Alabama Graphite Corp. is pleased to report positive pilot plant test results for its flagship Coosa Graphite Project.
AGC is the sole owner of the Coosa Graphite Project, located in east-central Alabama, USA. The Company's mission is to become a vertically integrated green-energy supply chain producer of coated spherical purified graphite ("CSPG") for the American lithium-ion battery industry.
The primary objectives for running the pilot-scale plant were as follows:
- Confirm the performance of the primary processing metallurgical flow sheet;
- Develop an optimized process design criterion (for primary processing) for the forthcoming Coosa Graphite Project Feasibility Study;
- Achieve a high-carbon concentrate suitable for AGC's proprietary secondary processing to produce specialty graphite products, namely CSPG for lithium-ion batteries; and
- Produce concentrate material for AGC's secondary processing development and optimization, subsequent secondary processing pilot plant (in support of the forthcoming Feasibility Study), and for evaluation by potential offtake partners.
The following results support the effectiveness of the AGC's primary processing metallurgical flow sheet and that the graphitic material from the Coosa Graphite Project can be upgraded to high-grade graphite concentrate by mechanical means - specifically, flotation and polishing - without the use of hydrofluoric, hydrochloric, sulfuric, nitric acids, and alkalis. The flow sheet will form the basis for a significant component of the Company's upcoming Feasibility Study.
The main objective in designing the pilot plant was to achieve a high grade output regardless of the flake sizes of the input material - including the smaller flakes. Achieving this objective is expected to be a key requirement for easily and cost-effectively purifying all primary concentrate produced via AGC's low-temperature thermal purification (a critical step in the Company's secondary processing to produce CSPG). As a result of management's graphite processing and optimization experience, AGC had the ability to design the circuit process to achieve this high overall grade for the pilot plant.
Some graphite development companies with traditional business plans focus on producing and selling a primary processed, run-of-mine, concentrate material and are most concerned with the disposition of flake sizes and the associated carbon grade. However, since AGC intends to divert all of the primary processed graphite concentrate that it will produce to secondary processed specialty graphite products, flake sizes are not the primary focus. AGC's management believes that the primary evaluation metric for the Coosa Graphite Project's pilot plant is carbon grade since jumbo or large flake sizes are not required for the manufacture of CSPG. Concentrate grade - not flake size - is what is important to AGC for secondary purification and processing.
AGC's pilot plant has exceeded expectations in that a high carbon grade - averaging 96.7% Cg across all flake sizes - has been produced, meaning 100% of the concentrate to be produced via primary processing from the Coosa Graphite Project is expected to be suitable for secondary processing.
- The AGC pilot plant was able to produce a high carbon grade, averaging 96.7% across all flake sizes;
- All size fractions greater than 325 mesh yielded between 96.2% and 97.2% total carbon; even -325 mesh material yielded 94.6% Cg;
- Overall recovery was 88.2%, which management considers good given the inversely proportional relationship between high concentrate grade and recovery; opportunities for improvement were identified, as first-stage cleaner recoveries achieved 99.3%;
- 130 tons of graphitic material from the Coosa Graphite Project was processed in the pilot plant, netting the Company 3 tons of graphite concentrate;
- Average head grade of 3.09% total carbon (ranging from a minimum of 2.54% total carbon to a maximum of 3.48% total carbon); and
- AGC's graphite concentrate is expected to be quite amenable to secondary processing.
The testing of the pilot plant has supported (at the scale of the pilot plant) the technical viability and operating performance of the process plant design for production of high-grade primary processed concentrate material, which, as outlined in AGC's Preliminary Economic Assessment* for the Coosa Graphite Project (announced on November 30, 2015), would be diverted to secondary, specialty processing to produce CSPG for use in lithium-ion batteries, and purified micronized graphite ("PMG") for use in polymer, plastic and rubber composites, powder metallurgy, energy materials, and friction materials, among other applications.
President and Chief Executive Officer Donald Baxter commented, "The pilot plant results have demonstrated that the Coosa Graphite Project holds the potential to produce a high-carbon concentrate, across all flake sizes, from mechanical means - without chemical or thermal treatment. More importantly, however, is that the graphite concentrate produced is well suited for our secondary processing to produce specialty CSPG graphite."
"Typically, when processing graphite, one expects to experience a significant drop off in grade with the smaller flake sizes. This is not the case with the Coosa material, with the -325 Mesh graphite concentrate grading 94.6% Cg," stated Mr. Baxter. "Based on our graphite experience, we designed this circuit to maximize the grade of the fines and we are very pleased with this achievement. What I am most pleased with is that these pilot plant results support our business strategy in that all flake sizes appear to be suitable for our specialty secondary processing."
The overall pilot plant recovery was 88.2% and the Company is confident that there is significant room to improve this metric. The first cleaner stage recoveries achieved 98.7% and 99.3% respectively, and it was noted that the main loss in recovery was from a single stream, namely the rougher tails. Accordingly, AGC's management has identified this situation as an opportunity since management expects that the loss in recovery can be corrected by developing and optimizing a secondary grinding circuit.
The pilot plant was designed in collaboration with, and built and operated by SGS Mineral Services ("SGS") of Lakefield, Ontario (which is a division of SGS Canada Inc.) and the testing of the pilot plant was managed by a Consulting Metallurgist for SGS, renowned graphite metallurgist Oliver Peters (the Principal Metallurgist of Metpro Management Inc.). In August 2015, AGC prepared a 200-ton bulk sample of graphitic material from the Coosa Graphite Project's resource grid, which was shipped to SGS. SGS processed a 130-ton sample of this material. Based on the successful yield and results of the pilot plant and for maximum cost efficiencies, the Company and SGS decided not to process the remaining 70 tons of graphitic material.