JPS6010127B2 - Method for producing fibers of specific size from melt - Google Patents

Description

[Detailed description of the invention]

The present invention manufactures fibers of a specific size by forming a thin film flow of molten material such as metal, slag, and flux on a smooth rotating disk and ejecting this into space at high speed from the periphery of the disk. Regarding the method. Various methods have been proposed in the past for producing fibers by dropping a melt stream onto the surface of a rotating body. Most of these known inventions describe methods for producing spherical or near-spherical particles in the case of metal melts, and methods for producing fibers in the case of inorganic or organic melts that are easily vitrified. Problems in the known inventions will be explained in detail with reference to typical examples. A. Typical examples of inorganic turning stitch manufacturing method {1) Japanese Patent Publication No. 49-43498: Rotating water lining with a V-shaped cross section This is a method of producing fibers by dropping a molten stream of a material that is easily vitrified into the center of the body, and coagulating many linear streams emitted from the periphery.Even with a V-shaped cross section, it is difficult to completely prevent droplets. The movement of the melt flow on the surface becomes three-dimensional, and the physical properties of the melt change on the surface of the rotating body, which is water-cooled from the inside, making accurate size control difficult. , it is impossible to process a large amount of high-temperature melt. ■ JP-A-51-88728: The melt flow is caused to fall and collide with the surface of a rotating disk, and at the same time the flow is directed downward from the upper part of the periphery of the disk at an angle of 50 degrees and 80 degrees. This method is a method for producing fibers by blowing a jet of gas. "Keep it at an appropriate temperature." Therefore, the material of the three bottom plates of the tundish and the disc are electrical conductors such as metal or graphite. However, it is not applicable to non-conducting melts such as highly silicic or highly acidic melts. According to the example, a disk with a diameter of 10 ribs was rotated at 150 pm and 2
Blast furnace slag is processed at a low flow rate of 0 to 4 feet/sec, and only short fibers with a length of 200 ribs or less can be obtained. For such low flow rates, arc heating of the melt by direct current flow may be effective in preventing the temperature drop. However, for high flow rates, preheating the disk surface is sufficient. be.
Moreover, the ripples on the melt surface during arc heating and the fall of the melt flow onto the disk surface promote irregular splitting of the melt flow. It is difficult to manufacture glue. Tokusekki Sho 52-34028: This is an invention related to the improvement of the above. Namely, when high-speed gas is injected downward from the annular nozzle in W, a vortex is generated on the inner disk surface. "Fiber cutting and spheroidization occur. To prevent this, a sub-annular nozzle is provided inside the annular nozzle to form a low-speed parallel jet. (1--

[3--Known inventions include free fall to the surface of a rotating body ({1,000~glue)], interaction with a gas jet (■, '3)
), etc.). Therefore, even if the flow rate and rotational speed of the Kuzumu body are held constant, spherical particles or long fibers of a constant size can be produced. In addition, neither rolling element can withstand the thermal shock stress and centrifugal stress generated by contact with a high-temperature melt and high-speed rotation.Therefore, as an example, a rotating disk of small diameter is 1
The results are only shown when rotating at a low speed of 50 pm, and it is difficult to process a large amount of high-temperature melt. As mentioned above, the idea of the so-called "melt processing method using a rotating body" is well known, but a method for producing fibers of a specific size has not yet been developed. The present inventors introduced the melt gently into the center of a rotating disk through a conduit, formed a stable thin film flow on the disk with two velocity components in the radial and tangential directions, and created a circular flow. The process by which particles move on the plate or are emitted into space from the surroundings and split into a large number of linear streams.Furthermore, we theoretically analyzed and experimentally confirmed the process by which these linear streams split into spherical particles. The research results are based on the results of this research.The research results will be explained below with reference to the drawings.Figure 1 shows the outlet radius r.The melt at a constant velocity Uo is flowed out from the conduit 1, and the angular velocity (
When a stable thin film flow 3 is formed on the surface of a disk 2 rotating at rad/sec), the process in which the thickness h and velocity distribution of the thin film flow change depending on the disk radius r will be explained. If the melt is approximated as a perfect fluid, then in order to change the vertical flow with velocity Uo into a stable thin film flow without turbulence, the cross-sectional area r must be increased. 2 in the vertical flow rate flowing out from r. 2Uo and radius r. Height h. The horizontal flow rate flowing out from the column surface is 2 t r. h. Uo
The height h of the conduit outlet such that the heights h of the conduit outlet are equal, i.e. the condition of continuity is satisfied. The following equation can be obtained from the condition that it is necessary to determine . h. =r. /2 {11 In Fig. 1, the scale of the vertical coordinate h is set to five times the scale of the radial coordinate r to make it easier to understand. When a viscous fluid flows over a flat plate, the flow velocity of the fluid layer near the surface is significantly reduced due to fluid friction, forming a so-called ``boundary layer''.
In the flow on a rotating disk, a "laminar boundary layer" is formed at low speed rotation, and a "turbulent boundary layer" is formed at high speed rotation. In Figure 1, even in the case of a stationary disk, a boundary layer is formed by the flow with an initial velocity Uo in the radial direction, but if the rotational speed is 50 pm or more, this boundary layer is ignored and the boundary layer is formed by the rotation of the disk. Only the boundary layer needs to be considered. In the present invention, the boundary layer on the rotating disk is important. The Raynozzle number Re for the boundary layer on the rotating disk is defined as the viscosity of the melt (
If the radius of the disk is R (skin), then it is expressed as R2/2 of Re, Re: ■R2 nore≧・XI and ■Narusama A turbulent boundary layer is formed, and Re= ■R2/Shiku6×1pi
{If Re is 2r, a laminar boundary layer is formed, and if Re is between the two, a transition region is formed. The thickness 6 (skin) of the turbulent boundary layer and the thickness 6' (arc) of the laminar boundary layer are given by the following equations, respectively. That is, the thickness of the turbulent boundary layer increases with the radial coordinate r, whereas the thickness of the laminar boundary layer does not depend on r. The present invention utilizes turbulent or laminar boundary layers. The theoretical configuration for the case of a turbulent boundary layer will be explained below. If the position in the turbulent boundary layer with a thickness of 6 is expressed by Z with the disk surface as the origin, then the tangential velocity component U8 and the radial velocity component Ur at that position are OS
In Z Mi 6, it is given by the following formula. Therefore, if the thickness of the thin film flow at the position of radial coordinate r is h (skin), then
The average values UO and Ur of U and Ur are respectively given by the following equations. U8: Three customers UhidZ '6) Ur 壬 {No customer Ur rudder ten U
. (h-6)} '71 However, {the second term on the right side of equation 71 is h
>6, that is, the thickness h of the thin film flow is greater than the boundary layer length 6, and the portion h-6 is added only when the flow has a uniform flow velocity Uo. The composite average speed U and its direction (angle formed by U and U) at the position r are determined by the following equation. ◇＝
The thickness h of the thin film flow at the position of {9, U8 r on leg-,'' can be determined by a ``trial method'' so as to satisfy the following equation. hUrni'CustomerUetalten(h-6)UO ■■The second term on the right side of the equation is also added only when h>6, similar to the {7} equation. 6-r curve, hr curve, U at a specific r in Fig. 1
a, Ur, U8, Ur, U, ◇ are the rotational angular velocity and the melt flow rate. If Uo and the kinematic viscosity of the melt are given, '2] ~ [1
■Can be calculated using formula. At r=R,
The thickness of the boundary layer, 6, is smaller than the thickness of the thin film flow, h, 6,
The part above has a radial velocity equal to the initial flow velocity Uo and no tangential velocity. The interior of the boundary layer with a thickness of 6 mm has two velocity components, a radial velocity Ur and a tangential velocity U8, and on the disk surface, Ur=◯ and Ua=max. The direction of the flow is the direction of the vector sum U of the average radial velocities U and r and the tangential velocity U8, and in Fig. 1, the angle of U with respect to U8? It is expressed as Even when r=R2, h2>62, but r=R3
, r=R4, h3<63 and L<64, and all of the thin film flow becomes a boundary layer flow. As r increases in this way, a boundary layer develops, and both Ur and U8 increase, but the increase in U becomes particularly remarkable. In other words, the direction of U approaches U, and ◇ takes a small value. Therefore, and y
The larger the value, the smaller the thickness h of the thin film flow, which forms a turbulent boundary layer. is fired at a large velocity U in a small direction. However, there is surface tension on the surface of the melt flow. (dy female/arc), it is impossible to maintain an infinitely thin film flow condition. Figure 2 shows that a thin film flow 3 with a thickness h and a flow velocity U is launched from the periphery of a disk with a radius R in the direction of an angle, immediately after which it splits into a free linear flow 4 with a radius rc.
This is an explanatory illustration of the process of further splitting into a spherical surface 5 of radius rs. surface tension. Since the thin film flow with (d skin e/en) and thickness h (skin) splits into a linear flow with radius rc (arc), the condition is that the pressure difference between the inside and outside of the linear flow is △p (dy thickening). /
), it is expressed by the following formula. rc=. /△p When the thin film flow of the boundary layer on the disk with average velocity components U8 and Ur is launched into space with the resultant velocity U, the fluid friction with the disk suddenly disappears, as shown in Fig. 2. , the minute velocity perpendicular to the direction of the spatial velocity U = Uasin = and -
V=-Urcos0 becomes a balanced state. Therefore, when linear flow 4 is formed, considering the twist of the linear flow, the static pressure of rcpg (dyne/) and V2 p/
The sum of the force pressures of 2 (dyne/ga) gives Δp in the above formula.
Here, p (g/ground) is the density of the melt, g (skin/sec2)
represents the acceleration of gravity. In general, a turbulent boundary layer thin film flow is formed at high speed rotation where U8 is large, and its thickness h
is small. Therefore, rcpg is generally a much smaller value than V2p/2. Therefore △p=rcpg+
If V2p/2 is set as V2p/2, the condition for forming a linear flow with radius rc is rC=rCpg0(pa2sin20/2
)~20 (11)p82sin20. Furthermore, in order for a thin film flow of thickness h around a disk of radius R to actually split into n linear flows of radius rc, the total cross-sectional area of the thin film flow, 2 mRh, is the sum of the cross-sectional areas of the linear flows. It must almost match n・m〆c. That is, nm〆C32
Also, the total circumference length 2R of the thin film flow is not smaller than the sum of the diameters of the linear flow cn. That is, public CnS2mR From the above two equations, the following conditional equation can be obtained. rC≧Water/Medium (12) When the condition (12) is satisfied, the splitting according to equation (11) actually occurs. Splitting of a thin film flow into a linear flow also occurs on a disk at low speed rotation in the case of a low-height enemy body (see the case of =no, in Figures 3 and 4), and on a disk (12 ) and (11) are satisfied, since U is small and angle is close to 90 degrees, UOSIn0 = U8, Ur = U, and a linear flow with large rc is formed, flowing over the disk. It moves in the radial direction while rolling. However, in the case of a bran flow with a large rc formed on a disc, the larger r is, that is, the closer to the periphery of the disc, the more U0sin? As the rays become larger, they reach the periphery while being split into small linear streams of rc according to equation (11), and are emitted into space as linear streams of various radii. Therefore, in this case, a linear flow of constant size cannot be obtained. Even in fairly high-speed rotation, at a position where r is small, that is, at a position close to the center of the disk, UO is small and becomes U8sin○3o, Ur3, and (11) and (
12), a thick linear flow is formed. However, the closer you get to the periphery of the disk, the more rapidly U8 increases and h becomes smaller, so (11) and (12) are no longer satisfied at the same time, and the flow changes to a thin film at this position (w in Figures 3 and 4).
(See case 2). In this case, since a thin film flow with a constant thickness h is ejected from the periphery of the disk, (11) and (12)
As a result, a free linear flow with a constant radius rc is formed. At sufficiently high speed rotation, the entire disk surface is covered with a thin film flow of the boundary layer, and a free linear flow with a constant radius rc is formed from the periphery (Fig. 2; Figs. 3 and 4). Nono=No3
). Regarding the splitting of a thin film flow into a linear flow, since h, U8, and J are determined by , and R, the radius rc of the linear underflow is determined by equation (11), and the radius rc of the linear underflow is determined by equation (12). Actual splitting occurs for small h. If a free linear flow 4 of radius rc breaks up into a spherical droplet 5 of radius rs, then the volume of the spherical droplet (4
3) mps is the volume gradient of a linear flow of length s. - If it is not larger than Zc, droplet formation will not occur. From this condition, the following equation can be obtained. 1111 (
13) rSZノ3/2rc In this way, the radius rs of a droplet formed by the splitting of a linear flow with a constant radius rc is always larger than rc, and (13
) determines the minimum radius. The condition for forming a spherical droplet with radius rs (arc) is the surface tension. (d
If the pressure difference between the inside and outside of the ball is △p (dyue/arc), it is given by the following equation. rs=20/△p here. p is the static pressure of the droplet rspg (dyne/) and the velocity U of the free linear flow in the direction of motion, pU2/2 0 k e/
) is the sum of rs・mln Kono 3/2rc (13
), a spherical droplet with radius rs is formed when U is decelerated by frictional resistance with the surrounding gas and falls to Us, which satisfies the following equation: 20 to 40
(14) The ball droplet with radius rs formed at the position rs=rSpg+(ps2/2Fps2U→Us further moves in space with an initial velocity Us. Next, as shown in FIGS. 3 and 4, a disk 2 with a constant radius R We will explain the process by which the thin film flow, linear flow, and motion of the spherical droplets on the disk change depending on the rotational speed when the melt is allowed to flow quietly down from the conduit 1 at a constant flow rate. The streamlines at Nono=○, 2, and 3 correspond to the plan view at each No1 position in Figure 4. When the disk is at rest (■:○), the molten body If the flow rate is sufficient, it will flow out from around the disk as a free film flow.In this case, U8
= ○, rc in equation (11) depends only on the static pressure, but since the static pressure changes depending on the thickness of the membrane flow, it splits into thick linear flows with various rcs, creating cavities. , it turns into a falling motion due to the action of gravity. Conditions (13) and (14) cause these thick linear streams to break up into large droplets with various radii rs. However, due to the action of gravity, a vertical velocity component Uy is added to the radial velocity component Ur, and the resultant velocity U increases, so that a droplet with a large radius rs separates a small droplet in its spatial motion (14 ) satisfies the formula. Therefore, it is not possible to flow linear streams or drops of fixed size. A phenomenon similar to this is also observed when the radius R and rotational speed of the disk are relatively small. The above-mentioned known invention kites are only inventions related to the formation range of this free membrane flow. At low speed rotation (no = no,), UO in equation (11) is small and 0 is close to 90 degrees, so a linear flow with a large rc is formed on the disk, and as it approaches the periphery of the disk, Due to the rise of U8sin◇, the small linear flow of rc is separated and reaches the periphery of the disk. Therefore, free linear flows with various radii are emitted from the periphery of the disk, and the streamlines are therefore not constant, (13) and (14)
The radius of the droplets formed under these conditions is also not constant. In the case of a fairly high rotational speed (=2), the area close to the center of the disk is under the same conditions as the rotating disk with a small radius, and the area around the center of the disk is under the same conditions as the rotating disk with a small radius. Since rc is large, a linear flow with a large rc is formed on the disk according to equation (11). However, as the radial coordinate r increases, U8sing increases, separation of the linear flow with small rc occurs, and as it approaches the periphery of the disk (r→R), the conditions (11) and (12) are satisfied. The turbulent boundary layer becomes thin film flow. This thin film has the effect that (11) especially 1
2) splits into a free linear stream of constant radius, which is further split into spherical droplets of constant size by (13) and (14). Under sufficiently high rotation speed (= 3), a thin film flow of boundary layer is formed over the entire disc surface, and when this is launched from the periphery of the disc in a small direction at high speed, it forms a free line of constant radius. It splits into a spherical flow, and then into spherical bottles of a certain diameter. As mentioned above, in order to obtain a linear flow or a spherical droplet of a certain size, it is necessary to form a thin film flow of the boundary layer at least around the disk, and therefore to provide a fairly high speed rotation under a constant flow rate. is necessary. Furthermore, in order to obtain a linear flow with a large rc or a spherical droplet with a large rS of a certain size, it is necessary to prevent irregular splitting of the linear flow on the disk. For this purpose, it is clear from the above explanation that it is rational to rotate a disk having a relatively small radius R at high speed. As in the known invention, even if a disk with a diameter of 50 to 20 mm is rotated at a low speed of 1500 to 50 mm, it is difficult to form a turbulent boundary layer, and therefore a linear flow or a sphere of a certain size is difficult to form. I can't get rid of the drops. In Figure 3, a linear flow is launched from a point 0 on the periphery of the disk as the origin? the x-axis in the direction of
Take the y-axis vertically. Let the velocity of a linear flow or a spherical droplet in the plane be u, its velocity components in the x and y directions be ux and uy, and the angle between u and rx be Q. ○′ of this two-dimensional motion
The initial velocity at is U given by equation '8}. The diameter of the spherical particle is the base (伽) (= 国S), and the time is a (sec).
, the acceleration of gravity g, and the drag force due to the stationary fluid with the surrounding density pf (g/ground) being (g), the equation of motion is given by the following equation. Here ux=u COSQ, uy=u
sinQ, zumi u2 x ten y,? is given by the following equation, assuming that the cross-sectional area of the particle is AP (=light d2s/4) and the drag coefficient is Co. ? =C. The cape is f (16) The drag coefficient Co in the spherical particle is “
It is a dimensionless number determined by the Ray nozzle number Re=dsU/w (where f is the kinematic viscosity of the stationary fluid) and is given a numerical value for engineering calculations. Even in the spatial motion of a linear flow with radius rc, is there a drag force acting on its tip? Using equation (13), rs=ノ3/21rc
It can be approximately determined from equation (16) as a sphere. In equation (15), Q changes with time and CD changes with u, so it is difficult to unambiguously solve this, but a solution can be determined by successive approximation. In other words, if initial velocity (u)8=o=U is given, velocity (u
x,uy) and position (x,y) can be determined over time. Further, the position where the linear flow splits into spherical droplets can be determined as the point where u coincides with U in equation (14). That is, the streamlines of spatial motion and the formation positions of the droplets in FIGS. 3 and 4 are all determined quantitatively by solving equation (15). Furthermore, the torque T (k91m) of the disk is the radius R (m) of the disk, the acceleration of gravity g (m/sec2 unit)
, can be calculated using the following formula using the unit of the density of the melt p (k9/me). T:cf etc. p (17> Therefore, the power days required to rotate the disk (
P. S. ) is calculated by the following formula, assuming the rotational speed is N (rpm). The drag coefficient Cf is known as a function of Re=■R2/Sh.
It can be calculated by (19). Equations '41 to (16) and (19) are {21 and '3}, that is, relational expressions when a turbulent boundary layer is formed on the rotating disk. Generally, in the case of a melt with a low working viscosity, the thickness 6 of the turbulent boundary layer increases in proportion to r3'5, and by using high-speed rotation, the turbulent range is set to Re=■R2/〃. As a result, a stable boundary layer thin film flow can be formed around the disk. However, in the case of a melt with high kinematic viscosity, (3}'
This makes the thickness 6' of the laminar boundary layer considerably large and, moreover, independent of the radial coordinate r. Therefore, even in a relatively low speed rotation, that is, in the laminar flow range of Re=R2/2, it is possible to form a thin film flow of a stepwise boundary layer on the disk. In the case of a laminar boundary layer, U8 and Ur can be found using the following equation instead of the {5} equation, and 8' can be used instead of 6 in the '7}, 00 equation. Fortress {・-(Yu)} 2 [4'' Shibu = Skin 5 {(Chi) - 2 (Yu) 20 (Ru) 3} [5-' Also, Cf in equation (17) is the equation (19) Instead, it can be calculated from the following equation regarding the laminar boundary layer. Cf = equal voice sign (19)' In other words, when a laminar boundary layer of ■', [milk'] is formed, the same theoretical calculation as in the case of a turbulent boundary layer is possible. As mentioned above, the present inventors assumed that the melt does not solidify and is always kept at a constant temperature, and that the surrounding area is a stationary gas with a constant temperature and pressure. The theory of formation was clarified. In this case, if the linear flow of a certain size is coagulated, long fibers of a certain size will be obtained, and if this linear flow is split into spherical droplets of a certain size and then coagulated, spherical particles of a certain size will be obtained. It will be done. When processing high-temperature melt with a rotating disk,
The surrounding stationary gas will cause convection as the temperature rises, its physical properties will change, and the drag force in equation (16) will also change. If a gas at a specific temperature is flowed at a flow velocity uf parallel to and in the opposite direction to the streamline of a free linear flow, the drag force in equation (16) is
increases to the value when u + uf. Also, even if the temperature of the gas is lowered and the pressure is increased, does equation (16) change?
rises. The rise in ◇ is the initial velocity of the linear flow (u)8=o=
The time required for U to drop to Us in equation (14) is shortened, the formation of a sphere is accelerated, and its movement distance is shortened. When creating a rational gas flow in this way, changes in the physical properties of the gas are also significantly reduced. On the other hand, if a body at a certain temperature is caused to flow parallel to the streamline of a free linear flow at a velocity uf, then (16)
The value of the equation decreases to the value when u decreases to u - uf. Furthermore, even if the temperature of the gas is increased and the pressure is decreased (16
) decreases. The decrease in M retards the decrease in the initial velocity U of the linear flow and prevents the formation of droplets. angle from the periphery of the disk)
A linear flow launched at high speed in the direction of , gradually changes from horizontal motion to falling motion. Therefore, in order to actually achieve good agreement between the directions of the linear flow and the gas flow, it is necessary to flow the horizontal gas flow at an angle ◇ in the horizontal movement section of the linear flow in the opposite direction or in the same direction as the linear flow. be. A well-known invented light, like the value,
Merely using jets at any downward angle may cause fiber breakage and spheroidization. In other words, is the combined use of gas flow in equations (15) and (16)? It is necessary to rationally determine the direction and velocity of the flow.
In general, the viscosity is large and the surface tension is high. The silicate melt easily forms a fine linear flow and solidifies as fibers under normal cooling rates.
On the other hand, 〃 is small. Melts of metals and alloys with a large diameter form a relatively thick linear flow, which solidifies after breaking up into spherical droplets under normal cooling rates. This is why many of the above-mentioned known inventions are clearly classified into inorganic fiber manufacturing methods and metal particle manufacturing methods. However, even with silicate melts, ``spherical particles can be obtained if the kinematic viscosity is lowered by heating at high temperatures, and ◇ is increased by flowing antiparallel linear flow of hot gas, and solidification is delayed. On the other hand, even though it is a molten metal, the surface tension can be lowered by heating it to a high temperature or adding components that significantly lower the surface tension (S, Se, Sb, La, Ce, 8, Sn, etc.), turning the cold gas into a bran-like flow. By measuring the decrease in coagulation rate and increase in coagulation rate when flowing in parallel, it is possible to coagulate it as a fiber.The basic theory of the present invention described above can be expressed in an easy-to-understand manner as follows.1 Constant kudzu body flow rate , the disk radius R depends on the kinematic viscosity 〃1
and rotational angular velocity to form a thin film flow of a boundary layer with a specific thickness h around the disk. 2. When a thin film flow is launched from the periphery of the disk, a free linear flow with a specific radius rc determined by a specific thickness h is formed due to the action of surface tension 〇. 3 A linear flow with a specific radius rc is caused by the surrounding gas and the drag force ◇
Due to the action of , it splits into spherical droplets with a specific radius rs determined by rc. 4. In order to speed up the formation of a ball droplet and shorten the moving distance,
By running a horizontal gas flow in exactly the opposite direction to the linear flow, or by decreasing the temperature and increasing the pressure of the gas?
Make it bigger. To prevent fiber breakage and droplet formation, by running a horizontal gas flow in exactly the same direction as the linear flow, or by increasing the temperature and decreasing the pressure of the gas? Make smaller. 5 All of these processes can be quantitatively determined by theoretical calculations. Furthermore, the differences from the known inventions '1}, {2', and '3}, which may seem similar to the present invention at first glance, will be clarified. {1}, '21, '3} are all from P. 156 of the Transactions of the Japan Society of Mechanical Engineers, No. 29, No. 879-905
“On the fiberization of liquid by a rotating disk” reported in
Based on the research titled. P. on that statement. 188 and P. of the specification of {3}. q,,q2 shown in 354
, q3 (earth/sec) is an experimental formula obtained in the above research, and is not a theoretical formula. These empirical formulas are based on the following equations: water, an aqueous solution of glycerin, and an aqueous solution of starch syrup, i.e., liquids with a velocity of 0.0114 to 28.7/sec, are placed on a rotating disk with a diameter D (=wave) of 50 to 20 m/sec. and the rotation speed n = 500 to 400 pm (no: 52.4
~418. The free liquid flow ejected from the periphery of the disk at ad/sec) was observed by photography, and the maximum flow rate q, which is ejected as droplets, the minimum flow rate q3 at which a free film-like flow is formed, and q. The flow rate q2 at which a good fibrous flow can be obtained when
dyne·sec/earth) and surface tension. It is expressed as a function of (d starvation/ga). 0 relates only to plane flow on a disk, and 0 relates only to spatial free flow, respectively.
These empirical formulas include both Hoshi and O. In addition, the experimental conditions Re=■R2/is in the range of 38 to 36×1, which includes the formation range of the low-velocity laminar boundary layer transition region and the turbulent boundary layer, but there is no effect on the formation of the boundary layer. No consideration was given. Therefore, these empirical formulas simply state that when the flow rate is below q (when the plane flow on the disk is thin), the formation of droplets occurs, and when the flow rate is above q (when the plane flow is thick), the formation of free membrane flow occurs. This merely indicates that a fibrous flow is formed at an intermediate flow rate q2 between the two critical flow rates. Therefore, it is not an equation that completely describes the theory of fiber or spherical particle formation, nor is it an equation that represents the manufacturing conditions for spherical particles and fibers of a particular size. Furthermore, let's pay attention to the examples '2} and '3'. [Example 3- of spherical particles has 1500q○ of molten blast furnace slag on D=40 side, n=100pm (=104
．． 7 rad/sec) on a rotating disk with q=10 ground/sec
This is the result when dropping at a flow rate of c. If we estimate the kinematic viscosity of the melt to be 1.5/sec, Re = R2/Hi3 is 272, and the thickness of the laminar boundary layer of {3}' is 6'30.
．． 405 skin. On the other hand, if we calculate the thickness h of the film-like flow around the disk according to the theory of the present inventors, it is probably h≦0.
, a value of 7 skin will be obtained. This thick film-like grain is in a state similar to the case of =◯ in Figs. 3 and 4, and is broken into droplets of various sizes of 0.45 skin (4500 french) or less by the above-mentioned mechanism. This almost coincides with the particle size distribution in Example {3l. In the production example of blast furnace slag fiber with m,
．． 1 rad/sec), q316/sec, p32. 5g/ground ~ If it is 1.5/sec, then Re = R
2/3 is 2618, and the thickness of the laminar boundary layer due to glue' is 6'...0. There are 33 kites. If we calculate the thickness of the film-like flow around the disk according to the inventors' theory, it will probably be h = 1.07 to 0.1 cm,
A linear flow of rc〒0.045 to 0.064 skin (450 to 640 peaks) should be emitted from the periphery of the disk. However, according to the embodiment, a total length of 200 mm or less and a diameter of approximately 10 Buddhas can be obtained. This is thought to be because, due to the low rotational speed, the thick linear flow curves vertically downward due to the action of gravity, becoming thinner due to its own weight, just like starch syrup hangs down and stretches.Also, from a downward angle of 500~ 8
The combined use of a 0° gas jet can also be understood as a means for promoting this elongation due to its own weight. In this case, if it becomes too thin, it will break, so the length remains at less than 20 ribs. According to the above explanation, the known invention ○-, [21
, [3} is clearly different in theoretical system and production conditions from the present invention, which concerns the production of long fibers of a specific size. The present invention is based on the theory based on the above-mentioned research by the inventor, and relates to a method for producing fibers of a specific size.
Any molten material selected from the following has a hard viscosity in the range of 0.001 to 10/sec and a ratio of surface tension to density of 40 to 40 M skin/g
Preferably, the melt is set to be in the range of 40 to 25 m/g; the radius of the outlet is r. through a conduit with a diameter in the range of 3 to 3 mm and a smooth refractory surface with a diameter of 50 to 200 mm, while maintaining the melt outflow rate at a specific value in the range of 5 to 500 mm/sec. to the center of the rotating disk and maintain the rotational speed of the disk at a specific value within the range of 3000 to 3000 pm; the radius r of the conduit. The distance between the outlet and the surface of the rotating disk is h.
When h. r. The diameter and rotational speed of the disk are selected in accordance with the kinematic viscosity of the melt, and the centrifugal force is used to determine the area at least near the periphery of the disk. Forming a thin film of the molten material having a thickness of While splitting, at the same time, gas around the disk is sucked in parallel to the linear flow and in the same direction as the direction in which the individual filaments of the free linear flow extend, thereby creating a space in which the linear flow moves. a reduced pressure condition, which reduces the resistance to spatial motion of the linear flow and the solidification rate, promotes elongation of the length of the free linear flow, and prevents undesirable droplet formation; The present invention relates to a method for producing uniform long fibers of a specific size from a melt characterized by: solidifying the linear flow at the reduced cooling rate, the long fibers having a specific cross section are characterized by scales; The rotating disk used in the method of the invention shall be formed of a block of one material selected from fused silica, graphite, silicon carbide, silicon nitride, zircon, chamotte, alumina, and magnesia. For example, basic blast furnace slag or "Example 2" described below.
A silicate melt such as the one shown in FIG. 1 becomes spherical particles when fed onto a rotating disk in a high temperature and low viscosity state within the cooling rate range in the air at room temperature, and becomes fibers in a low temperature viscosity state. In these silicate melts, the change in surface tension with temperature is negligible. When a linear flow of a certain size of these melts is fired from the periphery of the disk into a stationary gas and solidified as fibers, the temperature of the gas is low and the density is high at the beginning of the melt supply, so the linear flow is Spheroidization of the flow tends to occur locally. In addition, since fibers have a significantly lower settling speed in gas than spherical particles, entanglement of fibers is more likely to occur. Therefore, as mentioned above, suctioning gas in the same direction parallel to the linear flow is extremely effective in producing long fibers. FIG. 5 shows an example of a device that also uses the gas suction described above. This gas is sucked into an annular slot 9 having a large number of gas guide plates 8 as a horizontal air flow in the same direction as the linear flow, and is exhausted through an annular main pipe 7. In this case, if there is a large difference in direction between the linear flow of the melt and the gas suction flow, there is a risk that the fibers will be more likely to be cut. Therefore, a large number of information boards 8
to adjust the direction of gas flow. In the fiber manufacturing method according to the present invention, the outlet radius of the conduit that supplies the melt to the center of the rotating disk is r. , the distance between the disk and the outlet is h. When h
. r. It is preferable to set it as 12 ribs from /2 (r./2). In the fiber manufacturing method according to the present invention, a melt in which solid or liquid particles are suspended is supplied onto a rotating disk, and fibers in which solid or liquid particles are separated can be manufactured. For example, a melt of cupola slag or blast furnace slag, in which droplets of cast iron or pig iron are suspended, is fed onto a rotating disk, and the suspended heavy droplets are shortened and allowed to fall with a spatial motion distance, causing the melt to The free linear flow can be coagulated into fibers and both can be separated and collected. The method for producing fibers according to the present invention is a ``thin film flow in the boundary layer'' formed on a rotating disk, that is, a ``thin film flow in which velocity components in the tangential direction as well as in the radial direction occur over the entire thickness''. It is based on quantitatively controlling the thickness. When the kinematic viscosity of the melt is relatively high and the required radius of the fiber is relatively large, the thin film flow of the laminar boundary layer is When the required radius is low, 4 mm, a thin film flow of a turbulent boundary layer is formed on each rotating disk.The thin film flow is not formed even if a disk with a small radius is rotated at a low speed.The present invention They used a disk with a radius of 25 to 15 mm and a radius of 30.
Experiments were carried out in the rotational speed range from 0 to 100 pm, and
It has been confirmed through theoretical calculations and experiments that the thickness of the thin film flow in the boundary layer and therefore the radius of the fibers formed by its fragmentation can be adjusted over a wide range. This also allows the processing of large amounts of melt with a relatively small radius disk.When processing hot chicks with a rotating disk,
A large centrifugal force acts on the heated disk. Further, thermal shock stress due to rapid heating and rapid cooling acts at the start and end of the process, respectively. Metal materials have high thermal conductivity and are easily deformed, so they are unlikely to be destroyed by thermal shock. However, even if it is a heat-resistant steel, if it exceeds 60,000, the creep strength will be significantly reduced, and centrifugal failure will easily occur during high-temperature, high-speed rotation, making it difficult to withstand long-term use. Even though it is a superalloy, the allowable temperature is only 800 degrees Celsius or less. Therefore, when processing large quantities of high-temperature melts, it is necessary to use refractory or ceramic disks. However, basic and refractory viscous bricks such as magnesia brick and chamotte brick have a low high temperature softening point and a large coefficient of thermal expansion, so they cannot sufficiently withstand centrifugal and thermal shock stress. Fused silica and graphite bricks have extremely low coefficients of thermal expansion, excellent thermal shock resistance, and fairly high high temperature strength. However, even with these refractories, the tensile strength is significantly lower than the compressive strength, and it is difficult to use them under conditions where centrifugal stress is applied due to high-speed rotation. This is why many known inventions have been limited to processing a small amount of melt through low-speed rotation. Mass processing of high-temperature melt according to the present invention becomes possible only through the development of a disk that can withstand high-speed centrifugal rotation at high temperatures. The present inventors analyzed the thermal shock stress that occurs during rapid heating or cooling of a disk as well as the centrifugal stress that occurs during high-speed rotation. We have developed a structure of a rotating body that has a rotating disk surface of the required radius by integrating the two by fitting. The present invention requires an apparatus for producing long fibers that has a disk surface made of a specific refractory and a rotating body that can withstand high-speed rotation at high temperatures. FIG. 6 shows the principle of construction of a rotating body used in the fiber manufacturing method according to the present invention, and FIGS. 7 and 8 show examples of the rotating body. In FIG. 6, the refractory block 11 has a short cylindrical shape with a height t=1 to 2 fences with a required disk radius R at the top, and Q=
It transitions into a vice principal conical shape with a gentle slope of 12 to 35 degrees, and the bottom is 8
Transition into a battle cone shape with a steep slope of = 60 to 80 degrees. The heat transferred onto the disk with radius R "flows along the streamlines marked with arrows." Much of the heat flow is radiated to the outside world from the gently sloped conical surface in the middle, and the heat flow is radiated to the outside world from the gently sloping vice-principal conical surface in the middle. The heat flow reaching the annulus 12 and the bottom plate 3 is significantly less.That is, the middle part of the refractory block effectively prevents the temperature rise of the heat-resistant steel cage.The refractory has a high compressive strength, but a very low tensile strength. Low. Thermal shock stress can be reduced by high-temperature coheat on the disk surface. However, even though fused silica has the highest high-temperature strength among industrial refractories, it is susceptible to centrifugal stress generated by high-temperature and high-speed rotation. Therefore, as shown in Fig. 6, the refractory block turtle 1 is fitted into a retainer consisting of a heat-resistant steel side ring 12 and a bottom plate 13 with sufficient thickness, and the refractory block is Even if this happens, the centrifugal load F of the broken block is supported by the side ring 12 by swerving the inclination angle Q of the middle part to a small value, thereby preventing the centrifugal release of refractory fragments.That is, the refractory block The warhead conical surface with a small inclination angle in the middle part prevents the temperature rise of the heat-resistant steel side ring, maintains sufficient creep strength, and at the same time supports all the centrifugal load caused by the fracture of the refractory block on the side ring. Refractory block 11
The steeply sloped vice principal conical surface at the lower part of the head fits with the side ring 12 to prevent it from coming off due to lifting during high-speed rotation. Further, as shown in FIGS. 7 and 8 (omitted in FIG. 6), a plurality of recesses 11c perpendicular to the rotation direction are provided at equal intervals on the bottom side surface of the refractory block 11, and one side ring 12 There is a protrusion 12a corresponding to this recess on the inner surface of the
are provided, and the fit between the two prevents the refractory block from idling. Height of the upper part of the refractory block 11 1-2
The vertical cylindrical surface on the side emits a thin film flow of the "boundary layer" from the periphery of the disk surface into space with a constant thickness, so in other words, it causes "complete separation of the boundary layer" around the disk surface. Refractories for rotating bodies are made of fused silica, graphite, silicon carbide to silicon nitride, zircon, chamots,
Selected from alumina, magnesia, etc. Furthermore, in order to prevent the temperature rise of the side ring 12 and the bottom plate 13 of the cage, "in the example shown in Figures 7 and 8, a fireproof and insulating layer 6 is placed under the refractory blocks", and a mat-like layer is placed below that. Each part is fixed together by adhering the layers 17 of heat insulating material and filling the gap with the side ring 12 with castable refractory material. However, since graphite has a high thermal conductivity, there is a risk that the side ring 12 in the single block shown in Fig. 7 will be overheated when processing high-temperature melts.Other refractories are Its high temperature strength and thermal shock resistance are significantly lower than those of fused silica and graphite, making it difficult to use the single block of Figure 7 at high melt temperatures. Refractory block 11 for plates
The periphery of a is backed up with a fused silica block 11b, and the two are brought into close contact to form a combined block having the same shape as shown in FIGS. 6 and 7. The refractory block 11a has a cylindrical upper part and a regular polygonal columnar lower part having a smaller cross-sectional area than the upper cylinder.
The sides of the refractory block 11a are surrounded by a separate fused silica block 11b, except for one or two willow cylinders at the top thereof, and the bottom surface of the refractory block 11a is covered with a neutral refractory layer 19 selected as required.
The lower surface of the neutral refractory layer 19 is on the same horizontal plane as the lower surface of the fused silica block 11b. A combination block for an integrated rotating body is formed. As shown in FIG. 8, the combination refractory block has a refractory insulation brick layer 16, a mat-like insulation layer 1, similar to the single refractory block shown in FIG.
7 together with a side ring 12 and a bottom plate 13 in a heat-resistant steel retainer, and are fixed together by filling with Kistapple refractory 18. The bottom plate 13 of the heat-resistant steel cage is the sixth
, 7 and 8, it is fixed to the boss 15 by short legs 14 arranged at equal intervals around the center of the lower surface, and a space is formed between the lower plate 13 and the boss 15. As the disk rotates, gas flows within this space, so
A rise in temperature of the bottom plate 13 and boss 15 is effectively prevented.
In addition, in the examples shown in FIGS. 7 and 8, the boss 15 is mounted on the shaft by an inpolyute spline, so that
Discs can be replaced quickly. The present inventors have discovered that even when molten steel of 1600 qo is processed for a long time using a rotating body having the structure shown in FIG. ℃ or less, the temperature of the bottom plate 13 remained below 350 qo, and it was confirmed that the heat-resistant steel and the boss material maintained sufficiently high creep strength. The scope of application of the present invention is extremely wide. Namely: Methods for producing fibrous materials include metallurgical slags containing a considerable amount of silicic acid, such as blast furnace slag for iron making, electric furnace slag for iron making, slag from cast iron melting in cupolas or electric furnaces; glass, mineral fibers, various It can be applied to composites of various inorganic substances such as metallurgical fluxes, refractory silicates, and shelf salts; metals to which components that significantly reduce surface tension are added; and semiconductor materials such as silicon. Next, the present invention will be explained with reference to examples. Example Production of Fibers of Melted Flux The disk is driven by a hydraulic transmission device consisting of a variable flow rate hydraulic pump and a constant displacement hydraulic pump, and the rotational speed is measured and controlled by a control operation (PI). However, the output of the electric motor for driving the hydraulic pump is relatively small (1 W), but the rotation speed can be adjusted within the range of 0 to 3000.
I used one that was extremely wide, like the pm. Inside the outlet d. =1 Using a graphite conduit, introduce a molten flux with the following composition to a graphite disk with the configuration shown in Figure 8,
Spherical particles and fibers were produced. Composition of molten flux: 41.2%Si02, 4.0%AI203, 1.9%F
e203, 26.5%Ca0, 0.7%Mg0, 7.2
%Na20, 11.4%NaF, 7.4% Mountain F3 Molten flux density: 2.7 g This molten flux becomes spherical particles by lowering the viscosity by heating at high temperature, and by keeping it at a low temperature, the viscosity decreases. The temperature change in surface tension, which becomes fibers when the temperature is increased, is so small that it can be ignored in such a silicic acid melt. A rotating disk with an effective diameter De=9 was used to produce spherical particles and fibers under various rotational speeds. FIG. 9 shows the relationship between the rotational speed, the diameter of the obtained spherical particles and fibers, and the range of variation thereof. The melt temperature, processing speed, kinematic viscosity and surface tension in the production of spherical particles and fibers are as follows. Fiber production: European temperature: 1150qo Processing speed: 2k9/min Kinematic viscosity of the melt: 1.2/sec Surface tension of the melt: 51 Myne/skin Figure 9 Relationship between rotational speed and particle or fiber diameter is in close agreement with theoretical calculations, and the variation in size is also extremely small. The length of the obtained fibers reached more than 50 m.

[Brief explanation of the drawing]

Figure 1 is a longitudinal cross-sectional view explaining the process by which a thin film flow of the boundary layer is formed on the disk when molten material is supplied to the center of the rotating disk through a conduit, and Figure 2 A and the mouth are respectively the rotating circles. A plan view and a longitudinal sectional view showing the process in which a thin film flow of constant thickness launched from the periphery of a plate splits into a linear flow with a specific radius immediately after launch, and the linear flow further splits into spherical droplets with a specific radius. , Figure 3 is a longitudinal cross-section showing the process in which the spatial motion and size of droplets formed by linear flow and its breakup change depending on the rotational speed of the disk when melt is supplied onto a disk with a constant radius. Front view, Figure 4 A, Mouth,
C and 2 are plan views when the rotational speed of the rotating disk in Fig. 3 is different, and Fig. 5 shows a combination of a linear flow emitted from the periphery of the disk and a horizontal suction gas flow controlled in the same direction. A vertical cross-sectional view showing an example of a fiber manufacturing apparatus according to the present invention,
FIG. 6 is a longitudinal sectional view of a rotating body used in the fiber manufacturing method according to the present invention, and FIG. Figure 8A and Figure 8 are plan views and vertical cross-sectional views showing other embodiments of the rotating body used in the present invention, respectively, and Figure 9 shows fibers made from molten flux of the same composition by adjusting its viscosity. FIG. 3 is a blot of the dependence of particle and fiber diameters on rotational speed in manufactured examples. 1... Conduit, 2... Rotating disk, 3... Thin film flow, 4
... Linear flow, 5... Ball drop, 6... Tandesh,
7... Gas annular main pipe, 8... Guide plate, 9... Annular slit, 10... Link mechanism, 11... Refractory block, 11a... Refractory block of specified refractory,
11b... Fused silica block, 11c... Recess on bottom side of refractory block, 12... Side ring of retainer, 1
2a...Protrusion on the inner surface of the side ring, 13...Bottom plate of the retainer,
14...Short legs on the lower surface of the bottom slope, 15...Boss, 16 Fireproof insulation brick layer, 17... Layer of mat-like insulation material, 18...
- Castable refractories, 19...neutral refractories. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9

Claims (1)

[Scope of Claims] 1. Any molten material selected from metal, slag, and flux, whose kinematic viscosity is in the range of 0.001 to 10 cm^2/sec, and whose surface tension and density are The ratio is 40 to 400 dyne. cm^2/g
Preferably 40 to 250 dyne. cm^2/g; the melt is set to have a radius r_0 of the outlet.
through a conduit with a diameter in the range 3 to 30 mm, maintaining the outflow velocity of the melt at a specific value in the range 5 to 500 cm/sec, at the center of a rotating disk with a smooth refractory surface of diameter 50 to 200 mm. and set the rotational speed of the disc to 30
maintain a specific value within the range of 00 to 30000 rpm;
When the distance between the outlet with radius r_0 of the conduit and the surface of the rotating disk is h_0, h_0 is calculated from r_0/2 to (r
The diameter and rotation speed of the disk are selected in accordance with the kinematic viscosity of the melt, and the diameter and rotational speed of the disk are selected in accordance with the kinematic viscosity of the melt. Forming a thin film flow of the melt; Immediately after the thin film flow is radiated from the circumferential edge of the disk into space by the centrifugal force caused by the rotation of the disk, it is split into a free linear flow of a specific radius; At times, the space in which the linear flow moves is brought into a depressurized state by suctioning gas around the disk in parallel to the linear flow and in the same direction as the direction in which the individual filaments of the free linear flow extend. , thereby reducing the spatial movement resistance and solidification rate of the linear flow, promoting an elongation of the length of the free linear flow, and preventing undesirable droplet formation; A method for producing uniform long fibers of a specific size from a melt, characterized in that long fibers of a specific cross-sectional size are obtained by solidifying the flow at the reduced cooling rate. 2. Claim 1, wherein the rotating disk is formed of a block of any one material selected from fused silica, graphite, silicon carbide, silicon nitride, zircon, siyamoto, alumina, and magnesia. the method of.