Lithium Extraction from Oil and Gas Brine

Presently, the vast majority of lithium is produced by hard-rock mining operations predominantly in Australia, accounting for approximately 46% of global lithium supply, and 31% from brine in South America concentrated through the use of large-scale evaporation ponds, as of 2020.

These existing industry practices carry significant challenges, particularly with the open-air evaporation ponds in South America, such as geographic constraints impacting the feasibility of using ponds, large land usage requirements, high rates of underground water loss in regions with limited water resources, as well as long production lead times – typically 12 to 18 months from start-up – making it difficult to rapidly respond to market pressures.

Likewise, the evaporation ponds are not viable to implement for Alberta’s brines due to the province’s cooler and wetter climate, and relatively low lithium ion concentrations of approximately 75 parts per million (ppm) compared with up to 1000 ppm in South America, thereby requiring significantly more volumes of water to achieve comparable lithium production rates.

In order to support the effectiveness of our design at recovering lithium, while both minimizing environmental impacts and remaining economically feasible, our team implemented a variety of design improvements and solutions.

Typical industry practices of open-air evaporation for lithium salt recovery are time consuming, damaging to local ecology, and very much weather dependent. Our centralized processing facility utilizing direct lithium extraction with highly selective resins enables continuous operations independent of weather and dramatically reduces risk of contamination to surrounding areas, while also producing viable quantities of usable water resources.  Moreover, recovery of valuable strontium from what would otherwise be waste supports the value creation of our process. Likewise, selective ion exchange allows for further processes towards battery-grade lithium hydroxide monohydrate which sells at a premium market price compared to lower grade lithium salts typically produced from evaporation ponds. 

Hydrogen Sulfide Removal
When extracting brines from formations typically used for hydrocarbon production, approximately 300 ppm of H₂S is contained with the brine. H₂S is removed through the use of a stripping column with an diethanolamine (DEA) treating process, with further brine stream polishing through oxidation to ensure safe facility operations and meet regulatory requirements. H₂S can then be injected with wastewater streams back to the geological formation.

Premium Battery-grade Lithium Production

With the use of selective ion exchange resins, lithium-rich stream purities enable further processing to create lithium hydroxide monohydrate, maximizing the value of Alberta’s lithium resources. Through a combination of reactors and washing treatments designed to first precipitate a raw lithium carbonate using Na₂CO₃ reagent, and then further processing with Ca(OH)₂ to a highly pure LiOH solution. Final evaporative crystallization volume requirements are significantly reduced, along with subsequent energy demands, all the while maintaining greater than 99.3% final product purity and a relatively uniform crystal size distribution needed for the lithium-ion battery market.

Heat Recovery

The implementation of waste heat recovery reduces overall process requirements, improving operating costs while also decreasing utility demand, supporting process sustainability. For example, the DLE Ion exchanger used a closed loop system, reducing operations cost by $8,237.5/regeneration cycle and Natural Gas usage by 516.4 MCF/regeneration cycle. Similarly, brine needs to be cooled in order to precipitate the strontium hydroxide. Immediately after this the brine is reheated for the second reaction, the cold brine is run through a heat exchanger with the previous hot brine that needs to be cooled. This allows for the recovery of a large portion of the energy and in turn a large reduction in the utilities required.

The economics of this project have been calculated at an initial capital cost of approximately $143 million. The operating costs of this project are calculated at approximately $132 million, and the total revenue before tax is calculated at approximately $170 million. With all of this information,  the post tax revenue of this project stands at $20 million annually with a payback period of 8 years assuming 2 years initially to build the plant. 

To the left is a Strauss Plot for a sensitivity analysis. The plot considered a 20% change positive and negative for variables that affect the annual profit of the project. The selling price of Lithium has the largest effect on the annual revenue, and the purchasing price of raw materials is a significant variable that could change the profit by millions of dollars either way, highlighting the importance of managing material inputs.