The old sand of laminated sand has a resin film left on the surface, which cannot be reused without regeneration. The laminated sand regeneration line can regenerate and reuse the used waste sand. By reprocessing the sand at high temperature, the used sand can be restored to its original state, reducing the cost of production of laminated sand casting. and through the high temperature regeneration of sand compared to the original sand impurities less, the production of higher quality of cladding sand, Sanzhuji combined with the characteristics of the cladding sand regeneration equipment to explain.
1.Equipment composition and working principle
The process of laminated sand regeneration production line: waste sand bin -> magnetic separation conveyor -> crushing screen -> elevator -> furnace bin -> vertical regeneration furnace -> boiling cooling bed -> elevator -> grading screen -> finished product bin. Equipped with dust collector.
1.1 Waste sand bin
The feeding inlet adopts drape type seal, which is convenient for the loader to put in the waste sand and stop the dust from overflowing. The discharge port adopts the upper open design for easy cleaning of blockage.
The outlet is connected with the improved flat plate feeding device. It has the advantages of rapid discharge and stable operation. It adopts frequency conversion control to adjust the direction of long impurities during transportation and prevent the belt from scratching and scraping. It can also make the sand evenly lay flat on the belt, so that the magnetic separator can put forward the iron pin in the waste sand more effectively and improve the quality of recycled sand.
1.2 Magnetic Separation Conveyor
The magnetic separation conveyor produced by Sanzhuji has been continuously improved and uses two sets of combined upper and lower designs. The iron removal rate reaches more than 99%. Further ensure the quality of recycled sand products.
1.3 Crushing Screen
The crushing screen is equipped with 3.7kw motor, which can effectively grind and crush the large sand pieces. High-strength shock-absorbing spring and welded bracket box are not easy to be broken and durable.
The crushing screen adopts two layers of screens: the upper steel mesh is wear-resistant and impact-resistant; the lower stainless steel perforated plate with stronger wear resistance is used to enhance the service life.
Two waste slag discharge ports are installed on the side, which can conveniently clean up the impurities such as stones from the waste sand sieving.
The upper dust cover of the crushing screen is designed with a drape, which effectively prevents dust from overflowing and allows clear observation of the operation of the equipment for easy maintenance and screen replacement.
1.4 Elevator and furnace front bin
Use custom-made 10mm, 6-layer line high quality wear-resistant rubber belt. The service life is more than 3 times that of normal flat-based belts. The belt life is more than 5 years under continuous production all day long.
After magnetic separation and crushing, the waste sand enters the furnace front bin, which is equipped with an auger conveyor to convey the sand to the vertical regenerative furnace at a uniform speed.
1.5 Vertical regeneration furnace
The vertical roaster is composed of preheating system, thermal regeneration system, dust removal system and electric control system together. The waste sand is fed into the regeneration furnace through the spiral auger. The upper part is the preheating system with buffer structure inside, the sand grains enter from the entrance and fall, the hot flue gas rises from below inside, so that the sand grains get preheated. The exhaust temperature is only 40℃ indicating that most of the heat is recovered and reused by the system, which greatly reduces the cost of regeneration.
The lower part is boiling roasting system, the sand is boiling and tumbling in the roasting system, and the sand is heated to 700~750 degrees Celsius by the burner, which can completely burn out the resin film of the outer layer of the waste sand and produce primary color regenerated sand.
The vertical roaster can regenerate 5~6 tons per hour, which has the advantages of high volume and good regeneration effect compared with horizontal roaster. It consumes only 10~13 cubic meters of natural gas per ton of regenerated sand. It is 50% lower than the horizontal regeneration furnace.
1.6 Boiling cooling bed
The cooling bed produced by Sanzhuji has a unique heat recovery structure, which recovers the waste heat of the sand through the heat recovery system during the cooling process and reuses it, converting it into energy to return to the regeneration furnace for reuse, with a heat recovery rate of more than 30%, which can effectively reduce the regeneration cost.
and the sand is boiled by high pressure wind during the heat recovery process, and the excess dust in the sand is effectively removed by the dust removal equipment, which reduces the regenerated sand magazine and improves the quality of the finished sand.
1.7 Grading screen finished product bin
The grading screen screens and filters the large particles and other impurities in the recycled sand again, and enters the finished product bin for storage.
2. Advantages of recycled sand
2.1 Lower thermal expansion rate, reduce casting defects
After the casting of waste shell type (core) sand, a part of the original sand in contact with the iron has undergone phase change, and the expansion rate is reduced from 1.3% to 1.5 to 0.5% after regeneration. The reduction of the high temperature expansion rate of silica sand can avoid or reduce the defects of the casting such as sand eye, deformation and so on. Therefore, the use of low expansion rate of recycled sand for precision casting production, while improving the quality of the castings, but also reduce the additional materials due to reduce production costs.
2.2 Reduced gassing, reduce casting porosity
After the regeneration of the sand alkaline earth metal oxides and organic matter reduced, the amount of gas generation reduced to 0.5ml/g, only one eighth of the original sand. The amount of gassing is the main cause of casting porosity, domestic general use to reduce the amount of resin added and its organic additional material, to ensure that the user strength requirements, from the past more than 30ml/g reduced to the current 16 ~ 18ml/g. Regenerated sand due to the basic removal of gassing impurities, the amount of gassing can be reduced to less than 12ml/g. The use of regenerated sand can significantly reduce the occurrence of casting porosity.
2.3 Improve bond strength and reduce phenolic resin dosage
Regenerated sand its silica silicon oxygen Jian activity enhanced, so that the phenolic resin coating improved, improve the bond strength between the overcoat sand and resin, help prevent castings sticky sand.
The overcoated sand produced with regenerated sand can reduce the resin dosage by 10%~15% than the original sand under the same technical index. The strength ratio of recycled sand to original sand is more than 1.12 to 1 under the same resin addition. The reduction of resin dosage in the casting production can improve the production environment, improve the strength to reduce sand core fracture, cracking of the mold surface and other phenomena.
2.4 Fluidity increase
Waste sand in the regenerative furnace for boiling roasting process of relative friction extrusion and impact to improve the roundness of the sand surface, the production of film sand fluidity also increased accordingly, the use of sand core or sand filling degree significantly improved.
Qingdao Sanzhuji Equipment Manufacturing Co., Ltd. specializes in the production of Green Sand Molding Line,Self-hardening sand molding line,foundry machines,Sand molding machine,Sand casting equipment,sand mixer,GS high efficiency rotary mixer,Resin sand mixer,no-bake resin sand mixer,Jolt squeeze molding machine/Jolt-squeezing moulding machines,Multi- Piston Moulding Machine/Hydraulic multi-piston moulding machine,sand casting molding machine,sand reclamation equipment，foundry molding machine,flaskless moulding machine,shot blasting machine,dust collector,according to the amount of old sand recovered Carry out plan customization, and provide sand reclamation equipment installation, commissioning, and training. Welcome guests to visit the factory.
