CN103394638A - Method and apparatus for backwashing and regenerating casting used sand - Google Patents

Abstract

A method and device for backwashing and regenerating old foundry sand, which uses friction and cleaning to remove the film, and realizes repeated rinsing of the old sand by water through the opposite movement of the old sand and water flow, so that the used foundry sand can be continuously regenerated. The device consists of a rotating shaft equipped with spiral blades and a sand washing tank. The rotating shaft is installed on the bearing seats at both ends of the sand washing tank through bearings, and the shaft head at one end of the rotating shaft is connected with the driving device. The driving device is generally a motor and a reducer. The sand washing tank has a sand inlet, a sand outlet, a water inlet and a liquid outlet. The old sand is fed from the feeding hopper. When the rotating shaft rotates, the old sand moves along the axial direction of the sand washing tank under the action of the axial component force of the normal thrust of the spiral blade. It moves downward to the liquid outlet, forms a reverse flow with the sand, and cleans the sand. The cleaned sand is discharged from the sand outlet, and the sand washing sewage is discharged from the liquid outlet. In order to improve the cleaning and regeneration effect, hot water and thermal insulation materials can be used.

Description

A method and device for backwashing recycled foundry sand

technical field

The invention relates to a method and device for regenerating used casting sand. In particular, a backwashing type used sand regeneration method and device can be used for regeneration of sodium silicate used sand, alkali phenolic resin used sand and clay used sand.

Background technique

The main purpose of the regeneration of old foundry sand is to remove the residual binder film and sundries wrapped on the used sand grains, and restore the physical and chemical properties close to new sand for repeated use. At present, in addition to dry regeneration and chemical regeneration. The wet regeneration and stripping effect of foundry old sand is particularly good. The quality of regenerated sand is high, and its basic performance indicators are close to that of new sand. It can be used as surface sand, and the recovery rate of regenerated sand is also high (up to 95%). However, the structure of the previous wet regeneration system is complex and large, the water consumption is large, the cost of wet regeneration is high, the amount of sewage is large, and the treatment is difficult. Reducing the water consumption and drying energy consumption of wet regeneration is the key to the application of wet regeneration. For example, wet regeneration of old sodium silicate sand can remove 70% to 90% of the residue on the surface of the old sand, but the water consumption is large, and the treatment of one ton of sand consumes 2 to 3 tons of water, resulting in high regeneration costs and difficult treatment of recycled sewage . Due to factors such as rising freight costs, the price of new sand has been on the rise; in addition, with land reduction and increasing pressure on resources and the environment, the discharge fee for old sand has continued to rise. In Europe, the cost of regeneration has accounted for 85% to 400% of the purchase cost of new sand; therefore, continuing to discharge old sand not only wastes limited silica sand resources, increases costs, but also pollutes the environment (including alkali pollution and Pb, Ni, Cu, Hg and other heavy metal pollution). It can be seen that it is imminent to realize the regeneration and recycling of old sand.

Publication No. CN1274627A and Publication No. CN101209485A disclose a heat flow old sand reclamation machine, which is mainly composed of a barrel body, an impeller stirring device, a heating device, a dosing device, a frame and the like. The upper part of the barrel body is provided with a dosing device, and the lower part of the barrel body is provided with a heating device. Due to the joint action of mechanical stirring, high-temperature washing and chemicals, to increase the shedding speed and dissolution amount of the inert film on the surface of the old sand in water, and then let the sewage pass through the regenerated sand layer, and propose to collect sewage repeatedly for cleaning Conception of old sand. So as to achieve the purpose of improving the quality of recycled sand and reducing the generation of sewage.

Publication No. CN2412680Y (Patent No. 200910060572.8) and Publication No. CN201423427Y (Application No. CN200920083465) disclose a regeneration method and device for immersion percolation. After vibrating the sodium silicate sand in the container by soaking and percolating, add water to the container to make the water submerge the upper surface of the sand. After soaking for 2-4 hours, open the valve at the bottom of the container to slowly discharge the water; finally, put The water glass sand in the container can be reused after being released and dried. The water glass old sand regeneration treatment method uses less water. But because the gel film formed by the old water glass sand is insoluble in water at normal temperature, the residue wrapped by the gel film has not been really removed. Therefore, in fact, the claimed effect cannot be achieved, and the treatment time is long, the regeneration efficiency is low, and the practical application is difficult.

Patent 200910310570.X proposes the idea of dry recovery and wet regeneration, and uses comprehensive utilization and face-back sand molding technology to regenerate the old water glass sand.

Publication No. CN102527929A (Application No. 201210012373.1) discloses a method for regenerating old water glass sand by steaming and leaching. The broken and screened old water glass sand in the container is fed with high-temperature steam at 100°C or above to cool the water. The old glass sand is steamed, which can effectively remove the sodium oxide in the old water glass sand. The sodium oxide content is less than 0.25%, and the stripping rate is over 90%. The water consumption in the treatment process is less, only 1/10 to 1/5 of the amount of sand to be treated. But this method has high energy consumption, which is not conducive to popularization and application.

CN201210084186 Publication No. CN102615243A discloses a wet-process intermittent regeneration method and equipment for used foundry sand. The regeneration method includes a scrubbing step, a scrubbing step twice, a scrubbing step three times and an inspection step. The regeneration equipment includes a mixer and a sand-water separation device. The mixer is composed of a support frame, a scrubbing cylinder, a driving cylinder, a motor and a main shaft. The scrubbing cylinder has a sand inlet and a water inlet, and has a drain valve and a sand discharge valve. The regeneration method integrates the combined effects of mechanical stirring, clean water washing and pickling, has low water consumption, high removal rate of residual binder, and good quality of regenerated sand; the regeneration equipment has simple structure, low energy consumption, is easy to control, and is easy to realize automation. However, this method adopts an intermittent regeneration method, and the regeneration process cannot realize the conveying function.

CN201110056006 Publication No. CN102133616A provides a recycling method for foundry mixed waste sand. In this method, the waste sand is first classified, screened, dried and dehumidified, and regenerated by dry method. Secondly, the regenerated sand suitable for wet regeneration is wet-processed. Regeneration and dehydration treatment, the regenerated sand suitable for thermal regeneration is regenerated by thermal method, and the two parts of regenerated sand are mixed again according to a certain ratio, and the heat of thermal regenerated sand is used to heat and dry the wet regenerated sand. Adjust the temperature to obtain recycled sand. This method organically combines the advantages of the wet regeneration process and the thermal regeneration process, and regenerates the mixed waste sand synchronously, avoiding the large energy consumption of the post-drying of the regenerated sand in the single wet regeneration process and the single thermal regeneration process The waste of heat during the cooling of regenerated sand reduces energy consumption and the cost of reclaiming old sand.

CN201010170597 Publication No. CN101829759A and CN201020188262 Publication No. CN201669371U disclose the rotary vibration grinding wet-type recycling machine of used water glass sand, including steel spiral rubber composite spring, frame, outer cylinder, inner cylinder, cylinder side plate, ceramic grinding ball and vibration The motor and the ceramic grinding ball are placed in the cavity formed between the outer cylinder and the inner cylinder. There are two vibration motors, one left and one right fixedly connected to the frame on the left and right sides of the outer cylinder. The recycling machine adopts the rotary vibration grinding method to regenerate the old water glass sand by wet method, and has many parts and relatively complex structure.

Publication (announcement) No. CN103056291A invention discloses a combined regeneration method of hot-wet-dry method for used water glass sand. The old water glass sand is vibrated and crushed to remove impurities, then washed with high temperature water to remove the adhesive film on the surface of the sand grains; the water glass particles after washing are dried at a high temperature of 300-350°C, and dry regeneration is carried out to remove the old sand Sodium oxide, dust and residual sintered matter. The combined wet-dry regeneration method has complicated process and high energy consumption.

Publication (Announcement) No. CN102756073A invention relates to a kind of equipment for refurbishing old water glass sand, which uses crushing equipment, screening equipment, stripping equipment, and grading equipment to regenerate old water glass sand, including a feeding device. The refurbishment equipment also includes a fine crusher , a screening machine, a peeling machine, a classifier, a belt dust collector, the feeding device is connected to a fine crusher, the fine crusher is connected to the screening machine through a bucket elevator, the screening machine is connected to the chute, and the screening machine is simultaneously It is connected with the peeling machine, which is connected with the classifier. The bottom of the classifier is equipped with a gravity lock air discharge valve, and the classifier is connected with the belt dust collector. This production process is more traditional wet washing renovation The advanced production process has a small footprint, is less affected by the climate, and does not cause pollution to water sources. Compared with another advanced production process of dry refurbishment of old sodium silicate sand, it has the advantages of simple process flow, less investment and less floor space.

CN101780521A discloses a wet regeneration process for strong scrubbing sodium silicate old sand. Its main features are: the sand particles after magnetic separation pass through the first-stage spiral sand-water separator, the first-stage wet regeneration machine and the second-stage spiral sand-water separator. Separation of sand and water for the old sand; then neutralize the separated sand through the neutralization sedimentation tank; and then carry out secondary sand-water separation through the secondary wet regenerator and the three-stage spiral sand-water separator to ensure that the old sand The water glass existing in it can be completely removed; but the steps are complicated and the equipment is complicated.

Contents of the invention

The present invention proposes a backwash regeneration method for old foundry sand to reduce the water consumption of wet regenerated old foundry sand and realize the transportation of regenerated sand so as to achieve the effect of full utilization of old sand and environmental protection; at the same time, it provides the method for The equipment solves the problem of complex structure of the existing regeneration equipment, and is used for the wet regeneration of clay old sand, alkali phenolic resin old sand and sodium silicate old sand. The regeneration method and regeneration device mainly have the following features.

1. The regeneration method mentioned in the present invention removes the film by means of scrubbing, and realizes the repeated leaching effect of water on the old sand through the relative movement of the old sand and the water flow, so as to achieve continuous regeneration of the old casting sand. The regeneration method process and equipment are simple and easy , A wide range of applications.

2. The sand inlet and clean water inlet of the used sand device for backwashing regenerative casting are respectively located at both ends of the regenerator, and the old sand moves toward the sand outlet under the push of the recycler; the water pressure of the water inlet is greater than the water pressure of the water outlet , the clean water entering from the water inlet moves towards the liquid outlet and the old sand under the action of pressure or gravity, so as to realize the repeated washing effect of water on the old sand.

3. The used sand regeneration device is mainly composed of a rotating shaft equipped with spiral blades and a sand washing tank. The rotating shaft is installed on the bearing seats at both ends of the trough through bearings, and the shaft head at one end of the rotating shaft is connected with the driving device. The driving device is generally a motor and a reducer. The sand washing tank has an inlet and an outlet, a water inlet and a liquid outlet. There is a certain distance between the clean water inlet and the sand outlet of the backwash regeneration casting used sand device to realize the separation of sand and water. According to the distance to the sand inlet, compared with the water inlet, the sand outlet is far away from the sand inlet, and the sand outlet The wet sand after sand-water separation is discharged from the sand outlet, and after dehydration and drying, the quality is qualified before being used for later use.

4. The old sand regeneration process is as follows: put the old sand in the sand hopper into the regeneration material tank from the sand inlet of the regeneration device, add clean water from the water inlet of the regeneration machine, and start the regeneration machine for regeneration. When the rotating shaft rotates, the material is affected by the thrust of the helical blade, and the old sand moves along the axial direction of the sand outlet of the trough under the action of the axial component of the normal thrust of the blade, and the clean water from the water inlet flows downward under the action of gravity The liquid outlet moves and forms a reverse flow with the sand to clean the sand. Finally, the cleaned sand is discharged from the sand outlet, and the sand washing sewage is discharged from the liquid outlet. The sand is cleaner because it is scrubbed and rinsed repeatedly with clean water before being discharged.

5. In order to improve the cleaning and regeneration effect, hot water can be used for cleaning water, and a hot water device can be installed at the water inlet, or a hot water boiler can be installed separately, or the hot water generated by cooling in the smelting process can be used to save energy. When hot water is used, it is better to cover the sand washing tank with a layer of thermal insulation material.

6. According to the quality requirements of regenerated sand, it can be realized by lengthening the length of the working part of the reclaiming device and adjusting the working parameters such as the screw speed.

7. The regeneration device can be installed at a certain angle, and the installation angle is between 0-90°.

The characteristics of the method and device for backwashing recycled foundry sand are as follows.

1. The old sand is continuously regenerated, and the regenerated old sand has uniform sand grains.

2. Simple structure, convenient operation and maintenance.

3. The volume is small, the cost is low, and the manufacturing materials are easy to obtain.

4. Under the same productivity conditions, it can save 50-100% of water compared with existing similar equipment.

5. It can realize transportation while regeneration, which reduces power consumption and saves energy by 50%.

Sixth, it can be realized by appropriately changing the structure size and working parameters of the regeneration equipment according to the type of sand and the different requirements of the output and stripping rate of the regenerated old sand.

Description of drawings

Figure 1 is a schematic diagram of the overall structure of the foundry old sand regeneration device of the present invention

Reference signs in the figure: 1-tank body; 2-spiral shaft; 3-insulation layer; 4-sand outlet; 5-bearing seat; 6-coupling; 7-driving device (motor and reducer); 8 -water inlet; 9-water inlet valve; 10-liquid outlet; 11-sand bucket and sand inlet; 12-bearing seat; 13-bearing.

specific embodiment

The sand washing tank, sand inlet pipe, sand outlet pipe, screw shaft, spiral blade, water inlet pipe, and liquid outlet pipe of the used sand recycling device are all made of 304 stainless steel; the insulation material is made of glass fiber cloth.

Embodiment 1, the angle between the sand washing tank and the ground of the regeneration device is 90°; the outer diameter of the sand washing tank, the sand inlet pipe and the sand outlet pipe are all 100 mm, the thickness is 5 mm, and the lengths are 2000 mm and 200 mm respectively , 1800 mm; the diameter of the screw shaft is 20 mm, and the diameter of the screw blade is 88 mm; the elbow of the sand inlet pipe is welded on the left side of the lower end of the sand washing tank, the sand outlet pipe is welded on the right side of the upper end of the sand washing tank, and the sand inlet is connected by a flange Sand bucket; the outer diameter of the water inlet pipe and the liquid outlet pipe is 30 mm, and the thickness is 5 mm. The water inlet pipe is welded on the left side of the upper end of the sand washing tank, and the upper edge of the weld between the water inlet pipe and the sand washing tank is lower than the lower edge of the sand outlet pipe 10 mm; the liquid outlet pipe is welded on the left side of the upper end of the sand inlet pipe, and the upper end of the liquid outlet pipe is 10 mm lower than the sand inlet; the driving device adopts a stepless speed regulating motor with a power of 0.25-1.5 KW and a speed range of 40- 200 rpm; the thickness of the insulation layer is 6 mm. The experimental data are shown in Table 1.

Table 1 Experimental parameters and effects of Example 1

Embodiment 2, the diameter of the screw shaft of regeneration device 2 is 25 mm, the diameter of the screw blade is 140 mm, the angle between the sand washing tank and the ground is 45 °; the outer diameters of the sand washing tank, sand inlet pipe and sand outlet pipe are 168 mm and 150 mm respectively , 150 mm, the thickness is 10 mm, and the lengths are 2000 mm, 150 mm, 150 mm respectively; the sand inlet pipe and the sand outlet pipe are respectively welded above the lower end of the sand washing tank and below the upper end, and their centers are respectively separated from the lower end of the sand washing tank and The upper ends are 125 mm each; the sand inlet is connected to the sand bucket with a flange. The driving motor is a three-phase asynchronous motor with a power of 5.5 KW. The reducer is an R coaxial helical gear reducer with a speed range of 40-200 rpm. The thickness of the insulation layer is 10 mm. The experimental data are shown in Table 2.

Table 2 Experimental parameters and effects of embodiment two

Embodiment 3, the angle between the sand washing tank and the ground of the old sand regeneration device 3 is 0°; the outer diameter of the sand washing tank, the sand inlet pipe and the sand outlet pipe are all 100 mm, the thickness is 5 mm, and the lengths are respectively 2000 mm, 200 mm, 1800 mm; the diameter of the screw shaft is 20 mm, and the diameter of the screw blade is 88 mm; the sand inlet pipe is welded at the upper left end of the sand washing tank, the elbow of the sand outlet pipe is welded at the upper right end of the sand washing tank, and the middle of the sand outlet pipe The axis and the central axis of the sand washing tank are perpendicular to each other; the sand inlet is connected to the sand bucket with a flange; the outer diameter of the water inlet pipe and the liquid outlet pipe are both 30 mm and the thickness is 5 mm, and the water inlet pipe is welded on the upper end of the sand washing tank On the left side, the upper edge of the welding part with the sand washing tank is 10 mm lower than the lower edge of the sand outlet pipe; the liquid outlet pipe is welded on the left side of the upper end of the sand inlet pipe, and the upper end of the welding part of the liquid outlet pipe is 10 mm lower than the sand inlet; The device adopts a stepless speed regulating motor with a power of 0.25-1.5 KW and a speed range of 40-200 rpm; the thickness of the insulation layer is 6 mm. The experimental data are shown in Table 3.

Table 3 Experimental parameters and effects of Example three

Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the present invention can be Modifications or equivalent replacements of the technical solutions without departing from the spirit and scope of the technical solutions of the present invention shall fall within the scope of the claims of the present invention.

Claims (8)

1. A method and device for backwashing reclaimed foundry sand, characterized in that it comprises the following steps: Put the foundry old sand into the old sand regeneration device through the sand bucket and the sand inlet; at the same time, put the sand washing water into the old sand regeneration device through the water inlet, and mix the water and sand in the regeneration device; In the regeneration method, the sand-water mixture is stirred by means of a regeneration device, and the film is removed through the double action of friction and washing; The regeneration method realizes the repeated rinsing of the old sand by water through the opposite movement of the old sand and the water flow, and separates the binder from the sand particles. Discharge to realize the regeneration of foundry old sand. 2. The method and device for backwashing regenerating foundry old sand according to claim 1, characterized in that: the old sand regenerating device is mainly composed of a rotating shaft equipped with a spiral blade and a sand washing tank; the rotating shaft is installed on the sand washing tank through a bearing On the bearing seats at both ends of the groove, the shaft head at one end of the rotating shaft is connected with the driving device, and the driving device is composed of a motor and a reducer. 3. The method and device for backwashing and regenerating foundry old sand according to claim 2, characterized in that: the sand washing tank of the old sand regeneration device is provided with a sand inlet, a sand outlet, a water inlet, and a liquid outlet; The water inlet and the water inlet are respectively located at the two ends of the regenerator, and the water inlet and the sand outlet are separated by a certain distance to prevent the water from flowing out of the sand outlet directly without passing through the sand washing tank. 4. The method and device for backwashing reclaimed foundry sand according to claim 2, characterized in that: according to the quality requirements of regenerated sand, it can be realized by lengthening the length of the working parts of the regenerating device and adjusting the working parameters of the screw speed. 5. The method and device for backwashing and regenerating old foundry sand according to claim 1, characterized in that: the regenerated old sand is driven by the spiral blade of the regenerating device to move to the sand outlet and discharged; the regenerated liquid is discharged under the action of pressure or gravity It moves toward the liquid outlet and the sand grains and flows out. 6. The method and device for backwashing and regenerating old foundry sand according to claim 1, characterized in that: cold water or hot water can be used for cleaning water; when hot water is used, a hot water device is installed in front of the water inlet or hot water is installed separately boiler, or use the steam generated during the regeneration liquid concentration process to heat water to save energy. 7. The method and device for backwashing and regenerating old foundry sand as claimed in claim 5, characterized in that when hot water is used for washing, the sand washing tank as claimed in claim 3 is preferably coated with a layer of heat-insulating material. 8. The method and device for backwashing and regenerating old foundry sand according to claim 1, characterized in that the regeneration device can be installed at a certain angle, and the installation angle is between 0-90°.

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