Possibilities and prospects for producing silumins with different silicon contents using amorphous microsilica

利用无定形微硅粉生产不同硅含量硅铝合金的可能性与前景

The main objective of this work is to research complex physical-chemical processes of Al(l)-SiO2 interface and develop a new technology for producing foundry silumins based on amorphous microsilica obtained from silicon production waste. Effective methods for producing hypoeutectic, eutectic, and hypereutectic silumins using amorphous microsilica were developed. Alloys with a silicon content of 7 wt.% were obtained by blowing preheated amorphous microsilica into the aluminum melt(t=900 ℃) along with the stream of argon followed by intense mixing. Alloys with a silicon content of 21 wt.% were manufactured by induction melting of a silicon-containing mixture(60% Si O2, 40%Al + 20%3 Na F·2 Al F3) subjected to the presintering when the amorphous microsilica was reduced to crystalline silicon. It is found that crystalline silicon, which is formed during the roasting of the tableted burden, is smoothly absorbed by the aluminum melt. Aluminum oxide, obtained during the redox reaction, dissolves in cryolite, after which aluminum and silicon are fused together and transferred to the melt. The calculation of the economic efficiency of producing silumins using amorphous microsilica demonstrates a quick project payback period, as well as a high level of its profitability.

本工作的主要目的是研究Al(l)-SiO2界面的复杂物理化学过程,开发一种利用由硅生产废料得到的无定形微硅粉生产铸造硅铝合金的新技术。开发使用无定形微硅粉生产亚共晶、共晶和过共晶硅铝合金的有效方法。将预热的无定形微硅粉用氩气流吹入铝熔体(t=900℃),并进行剧烈混合,得到硅含量为7wt.%的硅铝合金。先将含硅混合物(60%SiO2,40%Al+20%3Na F·2Al F3)进行预烧结,使无定形微硅粉还原成结晶硅;再将预烧结产物进行感应熔炼,制备硅含量为21wt.%的硅铝合金。已经证实,在压片炉料烧结过程中形成的结晶硅可以顺利被铝熔体吸收。氧化还原反应生成的氧化铝溶解在冰晶石中,铝和硅则融合并进入(合金)熔体中。使用无定形微硅粉生产硅铝合金的经济效率计算表明,该项目投资回收期短、盈利能力强。