Smelting and Recycling of Hafnium

Ho-Sang Sohn

doi:10.7844/kirr.2025.34.6.3

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2025 Vol.34, Issue 6 Next Page

Article Review

Smelting and Recycling of Hafnium 하프늄의 제련과 리사이클링

31 December 2025. pp. 3-13

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Abstract

Hafnium (Hf) is a rare metal that is essential for advanced industries such as nuclear power, superalloys, and semiconductors. This paper reviews Hf production, utilization, and smelting technologies. The global annual production of Hf is only about 80 tons, with 45 % of metallic Hf used in Ni-based superalloys and 13 % used in control rods for nuclear reactor. Hafnium is recovered as a by-product in the production of high-purity metallic zirconium for the nuclear industry. Metallic Hf is produced either by molten salt electrolysis or by the Kroll process, which reduces hafnium tetrachloride (HfCl₄) with magnesium (Mg). High-purity Hf is produced from crude Hf through iodine refining, as well as via molten salt electrolysis and electron beam melting. Hf is used as an additive in superalloys and machining tools. However, the extent to which it is recycled is not well-known due its low contents in these materials, although. Hf used in superalloys is presumed to be recycled back into Ni-based alloys. In contrast, Hf used in control rods is stored as radioactive waste and therefore cannot be recycled. Waste targets used for semiconductors and machining chips are recycled through electron beam melting and refining. To recycle such hafnium scrap, it is necessary to achieve economies of scale.

Keywords

hafnium

smelting

superalloy

nuclear power

recycling

하프늄은 원자력, 초합금, 반도체 등의 첨단산업에 필수적인 희소금속이다. 본 논문에서는 이러한 Hf의 생산량과 용도 및 제련 기술 등에 관하여 고찰하였다. Hf의 전 세계 연간 생산량은 약 80 톤에 불과하며, 금속 Hf의 45 %는 Ni계 초합금에, 13 %는 원자로의 제어봉에 사용되고 있다. 이러한 Hf은 원자력 산업용의 고순도 금속 Zr을 생산하는 과정에서 부산물로 회수하고 있다. 금속 Hf은 Hf 염화물(HfCl₄)을 Mg으로 환원하는 Kroll법이나 용융염 전해법으로 제조하고 있다. 조금속 Hf은 아이오딘법, 융용염 전해정련, 전자빔 용융정제를 거쳐 고순도 Hf으로 정제된다. Hf은 초합금 및 기계 가공용 등의 용도로 사용되고 있으나 Hf의 함유량이 낮아 리사이클링 실태에 관하여 잘 알려져 있지 않다. 그러나 초합금으로 사용된 Hf은 다시 Ni계 합금으로 리사이클링되는 것으로 추정된다. 원자로의 제어봉으로 사용된 Hf은 방사성 폐기물로 저장되어 있으므로 리사이클링 대상이 되지 못하고 있다. 반도체용의 타깃이나 가공 과정에서 발생하는 칩 등은 전자빔 용융 및 정제를 통하여 리사이클링하고 있다. 이러한 Hf 스크랩의 리사이클링을 위해서는 규모의 경제성을 확보하는 것이 필요하다.

키워드

하프늄

제련

초합금

원자력

리사이클링

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Information

Publisher :The Korean Institute of Resources Recycling
Publisher(Ko) :한국자원리싸이클링학회
Journal Title :Resources Recycling
Journal Title(Ko) :자원리싸이클링
Volume : 34
No :6
Pages :3-13
Received Date : 2025-09-15
Revised Date : 2025-09-30
Accepted Date : 2025-10-02
DOI :https://doi.org/10.7844/kirr.2025.34.6.3

Resources Recycling ISSN:2765-3439(Print) 2765-3447(Online) 자원리싸이클링

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