Magnetic separator and pulverized coal combustion apparatus using the same

In a vacuum housing (1), an inner duct (17) is disposed. Quadrupole magnets (superconducting coils) (4) is placed around the inner duct (17) is excited by a DC power supply (10). Quadrupole magnets (4) are cooled by liquid helium contained in a helium housing and outer tubes (2, 3) and is brought into a superconducting state. Pulverized coal X is ejected together with air Y from a header (11) through piping (12) and a valve (13) to a baffle plate (14). Pulverized coal is made to fall into the inner duct (3). Paramagnetic materials such as ash are attracted by magnetic force to the tube and are then collected by a collection tube (26). Combustible diamagnetic materials are collected by a combustible collecting tube (18) extending in the central axis. Intermediate materials are collected by an intermediate collection tube (23) and are put back to the head (11) through a bypass tube (25). There are no mechanical parts in the inner duct (3). Consequently, rotation loss and eddy-current heating are prevented.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a magnetic separator (namely, a magnetic 
separation apparatus) used for coal cleaning and to a pulverized coal 
combustion (or firing or burning) apparatus using the magnetic separation 
apparatus (or system). 
2. Description of the Related Art 
FIG. 9 is a diagram illustrating the principle of magnetic separation, 
which shows the distribution of lines of magnetic force of quadrupole 
magnets and the magnetic field strength distribution in an inner duct 
thereof. In this figure, reference numeral 40 designates quadrupole 
magnets that have a quadrupole structure provided in a circle therein. The 
lines 41 of magnetic force are generated by this magnet 40. Here, let 
(dH/dZ), H, X and V denote magnetic field gradient, magnetic field 
strength, magnetic susceptibility and the volume of a fine particle, 
respectively. Magnetic force Fm given by the following equation (1) acts 
in the direction of the magnetic field gradient: 
EQU Fm=.chi..mu..sub.o VH(dH/dZ) . . . (1) 
Incidentally, in the aforementioned equation (1), .mu..sub.o denotes an 
absolute permeamibility of vacuum. Magnetic separation is performed by 
utilizing a variation in this magnetic force, which is caused due to a 
change in the magnetic susceptibility of this fine particle. As 
illustrated in FIG. 9, the magnetic force Fm given by the aforementioned 
equation (1) acts upon a fine particle contained in the inner duct 42 of 
the four-pole magnet 40. Variation in this magnetic force results in a 
change in the position in the Z-direction of each fine particle, so that 
the magnetic separation is achieved. 
FIG. 10 is a diagram conceptually illustrating a section of a conventional 
magnetic separator employing such a principle of magnetic separation and 
illustrates an apparatus 110 for separating a dry paramagnetic material 
from a dry diamagnetic fine-grain material. Hereinafter, this apparatus 
will be described in detail. 
A wall 114 and an inner space 116 vertically extend in the axial direction 
of the apparatus and thus compose a cylinder 112. Rotary screw 118 is 
installed in the cylinder 112. The screw 118 consists of the shaft 120 and 
a helical blade 122. The helical blade 122 is angled downwardly in both of 
the radial and axial directions and is accommodated inside the wall 114. 
The screw 118 is connected to a motor 124 and is rotated by this motor 
124, so that fine particles are carried from the top portion of the screw 
118 downwardly. A vibration drive or exciter (namely, a shaker) 126 is 
connected to the screw 118. The screw 118 is shaken during the rotation 
thereof. 
A magnet 128 is disposed around the wall of the cylinder 112. This magnet 
128 acts the magnetic field in the inner space 116. Thus, there is 
constructed a four-pole magnet, by which the magnetic field gradient is 
given in the inner space 116. The magnetic field (strength) has a maximum 
value on the wall 114. Further, the magnetic field strength at a point 
decreases as the point approaches the shaft 120. This magnetic field is 
constant in a central zone 129. In an edge portion 132, the magnetic field 
decreases linearly in the upward direction from an edge 132 of the magnet 
128. 
To enhance the separation ability or performance, a pulverizer 134 is used. 
Pulverized coal is sent by an auger 136 to a movable coal feeder 138. 
Then, the pulverized coal is sent from the coal feeder 138 to the helical 
blade 122. Rotation of the screw 18 brings the pulverized coal into the 
apparatus 110. 
Paramagnetic fine particles of kaolinite and ash undergo the magnetic force 
Fm illustrated in FIG. 9 and move toward the wall 14, while fine particles 
of combustible (organic) content contained in the coal, which are 
diamagnetic fine particles, move along the direction of the shaft 120. 
A splitter 142 is provided in a lower portion of the apparatus 110 and is 
composed of three concentric cylinders or tubes 144, 146 and 148. The tube 
144 collects fine particles (incidentally, major constituents thereof are 
diamagnetic fine particles), which approaches the shaft 120. The tube 148 
collects fine particles (incidentally, major constituents thereof are 
paramagnetic fine particles), which approaches the wall 114. The tube 146 
collects a mixture of antimagnetic and paramagnetic fine particles. 
The aforementioned conventional magnetic separator 110 has the following 
problems: 
(1) Mechanical drive parts such as the screw 118, the rotary shaft 120, the 
motor 124, the vibration exciter 126 and the helical blade 122 are 
provided in the inner duct of the quadrupole magnet, so that the clogging 
thereof owing to the fine particles and the abrasion thereof occur. 
(2) Residual magnetization occurs in machine parts with the result that the 
fine particles adhere to the blade and so forth. Consequently, the 
separation performance is degraded. 
(3) Leakage current occurring in the rotating parts results in the 
generation of heat and in the occurrence of rotation loss. 
(4) When using a superconducting magnet in the case that electric current 
is directly supplied to the quadrupole magnets from the power supply, 
losses occur in an electric lead and in a normal conducting part of the 
power supply. Further, in the case of using the normal conducting magnet, 
losses are produced in the entire system. 
(5) In the case that the aforementioned conventional magnetic separator 110 
is applied top as an apparatus of separating combustible (organic) 
materials from incombustible materials (such as pearlite, kaolinite and 
ash), if this magnetic separator is provided separately from a combustion 
apparatus, there is the necessity of labor and space for the storage, 
retention and conveyance of separated materials. Consequently, the cost of 
the magnetic separator is increased. 
OBJECT AND SUMMARY OF THE INVENTION 
Accordingly, an object of the present invention is to provide means for 
solving the aforementioned problems of the conventional apparatus. 
A practical object of the present invention is to prevent occurrences of 
rotation losses and eddy currents in a magnetic separator used for coal 
cleaning and in a pulverized coal combustion apparatus, which uses the 
magnetic separator, by eliminating the mechanical parts and using a 
superconducting coil. 
Another object of the present invention is to provide a compact 
high-quality high-efficiency pulverized coal combustion apparatus (or 
system), by which the labor and space to be taken to achieve the storage, 
retention and conveyance of combustible (organic) materials that are 
separated and collected for coal leaning. 
To achieve the foregoing objects, in accordance with the present invention, 
there is provided the following means. 
(1) Namely, there is provided a magnetic separator (hereunder sometimes 
referred to as a first magnetic separator of the present invention) which 
comprises a cylindrical inner duct disposed along the vertical direction; 
quadrupole magnets constituted by superconducting coils, which are placed 
around the aforesaid inner duct and are cooled by liquid helium and are 
excited by use of a DC power supply; fine-particle supply means for 
ejecting and dropping fine particles, which consist of a plurality of 
elements and compounds, from a top end of the aforesaid inner duct; and 
first and second collection tubes, which are provided at a bottom portion 
of the aforesaid inner duct, for separating and collecting a paramagnetic 
material and a non-magnetic material, which are included in the 
aforementioned fine particles, owing to a difference between magnetic 
forces respectively acted on the aforementioned fine particles, which are 
ejected from the aforementioned fine particle supply means and drop. 
(2) Further, in the case of an embodiment (hereunder sometimes referred to 
as a second magnetic separator of the present invention) of the magnetic 
separator described in the aforesaid first magnetic separator of the 
present invention, the aforesaid fine-particle supply means comprises an 
umbrella-like baffle plate disposed in the aforesaid top end portion, 
wherein fine particles are ejected upwardly toward the aforesaid baffle 
plate from a lower portion thereof, and then the fine particles having 
collided with the aforesaid baffle plate are caused to drop toward the 
aforesaid inner duct. 
(3) Further, in the case of an embodiment (hereunder sometimes referred to 
as a third magnetic separator of the present invention) of the magnetic 
separator described in the aforesaid first or second magnetic separator of 
the present invention), the aforesaid quadrupole magnets comprise normal 
conducting coils and are cooled with liquid helium. 
(4) Further, in the case of an embodiment (hereunder sometimes referred to 
as a fourth magnetic separator of the present invention) of the magnetic 
separator described in the aforesaid first or third magnetic separator of 
the present invention), a persistent current circuit switch is connected 
in parallel with the aforesaid quadrupole magnets. 
(5) Further, in the case of an embodiment (hereunder sometimes referred to 
as a fifth magnetic separator of the present invention) of the magnetic 
separator described in the aforesaid first or second magnetic separator of 
the present invention), an intermediate-material collection tube, which is 
operative to collect intermediate materials, and a bypass collection tube, 
which is operative to supply the material collected by the aforesaid 
intermediate- material collection tube, are provided between the aforesaid 
first and second collection tubes. 
(6) Furthermore, there is provided a pulverized coal combustion apparatus 
(hereunder sometimes referred to as a sixth apparatus of the present 
invention) that comprises: 
a magnetic separator having a cylindrical inner duct; quadrupole magnets 
constituted by superconducting coils, which are placed around the 
aforesaid inner duct and are cooled by liquid helium and are excited by 
use of a DC power supply; fine-particle supply means for ejecting and 
dropping fine particles from a top end of the aforesaid inner duct; and 
first and second collection tubes, which are provided at a bottom portion 
of the aforesaid inner duct, for separating and collecting a paramagnetic 
material and a non-magnetic material, which are included in the 
aforementioned fine particles ejected from the aforementioned fine 
particle supply means and drop; 
a pulverized coal manufacturing unit, which is connected to the aforesaid 
fine-particle supply means, for manufacturing pulverized coal; and 
a pulverized coal burner connected to the aforesaid second collection tube 
of the aforesaid magnetic burner. 
The present invention achieves the objects by such means. In the case of 
the first magnetic separator of the present invention, fine particles, 
which are ejected from the upper part of the inner duct by use of the 
aforesaid fine-particle supply means, fall under their own weight. 
Further, paramagnetic materials contained in fine particles are attracted 
by the force of attraction of the quadrupole magnets to the tube while 
dropping. Then, the paramagnetic materials are collected from the first 
collection tube placed at the lower portion of the inner duct. Moreover, 
non-magnetic materials fall on or along the central axis of the inner duct 
without being attracted by the second collection tube, and are then 
collected by the second collection tube. In the case of the second 
magnetic separator of the present invention, the fine-particle supply 
means is constituted by the umbrella-like baffle plate, so that after 
colliding with this baffle plate, the fine particles can be diffused, and 
can be further scattered uniformly, and can fall under their own weight. 
Therefore, in this case, the accuracy of the magnetic separation can be 
enhanced, in addition to the case of the first magnetic separator of the 
present invention. Moreover, in the case of the fifth magnetic separator 
of the present invention, the intermediate-material collection tube and 
the bypass tube are added thereto. Thus, the intermediate material are 
ejected from the inner duct again. Consequently, in addition to the 
advantages of the first and second magnetic separators, the fifth magnetic 
separator of the present invention has the advantage in that the accuracy 
of the magnetic separation is enhanced. 
Thus, in the case of the first, second and fifth magnetic separators of the 
present invention, there are no rotation drive mechanical parts in a 
working or operating space. Therefore, troubles due to the mechanical 
parts in the operating space, such as the clogging, which is owing to the 
fine particles, and the abrasion, are not caused. Thus, the problem of the 
residual magnetization, which has been caused in the mechanical parts of 
the conventional apparatus, does not occur. Moreover, heat emission and 
rotation loss due to eddy current, which has been generated in the 
rotating portions of the mechanical parts in the conventional case, are 
not caused. 
Further, in the case of the first magnetic separator, the quadrupole 
magnets are operated in a persistent current mode, because the 
superconducting coils are used. Thus, all of the electric circuit is in a 
superconducting state. Consequently, this prevents an occurrence of power 
loss due to Joule's heat. Moreover, in the case of the third magnetic 
separator, the quadrupole magnets are constituted by normal conducting 
coils. Therefore, for example, when a copper line reaches a liquid 
nitrogen temperature (-196 degrees centigrade), the resistance of the 
copper line is reduced by a factor of 5 to 10. Thus, a current passing 
through the copper line can be increased. Thereby, a high magnetic field 
can be obtained by the circuit of the same size. Further, a compact 
apparatus can be realized. The cost of refrigerant can be reduced. 
Furthermore, the fourth magnetic separator of the present invention is 
provided with a persistent current circuit switch, so that a persistent 
current flows through the quadrupole magnets. There is little necessity of 
supplying power to the apparatus during an operation thereof. Evaporation 
of liquid helium is supplemented by heat of penetration (or penetrating 
heat). 
Further, in the sixth apparatus of the present invention, the magnet 
separator is incorporated into the pulverized coal manufacturing apparatus 
and combustion facilities. Thus, the magnetic separator separates 
paramagnetic materials such as ash from non-magnetic materials, which are 
combustible materials, in pulverized coal and supplies combustible fine 
particles to a coal combustion burner. Therefore, the labor and space for 
the storage, retention and conveyance of combustible (organic) materials 
obtained by the magnetic separation and collection become unnecessary. 
Consequently, a compact, high-quality high-efficiency coal combustion 
apparatus (or system) is obtained.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Hereinafter, the preferred embodiments of the present invention will be 
concretely described in detail by referring to the accompanying drawings. 
FIG. 1 is a sectional view of a magnetic separator which is a first 
embodiment of the present invention. FIG. 2 is a sectional view taken on 
line A--A of FIG. 1. In both diagrams, reference numeral 1 designates a 
vacuum housing; 2 an inner tube or cylinder of a helium housing; 3 an 
outer tube of the helium housing; 4 quadrupole magnets (superconducting 
coils); 5 a coil presser; 6 a liquid helium shield (at about 80 K); 7 a 
current lead; 8 a bus bar; 9 a switch; and 10 a DC power supply. After the 
coils 4 are cooled with liquid helium Z, the switch 9 is closed, so that 
electric current is made to pass therethrough. The quadrupole magnets are 
in an superconducting state. Thus, power loss due to Joule's heat does not 
occur. During operation, no power is supplied. Evaporation of liquid 
helium has only to be supplemented by heat of penetration. 
Reference numeral 11 is supplied with pulverized coal from X and is fed 
with air from Y and ejects pulverized coal in solid-gas two-phase state to 
the umbrella-like baffle plate 14 through the piping 12 and the valve 13. 
Reference numeral 15 denotes an exhaust duct; and 16 an exhaust valve. Air 
is exhausted from Y' and pulverized coal is made to fall from B. 
Reference numeral 17 designates an inner duct; 18 a combustible-material 
(diamagnetic) collection tube; 19 collection piping; 20 a collection tube; 
21 flow regulating valve; and 22 a blower. Further, reference numeral 23 
designates an intermediate collection tube; and 24 a blower. Pulverized 
coal collected by the intermediate collection tube 23 is put back to the 
header 11 through a bypass tube 25. Reference numeral 26 denotes a 
collection tube for collecting ferromagnetic fine particles such pearlite 
and paramagnetic fine particles such as kaolinite and ash; 27 collection 
piping; 28 a collection tube; and 29 a flow regulating valve. 
In such a configuration, the fine particles B fall under their weight from 
the top end portion of a quadrupole magnets 4 consisting superconducting 
coils. Further, paramagnetic fine particles, such as kaolinite and ash, 
undergo magnetic force as illustrated in FIG. 9 and is attracted to the 
tube or cylinder wall of the inner duct 17, and combustible constituents 
(organic constituents), which are diamagnetic fine particles, contained in 
coal are attracted to the central axis of the pulverized , and are 
collected by the collection tube 26 and the combustible-material 
collection tube 18, respectively. 
Pulverized coal collected by the intermediate collection tube 23 is put 
back to the header through the bypass tube 25 and is then made to fall 
under its weight again from the upper part of the inner duct 17. Thus the 
degree of separation is enhanced. 
Incidentally, when this magnetic separator employs a configuration in which 
normal conducting coils 60, as illustrated in FIGS. 6 and 7, are used 
instead of the superconducting coils 4 and further liquid helium is used 
as the refrigerant so as to obtain a compact separator and reduce the cost 
of refrigerant, advantages similar to those described hereinabove are 
obtained. 
Namely, a plurality of homopolar opposing solenoid magnets 60 as 
illustrated in FIGS. 6 and 7 may be used instead of the quadrupole magnets 
4. In this case, a plurality of solenoid magnets 60 excited in such a 
manner as to have homopole and are arranged in such a way as to be 
concentrically along the axis at almost uniform intervals. With such a 
configuration, the lines of magnetic force 70 are generated as shown in 
FIG. 8. Thus, the magnetic field distribution as shown in the figure. 
Therefore, the magnetic separation action is achieved on the same 
principle as above described. 
FIG. 3 is a side view of the magnetic separator, which is the second 
embodiment of the present invention. In FIG. 3, reference numerals 1 to 29 
are the same as of the first embodiment of FIG. 1. Thus, the redundant 
description thereof is omitted. Characteristic portion of the second 
embodiment is a portion to which a persistent currant switch is added. 
FIG. 4 is a schematic diagram illustrating the electrical wiring system of 
a persistent current switch of the second embodiment of the present 
invention. During operation of this separator, a DC current is supplied to 
the quadrupole magnet (superconducting coils) by an current lead 7 through 
a switch 9 and a bus bar 8 from a DC power supply 10. Moreover, the 
quadrupole magnets 4 is connected in parallel with a persistent current 
switch 30. The persistent current switch 30 is cooled. Furthermore, the 
entire electrical circuit is in a superconducting state as a result of 
persistent current mode operation, so that the power loss due to Joule's 
heat is eliminated. Thus, during a closed circuit indicated by letter C, 
an electric current can be the quadrupole magnet 4 only by supplementing 
the evaporation of liquid helium, which is caused to heat of penetration 
almost without supplying power. 
Incidentally, the copper line is cooled. When reaching a liquid nitrogen 
(-196 degrees centigrade) , the resistance of the copper line is reduced 
by a factor of 5 to 10. Thus, a current passing through the copper line 
can be increased. Thereby, a high magnetic field can be obtained by the 
circuit of the same size by using the normal conducting coils which is 
cooled with liquid crystal. 
FIG. 5 is a diagram illustrating the configuration of a pulverized coal 
combustion apparatus which uses a magnetic separator and is the third 
embodiment of the present invention. In FIG. 5, portions indicated by 
reference numerals 31, 7, 19', 21' and 22' are characteristic portions of 
this third embodiment. The rest is a magnetic separator which is the same 
as of the first and second embodiments of FIGS. 1 and 3. Such a magnetic 
separator is indicated by a reference numeral 50. 
In FIG. 5, reference numeral 50 designates the aforementioned magnetic 
separator; 31 a coal bunker; 32 a coal gate; 33 a coal feeder; 34 a 
pulverizer; 35 a blower; 36 a pulverized coal reservoir for supplying 
pulverized coal to the header 11 of the magnetic separator 50; 37 a coal 
burner; 19' collection piping; 21' a flow regulating valve; and 22' a 
blower for supplying collected pulverized coal to the coal burner 37. 
In the pulverized coal combustion apparatus having such a configuration, 
coal is first thrown into the coal bunker 31. Then, coal is led from the 
coal gate 32 to the coal feeder 33. Subsequently, the coal is supplied to 
the pulverizer 34 whereupon the coal is pulverized to obtain pulverized 
coal. The pulverized coal is held in the pulverized coal reservoir 36. 
Subsequently, the pulverized coal is supplied therefrom to the header 11 
of the magnetic separator 50. 
The pulverized coal passes through the magnetic separator 50 to thereby 
separate impurities such as pearlite and kaolinite and ash therefrom. 
Then, only combustible materials (organic constituents) is led from the 
collection piping 19' to the coal burner 37 and is burned therein. 
In the case of the first embodiment described above (see FIGS. 1 and 2), 
rotation drive mechanical parts are not present in the working or 
operating space. Thus, troubles due to the mechanical parts in the 
operating space, such as the clogging, which is owing to the fine 
particles, and the abrasion, are not caused. Thus, the problem of the 
residual magnetization, which has been caused in the mechanical parts of 
the conventional apparatus, does not occur. Moreover, heat emission and 
rotation loss due to eddy current, which has been generated in the 
rotating portions of the mechanical parts in the conventional case, are 
not caused. Furthermore, the pulverized coal collides with the baffle 
plate 14 and is diffused. Thus, the fine particles are uniformly 
scattered. Additionally, the particles fall under their weight, so that 
the accuracy of the magnetic separation is enhanced. 
In the case of the second embodiment (see FIGS. 3 and 4), advantages and 
effects, which are similar to those of the aforementioned first 
embodiment, are obtained. Moreover, the persistent current mode operation 
is performed, so that the entire electrical circuit is in a 
superconducting state as a result of persistent current mode operation, 
and thus the power loss due to Joule's heat is reduced. Further, the 
copper line is cooled. When reaching a liquid nitrogen (-196 degrees 
centigrade) , the resistance of the copper line is reduced by a factor of 
5 to 10. Thus, a current passing through the copper line can be increased. 
Thereby, a high magnetic field can be obtained by the circuit of the same 
size. 
Furthermore, in the case of the third embodiment (see FIG. 5), the labor 
and space for the storage, retention and conveyance of combustible 
(organic) materials obtained by the magnetic separator 50 for coal 
cleaning become unnecessary. Consequently, a compact, high-quality 
high-efficiency coal combustion system is obtained. 
Incidentally, the embodiments of the present invention have been described 
in connection with the pulverized coal by way of example. The present 
invention is, however, not limited thereto. For example, the present 
invention can be applied to the recycling of various kinds of resources 
and to a waste treatment. Thereby, similar effects and advantages are 
obtained. 
Further, in the case of the second and third embodiments of the present 
invention, a plurality of the homopole opposing solenoid magnets 60 as 
illustrated in FIGS. 6 and 7 may be substituted for the quadrupole magnets 
4 incorporated into the aforementioned magnetic separator. In this case, 
the plurality of solenoid magnets 60 excited in such a way as to have 
homopole and be opposed are arranged concentrically and in the axial 
direction. In the case of using the homopole opposing solenoid magnets 60, 
the distribution of lines of magnetic force and the magnetic field 
distribution as illustrated in FIG. 8 are exhibited. However, the magnetic 
separation can be achieved on the same principle as above described. 
As above described concretely, the present invention basically provides a 
magnetic separator which comprises an inner duct, quadrupole magnets 
disposed around the inner duct, fine-particle supply means provided on the 
top end portion of the inner duct, first and second collection tubes that 
are provided at the bottom portion of the inner duct and are used for 
collecting paramagnetic materials and non-magnetic materials, 
respectively. Moreover, the present invention further provides a magnetic 
separator having an umbrella-like baffle plate provided in the 
fine-particle supply means; a magnetic separator having quadrupole magnets 
respectively constituted by normal conducting coils; a magnetic separator 
having a persistent current switch in parallel with the quadrupole 
magnets; and a magnetic separator having a collection tube for collecting 
intermediate materials, in addition to the first and second collection 
tubes. Additionally, the present invention provides a pulverized coal 
combustion apparatus using the magnetic separator. Thus, the present 
invention has the following advantages. 
(1) No mechanical parts are provided in the duct. Thus, troubles due to the 
mechanical parts in the operating space, such as the clogging, which is 
owing to the fine particles, and the abrasion, are not caused. Moreover, 
heat emission and rotation loss due to eddy current are not caused. 
(2) The separator is provided with an umbrella-like baffle plate. Thereby, 
pulverized coal is ejected upwardly from the lower portion. Thus, after 
the pulverized coal collides with the baffle plate, the pulverized coal is 
diffused. Thus, the fine particles are uniformly scattered. Additionally, 
the particles fall under their weight, so that the accuracy of the 
magnetic separation is enhanced. 
(3) In the case that normal conducting coils are cooled by liquid nitrogen 
and are used as the quadrupole magnets, a large current can be made by a 
compact apparatus to flow. Moreover, a high magnetic field are obtained. 
Furthermore, the cost of refrigerant can be reduced. 
(4) In the case that the quadrupole magnets are constituted by combining 
superconducting coils with a persistent current switch, a persistent 
current mode is used. Thus, during operation, it is unnecessary to supply 
power thereto. The evaporation of liquid helium due to heat of penetration 
has only to be supplemented. 
(5) In the case of a pulverized coal combustion apparatus using a magnetic 
separator, combustible (organic) materials are used directly for 
combustion in a boiler. Thus, the storage space for combustible materials 
is unnecessary. Time and effort on the control of quality, which is 
associated with the storage of the combustible materials, are saved. 
Moreover, the conveyance thereof to the coal feeder, the space for the 
coal feeder become unnecessary. Consequently, a compact high-quality 
high-efficiency coal combustion system are obtained. 
Although the preferred embodiments of the present invention have been 
described above, it should be understood that the present invention is not 
limited thereto and that other modifications will be apparent to those 
skilled in the art without departing from the spirit of the invention. 
The scope of the present invention, therefore, should be determined solely 
by the appended claims.