Lithium refining filtration
Imerys DE and expanded perlite solutions for lithium filtration and processing
When it comes to lithium filtration solutions and processing, Imerys has been innovating to help producers meet the growing demand of battery-grade lithium salts. The use of filter aids like diatomaceous earth (DE) and expanded perlite has played a crucial role in solid/liquid separations for over a century. Recently, professionals in the lithium processing industry have recognized the value of these unique materials in improving filtration operations which enhance filtration unit operation, making them essential in creating filtrates with low turbidity at high flux rates, and with the lowest cost when compared with alternative technologies.
How can Diatomaceous Earth (DE) help lithium filtration technology?
Diatomaceous earth is composed of the fossilized remains of diatoms, which are microscopic algae. The structure of DE is characterized by its rigid and porous nature, allowing it to act like a sieve, which effectively captures extremely fine solids while permitting liquids to flow freely. This unique property makes DE particularly effective in applications where the removal of ultrafine particles is critical, such as in lithium brine purification. DE is first used as a precoat, where a layer of DE is deposited on the filter medium. This layer helps to trap fine particles, resulting in a clearer filtrate. Moreover, DE's ability to extend treatment cycles and optimize clarification enhances operational efficiency.
Additional benefits can be gained by adding a second dose of DE, known as body-feed, to further extend the filtration cycle run time and / or increase the flux rate. This technique can debottleneck filtration steps in an industrial process, or reduce capital costs altogether by requiring fewer pressure filters in the design of a new circuit.
Advantages in lithium brine and hard rock purification processes
The removal of ultrafine solids from lithium containing brine is crucial in all lithium refining processes, from all types of hard rock and brines. Hard rock sources of lithium include spodumene, zinnwaldite, lepidolite and sedimentary clays. Brine sources include salars and geothermal wells. For example:
Extracted brines, particularly from deep wells, can contain ultra fine precipitates due to brine oxidation or colloidal clays. These micron and sub-micron sized solids cannot be removed by traditional media filtration such as sand or walnut shells. Nor can they be removed via centrifugation or hydro-cyclones.
For both hard rock and traditional brine processes, during the precipitation step to remove soluble calcium and magnesium ions, the subsequent precipitate can be in the form of a hydrogel, which is difficult to remove cost-effectively.
In both situations, the addition of DE filter aid as a precoat into the filtration process creates a high clarity filtrate whilst preventing screen blinding, pressure rise, and short filtration cycles. DE is designed to be used in all types of filtration equipment, from pressure leaf, to candle filters, to plate-and-frame filters.
Value of surface treated Diatomaceous Earth (Diactiv - Li)
Imerys’ new product offering solves issues of traditional DE filter aids leaching silicon (Si) in highly alkaline environments. Surface-Treated DE (Diactiv-Li) reduces the leachability of silicon by 80 -100 percent. This development allows the production of higher purity Lithium salts for next-generation battery technologies while maintaining the high filtration rate benefits of traditional filter aids.
Imerys’ mineral solutions to improve solid/liquid separation in your Lithium refining process
Let us be your trusted supplier in Lithium Filtration solutions. Imerys offers comprehensive technical support to potential and existing customers, ensuring a seamless integration and optimal performance of Celite® brand and Diactiv brand diatomaceous earth filter aids. Our expertise ensures reliable filtration solutions tailored to the battery grade lithium hydroxide and lithium carbonate producers. Contact us today to start collaborating to create innovative, sustainable solutions for the future.
