Demonstration plant for lithium recovery from salt lake brines by newly developed solvent extraction methods: “A multi-functional chelate extraction coupled with three-phase stripping technology” for lithium recovery from carbonated salt lake bines and "A multi-component synergistic extraction coupled with water stripping technology" for lithium recovery from high magnesium content salt lake brines have been developed. Pilot plant to produce about 100 ton lithium carbonate annually has been built in Ali district, Tibet China. Battery grade lithium carbonate was firstly yield in such high altitude areas of 4600 meters; A plant for 10000 ton lithium (counted by carbonate) production was established using newly developed solvent extraction method in Qinghai provinces of China, largely reducing the cost of lithium recovery from high magnesium content salt lake brines and realizing the clean production as well.

Fig. 1 Demonstration plant of lithium recovery from salt lake brines by newly developed solvent extraction methods

Clean and high-quality utilization technology for polymetallic vanadium & chromium industrial hazardous wastes: more than 5 million tons of polymetallic vanadium & chromium industrial hazardous wastes are produced annual, and these wastes are difficult to treat and utilize, becoming a bottleneck problem for the sustainable development of relevant industries. Key technologies and equipment with respect to intensified leaching by reactive oxygen species, selective separation of similar metal compounds via controlled crystallization, and product phase reconstruction via cation exchange were broken through, providing innovative technical support for the high-quality utilization of vanadium & chromium containing hazardous wastes such as industrial residue and spent catalysts, which has won the first prize of technical invention of nonferrous metals industry association and selected for the national "13th Five-Year" scientific and technological innovation achievement exhibition.

Fig. 2 Demonstration plant of Clean and high-quality utilization for vanadium & chromium industrial hazardous wastes

Key technologies of physical and chemical collaborative utilization of lithium battery waste sagger: For the high-standard safe disposal and recycling of lithium battery waste/waste saggars, key technologies such as physical separation of waste saggars - reduction leaching - gradient separation have been broken through. The recovery rate of lithium is > 90%, and the recovery rate of nickel and cobalt is > 95%. The demonstration project of wet separation of nickel, cobalt, manganese and lithium in lithium battery waste sagger has been completed, with a treatment capacity of 2 million per year. This technical achievement was selected into the national "13th Five-Year Plan" scientific and technological innovation achievement exhibition and won the second class prize of scientific and technological progress award of the Nonferrous Metals Society of China in 2021.

Fig. 3 Demonstration plant of physical and chemical collaborative utilization of lithium battery waste saggars

A short process preparation technology of soda ash and ammonium sulfate use Sodium sulfate: sodium sulfate is a by-product in nearly 30 industrial fields in China, with an annual output of more than 10 million tons, which has low added value and difficult to use. It broke through the differential phase change free cycle of ammonia medium and the directional control technology of crystallization interval, revealed the phase equilibrium strengthening mechanism of multiple systems, and formed a complete set of short process for preparing soda ash use sodium sulfate. The investment driven by the promotion of new technologies is about 1 billion yuan, and the maximum scale of demonstration projects under construction is 200000 tons per year.

Fig. 4 Demonstration plant of making soda from sodium sulfate