珍珠岩预膨化处理工艺研究及其尾矿复合聚渣剂的研制

发布时间：2019-04-24 06:14

【摘要】：聚渣剂作为铸造生产过程中一种重要的辅料,从上世纪80年代开始,已经广泛的应用到钢铁铸造生产工程中。但是随着我国铸件产量逐年增加以及装备制造业对铸件性能要求的提高,单一的珍珠岩聚渣剂产品已经不能满足其性能要求。同时由于珍珠岩过度的开采加工,造成了大量珍珠岩尾矿的废弃,严重影响生态环境。本课题设计不同预处理工艺参数,采用SEM、DTA等试验设备,研究了烘干温度、预膨化温度、保温时间对珍珠岩组织、膨胀倍数、失重率、容重等性能的影响规律;基于优化的预膨化处理工艺,以珍珠岩尾矿为主要原料,通过工业试验,研究开发新型复合聚渣剂的配方。研究结果表明:信阳珍珠岩中水有两种存在形式,一种是吸附在珍珠岩表面的自由水;另一种是被玻璃质包裹的结构水;随着烘干温度的升高,珍珠岩的失重率逐渐增大,当温度高于450℃时,珍珠岩的失重率稳定在3.85%。随着预膨化处理温度的升高,预膨化后的珍珠岩失重率逐渐降低,膨胀倍数先增大后降低,容重则先降低后升高;预膨化处理后的珍珠岩表面出现微孔,断面呈现层片状,并且含有少量的空腔结构,且随着预膨化温度的升高,微孔的数量逐渐增多,空腔结构的直径逐渐增大,但是当预膨化温度达到1050℃时,表面出现细长的裂纹产生。随着保温时间的延长,预膨化后的珍珠岩失重率逐渐降低,当保温时间高于23s时,失重率则趋于平稳;膨胀倍数呈现先升高后降低,容重则相反,先降低后升高。随着保温时间的延长,珍珠岩表面无裂纹,逐渐出现分布均匀、孔径相差较小的微孔,断面的空腔直径则呈现先增大后降低的趋势,当保温时间高于23s的时候,部分空腔破碎,导致碎屑产生。因此,当预膨化温度为950℃,保温时间为15s时,膨胀倍数最大,为2.733,容重最低,为912kg/m3。与优化预膨化处理后的珍珠岩相比,未经预膨化处理以及随炉加热处理后的珍珠岩的容重较大,膨胀倍数较小,尤其是随炉加热处理后的珍珠岩,甚至出现颗粒萎缩的现象。通过对珍珠岩尾矿复合聚渣剂的研制及工业试用试验,与单一珍珠岩聚渣剂相比,复合聚渣剂在铁液中的铺展效果、聚渣效果更优异,且更易扒渣。优化了珍珠岩尾矿复合聚渣剂配方,其主要组分为8%活性Si O2、4%活性Al2O3、4%水玻璃以及珍珠岩尾矿。
[Abstract]:As an important auxiliary material in casting process, slag-accumulating agent has been widely used in iron and steel foundry engineering since 1980s. However, with the increasing production of castings in our country year by year and the improvement of casting performance requirements in equipment manufacturing industry, the single perlite slagging agent can no longer meet its performance requirements. At the same time, due to the excessive exploitation and processing of perlite, a large number of pearlite tailings were abandoned, which seriously affected the ecological environment. The effects of drying temperature, pre-expansion temperature and holding time on perlite structure, expansion ratio, weight loss rate and bulk weight were studied by using SEM,DTA and other test equipment in this paper. The effects of drying temperature, pre-expansion temperature and holding time on perlite structure, expansion multiple, weight loss rate and bulk weight were studied. Based on the optimized pre-expansion treatment process, the formula of a new type of compound slagging agent was developed by industrial test with pearlite tailing as the main raw material. The results show that there are two kinds of water in Xinyang perlite, one is free water adsorbed on perlite surface, the other is glass-coated structural water. With the increase of drying temperature, the weight loss rate of perlite increases gradually. When the temperature is higher than 450 鈩，

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