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Synthetic Sand and Refractory Coating Application


By establishing the correct synthetic sand, binder and coating combination, it is possible to use a single sand type, eliminating the use of expensive speciality sands for mold facing. TAKUYA OKADA (SAND PRODUCTS MANAGER) AND TAKESHI IKEUCHI (PRODUCTS DEVELOPMENT), FOSECO JAPAN LTD.


合成砂及其所用耐火涂料的特性


通过正确地选用合适品级的合成砂、粘结剂及涂料之组合,有可能实现仅使用单 一砂,而避免使用昂贵的特种砂作面砂。


Takuya Okada (Sand PrOducTS Manager) and TakeShi ikeuchi (PrOducTS develOPMenT), FOSecO JaPan lTd.


Traditional foundry sands systems often are based on silica sand, with speciality sands, such as chromite, being used in areas of the mold where higher refractoriness or thermal stability is required. However these additions of speciality sands (specifi- cally chromite) can have a detrimental effect on the performance of the reclaimed sand reducing its refractoriness and increasing the potential of sand fusion and metal penetration, and should be effectively separated before re-use of both the reclaimed silica and chromite components. Additionally, the physical characteristics of silica sand, such


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as grain shape, angularity and porosity, can limit the effective- ness of mechanical reclamation by preventing the easy removal of the binder without damaging or fracturing the sand grain. High intensity scrubbing of the sand to remove residual binder can lead to a reduction in the average grain size of the reclaimed sand. Tis will then require increased binder additions to re- bond the processed sand and increase dust levels. Te synthetic sands offer the opportunity to eliminate the use of both silica and special refractory sands and provide good yield during the reclamation process: • Superior refractory properties compared with silica sand.


• Low thermal expan- sion.


• High strength, resistant to breakage during reclamation.


• Spherical shape, enabling easier removal of residual binder. Synthetic sands have a different composition and


Fig. 1. All of the syn- thetic sands have a distinct spherical form.


ecently, there has been a drive to increase the reuse of foundry sands to limit the cost of new sand purchases and to minimize both the cost of dumping used sand and environmental impact.





年来,铸造厂旧砂回用的压力持续增加, 一方面是为了减少新砂采购成本,另一方 面是为了减少旧砂处理费用和对环境的影


响。传统的铸造用砂主要是硅砂,在耐火度或热稳定性 要求较高的地方,局部使用特种砂如铬铁矿砂。但是, 特种砂,特别是铬铁矿砂的加入会影响再生砂的性能, 降低耐火度,增加粘砂倾向。因此,在旧砂回用之前应 有效分离硅砂和铬铁矿砂。


另外,硅砂本身的物理状态如粒形和孔隙也会影响砂 粒表面粘结剂膜的去除和砂粒的破碎,影响机械再生的 有效性。清理摩擦会导致粒度减小,从而导致粘结剂加 入量的增加和微粉含量上升。


合成砂可以代替硅砂和特种砂,提高旧砂的再生率:


• 与硅砂相比具有优越的耐火性能 • 低的热膨胀性能 • 砂粒强度高,再生回用过程中不易破碎 • 圆球形,粘结剂易去 除。


与硅砂及铬铁矿砂相 比,合成砂具有不同化 学成分和形态,因此对 于合成砂铸型,涂料在


另外,合成砂都呈独特的 球形.


64 | FOUNDRY-PLANET.COM | MODERN CASTING | CHINA FOUNDRY ASSOCIATION February 2013


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