Thor Project: Alumina Recovery via HCl Leaching & Crystallization

Source: Canadian Energy Metals Corp (2026)
Website: https://canadianenergymetals.com/thor-project

Critical Data

Overview

Canadian Energy Metals Corp. is advancing the Thor Property, a black shale deposit in Tisdale, Saskatchewan, with a candidate flowsheet designed to produce high-purity alumina (HPA) and chemical-grade alumina (CGA). The Preliminary Economic Assessment (PEA) dated February 2025 details a multi-step recovery method centered on hydrochloric acid (HCl) leaching, crystallization, and proprietary pyrometallurgical processing. This alumina recovery method is significant because it targets a previously untapped resource—black shale clay—and aims to produce custom CGA at 99.9% purity and custom HPA at 99.99% purity, with an overall process recovery of 81.1%. The flowsheet integrates comminution, atmospheric HCl leaching, residue neutralization, impurity removal, and HCl recovery to achieve high efficiency and recycle most acid and water. With an annual feed tonnage of 16.4 million tonnes and a product recovery of 1.78 million tonnes of alumina per year, the Thor Project represents a major potential source of specialty alumina for North American markets. The innovative use of HCl gas sparging to selectively precipitate aluminum chloride hexahydrate (ACH) and the novel pre-crystallizer impurity removal system are central to achieving the required product grades. The facility is planned for a location in Saskatchewan, leveraging existing rail and municipal infrastructure. This alumina recovery method is designed to address both economic viability and environmental stewardship through acid recycling and residue management.

Key Process Stages

• Stage 1: Comminution (Crushing and Grinding) – Run-of-mine ore passes through a grizzly and roll sizer to achieve a P80 of approximately 75 mm. Crushed material is stored in a coarse feed stockpile dome, then reclaimed and fed to a Vertical Roller Mill (VRM) with an integrated classifier for dry grinding to a target P80 of approximately 1,000 µm. Grind size optimization is ongoing through leach testing.
• Stage 2: Hydrochloric Acid Leaching – Ground feed is combined with recycled HCl solution in a series of agitated atmospheric tanks. The acid solubilizes aluminum and other metals, generating aqueous aluminum chloride, metal chlorides, water, and silica-bearing residue. The resulting slurry is filtered on horizontal belt filters to separate the aluminum-rich Pregnant Leach Solution (PLS) from washed leach residue.
• Stage 3: Residue Neutralization – Washed leach residue is repulped with lime (calcium hydroxide) in an agitated tank to neutralize residual acid. The neutralized slurry is then filtered, with the liquid sent to a lime slaker to regenerate calcium hydroxide for reuse. The solid waste, classified as potentially acid-generating (PAG), is transferred to a residue treatment and storage system designed to manage acid mine drainage.
• Stage 4: Crystallization (High-Purity and PLS) – Two parallel crystallization circuits operate using recycled HCl-rich vapour sparged into agitated tanks. Sparging increases free acidity, reduces aluminum solubility, and selectively precipitates aluminum as Aluminum Chloride Hexahydrate (ACH). For HPA production, PLS first undergoes a proprietary pre-crystallizer impurity removal step. The ACH crystals are separated via belt filtration from the mother liquor.
• Stage 5: Calcination and HCl Recovery – ACH from high-purity crystallization is converted to custom High Purity Alumina (HPA) via proprietary pyrometallurgical methods. ACH from the PLS crystallization is similarly processed to produce Chemical Grade Alumina (CGA). Both products are bagged and stored. Meanwhile, a proprietary HCl recovery system recycles the majority of acid and water from the crystallization mother liquors, minimizing fresh reagent consumption.

Additional Interesting Data and Summary

The Thor Project’s recovery methods rely on a carefully designed mass balance that handles 17.0 Mt/year of wet feed, 54.7 Mt/year of water, and 66.2 Mt/year of air, while generating 15.3 Mt/year of leach residue, 1.43 Mt/year of custom CGA, 0.35 Mt/year of custom HPA, and 2.21 Mt/year of other oxide byproducts. The total energy demand is substantial, with CGA calcination alone consuming 43.2 million GJ/year and the HCl recovery system requiring 71.3 million GJ/year. Steam generation adds 57.7 million GJ/year, highlighting the energy-intensive nature of the flowsheet. Environmental considerations are central: the leach residue is classified as potentially acid generating (PAG), necessitating a dedicated residue treatment and storage facility designed to prevent acid mine drainage. Lime neutralization and lime slaking circuits ensure residual acid is managed, with quicklime (CaO) consumption estimated at 0.59 Mt/year and caustic (NaOH) at 0.47 Mt/year for scrubbing applications. Economically, the project is designed to produce two alumina grades—CGA at 99.9% purity and HPA at 99.99% purity—each targeting specialty markets. The estimated daily production at 90% availability is 3.9 kt/day of CGA and 1.0 kt/day of HPA, totaling 1.4 Mt/year and 0.4 Mt/year respectively. Sustainability initiatives include investigating biomass as an alternative fuel source to natural gas (4.47 Mt/year planned) and recycling the majority of hydrochloric acid through a proprietary recovery system, reducing fresh acid make-up to just 0.02 Mt/year. The future outlook includes further leach testing to optimize grind size (currently targeting P80 1,000 µm but with leach kinetics validated at P88 595 µm) and refining the proprietary impurity removal and crystallization steps. The significance of this facility lies in its pioneering approach to recovering high-value alumina from black shale clay in Saskatchewan, a region with established mining infrastructure. With a total electrical power demand of 108 MW and reliance on rail delivery for reagents (HCl, quicklime, caustic) and municipal potable water from Tisdale, the Thor Project is positioned as a potential cornerstone for North American non-bauxite alumina production. Forward-looking statements in the PEA emphasize that the candidate flowsheet is based on bench-scale testing and assumptions that will require pilot-scale validation and detailed engineering prior to construction.

Key Processes: Crushing

Target Commodities: N/A