Chinese plant extracts critical rare metals from lithium waste in world first

China has unveiled a 500-tonne production line designed to extract rubidium and caesium from lithium waste, marking the world's first successful implementation. This demonstration line, located in Jiangxi province, operates continuously and has demonstrated stable production. Rubidium and caesium, critical elements for fields ranging from aerospace to biomedicine, are not found in significant amounts as independent minerals within the Earth's crust.

Instead, they are present at low concentrations within lithium ores and salt-lake brines. By recovering these elements from lithium extraction waste, China has not only enhanced its new energy industry but also ensured a more secure supply of rubidium, a strategic rare metal. Despite China possessing substantial rubidium reserves estimated at 1.16 million tonnes of rubidium oxide and 140,000 tonnes of caesium oxide as of 2024, these resources are typically associated with specialized lithium ores and salt-lake brines, with low grades and complex compositions that complicate extraction and recycling.

For instance, lithium-rich lepidolite in Jiangxi holds nearly 40% of China’s rubidium reserves, but the conventional high-temperature sulphate roasting method can reach temperatures between 800 to 1,000 degrees Celsius, causing much of the rubidium and caesium to become embedded in aluminosilicate waste that is eventually discarded with lithium slag.

The pollucite, the primary industrial source of caesium, is also in short supply within China, necessitating imports from countries such as Canada, Australia, and Zimbabwe. China’s caesium is predominantly found alongside lepidolite and salt-lake brines, further complicating extraction. The advancement in this field is attributed to a high-efficiency tower extraction system developed by the Institute of Process Engineering under the Chinese Academy of Sciences (CAS), which boasts independent intellectual property rights.

This system employs differential counter-current extraction, offering advantages such as a reduced footprint, minimal extractant usage, and enhanced containment. A single extraction tower in the system is reportedly up to 15 times more efficient than traditional extraction tanks, cutting extractant consumption by 40% and equipment size by over 50%.

The team designed an industrial unit comprising 17 extraction towers in collaboration with Jiangxi Ganfeng Lithium and other partners. The system commenced operation on its first attempt and has maintained consistent performance ever since. It successfully recovers over 98% of caesium and more than 95% of rubidium, with both products exceeding 99.9% purity and now being commercially distributed.

The generated output annually stands at 500 tonnes of rubidium and caesium carbonates. The ratio of rubidium to caesium in the output remains undetermined, but the demonstration line confirms the feasibility of industrially separating low-grade associated rubidium and caesium resources through an efficient and environmentally friendly process, setting a precedent for potential larger-scale commercialization.

This technology holds significance for China’s strategic development and reliable supply of rubidium and caesium resources, crucial for advancing specialized lithium ores and fostering technological innovation. China already holds a dominant position in the global rubidium resource landscape, as evidenced by its possession of the world’s richest rubidium resources and the most centralized production capacity.

As of December 2025, China had established five core rubidium production lines, boasting world-leading technology and a total annual capacity of approximately 3,000 tonnes of rubidium salt equivalent. Additionally, Sinomine Resource Group controls the largest pollucite, or caesium ore, mine globally, contributing to a self-sufficient resource, technological, and production base that solidifies China’s leading role in the industry.

Looking forward, breakthroughs in emerging technologies like perovskite solar cells, solid-state batteries, and quantum computing could expand the applications for rubidium salts, potentially positioning rubidium as the next rare earth element.