Zenyatta Ventures Ltd

“Seems like some think that Thermal is better then caustic bake...from all my readings thermal is harsher then caustic bake on graphite crystals...Someone on Graphite News is asking the same question....” Arctic99

Mostly conjecture, and not based on the reality of the facts. It is true though, that this Graphite in question, has been Thermally upgraded and purified to the Nuclear Standard by an End-User/Producer of Synthetic Graphite under contract for the Nuclear Industry. It is also true, any Graphite can be upgraded to Nuclear Specs using Thermal Purification processes, just as this End-user/Producer cooks his Petroleum Needle Coke or Coal Pitch Tars to rid impurities in making Nuclear Grade Graphite (Synthetic), in processes taking over 4 months’ time. Just a matter of what the impurities there are in the Natural Graphite Concentrate and the time required to cook them off.

The problem, is this End-User/Producer of Nuclear Graphite (Synthetic) may buy your concentrate at reduced pricing that still requires Thermal Upgrade, but may or may not buy your product that has been Thermally Treated in-house for top dollars, as you are now his competition and they have the contract to supply Nuclear Grade Graphite.

Most in the Graphite Industry would argue Chemical is the less expensive option over Thermal, as cited in this Scientific Journal(s) below and noted in the following Investor Intel interview with Oliver Peters.

Seems very evident, that Science would back that, “Chemical is cheaper than Thermal”, and that, “Caustic Bake is preferred over Acid”, for Health, Safety and Environmental reasons.

Cheers, Mark (Thermal is the reason why Synthetic is more expensive than Natural at the same High Purity)

Purification process of natural graphite as anode for Li-ion batteries: chemical versus thermal

Abstract

The intercalation of Li ions in natural graphite that was purified by chemical and thermal processes was investigated. A new chemical process was developed that involved a mixed aqueous solution containing 30% H2SO4 and 30% NHxFy heated to 90 °C. The results of this process are compared to those obtained by heating the natural graphite from 1500 to 2400 °C in an inert environment (thermal process). The first-cycle coulombic efficiency of the purified natural graphite obtained by the chemical process is 91 and 84% after the thermal process at 2400 °C. Grinding the natural graphite before or after purification had no significant effect on electrochemical performance at low currents. However, grinding to a very small particle size before purification permitted optimization of the size distribution of the particles, which gives rise to a more homogenous electrode. The impurities in the graphite play a role as microabrasion agents during grinding which enhances its hardness and improves its mechanical properties. Grinding also modifies the particle morphology from a 2- to a 3-D structure (similar in shape to a potato). This potato-shaped natural graphite shows high reversible capacity at high current densities (about 90% at 1C rate). Our analysis suggests that thermal processing is considerably more expensive than the chemical process to obtain purified natural graphite.

http://www.sciencedirect.com/science/article/pii/S0378775303001162

Concluding remarks

Analysis of the two processes, chemical and thermal,

indicate that high reversible capacity is obtained with short

chemical treatment time (4 h) or heat treatment at 2400C.

However, the thermal process of natural graphite to obtain a

highly purified sample is costly.

http://www.researchgate.net/publication/229372763_Purification_process_of_natural_graphite_as_anode_for_Li-ion_batteries_chemical_versus_thermal

Ty Dinwoodie (Investor Intel) interview with Oliver Peters, “What every investor needs to know about investing in graphite”

TD: So any type of natural flake graphite can be made into ultra high purity, but if it’s not a reasonable grade to begin with, it’s very expensive to do.

OP: Correct, at least based on my current experience with over a dozen graphite projects. However, there is no standard definition for “ultra high purity”. The concentration and type of impurities will differ between different deposits and a purified graphite concentrate from one deposit may be suitable for a specific ultra high-purity application, while another is not. But it is still an expensive process and the hydrofluoric acid route has a significant health & safety and environmental concern. That’s why the caustic bake is, at least from a health and safety point of view, less problematic.

TD: Caustic bake sounds like the most advantageous and cost effective of the three methods for achieving ultra high purity, is that correct?

OP: Well, it’s one route. You would not likely go with hydrofluoric in a commercial process if you can avoid it. Electro-thermal purification is carried out on a commercial scale – so that’s certainly an option too. It essentially comes down to how the graphite behaves and economics.

TD: Is there a reason why a graphite company — that has pretty potent graphite coming out of the ground — wouldn’t use caustic bake over the thermal process. Could that be more cost effectiveness or just a preference of the engineer?

OP: If the company is planning on carrying out the purification themselves in the commercial process, the chemical purification route may be easier to implement. Also, there are a number of off-takers of graphite concentrate that carry out the purification process in house, i.e. they would be interested in purchasing a flotation concentrate only with the highest grade possible to minimize the cost of their purification process.

TD: The simple caustic bake is not inherently expensive or unusual. Is that what you would normally be doing with any company that gives you conventional flake graphite when you’re trying to achieve ultra high purity?

OP: That’s why it is commonly employed as first pass — it is just a simple test with a set number of process variables. However, in order to determine the CAPEX and OPEX of your circuit, these process variables will have to be optimized as you don’t get sufficient information from a single test. It’s certainly not a cheap process, but can it be economic? Absolutely, although it’s obviously also affected by the market price for a purified product. In order to obtain the very high-grade concentrate grades, one of the purification approaches will have to be taken. That’s why battery grade graphite has a premium price over any other type of graphite — because there is additional processing involved and the processing costs are substantial. Flotation is definitely much cheaper in that regard and gives an indication of how well the graphite upgrades.

http://investorintel.com/graphite-graphene-intel/what-every-investor-needs-to-know-about-investing-in-graphite/