The Applied Research Of The Resin Core Sand's Regeneration

The leading products of our workshop include crankcase,226B engine blocks and EuroⅡandⅢengine blocks, the core of these casting are large and thick。After pouring and sand shakeout, molding sand mixed with high proportion of core sand (most of them is core sand without sintering which was grined by trommel screen and got into system), although these can be added in molding sand through mixing, There are still a lot of waste sand discharge. The waste core sand and waste molding sand which is discharged by our workshop amounted to more than 1000 tons. This is not only a huge waste of natural resources, but also a great pollution to the environment。So the research of old sand reclamation technique is an important measure to reduce the production cost of casting, reduce the environmental pollution and save resources, It has great significance for the sustainable development of foundry industry。At present, the resin sand reclamation is divided into complete and incomplete reclamation。Incomplete reclamation is a regeneration process through removing sub-soil of old sand by screening and mechanical friction mode, which can improve the process performance of the old sand, the sub-soil content of regeneration sand is still high, the influence of mixing core sand on the molding sand properties didn't get eliminate, regeneration sand can only be re-used for clay sand system to improve process performance of old sand, so as to reduce new sand addition amount and old sand emissions in the casting production process. Complete reclamation is a technique which is through reclamation, not only to improve particle size distribution of reclamation sand, and to make powder content in the reclamation sand to achieve the same or lower level of new sand, while partially or totally eliminate the influence of mixing core sand on the molding sand properties, the reclamation sand will eventually be used for the core.This paper use the method of theoretical analysis combined with experimental study, on the basis of in-depth understanding of the development status quo of old sand reclamation technologies at home and abroad, analyze the properties and reclamation mechanism of the resin core sand produced by workshop, and use screening, crushing, mechanical friction, dust, baking, washing and drying process for the old sand reclamation。Through performance tests at room temperature of the reclamation sand,evaluation the feasibility of old sand reclamation process for clay sand contains cold (hot) core box sand complete reclamation。The results show that1,Regeneration process can make the regeneration of sand, clay content, burning reduction, water and other properties than new sand, and grain concentration increased.2,Recycled sand used for cooling the core box resin sand mix, with the higher proportion of recycled sand added, cold-box resin sand tensile strength showed an increasing trend, gas evolution decrease. Cooling with 100% recycled sand-box sand core, in the cold box resin addition is 1.45% cases, you can get than the original sand, resin dosage of 1.70% of high strength, while reducing the sand core gas evolution.3,Ceramic sand and recycled sand mass ratio of 6:4 by mixing hot box water jacket sand core resin, resin dosage of 1.8%, the amount of curing agent is 0.8% of cases, to meet the production and technical requirements.4,The rough estimate, sand reclamation project carried out in Weichai can generate economic benefits 25 million yuan.