阅读说明：本技术 一种生产双层球团的方法及系统 (Method and system for producing double-layer pellets ) 是由 郭宇峰 陈凤 王帅 刘阔 杨凌志 刘雅婧 于 2021-08-16 设计创作，主要内容包括：本发明公开了一种用于生产双层球团的方法及系统,采用两段造球的方法分别制备双层球团的内层和外层,系统可细分为连续型系统和阶段型系统。连续型系统的造球机由直径不同的两台圆筒套合而成,两圆筒可分别以不同转速进行造球以提高双层球团的强度和粒度合格率。外层造球原料使用给料小车卸入到大直径圆筒内的头部位置,可根据双层球造球要求调整给料小车的下料位置。阶段型系统由两台圆筒造球机和两套筛分装置组成,将双层球内层和外层的制备分为两个阶段。两圆筒造球机间设置的筛分装置使制备出的双层球其碱度和内外层厚度更均匀,适用于批量制造强度高、粒度均匀的双层球团。可推进双层球团制备技术的发展。(The invention discloses a method and a system for producing double-layer pellets, wherein the inner layer and the outer layer of the double-layer pellets are respectively prepared by adopting a two-stage pelletizing method, and the system can be subdivided into a continuous system and a stage system. The pelletizer of the continuous system is formed by sleeving two cylinders with different diameters, and the two cylinders can respectively pelletize at different rotating speeds so as to improve the strength and granularity qualification rate of the double-layer pellets. The outer layer balling raw material is unloaded to the head position in the large-diameter cylinder by using the feeding trolley, and the unloading position of the feeding trolley can be adjusted according to the requirement of double-layer balling. The stage type system consists of two cylindrical pelletizer and two sets of screening devices, and the preparation of the inner layer and the outer layer of the double-layer pellet is divided into two stages. The screening device arranged between the two cylindrical pelletizer enables the prepared double-layer pellets to have more uniform alkalinity and inner and outer layer thickness, and is suitable for batch production of the double-layer pellets with high strength and uniform granularity. Can promote the development of the preparation technology of the double-layer pellet.)

1. A method for producing double-layer pellets is characterized by comprising the following steps: the method adopts a two-stage pelletizing mode to respectively prepare the inner layer and the outer layer of the double-layer pellet.

2. A double-layered pellet pelletizing system based on the method of claim 1, characterized in that: the system is a continuous production type system or a stage type production type system;

the continuous production type system comprises two cylinders with different diameters, which are arranged in the front and back of a coaxial axial center line and an inclination angle and are sleeved to form a composite type cylinder pelletizer, the rotating speeds of the two cylinders are different, the small-diameter cylinder is used for preparing an inner layer ball of a double-layer pellet and then enters a large-diameter cylinder, the large-diameter cylinder is internally provided with a double-layer pellet generated by rolling and adhering an outer layer pellet raw material, the double-layer pellet is discharged, and the double-layer pellet with qualified particle size is obtained after being screened by a screening device;

the staged production type system respectively prepares an inner layer ball and an outer layer ball of the double-layer pellet through two independent cylindrical pelletizer, the prepared inner layer ball is wetted and sent into another cylindrical pelletizer after being screened by a screening device, the double-layer pellet is generated by rolling and adhering outer layer ball raw materials in the cylindrical pelletizer and discharged, and the double-layer pellet with qualified particle size is obtained after being screened by the screening device.

3. The system of claim 2, wherein: the joint of the two cylinders is provided with a sealing ring.

4. The system of claim 2, wherein: the small-diameter cylinder is provided with an inner-layer ball mixture bin, an inner-layer ball raw material belt and a feeding chute as a feeding device.

5. The system of claim 2, wherein: the feed end of the small-diameter cylinder is provided with a water dripping device, and the water dripping device drips water drops to enable the powdery material entering the small-diameter cylinder to generate an inner layer ball core.

6. The system of claim 2, wherein: the large-diameter cylinder is provided with an outer-layer ball mixture bin, an outer-layer ball raw material belt and a feeding trolley as a feeding device, and the lower side of the head end of the outer-layer ball raw material belt is provided with a spray water sprayer.

7. The system of claim 2, wherein: the section type pelletizer system is characterized in that two cylindrical pelletizer of the section type pelletizer system are both provided with a batching system which is the same as a small-diameter cylinder of the continuous production type system, a water dripping device is arranged at the feed end of the cylindrical pelletizer for preparing the inner layer balls, and a mist water sprayer is arranged below a raw material belt of the cylindrical pelletizer for preparing the outer layer balls.

8. The system of claim 2, wherein: the screening device is a roller screen, the gap between a front-section roller and a roller of the screening device is smaller than the gap between a rear-section roller and the roller, and a material returning belt is arranged below the front section; a qualified ball belt is arranged below the rear section, and a ball groove for containing large-granularity pellets is arranged at the discharge end.

Technical Field

The invention relates to the technical field of pellet preparation, in particular to a method and a system for producing double-layer pellets.

Background

Pelletizing refers to a process of making fine powder materials into pellets with a particle size meeting the requirement of the next operation, and generally, the materials and liquid are added into a cylindrical, disc, vibrating or stirring pelletizer together to make the pellets. Pelletizing equipment is most commonly used with cylindrical and disc pelletizing machines, and pelletizing liquids are most commonly used with low viscosity liquids (usually water). The pelletizing process can be divided into three stages: forming a cue ball, which grows and grows compact. The three stages are mainly realized in a pelletizer by adding water for wetting and by a rolling method. The pelletizing technology is widely applied to the industrial fields of steel, nonferrous metallurgy, cement, fertilizer and the like.

All types of pelletizing systems and pelletizing methods known to date are mainly used for producing pellets of uniform composition, i.e. the chemical composition of the inner and outer layers of the pellets is essentially the same. The production mode is mature and widely applied to various industries. But the existing pelletizing technology cannot be used for producing newly developed double-layer pellets. The double-layer pellet means that the inner layer of one pellet is made of raw materials with specific chemical components, and the outer layer is made of another raw material with completely different chemical components. Namely, a double-layer pellet is composed of an inner-layer pellet and an outer-layer pellet, the inner-layer pellet with a certain particle size is prepared in the pelletizing process, and then another powdery raw material is continuously added to prepare the outer-layer pellet wrapped on the outer side of the inner-layer pellet, so that the double-layer pellet is finally obtained.

Disclosure of Invention

The invention aims to solve the technical problem that the conventional pelletizing system cannot prepare double-layer pellets, and provides a pelletizing method and a pelletizing system for quickly preparing the double-layer pellets with qualified quality, wherein the pelletizing method and the pelletizing system have optional processes and systems.

The method for producing the double-layer pellets provided by the invention adopts a two-stage pelletizing mode to prepare the inner layer and the outer layer of the double-layer pellets respectively.

The double-layer pellet pelletizing system based on the method is a continuous production type system or a stage production type system. The continuous production type system comprises two drums which are arranged in the front and back direction of a coaxial central line and an inclination angle, the two drums are in unequal diameter and are sleeved to form a composite drum pelletizer, the rotating speeds of the two drums are different, inner layer balls of double-layer pellets are prepared by the small-diameter drum and then enter the large-diameter drum, the double-layer pellets are generated by rolling and adhering outer layer ball raw materials in the large-diameter drum and are discharged, and the double-layer pellets with qualified particle sizes are obtained after being screened by a screening device. The staged production type system respectively prepares an inner layer ball and an outer layer ball of the double-layer pellet through two independent cylindrical pelletizer, the prepared inner layer ball is wetted and sent into another cylindrical pelletizer after being screened by a screening device, the double-layer pellet is generated by rolling and adhering outer layer ball raw materials in the cylindrical pelletizer and discharged, and the double-layer pellet with qualified particle size is obtained after being screened by the screening device.

In one embodiment of the continuous pelletizing system, a sealing ring is disposed at the joint of the two cylinders.

In one embodiment of the continuous pelletizing system described above, the small diameter cylinder is provided with an inner-layer ball mixture bin, an inner-layer ball raw material belt, and a feed chute as the feeding device.

In one embodiment of the continuous pelletizing system described above, the feed end of the small-diameter cylinder is provided with a water dripping device, which drips water droplets to form inner-layer ball cores from the powdery material entering the small-diameter cylinder.

In one embodiment of the continuous pelletizing system, the large-diameter cylinder is provided with an outer-layer ball mixture bin, an outer-layer ball raw material belt and a feeding trolley as a feeding device, and the lower side of the head end of the outer-layer ball raw material belt is provided with a water spray nozzle.

In one embodiment of the continuous pelletizing system, the two cylindrical pelletizing machines are both provided with a batching system which is the same as the small-diameter cylinder of the continuous production system, the feeding end of the cylindrical pelletizing machine for preparing the inner-layer balls is provided with a water dripping device, and the lower part of the raw material belt of the cylindrical pelletizing machine for preparing the outer-layer balls is provided with a mist water sprayer.

In one embodiment of the continuous pelletizing system and the stage pelletizing system, the screening device is a roller screen, a material returning belt and a qualified pellet belt are arranged below the roller screen, and a pellet trough for containing large-granularity pellets is arranged at the discharge end of the roller screen.

The pelletizing idea of the double-layer pellet is to respectively prepare the inner layer and the outer layer of the double-layer pellet by adopting a two-section pelletizing mode. The pelletizing system guided by this idea is classified into a continuous type system and a stage type system. The continuous system adopts a small-diameter cylinder and a large-diameter cylinder which are coaxially arranged along the axial center line from front to back to form a composite type cylindrical pelletizer in a sleeved mode, firstly, a fully qualified inner-layer ball is prepared through the small-diameter cylinder and directly enters the large-diameter cylinder to be adhered with an outer-layer ball raw material to roll to generate an outer-layer ball, and finally, a double-layer pellet is formed and is screened to obtain the double-layer pellet with qualified particle size. Namely, the continuous system only screens the double-layer balls, the system configuration is simple, and the arrangement of the two cylinders has the advantages of small floor area and higher compactness of the prepared double-layer balls. The stage type system respectively prepares an inner layer ball and an outer layer ball through a cylindrical pelletizer, the inner layer ball is screened after being prepared and then enters another cylindrical pelletizer to prepare the outer layer ball, and finally double-layer pellets are formed, and the double-layer pellets are screened to obtain the double-layer pellets with qualified particle sizes. Namely, the stage-type system comprises two cylindrical pelletizer and two sets of screening devices, the system configuration is relatively complex, but the double-layer pellets prepared by the system have the advantages of more uniform alkalinity and inner and outer layer thickness of the double-layer pellets. When the method is applied specifically, corresponding selection can be made according to needs. Therefore, the invention can make up for the deficiency of the research and development results of the current double-layer pelletizing system in China to a certain extent and promote the further development of the double-layer pelletizing preparation technology.

Drawings

Fig. 1 is a schematic view of an apparatus arrangement of a continuous pelletizing system according to an embodiment of the present invention.

Fig. 2 is a schematic view of the layout of an apparatus for implementing the two-stage type pelletizing system according to the present invention.

Number in the figure:

1. an inner layer pelletizing cylinder; 2. an inner layer ball mixture bin; 3. an inner layer ball raw material belt;

4. a feeding chute; 5. supporting carrier rollers and catch wheels; 6. a motor and a speed reducer; 7. a transmission gear;

8. a water dripping device; 9. a material scraping device of the cylindrical pelletizer; 10. an outer layer ball mixture bin;

11. an outer layer ball raw material belt; 12. an outer layer pelletizing cylinder; 13. a seal ring; 14. a feeding trolley;

15. a dust cover of the belt conveyor; 16. a belt conveyor access hole; 17. a water sprayer with a mist-like water is arranged inside;

18. double-layer ball roller screen; 19. a double-layer ball return belt; 20. a double-layer spherical wide belt;

21. double-layer ball grooves with large granularity; 22. a cylindrical pelletizer for the inner layer balls; 23. a cylindrical pelletizer for the outer layer balls;

24. an inner layer ball roller screen; 25. an inner layer ball return belt; 26. an inner layer ball belt;

27. large-granularity inner-layer ball grooves; 28. an outer ball feeding belt; 29. an external water sprayer for spraying water.

Detailed Description

In order to make the technical solutions of the present invention better understood by those skilled in the art, the present invention will be further described in detail with reference to the accompanying drawings and specific embodiments.

First embodiment, as shown in fig. 1, the pelletizing system disclosed in this embodiment is a continuous system, and includes a composite cylindrical pelletizer in which two cylinders with different diameters are nested, a small-diameter cylinder 1 and a large-diameter cylinder 12 are installed in front and back of a coaxial center line and an inclination angle, and a sealing ring 13 is disposed at a joint of the two cylinders. The small-diameter cylinder 1 is used for preparing an inner layer ball of the double-layer pellet, and the large-diameter cylinder 12 is used for preparing an outer layer ball of the double-layer pellet. The two cylinders are respectively provided with a supporting device and a driving device, and can respectively carry out pelletizing at different rotating speeds so as to improve the strength and the granularity qualification rate of the double-layer pellets.

Specifically, the small-diameter cylinder 1 is provided with an inner-layer ball mixing bin 2, an inner-layer ball raw material belt 3, and a feed chute 4 as a feeding means. The mixed inner layer ball raw materials are sent into an inner layer ball mixture bin 2 with a disk feeder and a quantitative feeding belt, and the bin feeds the mixture into the small-diameter cylinder 1 through the inner layer ball raw material belt 3 and a feeding chute 4 according to the set feeding amount.

The small-diameter cylinder 1 is supported by a supporting carrier roller and a catch wheel 5, and a variable speed motor and a speed reducer 6 drive a transmission gear set 7 to transmit so as to provide rotating speed for the pelletizing cylinder.

A water dripping device 8 is arranged above the feeding end of the small-diameter cylinder 1, and water drops dripped by the water dripping device enable powdery materials entering the pelletizer to form an inner layer pellet core. The rotation of the inner layer pelletizing cylinder drives the ball core to roll and grow gradually to form the inner layer balls with qualified granularity.

The small-diameter cylinder 1 is internally provided with a scraping device 9 for scraping off the sticky materials on the cylinder wall.

The large-diameter cylinder is provided with an outer layer ball mixture bin 10, an outer layer ball raw material belt 11 and a feeding trolley 14 as a feeding device. The supporting means and the driving means of the large diameter cylinder are configured the same as the small diameter cylinder.

The mixed outer layer ball raw material is sent into an outer layer ball mixture bin 2 with a disk feeder and a quantitative feeding belt, and the bin discharges the mixture into a large-diameter cylinder 12 through an outer layer ball raw material belt 11 and a feeding trolley 14 according to the set feeding amount.

And a dust cover 15 is arranged on the outer sides of the feeding trolley 14 and the outer layer ball raw material belt 11, and a maintenance hole 16 with a certain width is reserved in the dust cover. The lower end of the head of the outer ball raw material belt 11 is provided with a water spray sprayer 17.

When the inner layer balls prepared by the small-diameter cylinder 1 enter the large-diameter cylinder 12, the inner layer balls can be further wetted by the mist water sprayer 17, the inner layer balls can be adhered to outer layer ball raw materials unloaded by the feeding trolley 14 and roll to generate double-layer pellets, the double-layer pellets are discharged from the port of the large-diameter cylinder and roll down on the roller screen 18 for screening, crushed balls and small balls with the qualified particle size are conveyed to a batching room by the double-layer ball return belt 19 below the roller screen 18, the double-layer balls with the qualified particle size are conveyed to the chain grate machine for drying and preheating by the double-layer ball wide belt 20 below the roller screen, and the large balls with the qualified particle size enter the ball groove 21 and are conveyed to the batching room together with other returned materials by the double-layer ball return belt 19.

The length of the large-diameter cylinder 12 is required to ensure that double-layer pellets with qualified particle sizes can be formed, and the problem that powdery or small-particle outer layer pellet raw materials are discharged out of a pelletizer without being adhered to the pellets yet to cause the alkalinity deviation of the double-layer pellets is avoided.

Second embodiment, as shown in fig. 2, the pelletizing system disclosed in this embodiment is a staged system, and includes independent cylindrical pelletizing machines, i.e., an inner-layer pellet pelletizing machine 22 and an outer-layer pellet pelletizing machine 23, which are respectively provided with a batching device and a screening device.

As can be seen from fig. 1 and 2, the batching device of the two pelletizer in this embodiment is basically the same as that of the small-diameter cylinder in this embodiment, except that the outer layer ball batching device is provided with an external water spray sprayer 29 below the raw material belt. The supporting device and the driving device of the two pelletizer are the same as the configuration of the first embodiment.

As shown in fig. 2, an inner layer ball roller sieve 24 is disposed at a ball outlet of the inner layer ball pelletizer 22, an inner layer ball returning belt 25 is disposed below a front section of the inner layer ball roller sieve, an inner layer ball belt is disposed below a rear section of the inner layer ball roller sieve, and a high-strength inner layer ball groove 27 is disposed outside a lower end of the roller sieve.

The mixed inner layer ball raw materials are sent into an inner layer ball mixture bin 2 with a disc feeder and a quantitative feeding belt, the bin feeds the mixture into an inner layer ball pelletizer 22 through an inner layer ball raw material belt and a feeding chute according to the set feeding amount to prepare inner layer balls, the prepared inner layer balls are firstly screened by an inner layer ball roller screen 24, and crushed balls and small balls with the granularity smaller than the qualified granularity are transported to a raw material mixing room by an inner layer ball return belt 25 to be used as the inner layer ball raw materials. The inner layer balls with qualified particle sizes fall on the inner layer ball belt 26 and are sent into the outer layer ball pelletizer 23 through the outer layer ball feeding belt 28, and are mixed with the outer layer ball raw material to prepare the double-layer pellets. An external spray water sprayer 29 is arranged above the outer-layer ball feeding belt 28 to wet the surface of the inner-layer pellets, so that the outer-layer ball raw materials can be adhered to the inner-layer pellets to roll in the outer-layer ball pelletizer 23 to generate double-layer pellets, and the outlet end of the outer-layer ball pelletizer 23 is provided with a roller sieve 18, a double-layer ball returning belt 19, a double-layer ball width belt 20 and a large-particle-size double-layer ball groove 21 which are used as sieving devices and have the same large-diameter outlet end as that of the first embodiment.

That is, after the double-layer balls discharged from the outer-layer ball pelletizer 23 are screened by the roller screen, the crushed balls and the small balls with the granularity smaller than the qualified granularity are conveyed to the batching room by the double-layer ball returning belt 19, the double-layer balls with the qualified granularity are conveyed to the chain grate machine by the double-layer ball width belt 20 for drying and preheating, and the large balls with the granularity larger than the qualified granularity enter the ball groove 21 and are conveyed to the batching room together with other returning materials by the double-layer ball returning belt.

The pelletizing process of the two embodiments of the invention is as follows:

in the first embodiment, two cylinders with different diameters are continuously arranged, raw materials for preparing inner layer balls are fed into a feeding chute at one end of a small-diameter cylinder through a raw material belt of the inner layer balls, water drops dropped by a water dropping device enable powdery materials entering a ball making machine to form inner layer ball cores, and the ball cores continuously roll and grow in the cylinders to form the inner layer balls with qualified particle sizes. The processing amount of the inner layer ball raw material is ensured to be capable of completely forming the inner layer ball with qualified granularity in the small-diameter cylinder, and the inner layer ball raw material of powder or small particles is prevented from entering the large-diameter cylinder. The green performance of the inner layer ball is mainly adjusted by changing the rotation speed of the small diameter cylinder. The pelletizing powder material of the outer layer ball is discharged into the head of the large-diameter cylinder through a remote control feeding trolley. The most front end of the outer-layer ball raw material belt dust cover is provided with a mist water sprayer for wetting the inner-layer balls rolled into the large-diameter cylinder so as to ensure that the inner-layer balls can be quickly adhered with outer-layer ball powder. The large diameter cylinder is provided with an independent transmission so that it can have a different rotational speed than the small diameter cylinder. The processing amount of the raw material of the outer layer ball is ensured to be completely adhered to the outer side of the inner layer ball in the large-diameter cylinder to form the double-layer ball with qualified granularity. The method avoids the problem that the powdery or small-particle outer layer ball raw material is discharged out of the pelletizer before being adhered to the large-particle-size balls to cause the alkalinity deviation of the double-layer balls. The outer layer ball raw material belt extending into the tail part of the large-diameter cylinder and the feeding trolley are both provided with dust covers so as to avoid the accumulation of dust to influence the running of the belt and the trolley. And an opening with a certain width is reserved at each distance of the dust cover and is used for overhauling the belt and the trolley. The feeding trolley is provided with a remote control system, and the blanking position of the feeding trolley can be adjusted according to the requirement of double-layer ball-making. The prepared double-layer pellets are discharged from the large-diameter cylinder and roll down on a roller screen, after screening, the double-layer pellets with unqualified particle size are returned to the batching, and the double-layer pellets with qualified particle size are sent to the preheating roasting process.

In the second embodiment, the preparation of the double-layer pellets is divided into two stages, two independent cylindrical pelletizer is adopted to respectively prepare the inner-layer pellets and the outer-layer pellets of the double-layer pellets, the inner-layer pellets prepared by the inner-layer pellet pelletizer are screened for the particle size by a roller screen, the inner-layer pellets with unqualified particle size return to the mixing chamber of the raw materials of the inner-layer pellets to be mixed again, the inner-layer pellets with qualified particle size are wetted by a mist water sprayer and sent to the outer-layer pellet pelletizer by a ball belt of the outer-layer pellets, the raw materials of the outer-layer pellets are adhered in the outer-layer pellet pelletizer in a rolling mode to finally prepare the double-layer pellets and then discharge the double-layer pellets, the discharged double-layer pellets are screened by the roller screen to obtain the double-layer pellets with qualified particle size and sent to the preheating roasting process, and the pellets with unqualified particle size are used as return materials to be pelletized continuously.

The pelletizing system for producing the double-layer pellets, the continuous double-layer pellet pelletizing system and the double-cylinder pelletizing system provided with the inner-layer pellet screening device disclosed by the invention have substantial characteristics and technical innovations, and the innovations are essentially different from all pellet pelletizing modes invented and have practical significance for promoting the technical development of the double-layer pellets.

The above examples are merely illustrative of the inventive arrangements. The pelletizing system for producing double-layer pellets according to the present invention is not limited to the above description, but is subject to the scope defined by the claims. Various modifications or changes may be made by those skilled in the relevant art without departing from the spirit and scope of the invention. Accordingly, all equivalents are intended to fall within the scope of the invention, which is defined by the claims.