BEIJING – Tianqi Lithium, one of the world's biggest lithium producers, swung to a net loss in the third quarter as prices for the battery metal slumped.

Tianqi, which owns around a quarter of Chilean lithium producer SQM, processes spodumene, a mineral mined for its lithium content, into chemicals such as lithium carbonate and lithium hydroxide that are used in electric vehicle batteries.

Lithium carbonate prices in China, as assessed by Asian Metal, have fallen around 28% year-to-date to 49,500 yuan a tonne amid oversupply. Prices were around 150 000 yuan a tonne in early 2018.

Chengdu-based Tianqi reported a net loss of 53.9-million yuan for July-September 2019, versus net profit of 379.7-million yuan a year earlier and 82.1-million yuan in the second quarter.

The result, published in a filing to the Shenzhen stock exchange on Tuesday, is Tianqi's first quarterly loss since the first quarter of 2014, according to Refinitiv Eikon data. In the first nine months of 2019, net profits were down 91.7% year-on-year at 139.5-million yuan.

Third-quarter revenues were down 17.8% year-on-year at 1.21-billion yuan.

The company had earlier this month flagged an expected slump in nine-month profits of more than 90%.

It apologised to investors for the performance, which it blamed on a foreign exchange loss and lower than expected ore supply from its Greenbushes mine in Australia.

Tianqi's financial expenses – including those related to loans taken out to acquire the SQM stake for around $4.1-billion in 2018 – rose more than 500% year-on-year in the third quarter,

The company also said on Tuesday it had a relatively large amount of liabilities in foreign currencies. The yuan weakened by about 4% against the US dollar the third quarter.

The company now expects its full-year net profit to come in at 80-120 million yuan, implying an estimated net loss of at least 19.5 million yuan in the final quarter.