Titanium is the ninth most abundant element in the Earth’s crust and is the fourth most abundant structural metal after aluminum, iron, and magnesium. It exhibits a higher specific strength than steel along with an excellent corrosion resistance, highlighting the promising potential of titanium as a structural metal. However, titanium is difficult to extract from its ore and is classified as a rare metal, despite its abundance. Therefore, the production of titanium is exceedingly low compared to that of common metals. Titanium is conventionally produced as a sponge by the Kroll process. For powder metallurgy (PM), hydrogenation-dehydrogenation (HDH) of the titanium sponge or gas atomization of the titanium bulk is required. Therefore, numerous studies have been conducted on smelting, which replaces the Kroll process and produces powder that can be used directly for PM. In this review, the Kroll process and new smelting technologies of titanium for PM, such as metallothermic, electrolytic, and hydrogen reduction of TiCl4 and TiO2 are discussed.

Abstract
1. 서 론
2. 타이타늄의 생산량과 용도
3. 타이타늄 제련의 열역학
4. Hunter법과 Kroll법 프로세스
    4.1. TiCl4의 제조
    4.2 Hunter법
    4.3. Kroll법
5. Ti의 신제련법
    5.1. 금속 열환원법
    5.2. 수소를 이용한 환원법
    5.3 전해 채취법
5. 결 론
References

• 손호상(경북대학교 신소재공학부) | Ho-Sang Sohn (School of Materials Science and Engineering, Kyungpook National University) Corresponding Author