China has scrapped quotas on rare earths exports and will probably replace them with a resources tax, eliminating a policy that caused friction with its trading partners and heightened awareness of their importance as strategic assets.

China is home to most of the world's deposits and almost all processing of the 17 minerals classed as rare earths: elements with uses ranging from instrument panels to speciality steels.

A policy of export restrictions introduced a decade ago received worldwide attention in 2010, when a tightening of the quotas left traders scrambling and raised strategic concerns in Washington and Tokyo. The US won a challenge against the quotas at the World Trade Organisation in 2014.

Regulations for export quotas in 2015 issued by the Ministry of Commerce said that quotas for rare earths, as well as other products including tungsten and coke, would be replaced by an export licensing regime.

Metals analysts said that would probably include a resources tax.

The price impact in the market would be limited, said Peng Weiwei, an analyst at Beijing consultancy Asian Metal, and it was unclear which companies would receive permission to export.

More broadly, China has moved to implement resources taxes, which would allow the state to gain a simpler revenue stream from mining and energy production.

These are in place of quota systems that usually benefit well-connected companies or individuals by creating a lucrative price gap between domestic and international markets.

In some respects, China's quota policy has been a success. Implemented at a time when its rare earths were exported cheaply and processed primarily in Japan, the price differential created by the quotas inspired many Japanese companies to move their plants to the region around Baotou in Inner Mongolia, one of the centres of rare earths mining in China.

However, other goals of the quotas have not been successful: there has been little let-up in the environmental damage caused by rare earths mining and processing, and the pace at which they are mined has slackened little.

The run-up in prices as quotas tightened also spurred funding for rare earths mining outside China, which had previously been unprofitable.

The volatility in prices, particularly a 2011 spike after China tightened quotas, has also led manufacturers to find other materials for applications including magnets. That has alleviated some of the strategic concerns of China's trading partners, which centred on the minerals' importance to defence and high-tech industries.

Repeated attempts to consolidate the industry have sparked territorial battles between local and national state-owned mining companies, particularly in the region around Ganzhou, in Jiangxi province.

On Friday, the state-owned company that dominates rare earth production around Baotou said it had acquired nine rare earths mining companies from the Inner Mongolian government.

Additional reporting by Owen Guo