超细粉末改性水玻璃粘结剂试验研究.pdf

IV摘摘 要要建设环保型社会日益成为大众的共识，工业生产中污染环境的行业都面临着技术改革，铸造的“脏、乱、差”一直困扰着人们，铸造业改革的重点是无污染的砂型粘结剂的研制水玻璃砂，因无色、无味、无毒，在混砂、造型、浇注和落砂过程中没有刺激性气体和有毒气体产生，而成为了实现绿色铸造的首选但制约水玻璃砂发展的溃散性差、旧砂回收困难等问题，让大量的水玻璃旧砂被抛弃而污染了环境，使水玻璃砂工艺成为环境保护的双刃剑以纳米技术为主体的超细材料技术的发展为水玻璃砂技术的发展带来了新的希望本文结合超细粉末材料在高分子材料改性上的应用，提出了采用超细蒙托石粉、超细云母粉改性水玻璃粘结剂的构想通过进行一系列的单因子试验，研究超细蒙托石粉、超细云母粉、山梨醇和脱水硼砂等对水玻璃砂性能的影响，发现超细云母粉可以明显提高水玻璃的粘结强度、降低水玻璃的残留强度，山梨醇配合超细云母改性水玻璃可提高水玻璃砂的粘结强度、改善其溃散性，脱水硼砂配合超细云母粉改性水玻璃可提高水玻璃砂的抗潮性能采用超细云母粉、山梨醇、脱水硼砂三种物质进行正交试验，得到了改性配方水玻璃的较佳方案最后，通过 SEM 分析解释了超细云母粉改性水玻璃粘结剂成功的原因。

研究结果表明：超细云母粉在加入量为 1.5％时得到的改性水玻璃效果最好，此时水玻璃砂的常温强度比普通水玻璃的强度提高了约 21％，而残留强度则降低了约 34.5％；山梨醇配合超细云母粉改性水玻璃，可以在超细云母粉改性的基础上让水玻璃粘结剂的性能再提高一步，采用 1.5％的超细云母粉和 1％的山梨醇来改性水玻璃，能水玻璃砂的粘结强度提高约 32.6％，同时残留强度降低约 38.2％；经过脱水处理的硼砂可以加快水玻璃砂硬化的速度，同时改善了超细云母粉在水玻璃中的分散效果，提高水玻璃砂的抗吸湿性，但是过多的脱水硼砂的加入会影响水玻璃砂的溃散性正交实验结果表明，较好的水玻璃粘结剂的改性配方是：1.5％超细云母、0.5％山梨醇和 3％硼砂，此时，改性水玻璃砂的 24h 强度比未改性的提高了约 35％，残留强度降低了约 34.1％，抗吸湿能力也有不少提高关键词：关键词： 超细材料 水玻璃砂 粘结强度 溃散性 抗湿性VAbstractAs environmental protection becoming our social recognition day by day，technological innovation should be taken as a serious task in many industrial productionswhich can cause pollution. Specially, the development on the green binder forenvironmental protection will be the key point in the casting industry. The sodiumsilicate sand can get a position in green clean casting comparing to other mould sands forits advantages of achromatic color, tastelessness, non-toxic, and so on. Furthermore, thesodium silicate sand process can get rid of irritant odor or harmful gas during mixing,molding, pouring and knocking out. However, the defects, such as bad collapsibility andthe difficulty in sand reclamation, restrict the development of the sodium silicate sandprocess, which cause the used sand pollute the environment heavy. So the sodium silicatesand becomes the “double-edged sword” of the environmental protection, but a new hopeis appeared for the ultra-fine material technology (that is nano-meter material technology)development.In this paper, it is discussed that the possibility on the ultra-fine material modifiedsodium silicate binder at first, and then a series of single factorial experiments (includingultra-fine montmorillonite powder, ultra-fine mica powder，sorbitol, dehydrated borax,and so on) were made to demonstrate the influence on the performance of the sodiumsilicate sand. The results indicate that the ordinary temperature 24hr strength hasincreased and the residual strength has decreased by adding ultra-fine mica. Nextexperiments are made for the sorbitol and the borax, the results show that adding ultra-fine mica powder and sorbitol can get higher 24h strength and lower residual strength,and adding ultra-fine mica powder and dehydrated borax can increase the resisting wetability. The third are an orthogonal experiments that test the effects of ultra-fine micapowder, sorbitol and dehydrated borax on the sodium silicate binder to get an optimummodified material. Finally, an SEM photos are taken to explain the modifying reason ofVIultra-fine mica powder.Above experiment results indicate that:(1) The ultra-fine mica powder is a good modifying material for sodium silicatebinder, its function is mainly to increase the 24h strength and reduce the residual strengthof the sodium silicate sand. When the adding amount of ultra-fine mica powder is about1.5％, the 24h strength can be increased about 21% and the residual strength bedecreased about 34.5%.(2) The sorbitol can help the ultra-fine mica powder to improve the properties of thesodium silicate binder, not only increasing 24h strength but also reducing residualstrength. When about 1.5% ultra-fine mica powder and about 1.0% sorbitol are adding tothe binder, the 24h strength could be increased about 32.6% and the residual strengthwould be decreased about 38.2% for the sand.(3) The borax can increase the 24h strength and resisting wet ability of the sodiumsilicate sand, the dehydrated borax also possesses the abilities of quicking hardenvelocity of the sand and improving the decentralization of mica powder in the binder.(4) The optimizational proportion of the three materials from the orthogonal test is1.5% ultra-fine mica powder, 0.5% sorbitol and 3% borax. The 24h strength of themodified sodium silicate sands is increased about 35% and its residual strength isdecreased about 34.1%.Key words: ultra-fine material sodium silicate sand bonding strengthcollapsibility resisting wet abilityIII独创性声明独创性声明本人声明所呈交的学位论文是我个人在导师指导下进行的研究工作及取得的研究成果。

尽我所知，除文中已经标明引用的内容外，本论文不包含任何其他个人或集体已经发表或撰写过的研究成果对本文的研究做出贡献的个人和集体，均已在文中以明确方式标明本人完全意识到本声明的法律结果由本人承担学位论文作者签名：日期： 年 月 日学位论文版权使用授权书学位论文版权使用授权书本学位论文作者完全了解学校有关保留、使用学位论文的规定，即：学校有权保留并向国家有关部门或机构送交论文的复印件和电子版，允许论文被查阅和借阅本人授权华中科技大学可以将本学位论文的全部或部分内容编入有关数据库进行检索，可以采用影印、缩印或扫描等复制手段保存和汇编本学位论文保密□，在 年解密后适用本授权书本论文属于不保密□请在以上方框内打“√” ）学位论文作者签名： 指导教师签名：日期： 年 月 日 日期： 年 月 日11 绪绪 论论1.1 课题来源、背景和意义课题来源、背景和意义“十一五”规划明确提出要坚定不移的走科学发展的道路，建设资源节约型、环境友好型社会，把经济社会发展。