@Pavel - Here is my response to your statement below:

• That is supported by following statement “…Engaged third-party vendors to engineer and design …evaporator and crystallizer...”. Here I sense sizeable amount of uncertainty and my translation to plain English is : “Well, we had talked to few companies about our process and needed equipment, but they all thougt, that we are complete whackers and have turned us down. But hey, do not worry, we still have few phone calls to make.”

In my experience in industry, I have worked on a project where we commisioned a crystallizer at production scale. The technology is no mystery, but tailoring it to a specific process or product is not without some challenges. There will definitely be a period of optimization once they start putting their lithium solution through it to make sure they are getting sufficient recovery AND purity. Any third party vendors contacted will look at their process and I expect will offer some minimal guarantees as to recovery, operating cost, and perhaps purity. No one is going to consider LAC "whackers", they just may have difficulty providing the guarantees that LAC requires. I struggle to see this aspect of the lithium recovery process as a significant hurdle. It may cost more than initially anticipated in terms of CAPEX and/or OPEX, but it is not going to be difficult at scale and should not on its own make or break the project.

For anyone unfamiliar with the chemistry described in the PFS starting on pg 136, I will try to offer a simplified explanation. The sulfuric acid leaching of the clay doesn't just remove lithium (Li+, 0.3%), but also other elements such as potassium (K+, 3.6%), magnesium (Mg+, 5.6%), and sodium (Na+, 1.2%) with percentages provided representing the percent by weight of these elements in the clay/ore. Other impurities will also be leached out, but for simplicity I will ignore these for the sake of this discussion.

There are two options for purification, selectively remove lithium from solution or remove everything else leaving just lithium behind. LAC is using both approaches, first removing magnesium, then later removing lithium and leaving everything else behind. Removing something can be done by changing temperature, pH, or adding another chemical to the process. When adding chemicals to the process, the strategy is to add something to the solution that is relatively easy to separate from lithium in downstream process in order to remove something that is more difficult to separate from lithium in the downstream process. Sequentially, each step of chemical addition and removal should allow for separation of lithium at increasingly higher purity. 

I will give a quick example relevant to the initial point of discussion on crystallization and my previous concerns about the relatively low concentration of lithium in solution in previous posts. In figure 17-4 of the PFS on pg 137 describes the process flow sheet. The last step describes removing Li+ in the form of lithium carbonate and leaving behind Na+ and K+ in solution. This is done by adding sodium carbonate to the solution. The way this works is that the sodium (Na+) and carbonate (CO3-) dissociate in solution and are free to react with other species. For reference, the solubility of sodium carbonate is ~35% weight per volume of water at room temperature and the solubility of lithium carbonate is ~1%. I presume the concentration of lithium at this step will be below 1%, lets presume 0.3% which was measured in the starting sulfuric acid leachate. When adding sodium carbonate, nothing should precipitate out if lithium carbonate remains below its limit of solubility. When this liquid is sent to the evaporator, heat (and maybe vacuum pressure) is used to remove water and increase the concentration of the lithium in solution. Once  the concentration exceeds the limit of solubility ~1%, lithium carbonate (Li2CO3) will spontaneously crystallize, precipitate out and can be removed by filtration. After lithium crystalls are filtered out the solution still contains ~1% lithium. They will cycle this stream back into the process per: "The zero-liquid discharge crystallizer will purge a small amount of barren lithium brine back to the liming system (Section 17.2.2) to maintain a predetermined lithium concentration in the crystallizer that will optimize lithium recovery." My concern is with the amount of energy required to remove the water during evaporation. If the concentration of lithium in solution is lower at this step, say 0.1% instead of 0.3%, this requires 3X more energy to remove the water. I don't know at what concentration of lithium the process becomes economically unfeasible. I have this same concern for direct lithium extraction methods. 

I want to raise awareness about a detail of the lithium recovery process that may affect the ESG claims with regards to carbon dioxide generation. LAC touts their process as not generating carbon dioxide as they will generate an excess of electricity from their sulfuric acid plant. However, fossil fuels are not the only way carbon dioxide is sequestered out of the atmosphere or trapped in a non-gaseous form. Carbon dioxide can also precipitate out as minerals such as calcium carbonate, or limestone. I am making this point because their process utilizes limestone to neutralize their sulfuric acid leachate at a rate of 3.51 tonnes of limestone per ton of lithium carbonate. In other words, they are putting in 2.6 parts carbonate in the form of limestone for one part carbonate out in the form of lithium carbonate. This is in addition to sodium carbonate (a.k.a baking powder) added prior to crystallization where carbonate should be swapped 1 for 1 between sodium carbonate and lithium carbonate. Here is what happen when limestone (a.k.a CaCO3 or calcium carbonate) is added to a sulfuric acid solution. The carbonate spontaneously changes to carbonic acid, carbonic acid and interconverts to carbon dioxide, but the amount of carbon dioxide will exceed the solubility of the gas in solution and will fizz out. This is akin to mixing vinegar (acetic acid) and baking soda (sodium bicarbonate) which is done to make volcanos for science projects. None of the other streams appear to account for this excess carbonate or any recovery and recycling of carbon dioxide. This could be a very significant source of carbon dioxide emissions.

AXP