Tianqi late last year picked up a 23.77% stake in SQM from Nutrien for US$4.1 billion.

Among the key elements of the joint agreement were the provision that SQM board decisions and the company's operations would be independent of both parties.

The shareholders ironed out their differences during a high-level visit of Pampa management to Tianqi's headquarters in China earlier this month.

Pampa had tried to block the Nutrien transaction. It had argued in unsympathetic Chilean courts Tianqi, which controls Talison Lithium, a JV with the world's biggest lithium producer Albemarle Corp in Australia, could share trade secrets with its US-based competitor and neighbour in Chile's lithium-rich Salar de Atacama.

"During the visit we had frank and open discussions in respect to our relationship as shareholders and, subsequently, have concluded an agreement which we believe will contribute to the stability of SQM's governance for the benefit of all its shareholders," Pampa vice chairman Patricio Contesse said.

"As shareholders of SQM, we are aware of the challenges and opportunities that lie ahead and expect this will leave our discrepancies behind as each of us focus our energy going forward in supporting SQM, its management and its board."

The agreement cleared the path for Tianqi to take up a position on the SQM board following the scheduled April 25 AGM.