This technical report describes the proposed processing route for extracting metallurgical-grade alumina from clay using a hydrochloric acid leach process, with supporting pilot plant testwork completed as of November 2011.
Report context
The Preliminary Economic Assessment (PEA) technical report for Orbite Aluminae Inc.'s Metallurgical Grade Alumina Project in Quebec, Canada, is dated January 12, 2012, with an effective date of November 24, 2011. The report was prepared by GENIVAR Inc. Section 17 (Recovery Methods) provides the detailed processing design for the commercial-scale plant, supported by pilot plant testwork described in Section 13 (Mineral Processing and Metallurgical Testing). The project is based on clay feed material from the company's property in Quebec.
Processing route
General Overview of Recovery Method and Plant Design
The recovery method centers on the Orbite Alumina Extraction Process, a hydrochloric acid leach process designed to extract aluminum from clay. The commercial plant design consists of several integrated processing areas: Primary Crushing and Transportation, Secondary Crushing and Grinding (Clay Preparation Plant – CPP), Leaching (Acid Leaching plant – ALP), Separation of Aluminum Chloride from Other Chlorides, Calcination (Alumina Calcining Plant – ACP), Hydrothermal Acid Recovery/Hematite (Acid Regeneration Plant APP), and Magnesium and Other Oxides Production. The process also includes provisions for Rare Earths and Rare Metals concentration.
Primary Crushing and Transportation
Run-of-mine clay material is to be reduced in size through primary crushing before being transported to the processing facilities. No specific crusher type or transport method is provided in the cited section.
Secondary Crushing and Grinding (Clay Preparation Plant – CPP)
The clay is further prepared through secondary crushing and grinding to achieve the appropriate particle size for leaching. The report does not specify target grind size or mill type in the cited recovery methods section.
Leaching (Acid Leaching plant – ALP)
The prepared clay is leached with hydrochloric acid to dissolve aluminum and other metal chlorides into solution. This step operates at elevated temperature and pressure conditions. The pilot plant testwork (Section 13.6.2) describes acid leaching of the clay slurry to extract aluminum, iron, and other elements.
Separation of Aluminum Chloride from Other Chlorides
After leaching, the solution undergoes processing to selectively separate aluminum chloride from iron chloride and other metal chlorides present in the solution. The pilot plant testwork (Section 13.6.3) includes separation of soluble iron as a dedicated step.
Calcination (Alumina Calcining Plant – ACP)
Aluminum hydroxide is calcined to produce metallurgical-grade alumina. The pilot plant testwork (Section 13.6.5) describes alumina calcining as the final conversion step to produce aluminum oxide.
Hydrothermal Acid Recovery/Hematite (Acid Regeneration Plant APP)
Hydrochloric acid is regenerated from the process solutions, allowing recycle of the leaching reagent. Hematite (iron oxide) is produced as a byproduct during this step. The report notes this is a key feature of the process economics through reagent recycle.
Magnesium and Other Oxides Production
The process design includes recovery of magnesium oxide and other oxide products from the remaining process solutions. No specific recovery methods or product grades are detailed in the cited section.
Rare Earths and Rare Metals Concentration inside Orbite's Process
The process design includes concentration of rare earths and rare metals as value-added byproducts. The report states "Typical Extraction Technique and Recovery Observed" as a subsection but provides no numerical extraction data in the cited section.
Water Management and Solid Waste Management
The report includes dedicated sections for water management and solid waste management, but provides no technical details in the cited recovery methods section.
Reagents
A reagents section is listed but no specific reagent consumption rates or types are provided in the cited recovery methods section.
Services & Utilities
A services and utilities section is listed but no specific utility consumption figures are provided in the cited recovery methods section.
Pilot Plant Testwork (Section 13)
Basis of Recovery
The pilot plant testwork formed the basis for the proposed plant design recoveries. The report (Section 13.7) describes testing completed on clay samples collected from the project property.
Representativeness of Samples
The report states the clay samples used for testing were collected from the property and subjected to leaching tests across different clay families (Section 13.7.2). The degree of representativeness is discussed but no quantitative assessment is provided in the cited sections.
Comminution and Head Assay
Head assays were completed on the test samples. Comminution testing established grinding parameters for the clay material (Section 13.7.3).
Leaching Testwork
Leaching tests were conducted to determine aluminum extraction efficiency under various acid concentration, temperature, and retention time conditions (Section 13.7.4).
Iron Removal
Iron removal from the leach solution was tested as a separate unit operation (Section 13.7.5).
Aluminum Hydroxide Synthesis
Aluminum hydroxide was synthesized from the purified aluminum chloride solution through precipitation (Section 13.7.6).
Calcination
Both aluminum hydroxide and aluminum chloride hexa-hydrate were tested for calcination to alumina (Section 13.7.7).
Value Added Product Recovery
The pilot plant included testwork on recovery of value-added products, including magnesium and rare earths (Section 13.7.8).
Reagent Recycle
The pilot plant testwork included evaluation of hydrochloric acid recycle from the process solutions (Section 13.7.9).
Key reported parameters
The following table presents the key processing parameters reported in the report, distinguishing between design basis, historical testwork data, and basis of recovery assumptions.
| Parameter | Reported Value | Unit | Basis | Section Reference |
|---|---|---|---|---|
| Alumina product target | Metallurgical Grade | Grade | Design | Sec. 17 |
| Feed material | Clay | Material type | Design/Testwork | Sec. 13, 17 |
| Leach reagent | Hydrochloric acid | Reagent | Design/Testwork | Sec. 13, 17 |
| Primary processing stages | 8 identified stages | Number | Design | Sec. 17.2 |
| Pilot plant unit operations | 8 identified steps | Number | Testwork | Sec. 13.6 |
| Reagent recycle | Hydrochloric acid regeneration | Process step | Design/Testwork | Sec. 13.7.9, 17.2.6 |
| Byproduct hematite | Produced | Product | Design | Sec. 17.2.6 |
| Byproduct magnesium oxide | Produced | Product | Design | Sec. 17.2.7 |
| Recovery basis | Pilot plant testwork | Basis | Testwork | Sec. 13.7 |
*Note: No numerical recovery percentages, production rates, or reagent consumption rates are explicitly stated in the cited recovery methods section. The table shows the parameters described qualitatively in the report.*
Technical qualifications
This report is a Preliminary Economic Assessment as defined under NI 43-101. The report explicitly states in Section 13.9 (Conclusions on Mineral Processing and Chemical Testwork) that the process design is based on pilot plant testwork and METSIM/ASPEN mass and heat balance modeling. Section 17 (Recovery Methods) presents a conceptual plant design that has not been demonstrated at commercial scale. The report does not provide detailed flowsheets, equipment specifications, or mass balance data within the recovery methods section cited. No mineral reserve estimates are included in the recovery methods section; mineral resource estimates are provided separately in Section 14. The report effective date is November 24, 2011, and all scientific and technical information is current as of that date.
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*Source: Preliminary Economic Assessment on Metallurgical Grade Alumina Project, NI 43-101 Technical Report, Orbite Aluminae Inc., Quebec, Canada. GENIVAR Inc., January 2012. Sections 13 and 17.*
