China's alumina imports for May surged nearly seven times year on year to 720,000 mt, preliminary data released by the General Administration of Customs showed.
The May figure was 157.1% higher than April's imports at 280,000 mt.
Alumina imports over January-May totaled 2.2 million mt, up 128.6% year on year.
China has accumulated 700,000-800,000 mt of alumina port stocks over past weeks and months, as contingency for interrupted bauxite shipments from Indonesia, local participants estimated last week.
Indonesia imposed a 20% tax on bauxite exports in May, as well as revoking mining and export permits of certain companies. The curbs are part of a drive to encourage local processing of metal ores. Jakarta has said it plans to ban all exports of bauxite and other raw minerals by 2014.
In the interim, the government put in place from May a new system of granting local companies short-term mining and export permits, and quotas to be renewed every three months. Meanwhile, China's imports of unwrought aluminum and aluminum products in May reached 91,083 mt, up 21.6% year on year, but down 3.5% from April.
The country imported 524,157 mt of aluminum and aluminum products in the first five months of the year, which was up 32.4% from a year ago.
Aluminum scrap imports in May stood at 240,000 mt, which was up 9.1% year on year and up 14.3% from April.
Imports of aluminum scrap over the five-month period amounted to 1 million mt, which was up 0.3% from a year ago.
Source: Platts