Guide - Use of Lime in Lithium Extraction and Processing
Introduction
Lithium, often referred to as "white gold," is a critical component in the production of batteries for electric vehicles (EVs), renewable energy storage systems, and various consumer electronics. As the demand for lithium continues to surge, understanding the extraction and processing methods becomes essential. This article delves into the technical aspects of lithium extraction, refining, and processing with an in-depth look at how lime and the products provided by Carmeuse are a critical component of these processes. Also, we will dive into the lime handling equipment that is a necessary part of utilizing lime appropriately in lithium mining and processing.
Extraction Process of Lithium / Lithium Mining Processes
Extracting lithium involves isolating lithium from various sources, including brine, mineral ore, and clay. Two primary methods are:
- Brine Extraction: This method of brine-based lithium mining involves pumping lithium-rich brine from underground reservoirs to the surface, where it is stored in large evaporation ponds. Over several months, the water evaporates, leaving behind a concentrated lithium solution. This solution is then processed to extract lithium carbonate or lithium hydroxide[1].
- How to Extract Lithium from Brine: After lithium-rich brine has sat in concentration ponds and undergone significant evaporation, the next step is to extract lithium from the concentrated solution. This process typically involves several stages of chemical treatment and purification. Hydrated lime (calcium hydroxide, Ca(OH)₂) plays a crucial role in this phase. First, a slurry of hydrated lime is added to the concentrated brine to adjust the pH levels, which helps precipitate out impurities such as magnesium and boron. These impurities form insoluble compounds like magnesium hydroxide and calcium borate, which can be easily removed through filtration or settling[2][3]. The purified brine, now free of most contaminants, is then subjected to further chemical processes to precipitate lithium carbonate or lithium hydroxide. This step ensures that the lithium extracted is of high purity, suitable for use in battery production and other applications.
- How to Extract Lithium from Brine: After lithium-rich brine has sat in concentration ponds and undergone significant evaporation, the next step is to extract lithium from the concentrated solution. This process typically involves several stages of chemical treatment and purification. Hydrated lime (calcium hydroxide, Ca(OH)₂) plays a crucial role in this phase. First, a slurry of hydrated lime is added to the concentrated brine to adjust the pH levels, which helps precipitate out impurities such as magnesium and boron. These impurities form insoluble compounds like magnesium hydroxide and calcium borate, which can be easily removed through filtration or settling[2][3]. The purified brine, now free of most contaminants, is then subjected to further chemical processes to precipitate lithium carbonate or lithium hydroxide. This step ensures that the lithium extracted is of high purity, suitable for use in battery production and other applications.
- Hard Rock Mining: Lithium is extracted from spodumene, a lithium-rich mineral found in igneous rocks. The ore is mined, crushed, and then subjected to a series of chemical processes to extract lithium.
- How to Extract Lithium from Ore / Spodumene: The extraction of lithium from spodumene, a lithium-rich mineral, involves several key steps, with hydrated lime (calcium hydroxide, Ca(OH)₂) playing a crucial role in the process. Initially, spodumene ore is mined and crushed, then subjected to high-temperature calcination to convert it from its naturally occurring alpha form (α-spodumene) to the more reactive beta form (β-spodumene). This conversion is essential for making the lithium accessible for extraction. In the alkaline process, the β-spodumene is then roasted with lime, which reacts with the spodumene to form a clinker. This clinker is subsequently leached with water in a process called ‘lithium leaching’, allowing the lithium to dissolve into the solution as lithium hydroxide. The use of lime in this process not only facilitates the breakdown of the spodumene structure but also helps in the precipitation of impurities, ensuring a higher purity of the extracted lithium.
It's important to note that these are not the only techniques for extracting lithium. There are several other methodologies that can be used, many in which lime can also play a role.
The Role of Lime in Lithium Mining and Production
Hydrated lime, chemically known as calcium hydroxide (Ca(OH)₂), plays a crucial role in the extraction and processing of lithium. Its applications include:
- pH Control and Neutralization: Lime is used to maintain the correct pH levels during lithium extraction processes. It neutralizes acidic solutions, ensuring stable and efficient processing conditions[2][3].
- Precipitation of Impurities: During lithium processing, impurities such as magnesium and calcium need to be removed to obtain high-purity lithium. Lime facilitates the precipitation of these unwanted compounds, improving the quality of the final product[2][3].
- Environmental Management: Lime is used in water treatment systems to neutralize acidic mine drainage and treat wastewater, ensuring compliance with environmental regulations[2][3].
- Enhancing Lithium Recovery: By optimizing pH levels and removing impurities, lime improves lithium yield from both brines and ores. This enhances the overall efficiency of the extraction process[2][3].
- Cost-Effective Solution: Lime is readily available and affordable, making it a practical choice for large-scale mining operations. Its use in various stages of lithium extraction and processing helps reduce operational costs[2][3].
- Versatility: Lime is applicable across various extraction methods, including hard rock mining and brine processing. Its chemical properties make it suitable for different stages of lithium production[2][3].
How Do I Refine Lithium?
The refining lithium process involves several steps to convert raw lithium into battery-grade lithium carbonate or lithium hydroxide. The process includes:
- Concentration: The lithium-rich brine or ore is concentrated to increase the lithium content.
- Purification: Impurities such as magnesium, calcium, and boron are removed through chemical treatments.
- Conversion: The purified lithium solution is converted into lithium carbonate or lithium hydroxide through precipitation and crystallization[1].
What Lime Handling Equipment is Necessary in Lithium Production?
Lime slaking and handling equipment is a crucial part of any lithium mining and processing application. As mentioned previously, lime plays an important role throughout the process of lithium mining and processing by being used to remove impurities and precipitate unwanted compounds, neutralize acidic solutions, and treat wastewater.
To appropriately utilize lime, lithium production facilities will need to be equipped with lime storage, feeders, and conveyors. If utilizing lime slurry, a lime slaking and storage system will be necessary.
Lime slaking is the process of converting quicklime to hydrated lime by adding water. This is typically done using a lime slaker, which ensures a controlled reaction and produces consistent lime slurry. The slaking process is critical because it determines the quality and reactivity of the hydrated lime used in the mining process
Contact Carmeuse Systems:
If you are currently mining and/or processing lithium and are in need of lime or lime handling equipment, please contact us directly to discuss your needs.
Frequently Asked Questions
Lithium is harvested from both brine and hard rock sources. In brine extraction, the lithium-rich brine is pumped to the surface and allowed to evaporate in ponds. In hard rock mining, spodumene ore is mined, crushed, and processed to extract lithium [1].
Lithium brine extraction is a straightforward but lengthy process. It involves drilling wells to access underground brine deposits, which are then pumped to the surface and distributed to evaporation ponds. The brine is left to evaporate, concentrating the lithium. Once the desired concentration is achieved, the brine is processed to extract lithium carbonate or hydroxide[1].
Lithium is separated from other materials through chemical treatments that remove impurities and concentrate the lithium solution [1].
Lithium mining involves extracting lithium from brine or hard rock sources. The extracted lithium is then processed to produce battery-grade lithium products [1].
Lithium is collected from brine or ore through extraction and processing methods [1].
A lithium leach field works by using chemicals to dissolve lithium from its ore, which is then processed to extract lithium. [1].
References
[1] Sustainable Lithium Extraction: How is Lithium Mined and Processed
[2] New technology extracts lithium from briny water | Stanford Report
[3] Direct Lithium Extraction (DLE): An Introduction