The JV produced the brine at German facilities owned by engineering firm GEA using a conventional technology that can be scaled up easily.
The brine was concentrated at the pilot plant solar evaporation ponds at the Maricunga site for almost 12 months, and then shipped for treatment at GEA's lab in Duisburg.
There it was purified and precipitated into a lithium carbonate suitable for battery grade specification similar to those produced in Chile by Albemarle and SQM.
The sample was tested at 99.4% purity.
LPI CEO Martin Holland described it as a "major milestone" on the company's path to become one of a select few lithium carbonate producers.
"Now we are able to produce a value added, refined product which we believe meets cathode manufacturers' rigorous material specifications," he said.
The company is advancing its environmental impact study, and expects to be able to submit it to the government within weeks.
That work is being undertaken in parallel with the definitive feasibility study that is being undertaken by WorleyParsons.
LPI describes Maricunga as one of the highest quality pre-production lithium brine project globally, with "a very high grade and strong flow rates".
Modelling released earlier this year supported strong economic returns for production of 20,000tpa of lithium carbonate, with production of 74,000tpa of potassium chloride from year three of the project operations.
Assuming a two-year ramp-up, payback would be less than three years for LPI's share of the development costs of US$366 million (net $183 million) with a total budget of $527 million to cover the contingency, indirect costs and the fertiliser plant.
The assessment showed that the lithium brine project would be among most efficient LCE producers in the nation with costs of $2938/t, reducing to $2635/t with the fertiliser credits.
The field would require 13 wells, a central pumping station and a salt removal plant.
The Sydney-based company had some A$34 million in the bank at the start of the year.
LPI last traded at up 4.5% to 46c, valuing the company at $120 million.
