Analytical Product Testing

Saint Jean Carbon Expands Graphite Market Opportunities Following Analytical Product Testing

SJL's  results of an array of detailed test procedures done by Evans Analytical Group (EAG) of Liverpool, New York.

Over a period of three weeks EAG carried out the tests on purified graphite concentrate from Saint Jean Carbon's 100% owned Walker hydrothermal lump/vein graphite property. 

The four tests conducted by EAG represented standard industry practice in efforts to create a comprehensive profile of graphite deposits from a chemical and crystalline structure perspective. This information is critical when it comes to product development for customers. Advanced product knowledge also reduces the development timeline for bringing products to market faster. In that regard the full suite of tests provided Saint Jean with the following summary points about the Walker material.

Summary Results

1)   The morphology, crystallinity, and structural makeup very closely resemble the best Sri Lankan vein graphite. Therefore its field of applicability is as broad as it is for any other kind of high purity vein graphites.
2)   The constituent analysis confirmed that the Walker Graphite is as suitable as flake graphite in a wide variety of side by side product applications. This includes all major market segments such as steelmaking, auto parts, paints, and industrial products such as gaskets, but also in much smaller specialized segments such as a neutron moderator in nuclear reactors.
3)   The crystallite structure shows a hexagonal and rhomohedral graphene layer structure that is consistent with good quality graphite.
4)   According to the Raman spectra results the ID/IG ratio of ~0.1 confirms that by published industry standards the Walker graphite is classified as “High purity, fine grained graphite”.
 

Test Background 

Each of the tests and a brief description are as follows:

1)     Glow Discharge Mass Spectrometer Testing - GDMS is designed to provide a cross section of the graphite morphology by identifying its constituent elements by parts per million (ppm).
2)     Raman Spectroscopy - provides important information on the structural characterization of graphitic materials. This includes details on defects, stacking of the graphene layers, and the finite sizes of crystallites parallel and perpendicular to the hexagonal axis.
3)     X-Ray Diffraction (XRD) Testing - provides information on crystallite size, and crystallinity or crystal structure. 
4)     Scanning Electron Microscope (SEM) Imaging - provides high resolution images that illustrate size, shape, distribution and orientation of graphitic flakes.
 

The Walker Property graphite tested was a composite grab sample that was collected from the site in June 2013 by the Company’s geologist Isabelle Robillard, P. Geo, QC. The material came from remnants of graphite veins that were formerly mined in shallow exploitation pits, in the west portion of the Property. As such, this material is representative of graphite vein-type occurrences that are found at Walker. The samples were subsequently the subject of upgrade testing done at Process Research Ortech (PRO) in Mississauga, Ontario and lab analysis done at Activation Laboratories Inc. (Actlabs) in Ancaster, Ontario. The results of this upgrade work were reported in the Company's press release dated October 15, 2013 in which it achieved purity levels in excess of 99% after a series of non-optimized flotation and purification processes that adjusted reagent concentrations and retention times. Approximately one kilogram of the original test material was then identified "T-1R" and shipped to EAG for testing. In correspondence with EAG, the Company outlined product-specific goals were designed to further its knowledge base on its potential graphite resources. The key test objectives were as follows:

1)   Provide broader confirmation of the lump/vein nature of the graphite.
2)   Provide an improved understanding of the morphology and crystalline structure of the graphite. This information is important for product design as various product applications have different thresholds for different contaminants, such as aluminum, boron, calcium, iron, or manganese. The data will also make up product spec sheets that will help define the graphite profile for prospective customers.
3)   Feedback on the suitability of Saint Jean's graphite for various product applications including fundamental market segments such as steelmaking, auto parts, and industrial items such as gaskets and lubricants. In addition, data supporting the material's suitability for high-purity applications such as lithium-ion batteries, and smaller segments such as nuclear and future graphene applications.
4)   Examine the type and nature of intercalation of non-graphite materials and any information that would help the Company further understand the degree of processing that may be required to purify the concentrate.
 

Test Results

With these objectives in mind the following is a brief summary of the four tests carried out by EAG.

1)   GDMS - the GDMS testing included analysis for 77 elements in total. Of that group the 18 elements listed in Table 1 below represent a good cross section of materials that are of importance to potential graphite customers. Of significance is that all of the elements are within acceptable levels for most traditional product market applications for graphite. This was confirmed in discussions with one of the Company's large prospective customers following the tests. In keeping with the goal of the tests, this is valuable insight into the potential of Saint Jean's material to meet the needs of a broad marketplace. This market includes large segments such as steelmaking, auto parts, paints, and narrower segments such as nuclear and fuel cell applications. In that regard the EAG testing included an Equivalent Boron Content (EBC) assessment of the Company's graphite. Too much Boron in nuclear graphite will increase neutron absorption which will negatively impact the chain reaction processes in a nuclear reactor.

Saint Jean's EBC count was determined to be 2.7 ppm, which is well within the 1-5 ppm tolerances for nuclear graphite. While good to know, it is only one very small item of information in a larger product development process.

Element Symbol Concentration (ppm wt) Element Symbol Concentration (ppm wt)
Aluminum Al 850 Nickel Ni 10
Boron B 0.30 Potassium K 190
Cadmium Cd <0.5 Sodium Na 290
Calcium Ca 460 Strontium Sr 8.1
Chlorine Cl 63 Sulphur S 19
Iron Fe 300 Thorium Th <.01
Lithium Li 0.44 Titanium Ti 150
Magnesium Mg 86 Tungsten W 0.07
Molybdenum Mo 0.28 Zirconium Zr 1.2


2)   Raman Testing - Raman spectroscopy uses a small laser beam of light to focus on a graphite sample. The light is “scattered” as its photons (light particle) interact with phonons (excited state) of the crystalline structure of the particular sample. The scattered light is passed on to the spectrometer which displays the unique structure of the graphite as a “peak” on the spectrum. A single crystal of pure graphite produces a single peak on the Raman spectrum. This is called the “G” peak - for graphite. As crystallite size changes a second “peak” will appear on the spectrum. This is called the “D” peak, where D stands for disorder.

The “intensity” ratio of these two peaks (ID/IG) helps diagnose the crystallite structure of the graphite, and also the amount of “disorganized’ carbon present. Knowing crystallite size is important as the larger it is the more it decreases resistivity and increases conductivity. This is critical information in many graphite product applications. The Raman spectra results on the Walker lump/vein graphite were typical of good quality graphite. The graphite sample had an average crystallite size of ~70 nm. The ID/IG ratio for the sample was ~0.1 which as Table 2 indicates, means that the Walker graphite is classified as “High purity, fine grained graphite”. 

3)   X-Ray Diffraction - XRD investigates crystalline structure including graphene layer configuration, crystalline size, and percent crystallinity. To put the results in context it is helpful to review graphite chemistry including atomic carbon, graphite carbon, graphite rings and graphite layers. 

i)     Carbon Atomic Structure

  • Figure_1.pngCarbon atoms have six electrons orbiting around a nucleus. These reside in various "energy levels" that can hold a maximum of two electrons.
  • The first level closest to the nucleus is the spherical energy level, or the "1s" level (see Figure 1). It holds two electrons.
  • Moving outwards, the next energy level is called the "2s" level. This has the same spherical shape as the 1s and also holds 2 electrons. .
  • Moving outwards again, the next energy level, or valence shell, is in the perpendicular plane, as in perpendicular to the "s" levels. There are three of these p orbits existing in the x, y, and z axis (see Figure 2). Each can hold a maximum of two electrons. The electrons move in a sort of "figure 8" pattern (electrons actually move in orbitals that are essentially called "probability clouds". This is due to a law called the Heisenberg Uncertainty Principle which loosely says: you can't know with certainty both where an electron is and where it's going next).
  • Electrons gravitate to these orbits sequentially. In carbon the fifth electron goes into the pxorbit, and the sixth or last goes in the py orbit. There are no electrons in the pz orbit.

ii)   Graphite Carbon Atomic Structure 

Figure_2.png

  • In graphite, carbon becomes hybridized. This means that the outer 2s shell and the three p shells merge to create three new sp2 orbits (or valence hells or energy levels), and one unhyrbidized pz valence shell (see Figure 3 below).
  • With two electrons still in 1s, the remaining four electrons are now re-distributed with one in each of the sp2 orbits and one in the pz orbit. The configuration of these sp2 orbits has a trigonal planar geometry (see Figure 4 below).
  • When two graphite carbon atoms are placed side by side, the overlap of an sp2orbit from each is called a sigma σ bond. The overlap between the two pz orbits is called a pi π bond.  Side by side the sigma and pi bonds form a double bond (see Figure 5). This double bond creates powerful covalent forces which give graphite its high temperature strength and ability to resist corrosion. The other two sp2 orbits in each carbon atom form single bonds with other surrounding hybridized carbon  atoms.

 

Figure_4.png

Figure_5.png

iii) Hexagonal Graphite Molecule

  • Six sp2 hybridized carbon atoms together form a graphite hexagonal ring. Multiple rings bonded Figure_3.png together form a single graphite layer, called graphene or the basal layer.

iv) Stacked Graphene Layers

  • Layers of graphene stacked on top of one another are held together by the single electrons in each of the pz orbits. This single delocalized π electron is not tightly bound between the planes and moves around freely (which explains graphite's electrical conductivity). The force between the layers is about 75 times weaker than covalent bonds (which also explains lubricity as layers easily slide over one another). It is called Van Der Waals force.
  • The distance between the layers occurs in two different lengths. This difference defines two types of graphene stacking, or graphite polymorphs. At one length, the layers alternate ABABAB, and this is called hexagonal or 2H graphite. When the layers alternate according to the second length, they do so in ABCABC pattern, and this is called rhombohedral or 3R graphite. The more 2H as defined by its crystallite structure, the better. The more 3R the worse. This is because 3R reduces the thermodynamic capabilities of graphite.

v)   XRD Test Results

Knowledge of carbon bonding, electron placement and the formation of graphene layers helps understand XRD tests results, particularly as they apply to the presence of hexagonal and rhombohedral layers. It also helps understand crystallite forms, and percent crystallinity. The latter is a measure of crystalline peaks versus non-crystalline peaks. The more non-crystalline peaks the more the likelihood that there are non-graphitic components intercalated (ie. between the layers) within the graphite crystal. If effect, the XRD diffraction pattern is like a fingerprint of the graphite. The diffraction data is also compared against the International Center Diffraction Database (ICDD) to further help identify all of the peaks on the XRD spectrum. Knowledge of other peaks such as aluminum (aluminum oxide - Al2O); boron; calcium (calcium oxide - CaO); iron (Fe2O3 - iron oxide); manganese (manganese oxide - MgO); and silicon (silicon dioxide - SiO2) is important as they all have the potential to disrupt the molecular structure of the graphite crystal. These types of materials between the layers or within the crystal structure is referred to as intercalation.

As the XRD test results shown in the table below indicate, the Walker graphite clearly displays the dominant presence of the 2R graphite crystallite, and a crystalline purity of 97.2%. In short, these two results further confirm that the Walker graphite would likely meet virtually all quality criteria for a wide variety of graphite product applications and target markets.

Phases Identified

Average Crystallite Size (nm)

% Crystallinity *

Graphite – 2H

Hexagonal P63/mmc (194)

PDF # 04-006-5764

56.4 +/- 11.7

97.2

Graphite – 3R

Rhombohedral R-3m (166)

PDF # 01-075-2078

 

8.0 +/- 2.2

 

 

% crystallinity = Total area of crystalline peaks / Total area of all peaks

where the total area of all peaks includes both crystalline peaks and amorphous scatter intensity.

 

4)   Scanning Electron Microscope (SEM) Imaging - EAG provided Saint Jean with ten SEM  images of the Walker graphite. The power point summary of those will be posted on the Company's website. The SEMs clearly illustrate images of size and uniform shape consistent with processed vein graphite. The size distributions ranged from 4-100 µm (ie. microns or micrometres), and there were no obvious extraneous elements associated or intercalated with the sample. As with all other parts of this test process Saint Jean will be able to offer this information to prospective customers as they review the Company's products.

e same applications as flake graphite. Moreover, these applications such as steelmaking (600,000 tons per year of graphite globally), auto parts, and paints tend to represent large market segments that can take up a large portion of the production a new graphite facility. This means that a new graphite facility can market the bulk of its product at solid and consistent market prices. Accordingly, while smaller segments will remain on Saint Jean's radar, some such as nuclear would likely be a second or third choice for an experienced graphite company to pursue 

Intelligent market decisions such as these are driven by a broad understanding of graphite morphology, production factors, and market dynamics. Saint Jean works closely with customers in addressing these issues and believes that it continues to represent one of the key core competitive advantages the Company is building as it moves forward. Communicating key business considerations to its shareholders is equally important. Paul Ogilvie, CEO, closed with this comment: "We feel we are best serving our shareholders and investors by not underestimating the barriers to entry associated with developing a new graphite company, and by limiting "blue sky" commentary that might exclude critical development information. Instead, providing insightful details on fundamental items such as sp2 hybridization or the potential impact on product quality due to alternating hexagonal or rhombohedral graphene layers, demonstrates that graphite requires the type of specialized knowledge we are continually developing at Saint Jean. Knowledge that is necessary as a viable new supplier to equally tech-savy customers. Saint Jean takes great pride in assessing all elements in its market, business and operational analysis and trusts that its shareholders will take equal confidence in testwork such as the EAG program."