve passage lies below 10 mm and then becomes the crusher already described fed. The interposition of a sieve is of the respective type and Condition, dry or moist, depending on the mineral to be sampled. In addition to raw lignite, other minerals such as hard coal or Ores can be sampled in this way.

The invention is explained in more detail below using an exemplary embodiment described. They do not show to scale and are greatly simplified as well as schematically the

Fig. 1 is a belt transfer of bulk goods in the view,

Fig. 2 shows a longitudinal section through a grid divider and

Fig. 3 shows the schematic flow of sampling, sample preparation and measurement.

A mineral bulk material stream 1 is brought in via a conveyor belt 2 and falls freely over a deflection drum 3 into the hopper 4 of a transfer station. Below the conveyor belt 2 there is a second conveyor belt 5 which is moved in the direction indicated by the arrow 7 via a deflection drum 6 . Accordingly, the bulk material stream 1 reaches the transfer point 8 in the direction of arrow 9 and leaves it again in the direction of arrow 10 . The mineral bulk material stream 1 is freshly obtained raw lignite, the particle size of which ranges from fine dust to large chunks.

In Fig. 1 shows a section A is shown from the case in free flow of bulk material 1. Section A shows a grid divider 11 , which is shown enlarged in FIG. 2. The grating divider 11 consists of a plurality of grating bars 12 , each of which has an approximately trapezoidal cross section. As a rule, there are four lattice bars 12 which delimit a shaft 14 at the top. The bars 12 are firmly connected to the wall 15 of the shaft 14 but in such a way that they can be replaced if necessary. The shaft 14 has a rectangular cross section and accordingly the bars 12 have a length between 200 and 400 mm. Their height 16 is approximately 40 mm and their mutual distance 17 on the top 18 is approximately 20 mm. The upper side 18 has a width 19 of approximately 30 mm and tapers to the parallel underside 20 over the two sides 21. The two sides 21 are each concave, as a result of which a sharp edge 22 is formed between the sides 21 and the upper side 18 .

The two opposing sharp edges 22 of two adjacent bars 12 cause, for example, a bulk particle 23 , which is only slightly larger than the distance 17 between two bars 12 , initially sticks to the bars 12 in its free fall, ie its falling speed is reduced briefly to zero. From the subsequent bulk material flow 1 , the particle 23 is then pressed through the sharp edges 22 into the shaft 14 . The speed of the particle 23 within the shaft 14 increases again in free fall.

It should also be noted that of the four lattice bars 12 which form the lattice divider 11 , the two lattice bars 24 adjacent to the wall 15 each have only half a cross-section. This has the effect that the clear width of the shaft 14 is particularly small, so that chunks 25 , which do not fit through the bars 12 , are laterally torn into the funnel 4 by the flowing bulk material stream 1 in the direction 26 and are again with the rest of the bulk material stream 1 unite.

Instead of a straight top 18 , as shown in FIG. 2, the top 18 of the bars 12 can also be curved or pointed. In comparison to the cross-sectional area (not shown) of the bulk material flow 1 , the grating divider 11 has only a small cross-sectional area; the ratios are approximately between 50 to 100: 1. The relatively smaller cross-sectional area of the grating divider 11 ensures that chunks 25 , which can no longer pass through the grating divider 11 , are pulled down laterally in the direction 26 , so that the top 18 of the grating divider is always cleans itself again.

A baffle plate 28 is arranged within the shaft 14 at an appropriate distance below the grid divider 11 . The baffle plate 28 is arranged at an angle 29 obliquely to the vertical within the shaft 14 . The angle of attack 29 of the baffle plate 28 is adjustable in the range of the angle 30 . The inclination of the baffle plate 28 can be adjusted from outside the funnel 4 via a slide rod 31 . The baffle plate 28 causes larger particles 23 and smaller 27, which have passed through the splitter 11 and hit the baffle plate 28 in free fall in the direction 9 , to bounce off it and continue to move in the direction of the curved arrow 32 . They come into the effective area 33 of the mouth 36 of a suction pipe 34 which is guided laterally through the wall 15 of the shaft 4 . The sucked-in particles 23 and 27 are conveyed further in the direction of arrow 35 within the suction pipe 34 . The mouth 36 of the suction pipe 34 has a bevel, as a result of which the inlet cross section is enlarged. In addition, a joint 37 can be provided on the wall 15 , about which the mouth 36 of the suction pipe 34 can be pivoted horizontally. The swivel direction is indicated by the curved arrow 38 . Particles 23 and 27 , which were not captured by the suction pipe 34 , leave the shaft 14 via a lateral opening 39 in the lower region of the wall 15 and combine with the rest of the bulk material flow 1 . Within the funnel 4 , the grating divider 11 is held by strong arms 40 , as can be seen in FIG. 1.

The illustration of FIG. 3 is divided into three areas inverted sampling I, II sample preparation, measurement device III and IV conveyed away.

Particles 23 and 27 that pass through the suction pipe 34 in the direction of arrow 35 first land in a coarse cyclone. A coarse separation 43 and a fine separation 41 take place there. The required suction is generated by a turbine 42 . The larger particles 23 preferably collect in the coarse separation 43 , while the smaller particles 27 predominantly end up in the fine separation 41 . From there they are carried out from time to time, but this is no longer of interest for the present description. The fill level of the coarse separation 43 is monitored by fill level sensors L. As soon as the predetermined fill level in the coarse separation 43 is reached, the particles are drawn off via lines 44 . The lines 44 open into a common line 45 .

In sampling I, two suction lines 34 and two coarse cyclones are arranged parallel to one another. These two facilities are operated discontinuously one after the other. During the operation of the 1st sampling, the operation rests in the 2nd sampling and cleaning takes place by means of a flow directed against the suction. After the fill level sensor L has reported the specified degree of filling in the coarse separation 43 to the sampling device, the device automatically switches the 1st sampling and switches to the 2nd sampling. The same happens with the deduction of the coarse separation via the lines 44 . Due to the discontinuous 1st and 2nd sampling, however, it is achieved that there is always a continuous stream of sample material in the line 45 , here referred to as the third subset.

The third partial quantity reaches the sample preparation II from the line 45. The sample preparation II first provides a crusher or a mill which comminutes the particles of the coarse separation 43 to particle sizes below 3 mm. These comminuted particles are then metered out in a measuring-fine manner and fed to the measuring device III. The measuring device III preferably works according to the X-ray fluorescence analysis method. The individual elements of the measuring device III are illustrated in FIG. 3. After the analysis has been carried out, the samples are discharged via a belt system 46 . FI sensors monitor the dosing fillings.

If necessary, a pre-metering can take place at the entrance of sample preparation II, ie behind line 45 . The particles recorded in the pre-metering are then sent through a sieving stage, from which particles with a diameter greater than 10 mm are discarded. The discarded particles reach the belt system 46 . Particles whose diameter is smaller than 10 mm are crushed by the crusher or the mill and fed to the measuring device III in the manner already described. The interposition of a pre-metering and a sieving stage at the entrance to sample preparation II depends on the type and the respective condition, dry or moist, of the mineral to be sampled.

Claims (21)

1. A method for taking samples from moving mineral bulk goods, characterized in that
with the aid of a grating divider ( 11 ), a first partial quantity, which is small in relation to the volume per unit time of the falling bulk material, branches off from a falling bulk material stream with an upper grain size,
by bouncing off an organ ( 28 ) or by applying external energy via a line or an electric field, the direction of movement of at least some particles ( 23 , 27 ) of the first subset changes,
sucks off a second partial quantity from the particles with a changed direction of movement and from the remaining first partial quantity with the aid of a turbine ( 42 ),
separates a third partial quantity from the second partial quantity with the aid of a coarse cyclone as a coarse separation ( 43 ), which has an increased proportion of particles with a large grain size,
crushed the larger grains of the third subset in a crusher or a mill,
in a metering device, a fourth portion is dosed from the comminuted grains and from the remaining particles of the third portion and
feeds the fourth subset to a measuring device operating according to the X-ray fluorescence analysis method, which analyzes the bulk material with regard to its inorganic constituents and their respective proportions. 2. The method according to claim 1, characterized in that temporally takes two samples in succession and the third subsets from the two Sampling combined into a continuous subset. 3. The method according to claim 1 or 2, characterized in that the third portion dosed and to grain sizes of less than 10 mm in diameter sieves.   4. Device for performing the method according to one of claims 1 to 3, characterized by the following components:

• - A lattice divider ( 11 ), which is arranged in a funnel ( 4 ), for branching off a first subset from a falling flow ( 9 ) of a bulk material ( 1 )
• - A shaft ( 14 ) below the grid divider ( 11 ), which is in its interior
• has an organ ( 28 ) for changing the direction of movement ( 32 ) of particles ( 23 , 27 ) of the first subset of the bulk material ( 1 ) which have passed the grating divider ( 11 ),
• - A suction pipe ( 34 ) for sucking a second subset of particles ( 23 , 27 ) from the first subset, the mouth ( 36 ) of which begins in the shaft ( 14 ) above the organ ( 28 ) and the other end of which outside the shaft ( 14 ) in
• a coarse cyclone ends where a coarse separation ( 43 ) of a third subset of particles ( 23 , 27 ) takes place,
• a turbine ( 42 ) for generating a suction draft in the suction pipe ( 34 ) and in the coarse cyclone,
• a crusher or a mill after the coarse separation ( 43 ) of the coarse cyclone for comminuting larger particles ( 23 ) of the third subset,
• a metering device following the crusher or the mill for dividing a fourth partial amount as a sample amount,
• - A complex measuring device (IV) for performing the X-ray fluorescence analysis on the sample amount and
• - A belt system ( 46 ) for removing excess portions.

5. The device according to claim 4, characterized in that the grating divider ( 11 ) consists of a plurality of parallel and spaced apart ( 17 ) from each other straight grating bars ( 12 ), each having an at least approximately trapezoidal cross-section ( 13 ), wherein the two mutually parallel sides (18, 20) of the cross section ( 13 ) are arranged horizontally with the wider side (18) at the top. 6. The device according to claim 5, characterized in that the wide, upper side (18) of the trapezoidal cross-section ( 13 ) of the bars ( 12 ) is straight or curved. 7. The device according to claim 5, characterized in that the two oblique, downwardly tapering sides (21) of the trapezoidal cross-section ( 13 ) of the bars ( 12 ) each have a concave shape. 8. Device according to one of claims 4 to 7, characterized in that the lattice bars ( 12 ) with the wall ( 15 ) of the shaft ( 14 ) are fixedly connected. 9. Device according to one of claims 4 to 8, characterized in that the shaft ( 14 ) has a square, round or oval cross section. 10. Device according to one of claims 4 to 9, characterized in that the shaft ( 14 ) is open towards the bottom or has a lateral opening ( 39 ) in its lower part of the wall ( 15 ). 11. The device according to any one of claims 4 to 10, characterized in that the organ ( 28 ) for changing the direction of movement of particles ( 23 , 27 ) is a baffle plate, which is in the shaft ( 14 ) at a reasonable distance below the grid divider ( 11 ) is inclined at an angle ( 29 ) to the horizontal. 12. The apparatus according to claim 11, characterized in that the angle of inclination ( 29 ) of the baffle plate is variable and adjustable. 13. Device according to one of claims 4 to 10, characterized in that the organ for changing the direction of movement of particles ( 23 , 27 ) is a line which opens into the shaft ( 14 ) and via which a pressure medium in the shaft ( 14 ) can be introduced. 14. Device according to one of claims 4 to 10, characterized in that an electric field is present for changing the direction of movement of particles ( 23 , 27 ). 15. Device according to one of claims 4 to 14, characterized in that the mouth ( 36 ) of the suction pipe ( 34 ) is chamfered upwards to enlarge the inlet cross section. 16. The device according to one of claims 4 to 15, characterized in that the mouth ( 36 ) of the suction pipe ( 34 ) on or in the wall ( 15 ) of the shaft ( 14 ) is horizontally pivoted. 17. Device according to one of claims 4 to 16, characterized in that the shaft ( 14 ) is arranged within the funnel ( 4 ) of a transfer station where the mineral bulk material ( 1 ) in free fall ( 9 ) from a first conveyor belt ( 2nd ) is transferred to a second conveyor belt ( 5 ). 18. Device according to one of claims 4 to 17, characterized in that a second suction pipe ( 34 ) and a second coarse cyclone with coarse separation ( 43 ) and turbine ( 42 ) are present parallel to the first suction pipe ( 34 ). 19. The apparatus according to claim 18, characterized in that at least one of the two coarse cyclones is followed by a fine separation ( 41 ) which can also be acted upon by the turbine ( 42 ). 20. The apparatus of claim 18 or 19, characterized in that either one of the two suction pipes ( 34 ) and the subsequent coarse deposits ( 43 ) or fine deposits ( 41 ) and turbines ( 42 ) can be operated. 21. Device according to one of claims 18 to 20, characterized in that the coarse separation ( 43 ) of both coarse cyclones opens in a common line ( 45 ) before the crusher, the mill or a sieve.