水玻璃旧砂的干法回用与湿法再生

根据水玻璃旧砂的特点和对其再生砂的不同使用要求,本文提出了“水玻璃旧砂干法回用与湿法再生”的观点。认为:如作背砂使用,水玻璃旧砂只需进行破碎、去磁、筛分、除尘等干法回用处理,没有必要对旧砂粒进行高强度的机械碰撞磨擦处理;但如作单一砂或面砂使用,水玻璃旧砂必须进行湿法再生,力求获得高的脱膜率。本文通过试验研究和比较水玻璃旧砂及其干法再生砂与湿法再生砂的性能特征,以及背砂、面砂(或单一砂)的使用要求,论证了上述观点的正确性。     

水玻璃砂旧砂再生方法的探讨

水玻璃砂具有锌型强度高，原材料来源广、价格低廉和无毒等优点。但它主要存在两个问题：一是型砂溃散性差；二是旧砂难以回用，致使它的应用受到限制，因而各国铸造工作者对改善它的清澈性，以及旧砂再生加以深入研究，力求克服上述缺点，扩大它的应用范围。1国内外承玻璃破旧砂再生发展状况1965年出现的水爆清砂，湿法再生装置开始应用于水玻璃砂再生，因包附在砂粒表面的硅胶薄膜被剥离不明显，再生效果不理想。1978年，用于水玻璃有机酯自硬砂旧砂的“螺旋研磨机”干法再生设备，及为被剥离下来的硅胶薄膜与砂粒分离，选用了水力旋流器…     

酯硬化水玻璃砂的再生及回用

介绍了酯硬化水玻璃砂旧砂干法再生的质量控制及再生砂回用中的技术问题.     

水玻璃砂工艺与材料研究的新进展

概述了水玻璃砂工艺与材料研究及应用方面取得的最新进展，笔者认为，采用改性水玻璃粘结剂的酯硬化工艺，可使水玻璃的加入量降为2.0%～3.0%，水玻璃砂的溃散性接近树脂砂；将水玻璃旧砂的回用与湿法再生结合起来，是目前最经济，最理想的选择，可以基本解决水玻璃旧砂再生难的问题。     

酯硬化水玻璃旧砂再生工艺方法的选择

根据酯硬化水玻璃旧砂的特征。本文介绍了该类旧砂干法再生和湿法再生的特点及工艺流程，阐述了它们的优，缺点，对酯硬化水玻璃旧砂再生工艺方法的选择阐述了作者的观点。     

影响酯硬化水玻璃干法再生砂性能的主要因素

试验研究了残留水玻璃和残留酯对酯硬化水玻璃旧砂及其干法再生砂性能的影响。结果表明,残留酯是使酯硬化水玻璃旧砂及其干法再生砂可使用时间变短、再粘结强度下降的主要原因。因此,去除残留酯是再生酯硬化水玻璃旧砂的主要任务之一。而采用湿法再生或干法再生前对旧砂进行３２０～３５０℃的加热处理,是除去旧砂中残留酯的有效方法。     

西安理工大学 焦作长城铸造机械有限公司研制成功水玻璃旧砂湿法干法联合再生机生产线

水玻璃旧砂湿法干法联合再生机生产线利用热湿法再生和干法清洁除尘的原理，对水玻璃旧砂进行综合处理，使表面惰性膜溶解，呈自由的砂粒状态，生产颗粒均匀的再生砂。     

西安理工大学焦作长城铸造机械有限公司研制成功水玻璃旧砂湿法干法联合再生机生产线

水玻璃旧砂湿法干法联合再生机生产线利用热湿法再生和干法清洁除尘的原理，对水玻璃旧砂进行综合处理，使表面惰性膜溶解，呈自由的砂粒状态，生产颗粒均匀的再生砂。     

西安理工大学 焦作长城铸造机械有限公司研制成功水玻璃旧砂湿法干法联合再生机生产线

水玻璃旧砂湿法干法联合再生机生产线利用热湿法再生和干法清洁除尘的原理，对水玻璃旧砂进行综合处理，使表面惰性膜溶解，呈自由的砂粒状态，生产颗粒均匀的再生砂。     

西安理工大学焦作长城铸造机械有限公司研制成功水玻璃旧砂湿法干法联合再生机生产线

水玻璃旧砂湿法干法联合再生机生产线利用热湿法再生和干法清洁除尘的原理，对水玻璃旧砂进行综合处理，使表面惰性膜溶解，呈自由的砂粒状态，生产颗粒均匀的再生砂。     

Dry reusing and wet reclaiming of used sodium silicate sand

1. Introduction Foundry workers and researchers around the world recognize the difficulty of reclaiming or reusing used sodium silicate sand. Among the possible reclaiming or reusing methods, there is no agreed single process that is the most rational, low cost and high quality [1-2]. It is generally accepted that dry reclaimed process is simple but the quality of dry reclaimed sand is poor, and that wet reclaimed process is complex but the quality of wet reclaimed sand is good. The authors be…     

A new low-cost method of reclaiming mixed foundry waste sand based on wet-thermal composite reclamation

A lot of mixed clay-resin waste sand from large-scale iron foundries is discharged every day; so mixed waste sand reclamation in low cost and high quality has a great realistic significance. In the study to investigate the possibility of reusing two types of waste foundry sands, resin bonded sand and clay bonded sand which came from a Chinese casting factory, a new low-cost reclamation method of the mixed foundry waste sand based on the wet-thermal composite reclamation was proposed. The waste resin bonded sand was first reclaimed by a thermal method and the waste clay bonded sand was reclaimed by a wet method. Then, hot thermal reclaimed sand and the dehydrated wet reclaimed sand were mixed in certain proportions so that the hot thermal reclaimed sand dried the wet reclaimed sand leaving some water. The thermal reclamation efficiency of the waste resin bonded sand was researched at different heat levels. The optimized wet reclamation process of the waste clay bonded sand was achieved by investigating the effects of wet reclamation times, sand-water ratio and pH value on the reclaimed sand characteristics. The composite reclamation cost also was calculated. The research results showed that the properties of the mixed reclaimed sand can satisfy the application requirements of foundries; in which the temperature of the thermal reclamation waste resin bonded sand needs to be about 800 oC, the number of cycles of wet reclamation waste clay bonded sand should reach four to five, the optimal sand-water ratio of wet reclamation is around 1：1.5, and the pH value should be adjusted by adding acid. The mass ratio of hot thermal reclaimed sand to dehydrated wet reclaimed sand is about 1：2.5, and the composite reclaimed sand cost is around 100 yuan RMB per ton.     

CO2硬化水玻璃砂添加剂及旧砂干法再生工艺

分析了水玻璃添加剂中有机水溶性高分子和无机纳米材料的组成特性,通过扫描电镜观察CO2硬化水玻璃砂试样的断口形貌,探讨了水玻璃添加剂的作用机制.生产实践表明,采用水玻璃添加剂并结合旧砂干法再生回用工艺,可使水玻璃旧砂的回用率达80％以上,且型砂工艺性能良好,能满足铸件生产的要求.     

水玻璃砂的再生

介绍了水玻璃旧砂湿法、干法和热法的再生原理,并简要说明了其应用情况.通过阐述人们对水玻璃硬化机理的认识,说明了水玻璃旧砂化学再生的基本原理,并对近年来水玻璃旧砂化学再生方面的研究及应用情况进行了总结概括.     

水玻璃改性对水玻璃砂再生循环使用性能的影响

水玻璃改性技术在提高水玻璃砂强度,改善其溃散性的同时,也对水玻璃旧砂经干法再生后循环使用的砂性能产生了影响。试验测试了水玻璃旧砂受热温度对其溃散性的影响,比较了普通水玻璃和改性水玻璃在水玻璃旧砂溃散性上的区别,测试研究了多次循环使用后水玻璃再生砂残留强度的变化,分析了所用改性水玻璃粘结剂对水玻璃旧砂再生回用后的性能产生影响的原因和机制。结果表明,水玻璃改性有利于水玻璃砂的再生循环使用。     

黏土旧砂完全再生技术

分析了旧砂中黏土膜的分离机制,采用不同的再生工艺评估了黏土旧砂再生技术的可行性,确定了700℃焙烧＋机械再生＋微粉分离的黏土旧砂完全再生工艺,研究了黏土完全再生砂的工艺适应性,并介绍了黏土砂完全再生系统的组成。结果表明,视不同的型砂工艺,黏土完全再生砂可分别用于混制水玻璃砂、覆膜砂、冷芯盒砂或热芯盒砂,但不能用于自硬呋喃树脂砂的制备。     

Inlfuence of wet activation of used inorganic binder on cyclically refreshed water glass moulding sands hardened by microwaves

The paper presents the research results of using an innovative method to reclaim the waste moulding sands containing water glass. Two of the examined processes are connected with “dry” or “wet” activation of inorganic binder in waste moulding sand mixtures physicaly hardened by microwave radiation. The sand mixtures consisting of high-silica sand and water-glass with average molar module 2.5, were subjected to the folowing cyclical process: mixing the components, compacting, microwave heating, cooling-down, thermaly loading the mould to 800 °C, cooling-down to ambient temperature, and knocking-out. After being knocked-out, the waste moulding sands were subjected to either dry or wet activation of the binder. To activate thermaly treated inorganic binder, each of the examined processes employed the surface phenomenon usualy associated to mechanical reclamation. The study also covered possible use of some elements of wet reclamation to rehydrate waste binder. To evaluate the effectiveness of the two proposed methods of waste binder activation, selected strength and technological parameters were measured. After each subsequent processing cycle, the permeability, tensile strength and bending strength were determined. In addition, the surface of activated sand grains was examined with a scanning electron microscope. Analysis of the results indicates that it is possible to re-activate the used binder such as sodium silicate, and to stabilize the strength parameters in both activation processes. Permeability of the refreshed moulding sands strongly depends on the surface condition of high-silica grains. The wet activation process by wetting and buffering knocked-out moulding sands in closed humid environment makes it possible to reduce the content of refreshing additive in water-glass. The moulding sands cyclicaly prepared in both processes do not require the addition of fresh high-silica sand. The relatively high quality achieved in the refreshed moulding sands alows them to be reused for manufacture of next moulds. Thus, the two proposed methods for cyclicaly processing used moulding sands containing sodium silicate, subject to microwave hardening, are suitable for economic and ecological circulation moulding mixtures.     

能有效提高CO2水玻璃砂溃散性和再生性的添加剂

针对CO2水玻璃砂溃散性差、旧砂回收难,铸件清砂困难等问题,论述了改善CO2水玻璃砂溃散性和再生性的机理,从而研制了一种能够提高CO2水玻璃砂溃散性和再生性的添加剂.介绍了这种添加剂的基本材料、工艺、特点、对水玻璃砂的改性作用以及这种工艺在生产厂的应用情况.     

酯硬化水玻璃砂工艺和设备的应用

为根据生产铁路货车摇枕、侧架、车钩等铸钢件的要求,设计建成了酯硬化水玻璃生产线。试生产表明:酯硬化水玻璃工艺和建成的高速造型圈、高速制芯圈和砂再生系统可以满足铸钢件生产的需要。     

酯硬化新型水玻璃砂无加热干法再生的实践

对酯硬化新型水玻璃砂采用无加热干法离心再生,使再生砂中Na2O残留量维持在一个合理水平,实现了再生砂在高Na2O残留量条件下,具有足够的强度和可使用时间,满足了生产工艺的要求。