许多厂家反映消失模生产旧砂多次回用后严重影响铸件品质 ;选取消失模生产线上回用旧砂为样品 ,对型砂的粒度分布、灰分含量、灼减量、透气性、流动性等基本性能进行了测试 ,同时对新砂样品进行对比测试 ;试验结果表明 ,旧砂中涂料碎片增多、砂粒之间磨损增加、残留热解产物增多 ,是导致旧砂基本性能变差的根本因素 Many manufacturers reflect the loss of mold production of old sand after repeated use of a serious impact on the quality of castings; select lost foam production line back to the old sand as a sample of the sand particle size distribution, ash content, ignition loss, permeability, fluidity and other basic properties The test results show that the increase of debris in the old sand, the increase of the wear between the sand and the increase of the residual pyrolysis products are the fundamental factors leading to the deterioration of the basic properties of the old sand