TW201510226A - Casting apparatus and method of controlling said apparatus - Google Patents

Abstract

A method or apparatus for dry slag granulation of hot liquid slag using a casting apparatus comprising an endless conveyor having a plurality of casting moulds, which endless conveyor is arranged to move said casting moulds in a first section from a slag pouring zone through a cooling zone to a discharge zone and in a second section back to the slag pouring zone, comprising the continuous steps of pouring an amount of hot liquid slag into a casting mould in a position N in the slag pouring zone, moving the hot liquid slag containing casting mould in a position N+n within the cooling zone, adding solid metallic particles to the hot liquid slag containing casting mould in position N+n by dropping a determined amount of said metallic particles into the mould from a dispensing device arranged above said mould and comprising at least one hopper for storing said solid metallic particles, discharging the cooled solidified slag from the mould in the discharge zone, wherein the actual amount of hot liquid slag poured in the casting mould is measured in a position between N and N+n, wherein the speed of movement is adapted based on the measured amount of hot liquid slag, wherein the amount of metallic particles is determined based on a fixed slag/metallic particle ratio, wherein the amount of metallic particles added by the dispensing device is controlled by opening of the at least one actuated sliding gate arranged at the hopper's outlet during a time determined based on the speed and wherein the opening stroke of the at least one actuated sliding gate is determined based on the determined amount of metallic particles, the determined opening time and characteristics of the at least one sliding gate.

Description

Casting equipment and method of controlling the same

The invention relates generally to granulation of slag from the metal industry, and more particularly from the iron industry.

Conventionally, metallurgical slag is granulated in water.

Water quenching ensures rapid solidification of the metallurgical slag, which is a necessary condition for obtaining valuable products in the case of blast furnace slag. A water sprayer is first used to split the hot liquid slag stream into very small particles and transfer the particles to a water bath. The energy from the hot slag is extracted via direct contact between the hot liquid slag and the water. Since this must occur under ambient pressure, the temperature of the slag is immediately reduced to a temperature level below 100 °C.

However, the main disadvantage of the water granulation method is that the sulfur contained in the hot liquid slag reacts with water to form sulfur dioxide (SO ₂ ) and hydrogen sulfide (H ₂ S).

In addition, it must be noted that care must be taken to reduce the temperature of the slag quickly enough and to obtain vitrified or amorphous slag instead of being much cheaper (about 15 times) on the market. Crystallized slag.

It will also be desirable to recover at least some of the heat from the slag in a usable form. To use this possibility in an efficient manner, it is necessary to rapidly cool the slag to a temperature level that is low enough to make the material easier to handle, but high enough to keep the energy at a usable level.

One possibility to overcome the disadvantages of generating a harmful gas and recovering at least a portion of the heat comprises mixing the liquid slag with cold slag particles of the same chemical nature. The slag can then be subjected to heat recovery in a heat exchanger. However, it has been found that due to the high viscosity of the liquid slag, the cold slag particles and the liquid slag are not easily mixed, and thus it is impossible to cool the liquid slag quickly enough to obtain the vitrified slag.

Another solution has been proposed in which (cold) solid metal particles are added to the hot liquid slag (WO 2012/034897, WO 2012/080364). The effect is that the slag is rapidly solidified into a vitrified state without generating harmful gases. Furthermore, the solid metal particles are chemically inert and can be easily separated, recovered and reused (see WO 012/034897). Finally, the heat from the solidified slag and metal particles can be recovered in a suitable device such as a heat exchanger (see WO 2012/080364).

However, in practice, the efficiency of the above solution is highly dependent on the proper casting of the slag and the correct formulation of the metal particles. The fact that the incoming liquid slag stream is generally uncontrollable even exacerbates the above problems unless it is foreseen that technically complex or energy-intensive additional equipment, such as freshly filled molds, heated or refractory-lined transfers The actual slag fill height determination in the pour and/or equivalent. In the absence of such additional measurements, any suitable metering of the metal particles becomes complicated and even unstable.

technical problem

One object of the present invention is to provide a method for granulating dry slag and a corresponding apparatus, the method and the apparatus permitting the benefits of reduced environmental impact and increased energy recovery possibilities, and the method and The device is easy to implement and safe and effective to use.

In order to achieve the object, the present invention provides a method for granulating hot liquid slag into a dry slag using a casting apparatus, the casting apparatus comprising an endless conveyor having a plurality of molds, the endless conveyor Arranging to move the molds from a slag casting zone through a cooling zone to a removal zone in a first section and moving back to the slag casting zone in a second section, the method The following successive steps are included: a) in the slag casting zone, a certain amount of hot liquid slag is poured into one of the molds N, and b) is moved in the cooling zone by a position N+n a mold for hot liquid slag, c) adding solid metal particles to a mold containing hot liquid slag in position N+n by causing a determined amount of the metal particles to fall from a dispensing device Performed in a mold, the dispensing device is disposed above the mold and includes at least one funnel for storing the solid metal particles, d) in the removal zone, the cooled solidified slag is removed from the mold, wherein Measured in a position between N and N+n in step (a) The actual amount of hot liquid slag cast in the mold, wherein n is between 1 and 10, preferably between 1 and 4, and n is optimally 2, wherein based on hot liquid slag Measured to adjust the moving speed V _caster in step (b), wherein the amount of metal particles required in step (c) is determined based on a fixed slag/metal particle ratio λ , wherein the determination is based on the velocity V _caster Opening at least one actuation sliding shutter disposed at the exit of the funnel during a time t to control the amount of metal particles added by the dispensing device in step (c), and wherein at least one sliding gate is based on the determination amount of the metal particles The opening time t and the characteristic are determined to determine the opening stroke x of the at least one actuating sliding brake.

As mentioned earlier, the main reason for the difficulty in practice is to cope with not only the uncontrollable and variable slag flow, but also a certain ratio between the slag and the metal particles.

The main advantage of the method is that the entire process can be controlled by measuring the amount of hot liquid slag in the mold only after step (a) and before step (c).

First, this measurement is used to control the amount of liquid slag in the mold. In fact, it seems obvious that the mould of the endless conveyor should be filled with a suitable (maximum) amount of slag, such that there is sufficient space in the mould to be based on the fixed slag/metal particles A certain amount of metal particles is added than λ. Thus, the measurement of the amount of hot liquid slag allows control of the amount by adapting the speed of the conveyor, such as by controlling the deceleration of the conveyor if the amount is below the desired (appropriate) amount, And if the amount of liquid slag exceeds the desired (appropriate) amount, the conveyor is accelerated. If the amount of liquid slag is approximately the desired amount, no speed adjustment is required.

Second, the same measurement of the amount of liquid slag is used to determine the amount of metal particles actually required for that particular mold.

In another aspect, the present invention also provides an apparatus for granulating hot liquid slag to dry slag, the apparatus comprising an endless conveyor having a plurality of molds, the endless conveyor being arranged Moving the mold from a slag casting zone through a cooling zone to a removal zone in a first section and moving back to the slag casting zone in a second section, and wherein the apparatus further Including a ‧ a dispensing device disposed above the mold at a position N+n in the cooling zone and comprising at least one funnel for storing solid metal particles, the dispensing device comprising at least one slip at the exit of the funnel The actuation of the or the sliding gates allows control of the amount of metal particles dispensed by the dispensing device, ‧ at least one sensor capable of being between the slag casting position N and the metal particle addition position N+n Measuring the actual amount of hot liquid slag cast in a mold in a position, where n is between 1 and 10, preferably between 1 and 4, and a control unit is used : based on a measure of the amount of hot liquid slag _Adapting the moving speed of the conveyor V _caster ; determining the necessary amount of metal particles to be added by the distributing device based on a fixed slag/metal particle ratio λ; by the time t determined based on the speed V _caster Opening at least one actuation sliding shutter disposed at an outlet of the funnel to control an amount of metal particles to be added by the dispensing device; and determining the at least based on a determination amount of the metal particles, a determination opening time t of the at least one sliding gate, and a characteristic An opening stroke x that activates the sliding gate.

In the context of the present invention, it should be noted that the transport of the molds in the casting zone and the cooling zone is preferably substantially linear, that is, the ore angles are in the casting zone and the cooling The zone is essentially constant. Moreover, in this case, the position indicated by the position N of the mold being filled in the slag casting zone is merely illustrative. In fact, the actual position of the dispensing device in one of the positions indicated by N+n in this document may be located at a distance d which is not a multiple of the length 1 of the mold, that is, when in position N When the mold is positioned below the slag flow path, the metal particles are not necessarily filled in the mold at the position N+n. Therefore, the distance d between the mold being filled in the slag casting zone and the dispensing device may be any distance between 0.1 l and 9 l, preferably between 0.5 l and 3 l, especially about 1 l (that is, n is about 2). In practice, limiting the lower limit of the distance d is merely to allow measurement of the actual amount of hot liquid slag cast into the mold. The upper limit generally depends on the fact that the slag should still be Sufficiently liquid to allow proper penetration of the metal particles into the slag.

In another aspect of the invention, the method or apparatus further comprises (mechanism for performing the following operation): measuring the melting in the mold after step (c) in a position downstream of the position N+n The actual combined amount of slag and metal particles (ie, the amount of slag/particle mixture); the actual amount in step (c) is calculated based on the measured combined amount of slag and metal particles and the previous determination of hot liquid slag The amount of metal particles added is adapted to the characteristics of the at least one sliding gate if the calculated amount of the actually added metal particles does not correspond to the previous determination amount of the metal particles.

The main advantage of this further preferred embodiment is that it allows the actual measurement of the amount of slag/particle mixture obtained to be used as feedback by acting on the dispensing device (especially acting on the or the sliding brake) To adapt (or correct) the amount of metal particles.

Advantageously, the characteristic of the at least one sliding gate comprises a particle mass flow □ _particles (□ _particles / x curve) that varies with the opening stroke x, wherein the opening stroke is that the sliding gate is in an open state and a closed state (or substantially closed) The distance that must be moved between the states, see below). In fact, this parameter basically defines the amount of particles flowing through the sliding gate per unit time, depending on the opening of the gate. This parameter can be expressed as a discrete curve and can be determined experimentally depending on the particular type of sliding gate and the particular type of particle (see details below).

In still another embodiment, the actual amount of hot liquid slag cast in the mold in step (a) and/or the actual combined amount of slag and metal particles in the mold after step (c) is The following operations are performed to determine the slag height h _slag , the slag/metal particle height h _mix in the mold, and calculate the corresponding volume V _slag and/or V _mix based on the known shape of the mold, and calculate The determined slag mass M _slag and/or the determined metal particle mass M _particles ' based on the difference between V _mix and V _slag .

Preferably, the measurement of the amount is achieved by measuring the slag height or the slag/metal particle mixture height in the mold in a contactless manner, such as by means of one or more laser rangefinders. Other mechanisms such as radar, acoustic detection or optical detection can also be used.

In still another aspect of the present invention, the conveyor is preferably a so-called double-slope casting machine in which the slag casting zone in the first section of the endless conveyor is arranged to An angle of inclination α conveys the molds to further control the amount of liquid slag in the mold, the angle of inclination α limiting the effective maximum fill volume of the mold in the slag casting zone to a value V _α , any excess slag tilt Returning to one of the upstream molds of positions N-1, N-2, etc., and wherein the cooling zone is arranged at a second inclination angle β < α such that the effective maximum filling volume of the mold in the cooling zone Has a value V _β >V _α .

Thus, another advantage of an embodiment incorporating such a dual slope conveyor is that the mold of the endless conveyor is filled with a defined amount of slag. For a given mold, the defined amount of slag depends on the inclination of the mold as it is being filled: the steeper the slope, the less slag that can be filled in the mold until the slag overflows or pours to The next (several) mold (ie, the next (several) mold upstream of the mold being filled). Therefore, at the tilt angle α, the effective maximum fill volume (ie, the useful volume) can be defined as V _α . If the tilt angle is reduced (not too steep or even horizontal), the actual fill height in the mold is reduced and the effective maximum fill volume (ie, useful volume) of the mold is increased to _Vβ , which in turn is to be The added solid metal particles provide space. Therefore, if the inclination angle β in the cooling zone is smaller than the angle α in the casting zone, the theoretical maximum amount of metal particles corresponding to V _β -V _α can be added to the mold without the risk of overflow or overflow.

In a preferred embodiment of the present invention, the inclination angle α in the slag casting zone and the inclination angle β in the cooling zone are selected such that the effective maximum filling volume V _α of the mold in the slag casting zone is Between 0.25 and 0.75 times the effective maximum filling volume _Vβ of the mold in the cooling zone, preferably between 0.30 and 0.60 times, even more preferably 0.45 to 0.55 times. In detail, the tilt angles α and β are selected such that V _α is approximately 1⁄2 V _β .

Although largely dependent on the geometry of the mold, the appropriate angle β is actually between 0° (horizontal) and 50°, more preferably between 10° and 40°, and the angle α is usually greater than the angle 5 ° to 20 °.

In the case of a dual-slope conveyor, by monitoring the temperature of at least two (or more) molds of the mold being filled upstream (positions N-1 and N-2) The movement speed in step (b) is changed to further control the movement of the molds.

It is especially preferred that if the temperature of the mold in the position N-1 is not significantly increased due to the return of the hot liquid slag from the position N (casting position), by lowering the moving speed in the step (b) Controlling the apparatus, and if the temperature of the mold in position N-2 is increased due to the reflow of the hot liquid slag from the mold in position N-1, the apparatus is controlled by increasing the moving speed in step (b) . Therefore, in other words, if the temperature of the mold being filled in the upstream (N-1) mold is not increased to a value close to the temperature of the hot liquid slag, that is, having a temperature far below this value, There is no slag pouring back, so the filling of the mold is sufficient, but may not be complete: the conveyor is decelerated. On the other hand, if only the mold in N-1 is hot (containing liquid slag) and the mold N-2 is not hot, the speed of the conveyor is considered to be appropriate without changing the speed. Finally, if not only the mold N-1 gets hot, but also the mold N-2 gets hot, the speed of the conveyor is too low and the speed must be increased.

The temperature can be accomplished by any suitable mechanism, such as with a thermocouple or the like Monitoring; however, the monitoring is preferably accomplished in a contactless manner, such as by means of a pyrometer.

Another general problem associated with uncontrollable and variable slag flows is that the addition of (determining amount) metal particles must be completed within the time period given by the slag stream. Thus, the resulting difficulty is that the time available to introduce the desired amount of metal particle addition to the partially filled mold is limited, while the conveyor needs to continuously move the molds continuously. Therefore, an important advantage of this method is that the use of a sliding gate to meter the amount of solid metal particles allows rapid opening and closing, thereby greatly reducing the time required to add the appropriate amount of particles.

A suitable sliding gate (valve) generally includes a sliding plate that is arranged to push and/or rotate the sliding plate generally along a sliding frame in front of an opening (in this case, the outlet of the funnel) The opening is closed. The sliding of the plate can be effected parallel to the direction of transport of the molds or preferably perpendicular to the direction. Thus, in the context of the present invention, the sliding movement can be a translational movement (eg, a linear sliding gate), a rotational movement (eg, a rotary sliding gate; the axis of rotation is preferably parallel to a plane formed by the opening or perpendicular to the Plane) or even a combination of the above (eg, a curve sliding gate). The term "open stroke" as used herein shall be interpreted accordingly as the magnitude of the sliding movement (push and/or rotation) required to open the sliding gate.

In a preferred embodiment of the sliding gate, a fixed plate having a plurality of spaced apart apertures is placed in front of the opening (the exit of the funnel) and thus partially (only) blocks the outlet. A corresponding movable sliding plate presents corresponding holes, and the corresponding holes can be slid to the front of the holes of the fixing plate to open the gate and slide into a different position to close the hole of the fixing plate. Preferably, the holes have a substantially rectangular or square shape for the linear sliding gate, or have a substantially fan shape for the rotary sliding gate perpendicular to the opening for the rotating axis, and the interval between adjacent holes in the sliding plate is set Dimensions to substantially close the corresponding holes of the fixed plate. complex One of the main advantages of one of the plurality of holes is that the stroke of the sliding gate (i.e., the sliding distance between the open state and the closed state) is substantially reduced, and the reduction is limited in consideration of the limited time for the action to be realized. benefit.

In another preferred aspect, the sliding gate comprises a plurality of holes of two or more columns. In this case, it is even more preferable to provide the adjacent rows of holes in a staggered (zigzag) manner to further improve the uniform distribution of the particles in the slag.

In yet another aspect, the dispensing device includes two or more individually controllable actuated sliding gates, each sliding gate being connected to an outlet of the same funnel or an outlet of a separate funnel. Advantageously, the dispensing device comprises one (or two) funnels and two individually controllable actuating slides, each sliding gate substantially covering one half of the surface of the mold. Providing two (or more) independently actuatable sliding gates allows for more flexibility in opening time when the mold is moved under the dispensing device, and in the event that one of the gates fails or is blocked The redundancy is more flexible.

The or each of the sliding brakes is actuated by any suitable mechanism, such as a pneumatic mechanism, a hydraulic mechanism, and/or one or more electric motors. Preferably, the actuation of the or each of the sliding gates is accomplished using one or more hydraulic cylinders.

In yet another aspect, the travel of the or the sliding gates is limited such that the holes of the fixed plate are not completely closed. The advantages of this practice are twofold, namely that the actuation is faster and the wear of the sliding gate and the fixed plate is substantially reduced. It has in fact been noted that for a given diameter of one of the metal particles, it is sufficient to close the or the sliding gates to leave a residual opening in each of the holes, the residual opening generally representing the particles or the smallest 0.3 to 1.5 times the diameter of the particles (if particles having different diameters are used at the same time), preferably about 0.8 to 1.3 times, preferably Between 1.1 times and 1.25 times.

In another aspect, the method and apparatus of the present invention also incorporates a mechanism for accurately determining the position of the molds (some of which are, in particular, the mold below the dispensing device). Any conventional mechanism can be used to achieve this, particularly for contact and/or contactless devices such as switches, lasers, inductions, and the like.

Preferably, the solid metal particles are dropped from a height of from about 0.1 m to about 3 m, preferably from about 0.2 m to about 2 m, to obtain a rapid and efficient mixing of the slag with the solid metal particles. The exact height (i.e., the exact amount of energy required for the particles to penetrate the liquid slag to the desired depth) depends on the composition of the slag, the temperature of the slag, the density and diameter of the solid metal particles, and the like. Because the metal particles fall into the hot liquid slag to cause some spillage or splashing, the dispensing device preferably includes a splash shield, and the splash shields are disposed at least on the or the funnel and the sliding On the side below the gate, and the splash shields extend substantially to the top of the upper portion of the mold.

Advantageously, the solid metal particles have a density of at least 2.5 g/cm ³ . Due to the difference in density between the slag and the metal particles, the metal particles are thoroughly mixed with the slag.

The solid metal particles are preferably spherical in order to have good mixing properties and to ensure rapid and efficient cooling of the slag.

The solid metal particles preferably have a diameter of at least 2 mm, preferably 5 mm or more, and most preferably 10 mm or more. Advantageously, the solid metal particles have a diameter of less than 80 mm, preferably less than 50 mm and most preferably less than 25 mm.

The solid metal particles are preferably made of a metal selected from the group consisting of iron and steel. A group of aluminum, copper, chromium, nickel, alloys thereof, and alloys thereof with other metals.

In practice, steel balls are preferably used because it is easy to obtain steel balls of different diameters.

Preferably, during and/or after the slag cake is removed from the conveyor, the cake is crushed to have a size of from about 40 mm to about 120 mm and a bulk density of from about 2 g/cm ^{3 to 5} g/cm ³ , preferably about Particles having a size of 40 mm to 90 mm and a bulk density of about 2 g/cm ^{3 to 5} g/cm ³ .

Thereafter, the still hot slag particles and the heated solid metal particles are preferably charged in a heat exchanger, cooled by reverse flow of the cooling gas, and discharged from the heat exchanger.

According to a preferred embodiment, the heat exchanger is subdivided into a plurality of subunits, each of the subunits having a particle inlet port, a particle outlet port, a cooling gas inlet port, and a cooling gas outlet port, wherein The particle inlet 装 is filled with at least one of the subunits with hot slag particles and heated solid metal particles, and the cooled slag is removed from the at least one of the subunits via the particle outlet The particles and the cooled solid metal particles, the cooling gas inlet port and the cooling gas outlet port are closed during loading and unloading of the particles, and simultaneously with the loading and unloading of the particles, by the cooling a gas inlet port injecting a cooling gas stream and discharging the heated cooling gas stream from the cooling gas outlet port to cool at least one of the other subunits, the particle inlet port and the particle outlet port being closed during cooling of the particles, and The heated cooling gas system is used for energy recovery.

Thus, a method in accordance with a preferred embodiment of the present invention proposes the use of a heat exchanger comprising a plurality of subunits that operate discontinuously. Since it is advantageous to obtain a constant flow of hot gas at the outlet of the heat exchanger to ensure the most efficient use of the power generation cycle, the plurality of heat exchanger sub-units are alternately operated in a manner that ensures a substantially constant flow of hot gas. Thereby A substantially continuous gas treatment can be obtained that is decoupled from batch type material processing.

At each point in which the one of the heat exchanger subunits is in the emptying/filling phase, no cooling gas flows through the heat exchanger subunit during the evacuation/filling.

The same amount of particles are filled in and withdrawn from the exchanger. At the same time, no material enters or leaves the other heat exchanger subunits; the subunits can thus be completely sealed from the environment during cooling.

Preferably, one of the subunits is filled with hot slag particles and heated solid metal particles via the particle inlet port, while the cooled slag particles are removed through the particle outlet of the same subunit. Cooled solid metal particles.

Once the heat exchanger subunit is filled, the particle inlet port and the particle outlet port are sealed and the subunit unit is reconnected to the cooling gas stream while another heat exchanger subunit can be disconnected. The cooling gas flowing through the heat exchanger subunits thus does not encounter any leakage, thereby preventing dust and energy from leaving the system. Thus, the heat exchanger subunits only need to be relieved during the loading and unloading of the slag.

According to a preferred embodiment, the hot slag particles and the heated solid metal particles are first loaded into a heat-insulating pre-chamber before being loaded into one of the heat exchanger sub-units. . The pre-chamber is preferably insulated by a refractory lining or a material stone box. The low thermal conductivity of the slag imparts excellent thermal insulation properties.

The slag particles and solid metal particles may also be loaded into an afterburner after cooling or after being removed from the heat exchanger subunit. In other words, the cycle time and the amount of loaded particles can thus be selected such that the heat transfer within the heat exchanger subunits can be controlled and maintained in a quasi-stationary state. Outlet gas temperature wave caused by loading/unloading of the heat exchanger subunits The movement will thus be minimized by selecting the cycle time accordingly.

According to another preferred embodiment, the hot liquid slag is solidified into a slag cake by mixing it with solid metal particles and cooled to about 650 ° C to 750 ° C. Advantageously, the hot liquid slag is mixed with the same volume, preferably resulting in a mixture comprising from about 40% to about 60% by volume of solid metal particles. The required volume of the metal particles depends on the desired target temperature, the density and heat capacity of the metal particles, etc., and for steel spheres, 40% to 60% (volume percentage by volume of the total volume) is preferred.

Preferably, the heat exchanger subunits are operated at a pressure of from 1.2 bar to 4 bar (i.e., the absolute pressure measured at the bottom of the slag layer in the subunit).

1‧‧‧ casting device

10‧‧‧Circular conveyor

11‧‧‧Molding

20‧‧‧ slag runner

21‧‧‧Hot liquid slag

30‧‧‧Distribution device

31‧‧‧ funnel

32‧‧‧Funnel exit

33‧‧‧solid metal particles, such as steel balls

35‧‧‧Sliding gate valve

351‧‧‧Sliding plate

352‧‧‧ holes in the sliding plate

353‧‧‧ fixed plate

354‧‧‧ holes in the fixed plate

355‧‧‧Hydraulic cylinder

36‧‧‧ splash guard

A‧‧‧ slag pouring area

B‧‧‧Cooling area

C‧‧‧Removal area

Sh _slag ‧‧‧Sensor for measuring the height of hot liquid slag

Sh _mix ‧‧‧Sensor for measuring the height of the slag/particle mixture

The inclination angle of the α‧‧‧ conveyor in the slag casting area A

The inclination angle of the β‧‧‧ conveyor in the cooling zone B

Effective maximum filling volume of V _α ‧‧‧ mould in slag casting zone A

Effective maximum filling volume of V _β ‧‧‧ mould in cooling zone B

T _N-1 ‧‧‧ Temperature sensor for mold position N-1

T _N-2 ‧‧‧ Temperature sensor for mold position N-2

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION The preferred embodiments of the present invention will be described by way of example with reference to the accompanying drawings in which: FIG. 1 is a schematic cross-sectional view of a preferred embodiment of a dry slag granulation apparatus; Schematic diagram of some components of a sliding gate valve useful for a dispensing device; FIG. 3 is a perspective top view of an embodiment of a dual sliding gate (not shown) having staggered holes; and FIG. 4 is a dry slag granulation device of FIG. a cross-sectional view of a portion of the method according to the present invention; FIG. 6 is a sketch of another preferred embodiment of the method according to the present invention; and FIG. 7(a) and Figure 7(b) illustrates a preferred embodiment of a self-calibration method as described herein.

Further details and advantages of the invention will be apparent from the following detailed description of the appended claims.

Fig. 1 schematically shows a cross section of a preferred embodiment of a dry slag granulation apparatus comprising a slag casting machine 1 having a linear endless conveyor 10 comprising a plurality of molds 11. It is to be noted that a so-called double-slope linear slag casting machine can also be used (for example, see Fig. 4).

The mold 11 is conveyed from the slag casting zone A through the cooling zone B to the discharge zone C in the first section, and the molds are removed from the solidified slag cake contained therein in the discharge zone. In the second section, the now empty mold is conveyed back to the slag casting zone.

The hot liquid slag 21 from the slag flow path 20 is poured into the casting mold 11 passing under the slag flow path 20.

In the particular case of a double slope conveyor (as in Figure 4), the angle of inclination a is relatively steep so that the maximum effective volume V[ _alpha] (i.e., when the slag overflows to the upstream mold N-1, the melting in the mold) The volume of the slag is smaller than the useful volume V _{β of the} mold when the mold reaches a position in the cooling zone B where the inclination angle β is small (>N+2 in Fig. 1). Preferably, the angles α and β are chosen such that V _α is approximately 1⁄2 V _β .

When the mold containing the hot liquid slag reaches a position between the casting position N and the position N+2 of the dispensing device 30 (ie, N+1 in FIGS. 1 and 4), by means of the sensor , preferably by means of a laser rangefinder (Sh _slag) to measure the mold of the hot liquid slag height (h _slag).

The result of this measurement is used on the one hand to adjust the speed of the conveyor (V _caster ) and on the other hand to determine the amount of particles of hot slag that will subsequently be added to the mold.

When the mold containing the hot liquid slag reaches the position below the dispensing device 30 (example) For example, when N+2 in FIG. 1 and FIG. 4, a certain amount of solid metal particles 33 (such as steel balls) contained in the storage funnel 31 (the amount is based on the amount of slag measurement and a predefined melting). The slag/particle ratio is determined to be introduced into the mold by opening the slide gate 35 mounted on the outlet 32 of the funnel for a predetermined time t. The particles 33 fall into the mold by gravity and are mixed with the hot liquid slag 21.

A splash shield 36 can be provided to prevent liquid slag and steel balls from splashing out of the mold during filling.

During the introduction of the metal particles 33 into the hot liquid slag 21, the slag is rapidly cooled and solidified into an amorphous state. The mold containing the solidified slag cake and the added metal particles (such as steel balls) is then further cooled while traveling to the removal zone C where the mold is emptied by turning over the mold . The solidified slag cake is then crushed and can travel to a heat recovery unit (not shown).

In a further preferred variant of the method, the height of the solidified slag/particle mixture in the mould is measured using a further sensor, preferably also by means of a laser range finder (Sh _mix ) (h _mix ). This value is used as feedback to the actual addition of particles, and the method can be adapted (self-correcting method). Further details are given below.

2 presents a schematic view of the components of the linear sliding gate valve 35. A preferred sliding gate valve for use in the present invention includes a fixed plate 353 having a plurality of spaced apart apertures 354. The corresponding sliding plate 351 also presents spaced apart apertures 352, but such holes are positioned such that the aperture 352 can be moved from the closed position into the open position by linear sliding (by sliding in the direction indicated by the arrow in Figure 2) ), in the closed position all of the holes 354 of the fixed plate (substantially, see above) are closed by the portions of the sliding plate that do not have holes, in the open position The centering hole 352 is substantially aligned with the hole 354.

Figure 3 shows a top perspective view of a preferred embodiment of a dual (linear) sliding gate valve 35 that does not have a top mounted funnel for temporarily storing metal particles. For illustrative purposes, only one of the valves further includes a splash shield 36 disposed below the valve. The sliding plate 351 of each valve is actuated by a separate hydraulic cylinder 355 relative to the fixed plate 353.

Figure 4 substantially corresponds to the lower portion of the embodiment of Figure 1 during operation. Recalling that for the purposes of the present invention, the dual slope conveyor shown in Figure 4 can also be a single slope conveyor.

As can be seen in Figure 4, the mold in position N is filled with hot liquid slag 21 from slag runner 20.

In the case of a single-slope conveyor, as described above, the casting machine is adjusted based on the amount of liquid slag of the mold in position N+1 by measuring the slag height (h _slag ) using a sensor (Sh _slag ) Speed (V _caster ).

In the case of a dual-slope conveyor (as shown in Figure 4), additional control over the amount of liquid slag can be controlled by the particular shape of the conveyor itself, and optionally with one or more temperature sensors. . If the amount of slag from the runner exceeds the (local) capacity ( _Vα ) of the mold, the excess slag overflows by gravity to the immediately adjacent mold in position N-1. If the amount (flow rate) from the flow path is even higher, the slag pours from the mold N-1 to the mold N-2 (this is the case shown in Fig. 4). Since it is known that the mold from the second section of the conveyor 10 has a temperature that is very far from the temperature of the liquid slag (in short, this temperature will also be referred to as "ambient temperature", although this temperature will generally be at 50 Between °C and 300 °C or even higher than 300 ° C), it has been found that by controlling the mold temperatures (T _N-1 and T _N-2 ) at these two positions N-1 and N-2 Simple and effective control of the casting method. It is to be understood that it is of course possible to monitor more than two temperatures, if deemed necessary or desirable.

In FIG. 4, the mold N+2 is located below the dispensing device 30 and is being filled with metal particles 33. The amount of metal particles to be added is determined as described in detail below.

The mold in position N+3 in Figure 4 shows a mold in which the calculated amount of metal particles has been added to the liquid slag. At this time, the slag is substantially solidified into an amorphous state due to the instantaneous addition of a large amount of cold particles. It appears that the position for inserting the particles indicated by N+2 in Figure 4 does not necessarily need to be the second position after the filling position, as long as the slag is still hot and liquid.

The amount of slag/particle mixture is thereafter measured as needed to verify that the results match the desired amount. As further described below, if the result does not match the expected amount, then the value is used as feedback to adapt the method.

The exact position of the mold within the conveyor (and especially the position of the mold below the slag runner and/or the dispensing device) can be determined by any known contact mechanism or contactless mechanism, such as switches, induction, lightning. Shoot and so on.

Method description - the purpose of regulation

In the dry slag granulation method, the liquid slag 21 is cooled by adding cold metal particles 33 such as steel balls. The purpose of this cooling is achieved

‧ rapid cooling of slag

‧High mixture temperature for further heat recovery

Therefore, the steel ball ingredients must be precise and must follow the steel/slag ratio.

In order to achieve material transportation, the slag casting machine 10 technology has been selected. Figure 1 and Figure As shown in 4, the slag 21 is poured from the upstream in the pouring zone A at the beginning of the conveyor 10, and then the steel ball 33 is added in the cooling zone B.

The composition of the steel balls 33 in the cooling zone B and the slag filling of the mold 11 in the position N should be adjusted. In the presently described adjustment mode, the adjustment is performed by measuring the amount of slag of the mold in position N+1 and by adding the calculated amount of steel balls 33 when the mold passes under the dispensing device 30. Finish in the mold. The amount of hot liquid slag in the mold is controlled by varying the speed of the casting machine 10.

Since the loading time is limited, the sliding of the steel ball 33 is accomplished using a sliding gate valve 35 as shown, for example, in Figures 2 and 3.

Description of the preferred adjustment mode

As already described above, the metal particles are preferably steel balls. The ingredients of such steel balls and the slag filling of the mold must be adjusted. This adjustment is preferably accomplished by changing the following two parameters:

‧ casting machine speed

‧ The amount of metal particles (steel balls) that fall into each mold.

Since the loading time of the metal particles is limited, the ingredients are completed using one or more gate valves as shown, for example, in Figures 2 and 3.

The filling is performed in each mold only when the mold is under the gate, so the mold to which the particles are loaded is not undetermined.

The material loaded by this gate depends on the following two parameters

‧Opening trip of the gate (x)

‧ brake opening time ( t )

As can be seen in Figure 5, the basic adjustment steps can be as follows:

1. Flow liquid slag (unknown amount) into the mold in position N

2. Once the mold has reached position N+1, use a laser to measure the slag height ( h _slag )

a) Convert the height ( h _slag ) to the slag volume ( V _slag ) in the mold and then convert to the slag mass ( M _slag ) in the mold.

b) Determine the steel ball ( M _steel ) required for this mold based on the slag/steel ratio ( λ ).

c) adapt the casting machine speed based on the recorded slag height ( h _slag ) ( V _caster )

3. Once the mold has reached position N+2, load the steel ball

a) Determine the opening time of the sliding gate based on the casting machine speed (V _caster ) (t)

b) determining the opening stroke of the gate based on each of the following (x)

i. above determines the desired mass M _steel ball

Ii. Open time ( t )

Iii. Characteristics of the sliding gate ( x curve)

This first adjustment method can be outlined as shown in FIG.

In still another preferred embodiment, the method further comprises the steps of:

4. Once the mold has reached position N+3, use a laser to measure the height of the ball/slag mixture ( h _mix )

a) Convert the height ( h _mix ) to the volume of the mixture ( V _mix ) in the mold. It is determined that the steel ball ( M _steel ' ) actually added to the mold.

5. Feedback - adjustment of the characteristics of the gate

a) If M _steel = M _steel ', the correct amount of steel balls has been dropped → not adjusted /x curve

b) If M _steel ≠ M _steel '; then adjust x curve to accommodate the measured mixture height. This adaptation is described below.

As shown in Figure 6, this further preferred method of adjustment can be summarized.

Adjustment of gate characteristics

If the amount of steel ball measurement does not meet the theoretical amount ( M _steel <> M _steel '); /x curve. The difference ΔM _{steel is} judged, because the filling time t is known, the difference between the calculated flow rate and the actual flow rate ( △ ) can be calculated.

If △ >0.2 x , no correction is applied and an alarm is issued. If △ <0.2 x , the correction of the mass flow characteristic curve of the batching valve will be performed.

curve The x curve is a discrete curve. Correction of this curve can be accomplished by adjusting the individual opening length x _n (see Figure 7(a)) for each flow value in the table (see Figure 7(b)). The further the position is from x , the smaller the correction will be.

The correction applied to x (the position contained between x _i and x _{i +1} ) to achieve the desired flow rate is Δ x . The corrected opening length is x' = x + △ x .

Since the correction Δ x for x has been calculated, the position value x _{n of the} material flow meter will be corrected Replaced. This update is done by using the following formula: for values higher than x x _n :

For values below x x _n :

Calculation limit:

x _min = minimum allowable opening length of the dosing valve

x _max = maximum allowable opening length of the dosing valve

among them: : new value in [mm]

x _n : old value in [mm]

N : the total number of values in the material flow meter

n : is the considered position in the material flow meter ( n =1... N )

K ₁ : constant factor to prevent overcorrection ( K ₁ 2)

1‧‧‧ manufacturing equipment

10‧‧‧Circular conveyor

11‧‧‧Molding

20‧‧‧ slag runner

21‧‧‧Hot liquid slag

30‧‧‧Distribution device

31‧‧‧ funnel

32‧‧‧Funnel exit

35‧‧‧Sliding gate valve

36‧‧‧ splash guard

A‧‧‧ slag pouring area

B‧‧‧Cooling area

C‧‧‧Removal area

Sh _slag ‧‧‧Sensor for measuring the slag height of hot liquid

Sh _mix ‧‧‧Sensor for measuring the height of slag/particle mixture

Claims (26)

A method for granulating hot liquid slag to dry slag using a casting apparatus (1), the casting apparatus comprising an endless conveyor (10) having a plurality of molds (11), the endless conveyor Arranging to move the molds from a slag casting zone (A) through a cooling zone (B) to a removal zone (C) in a first section and moving in a second section Returning to the slag casting zone, the method comprises the following successive steps: a) casting a quantity of hot liquid slag (21) in one of the molds N in the slag casting zone, b) The cooling zone moves the mold containing hot liquid slag in a position N+n, c) adding solid metal particles (33) to the mold containing hot liquid slag in position N+n, Performing by causing a determined amount of said metal particles to fall from a dispensing device (30) into the mold, the dispensing device being disposed above the mold and comprising at least one funnel (31) for storing the solid metal particles d) in the removal zone, the cooled solidified slag is removed from the mold, wherein the measurement is performed in a position between N and N+n (a) the actual amount of hot liquid slag cast in the mold, where n is a number between 1 and 10, wherein the movement in step (b) is adapted based on the amount of hot liquid slag a velocity V _caster wherein the amount of metal particles required for step (c) is determined based on a fixed slag/metal particle ratio λ , wherein the funnel is opened during the time t determined based on the velocity V _caster At least one of the outlets (32) actuates the sliding gate (35) to control the amount of metal particles added by the dispensing device in step (c), and wherein the determining amount based on the metal particles, the at least one sliding gate The opening time t and the characteristic are determined to determine the opening stroke x of the at least one actuating sliding brake. The method of claim 1, further comprising: measuring the actual combined amount of slag and metal particles in the mold after the step (c) in a position downstream of the position N+n; based on the slag Calculating the combined amount of the metal particles and the previous determination amount of the hot liquid slag to calculate the amount of the metal particles actually added in the step (c); and if the calculated amount of the actually added metal particles does not correspond to the metal particles The previous determination amount adapts the characteristics of the at least one sliding gate. The method of claim 1, further comprising the steps of: (e) crushing the solidified slag and/or (f) recovering heat in a heat exchanger. The method of claim 1, wherein the at least one sliding gate characteristic comprises a metal particle mass flow □ _particles as a function of the opening stroke x (□ _particles / x curve). The method of any one of claims 1 to 4, further comprising at least one sensor (Sh _slag , Sh _mix ), the at least one sensor capable of determining the slag height in the mold by respectively h _slag , slag / metal particle height h _mix to measure the amount of a hot liquid slag in a mold and / or the amount of a mixture of slag and metal particles, and wherein the control unit can: based on the mold The shape is calculated to calculate the corresponding volume V _slag and/or V _mix , and the determination quality M _{slag of the slag} and/or the determination mass M _particles ' of the metal particles are calculated based on the difference between V _mix and V _slag . The method of claim 5, wherein the at least one sensor comprises a laser range finder. The method of any one of claims 1 to 4, wherein the slag casting zone (A) in the first section of the endless conveyor is arranged at a first inclination angle输送 conveying the molds to further control the amount of liquid slag in the mold, the inclination angle α limiting the effective maximum filling volume of the mold in the slag casting zone to a value V _α such that any excess slag is poured Returning to one of the upstream molds of positions N-1, N-2, etc., and wherein the cooling zone (B) is arranged at a second inclination angle β < α to make the mold effective in the cooling zone The maximum fill volume has a value V _β >V _α . The method of claim 7, wherein the inclination angle α in the slag casting zone and the inclination angle β in the cooling zone are selected such that the mold is effectively effective in the slag casting zone. filling volume _V α is between 0.25 times the effective maximum filling volume of the mold _V β in the cooling zone with 0.75 times. The method of any one of claims 1 to 4, wherein the at least one actuated sliding gate (35) comprises one or more columns of aligned holes (352) or two or more columns of staggered holes. The method of any one of claims 1 to 4, wherein the dispensing device (30) comprises two individually controllable actuating sliding gates, each sliding gate covering half of the surface of the mold. The method of any one of claims 1 to 4, wherein the or the actuation sliding brake (35) comprises one or more hydraulic cylinders (355). The method of any one of claims 1 to 4, wherein the movement of the molds is performed by monitoring the temperature of at least two molds upstream of the mold (positions N-1 and N-2) being filled And further controlled by changing the moving speed in step (b). The method of claim 12, wherein if the temperature of the mold in the position N-1 is not increased due to no hot liquid slag returning from the position N, the moving speed in the step (b) is decreased, And wherein if the temperature of the mold in the position N-2 is attributed to the hot liquid slag from the position N-1 In the case where the mold is reflowed and increased, the moving speed in the step (b) is increased. The method of any one of claims 1 to 4, wherein the closing of the sliding gate or the sliding gate is achieved such that the hole (354) of the fixing plate (353) is not completely closed, thereby leaving each hole One of the residual openings, which generally represents 0.3 to 1.5 times the diameter of the metal particles. An apparatus (1) for granulating hot liquid slag with dry slag, the apparatus comprising an endless conveyor (10) having a plurality of molds (11) arranged in a In the first section, the molds are moved from a slag casting zone (A) through a cooling zone (B) to a removal zone (C), and moved back to the slag in a second zone. a casting zone, and wherein the apparatus further comprises a distribution device (30) disposed above the mold at a position N+n in the cooling zone and containing at least a solid metal particle (33) for storage a funnel (31), the dispensing device further comprising at least one sliding gate (35) at the outlet (32) of the funnel, the actuation of the sliding gates allowing control of the amount of metal particles dispensed by the dispensing device, ‧ at least one sensor (Sh _slag ) capable of measuring the actual amount of hot liquid slag cast in a mold at a position between the slag casting position N and the metal particle addition position N+n Where n is a number between 1 and 10, a control unit for measuring one of the hot liquid slag Adjusting the moving speed of the conveyor V _caster ; determining the necessary amount of metal particles to be added by the distributing device based on a fixed slag/metal particle ratio λ; by determining one based on the speed V _caster Opening the at least one actuation sliding gate disposed at the exit of the funnel during time t to control the amount of metal particles to be added by the dispensing device; and determining the opening time of the at least one sliding gate based on the determination amount of the metal particles And a characteristic to determine an opening stroke x of the at least one actuating sliding brake. The apparatus of claim 15 wherein the at least one sliding gate characteristic comprises a metal particle mass flow □ _particles as a function of the opening stroke x (□ _particles / x curve). The apparatus of claim 15 further comprising at least one sensor (Sh _slag , Sh _mix ) capable of determining a slag height h _slag , slag / in the mold, respectively The metal particle height h _{mix is} used to measure the amount of one of the hot liquid slag and/or the mixture of the slag and the metal particles in a mold, and wherein the control unit is capable of calculating a correspondence based on the known shape of the mold The volume V _slag and / or V _mix , and the determination quality M _{slag of the slag} and / or the determination mass M _particles ' of the metal particles based on the difference between V _mix and V _slag . The apparatus of claim 17, wherein the at least one sensor comprises a laser range finder. The apparatus of any one of claims 15 to 18, wherein the slag pouring zone in the first section of the endless conveyor is arranged to convey the first slant angle α The mold is further controlled to further control the amount of liquid slag in the mold, the inclination angle α limiting the effective maximum filling volume of the mold in the slag casting zone to a value V _α such that any excess slag is poured back to the position An upstream mold of N-1, N-2, etc., and wherein the cooling zone is arranged at a second inclination angle β < α such that the effective maximum filling volume of the mold in the cooling zone has a value V _β >V _α . The apparatus of claim 19, wherein the inclination angle α in the slag casting zone and the inclination angle β in the cooling zone are selected such that the mold is effectively effective in the slag casting zone. filling volume _V α is between 0.25 times the effective maximum filling volume of the mold _V β in the cooling zone with 0.75 times. The apparatus of any one of claims 15 to 18, wherein the at least one actuated sliding gate comprises one or more columns of aligned holes or two or more columns of staggered holes. The apparatus of any one of claims 15 to 18, wherein the dispensing device comprises two individually controllable actuating sliding gates, each sliding gate covering one half of the surface of the mold. The apparatus of claim 22, wherein the or the actuated sliding brake comprises one or more hydraulic cylinders (355). The apparatus of any one of claims 15 to 18, wherein the movement of the molds is performed by monitoring the temperature of at least two molds upstream of the mold (positions N-1 and N-2) being filled And further control by changing the moving speed. The apparatus of claim 24, wherein if the temperature of the mold in the position N-1 is not increased due to no hot liquid slag flowing from the position N, the moving speed of the mold is lowered, and wherein The temperature of the mold in position N-2 is increased due to the increase in hot liquid slag from the reflow of the mold in position N-1. The apparatus of any one of claims 15 to 18, wherein the closing of the sliding gate or the sliding gate is achieved such that the hole (354) of the fixing plate (353) is not completely closed, thereby leaving each hole One of the residual openings, which generally represents 0.3 to 1.5 times the diameter of the metal particles.