Resources Recycling (자원리싸이클링)

The Korean Institute of Resources Recycling (한국자원리싸이클링학회)
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Production Technology of Titanium by Kroll Process

Kroll법에 의한 타이타늄의 제조기술

  • Sohn, Ho-Sang (School of Materials Science and Engineering, Kyungpook National University)
  • Received : 2020.05.20
  • Accepted : 2020.07.17
  • Published : 2020.08.28
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Abstract

Titanium sponge is industrially produced by the Kroll process. In order to understand the importance of the emerging smelting and recycling process, it is necessary to review the conventional production process of titanium. Therefore this paper provides a general overview of the conventional titanium manufacturing system mainly by the Kroll process. The Kroll process can be divided into four sub-processes as follows: (1) Chlorination of raw TiO2 with coke, by the fluidized bed chlorination or molten salt chlorination (2) Magnesium reduction of TiCl4 and vacuum distillation of MgCl2 and Mg by reverse U-type or I-type with reduction-distillation integrated retorts (3) Electrolysis process of MgCl2 by monopolar cells or multipolar cells to electrolyze into chlorine gas and Mg. (4) Crushing and melting process in which sponge titanium is crushed and then melted in a vacuum arc furnace or an electron beam furnace Although the apparatus and procedures have improved over the past 80 years, the Kroll process is the costly and time-consuming batch operation for the reduction of TiCl4 and the separation of MgCl2.

현재 타이타늄 스펀지는 Kroll법에 의해 만들어지고 있다. 타이타늄의 새로운 제련법과 리사이클링 기술의 중요성을 이해하기 위해서는 기존의 타이타늄 제조기술에 대한 검토가 필요하므로 본 논문에서는 기존의 Kroll법을 중심으로 한 타이타늄 제조기술에 대해 고찰하였다. Kroll법은 아래와 같이 크게 네 가지 공정으로 구분할 수 있다. (1) 유동 염화법이나 용융염 염화법에 의한 TiO2의 염화 공정 (2) 반응기 결합방법에 따른 역U자형이나 I자형을 이용한 TiCl4의 Mg에 의한 환원과 Mg와 MgCl2의 증류 (3) 단극형이나 복극형 전해조에 의한 반응 부산물인 MgCl2의 전해와 Mg과 Cl2의 생성 (4) 스펀지 타이타늄의 분쇄와 VAR이나 EBM에 의한 용해 및 잉곳 제조 지난 80년 동안 제련공정이 많이 개선되었지만, Kroll법은 TiCl4의 환원과 MgCl2의 분리를 위한 비용이 많이 들고 시간이 많이 걸리는 회분식 조업이라는 문제점을 가지고 있다.

Keywords

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