Posted by Daniel Gleeson on 1st November 2019
Veolia’s exhaustive testing program and process design expertise with its HPD® evaporation and crystallisation technologies recently validated Bacanora Lithium’s product purity requirements at the Sonora lithium project in Mexico, while removing potassium and converting a waste stream into a high-value-added fertiliser, according to the water- and chemical-focused technology company.
The company’s Veolia Water Technologies division engineered and designed the production process that recovers lithium carbonate and sulphate of potash from clay deposits using HPD systems.
Veolia explained: “Although lithium is a relatively abundant metal, high-purity lithium chemicals used by battery makers are rarer because lithium extraction, either from brines or hard rock, consists of a series of complex operations that make design production rates hard to achieve.”
While these issues are also common in other mining sectors, the problems with lithium are compounded because of the reduced number of lithium plants in operation, meaning industry knowhow is limited, according to the company.
To mitigate the risks of the Sonora project and confirm that the proposed technical and commercial process is both feasible and scalable, Bacanora, a lithium exploration and development company, relied on Veolia’s lithium production expertise to test the process flowsheet developed during the feasibility study and simulate the unit operations planned for the project. The outline was an integrated mine in northern Mexico designed to reach a capacity of 17,500 t/y of battery-grade Li2CO3 (lithium carbonate) operation in its first phase.
Different from most of the world’s lithium produced from hard-rock mines in Australia or from brines in South America, the lithium at Sonora is mined from clay — a rare type of deposit with the potential to become one of the world’s largest and lowest-cost lithium resources, according to Veolia.
Integrated to this plant, Veolia designed an evaporation circuit with a double crystallisation sequence featuring HPD® thermal separation technologies to maximise the recovery of potassium sulphate – also known as sulphate of potash (SOP) – and sodium sulphate, a valuable salt recycled upstream as the reagent in the clay roasting process.
The production line is completed by ion-exchange purification, solid-liquid centrifugal separation and drying systems to achieve >99.5% battery-grade lithium carbonate.
“We are proud to help game-changing miners in search of a partner with the knowhow to produce lithium from a variety of feedstocks. Veolia looks forward to further supporting the transformation of Bacanora into a major supplier of battery-grade lithium chemicals,” Jim Brown, Executive Vice President Veolia Water Technologies Americas, said.