Closing The Material Cycle of Titanium - Thermochemical and Experimental Validation of a New Recycling Concept
Closing The Material Cycle of Titanium - Thermochemical and Experimental Validation of a New Recycling Concept
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关闭钛的材料循环 - 新回收概念的热化学和实验验证
DOI：
10.1007/s00501-008-0396-z
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
J. Reitz
中科院分区：
文献类型：
--
作者：
B. Friedrich;C. Lochbichler;J. Reitz
由于在钛和钛合金制成的半成品和最终产品的加工过程中产生大量废料，回收利用显示出替代海绵钛、节约钛市场和在新应用中应用二次低成本钛的巨大潜力。本文论述了一种新的回收工艺的发展，使用废料，目前降级，作为输入源。该工艺是真空感应熔炼（Vim）、金属热脱氧、电渣重熔（ESR）和真空电弧重熔（VAR）等工业化工艺的创新组合。废料的初步熔化是由Vim使用专门的陶瓷衬里完成的，并包括预脱氧。第二步是使用连续活化的Ca反应性炉渣通过室-ESR进行最终脱氧。第三个处理步骤是VAR，以去除小的熔渣夹杂物以及溶解的Ca，并允许氢气脱气。对于每个工艺步骤，指出了相应的设备、冶金挑战和机遇，并描述了在工艺路线中利用它们的方法。在IME进行半中试规模试验之前，对与液体钛和钛合金的耐火反应、钙母合金和活性ESR渣的脱氧以及VAR中过量Ca和H的去除进行了深入的热化学建模。这些试验通过对液相的热物理性质（如电导率、密度和粘度）的基础研究来辅助。采用电子束熔化（EBM）技术对氮化物溶解的动力学行为进行了进一步的研究。该论文将介绍理论建模的结果，作为在亚琛IME进行的实验室和半中试规模实验的基础，用于从100%废料生产100公斤VAR锭。
Due to high scrap generation in the processing of semifinished and final products made of titanium and titanium alloys, recycling shows a great potential to substitute titanium sponge, economize the titanium market and to apply secondary low cost titanium in new applications. This article deals with the development of a new recycling process using scrap, downgraded at present, as an input source. This process is an innovative combination of industrialized processes like Vacuum Induction Melting (VIM), Metallothermic Desoxidation, Electro Slag Remelting (ESR) and Vacuum Arc Remelting (VAR). The primary melting of scrap is done by VIM using specialized ceramic linings and includes pre-deoxidization. A second step is final deoxidization by chamber-ESR using a continuously activated Ca-reactive slag. The third processing step is VAR, in order to remove small slag inclusions as well as dissolved Ca and to allow for hydrogen degassing. For each process step the according equipment, the metallurgical challenges and opportunities are pointed out and the way to make use of them within the process route is described. An intensive thermochemical modeling on refractory reactions with liquid titanium and titanium alloys, on the involved deoxidization by calcium master alloys and by the active ESR slag, as well as for the removal of excess Ca and H in VAR is conducted before semi-pilot scale tests are done at IME. These trials are assisted by fundamental investigations of the liquid phases’ thermophysical properties like conductivity, density and viscosity. Further investigations on the kinetic behavior of nitride dissolution are conducted in parallel by Electron Beam Melting (EBM). The paper will present the results of theoretical modeling as a basis for laboratory and semi-pilot scale experiments at IME in Aachen for the production of 100 kg VARingots from 100 % scrap.