阅读说明：本技术 一种覆膜型砂再生工艺及系统 (Tectorial membrane molding sand regeneration process and system ) 是由 赵伟石 吴学庆 陈国兴 于 2019-11-15 设计创作，主要内容包括：本发明公开了一种覆膜型砂再生工艺,包括以下步骤：步骤S1：将需再生的覆膜型砂破碎；步骤S2：对破碎后的覆膜型砂进行筛分；步骤S3：对筛分后的砂粒进行电磁除铁；步骤S4：将电磁除铁后的砂粒送入振动提升机；步骤S5：在提升段设置管式煅烧炉,将砂粒表面的树脂层氧化并搓擦掉；步骤S6：将砂粒冷却得到再生砂；同时本发明还提供了一种覆膜型砂再生系统和一种振动提升煅烧炉,设备投入少,占地小,废气量少,对环境友好,可实现小型化覆膜砂的回收,特别适合中小型铸造企业。(The invention discloses a film-coated molding sand regeneration process, which comprises the following steps: step S1: crushing the coated molding sand to be regenerated; step S2: screening the crushed coated molding sand; step S3: performing electromagnetic iron removal on the screened sand grains; step S4: sending the sand grains subjected to electromagnetic iron removal into a vibration elevator; step S5: arranging a tubular calcining furnace at the lifting section, oxidizing and rubbing off the resin layer on the surface of the sand grains; step S6: cooling the sand grains to obtain reclaimed sand; meanwhile, the invention also provides a precoated molding sand regeneration system and a vibration lifting calcining furnace, which have the advantages of less equipment investment, small occupied area, less waste gas amount, environmental friendliness, capability of realizing the recovery of the small precoated sand and particular suitability for small and medium-sized casting enterprises.)

1. A tectorial membrane molding sand regeneration technology is characterized in that: the method comprises the following steps:

step S1: crushing the coated molding sand to be regenerated;

step S2: screening the crushed coated molding sand;

step S3: performing electromagnetic iron removal on the screened sand grains;

step S4: sending the sand grains subjected to electromagnetic iron removal into a vibration elevator;

step S5: arranging a tubular calcining furnace at the lifting section, raising the temperature to 700-800 ℃, improving the contact between sand grains and air by using the vibration rise of the sand grains, and oxidizing and rubbing off a resin layer on the surfaces of the sand grains by using the mutual friction of the sand grains;

step S6: and cooling the sand grains to obtain reclaimed sand.

2. The coated molding sand regeneration process according to claim 1, characterized in that: and step S7, sending the reclaimed sand into a sieving machine, grading to obtain coarse sand and fine sand, and respectively sending the coarse sand and the fine sand into different bins for storage.

3. The process for regenerating coated molding sand according to claim 1 or 2, wherein: in the step S5, the sand adding speed is controlled to ensure that the thickness of a sand layer is 2-10 mm, sand grains rise spirally in a vibration mode, the temperature is raised to 700-800 ℃ in a calcining furnace, and calcining is carried out for 2-5 minutes.

4. The utility model provides a tectorial membrane molding sand regeneration system which characterized in that: the system comprises a lifting machine (1), a storage bin (2), a classifying screen I (3), a magnetic separator (4), a vibration lifting calcining furnace (5) and a cooler (6) which are connected in sequence, broken waste sand is sent into the storage bin (2) through the lifting machine (1), then is screened by the classifying screen (3) and is magnetically separated and deironized by the magnetic separator (4), sand grains enter the vibration lifting calcining furnace (5) to be heated, and the processed sand grains are sent into the cooler (6) to be cooled.

5. The coated molding sand reclamation system as recited in claim 4, wherein: the system further comprises a classifying screen II (7), a hoisting machine I (8), a hoisting machine II (10), a high-position coarse sand bin (9) and a high-position fine sand bin (11), the cooled regenerated sand is classified by the classifying screen to obtain coarse sand and fine sand, and the coarse sand and the fine sand are respectively sent into the high-position coarse sand bin and the high-position fine sand bin for storage through the hoisting machine I and the hoisting machine II.

6. The coated molding sand reclamation system as recited in claim 4, wherein: : the vibration lifting calcining furnace comprises a frame (12), a base (15) is arranged on the frame, a spring (14) is arranged between the frame and the base, and a vibration motor is arranged on the base; the machine base is provided with a spiral track along the vertical direction and used for guiding materials to jump and rise along the spiral track, the middle part of the track is provided with a tubular calcining furnace, the calcining furnace is sequentially provided with an outer shell layer (18), a heat insulation layer (19) and an electric heating layer (20) from outside to inside, the lower part of the vibration lifting calcining furnace is provided with a sand inlet (16), and the upper part of the vibration lifting calcining furnace is provided with a sand outlet (21).

7. A vibration lifting calcining furnace is characterized in that: the calcining furnace comprises a frame (12), a base (15) is arranged on the frame, a spring (14) is arranged between the frame and the base, and a vibration motor is arranged on the base; the machine base is provided with a spiral track along the vertical direction and used for guiding materials to jump and rise along the spiral track, the middle part of the track is provided with a tubular calcining furnace, the calcining furnace is sequentially provided with an outer shell layer (18), a heat insulation layer (19) and an electric heating layer (20) from outside to inside, the lower part of the vibration lifting calcining furnace is provided with a sand inlet (16), and the upper part of the vibration lifting calcining furnace is provided with a sand outlet (21).

8. A vibration lift calciner according to claim 7 wherein: the vibration elevator has an amplitude of 6-9 mm, and a distance of 10-15 mm is kept between the innermost side of the tubular calcining furnace and the spiral track (17).

Technical Field

The invention belongs to the field of steel casting, and particularly relates to a coated molding sand regeneration process and a coated molding sand regeneration system.

Background

The reclaimed sand is silica sand, precious pearl sand, ceramic sand and the like which are used in the casting industry and processed to have service performance and value again, and can be recycled as the base material of coated molding sand or other sand products. China is a world-wide casting country, and the resource consumption and the environmental pollution caused by direct waste of waste molding sand are extremely remarkable. Therefore, the regeneration of the waste molding sand is a main way for solving the problem, and has great practical significance for realizing green sustainable development of the casting industry in China.

The regeneration of used sand starts in 1912, and has been already over 90 years of history so far, and dry regeneration, wet regeneration and thermal regeneration processes are developed successively.

(1) Dry regeneration

Dry regeneration is further classified into centrifugal, air-flow, vibration, rubbing, and the like. Centrifugal and airflow type regeneration is to accelerate used sand grains to a certain speed by using mechanical centrifugal force and high-pressure air flow, and to regenerate the used sand by means of the friction between sand grains and metal components or between sand grains. The vibration type regeneration is that under the action of vibration force, the machine body filled with the old sand blocks continuously vibrates, so that impact and friction among the sand blocks and impact and friction between the sand blocks and the inner wall of the vibrating body are caused, the sand blocks are broken, and the old sand grains are regenerated. The rubbing regeneration is to regenerate used sand by strong friction between sand grains and members.

The main advantages of dry regeneration are: the device has simple structure, less investment, quick effect, easy realization and no secondary pollution. Its main disadvantages are: the residual binder film on the old sand particles can not be completely removed, the quality of the regenerated sand is not too high, the equipment components are worn, the sand particles are broken, and the like. And the higher the stripping rate of used sand grains (i.e. the better the quality of reclaimed sand), the greater the impact force and friction required, the more severe the grinding of equipment components and the crushing of sand grains.

(2) Wet regeneration

The wet regeneration is to utilize the dissolving and scrubbing action of water and the mechanical stirring action, and is to crack, dissolve, fall off or remove the residual binder film in the used sand.

The main advantages of wet regeneration are: the sand has good regeneration effect on the used sand of some water-soluble binders, the quality of the regenerated sand is good, the sand can be used as facing sand, and the regeneration efficiency of the used sand is high. Its main disadvantages are: the energy consumption is great, and area is great, and has sewage treatment scheduling problem. The combination of wet regeneration and wet cleaning has good comprehensive effect, and the latest research shows that the ester hardened sodium silicate old sand is very suitable for wet regeneration, while the resin sand has poor effect.

(3) Thermal regeneration

The thermal regeneration is a regeneration method which takes natural gas, coal gas, diesel oil, coal oil and the like as fuels and heats old sand to the temperature of 650-900 ℃ through a roasting furnace so as to remove combustible resin residues on the old sand. The thermal regeneration method has the advantages of good regeneration effect on the organic binder sand, cleaner removal of residual binder, good thermal stability of the regenerated sand, restoration of original particle size distribution, high equipment investment, high cost and high energy consumption. At present, a boiling combustion method and a rotary kiln method are mainly used.

Disclosure of Invention

In view of the above, one of the objectives of the present invention is to provide a coated molding sand regeneration process, which solves the problems of large investment of current recycling equipment, high fuel consumption, large amount of waste gas, expensive equipment investment and large occupied area; the invention also aims to develop a film-coated molding sand regeneration system which is miniaturized, low in energy consumption, low in investment, green and environment-friendly and suitable for small and medium-sized casting enterprises.

One of the purposes of the invention is realized by the following technical scheme:

the regeneration process of the coated molding sand comprises the following steps:

step S1: crushing the coated molding sand to be regenerated;

step S2: screening the crushed coated molding sand;

step S3: performing electromagnetic iron removal on the screened coated molding sand;

step S4: feeding the coated molding sand subjected to electromagnetic iron removal into a vibration elevator;

step S5: arranging a tubular calcining furnace at the lifting section, raising the temperature to 700-800 ℃, improving the contact between sand grains and air by using the vibration rise of the sand grains, and oxidizing and rubbing off a resin layer on the surfaces of the sand grains by using the mutual friction of the sand grains;

step S6: and cooling the sand grains to obtain reclaimed sand.

Particularly, the method also comprises a step S7 of feeding the reclaimed sand into a sieving machine, obtaining coarse sand and fine sand after grading, and respectively feeding the coarse sand and the fine sand into different bins for storage.

Particularly, in the step S5, the sand adding speed is controlled to ensure that the thickness of a sand layer is 2-10 mm, sand grains rise spirally in a vibration mode, the temperature is raised to 700-800 ℃ in a calcining furnace, and calcining is carried out for 2-5 minutes.

The second purpose of the invention is realized by the following technical scheme:

the film-coated molding sand regeneration system comprises a lifter, a bin, a classifying screen I, a magnetic separator, a vibration lifting calcining furnace and a cooler which are connected in sequence, broken waste sand is sent into the bin through the lifter, then is subjected to screening by the classifying screen I and magnetic separation by the magnetic separator for iron removal, sand grains enter the vibration lifting calcining furnace for heating treatment, and the sand grains obtained after treatment are sent into the cooler for cooling.

Particularly, the system further comprises a grading screen II, a lifting machine I, a lifting machine II, a high-position coarse sand bin and a high-position fine sand bin, the cooled regenerated sand is graded by the grading screen to obtain coarse sand and fine sand, and the coarse sand and the fine sand are respectively conveyed to the high-position coarse sand bin and the high-position fine sand bin to be stored through the lifting machine I and the lifting machine II.

The invention also provides a vibration lifting calcining furnace, which comprises a frame, wherein a base is arranged on the frame, a spring is arranged between the frame and the base, and a vibration motor is arranged on the base; the machine base is provided with a spiral track along the vertical direction and used for guiding materials to jump and rise along the spiral track, the middle part of the track is provided with a tubular calcining furnace, the calcining furnace is sequentially provided with an outer shell layer, a heat insulation layer and an electric heating layer from outside to inside, the lower part of the vibration lifting calcining furnace is provided with a sand inlet, and the upper part of the vibration lifting calcining furnace is provided with a sand outlet.

Particularly, a distance of 10-15 mm is kept between the innermost side of the tubular calcining furnace and the spiral track.

The invention has the beneficial effects that: in the past, the boiling method and the rotary method need to use heat radiation generated by fuel combustion and gas as heat transfer media, and simultaneously, in order to ensure complete combustion of the residual resin, excessive air is blown, the amount of exhaust gas generated is large, therefore, the equipment is huge and the heat utilization rate is limited because of the need of a heat recovery system, and the invention solves the problems that the precoated sand rises spirally under the vibration of a vibration hoister and enters a tubular calcining furnace to be gradually heated, the resin is oxidized at the high temperature of 700-800 ℃, the sand particles jump under vibration to strengthen the contact with air, which is beneficial to the oxidation of the resin layer, meanwhile, the friction among the sand grains and between the sand grains and the equipment is also beneficial to the peeling and burning of the resin layer, the equipment of the invention has less investment, small occupied area and less waste gas, the method is environment-friendly, can realize the recovery of the miniaturized precoated sand, and is particularly suitable for small and medium-sized casting enterprises.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof.

Drawings

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail with reference to the accompanying drawings, in which:

FIG. 1 is a flow chart of a method of the present invention;

FIG. 2 is a schematic diagram of the system connection of the present invention;

FIG. 3 is a schematic view of the configuration of a vibration lift calciner of the present invention.

Detailed Description

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to fig. 2. It should be understood that the preferred embodiments are illustrative of the invention only and are not limiting upon the scope of the invention.

As shown in fig. 1, the regeneration process of the coated molding sand of the invention comprises the following steps:

step S1: crushing the coated molding sand to be regenerated;

step S2: screening the crushed coated molding sand;

step S3: performing electromagnetic iron removal on the screened coated molding sand;

step S4: feeding the coated molding sand subjected to electromagnetic iron removal into a vibration elevator;

step S5: arranging a tubular calcining furnace at the lifting section, raising the temperature to 700-800 ℃, improving the contact between sand grains and air by using the vibration rise of the sand grains, and oxidizing or rubbing off a resin layer on the surfaces of the sand grains by using the mutual friction of the sand grains;

step S6: and cooling the sand grains to obtain reclaimed sand.

Step S7: and (4) feeding the reclaimed sand into a sieving machine, grading to obtain coarse sand and fine sand, and respectively feeding the coarse sand and the fine sand into different bins for storage.

As a further improvement, in step S5, the sand adding speed is controlled to enable the thickness of the sand layer to be within the range of 2-10 mm, at the moment, the sand grains rise spirally in a vibration mode, the temperature is raised to 700-800 ℃ in a calcining furnace, calcining is carried out for 2-5 minutes, and experiments prove that under the condition that the thickness of the sand layer is 2mm and the temperature is 700 ℃, the calcining time is only 2 minutes, and the regeneration efficiency is highest.

Based on the design idea of the process, as shown in fig. 2, the film-coated molding sand regeneration system comprises a lifting machine 1, a bin 2, a classifying screen I3, a magnetic separator 4, a vibration lifting calcining furnace 5 and a cooler 6 which are connected in sequence, wherein crushed waste sand is sent into the bin 2 through the lifting machine 1, then is sieved through the classifying screen 3 and is magnetically separated and deironized through the magnetic separator 4, sand grains enter the vibration lifting calcining furnace 5 for heating treatment, and the treated sand grains are sent into the cooler 6 for cooling.

As a further improvement, the system also comprises a grading sieve II7, a hoisting machine I8, a hoisting machine II10, an elevated coarse sand bin 9 and an elevated fine sand bin 11, the cooled regenerated sand is graded by the grading sieve to obtain coarse sand and fine sand, and the coarse sand and the fine sand are respectively conveyed to the elevated coarse sand bin and the elevated fine sand bin for storage by the hoisting machine I and the hoisting machine II.

As shown in fig. 3, the vibration lifting calciner of the invention comprises a frame 12, a base 15 is arranged on the frame, a spring 14 is arranged between the frame and the base, two vibration motors 13 are arranged on the base, and the vibration motors and the spring act together to drive the base and upper connecting equipment, so as to realize a regular vibration lifting function. The vibration lifting function utilizes the asymmetry principle of the vibration motor: when the two motors run reversely at the same time, a vibration couple is generated, and the materials are lifted to a certain height from the horizontal direction through the vibration of the damping spring. The vibration screw conveyor conveys materials upwards in an inclined conveying groove in a micro-throwing moving mode, compared with linear vibration conveying, the conveying path of the screw conveyor is not straight, but is spiral, and corresponding torsional vibration is generated around the central shaft of the spiral tower under a set gradient; thereby causing the load to move up the spiral.

The machine base is provided with a spiral track 17 along the vertical direction and used for guiding materials to jump and rise along the spiral track, the middle part of the track is provided with a tubular calcining furnace, the calcining furnace is sequentially provided with an outer shell layer 18, a heat insulation layer 19 and an electric heating layer 20 from outside to inside, the lower part of the vibration lifting calcining furnace is provided with a sand inlet 16, and the upper part of the vibration lifting calcining furnace is provided with a sand outlet 21.

In the embodiment, the vibration elevator has an amplitude of 6-9 mm, and a distance of 10-15 mm is kept between the innermost side of the tubular calcining furnace and the spiral track 17. The vibration of the hoister and the collision of the tubular calcining furnace are prevented, and the safety performance is improved.

Finally, the above embodiments are only intended to illustrate the technical solutions of the present invention and not to limit the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all of them should be covered by the claims of the present invention.