Anson Resources Ltd (ASX:ASN) on-site pond evaporation tests on lithium brine at the Paradox project in the US state of Utah compare favourably with laboratory test work.
Lithium concentration in the evaporation ponds increased to 398ppm after 17 days of evaporation subject to variable temperature and weather conditions.
READ: Anson Resources continues to receive positive lithium brine test results
The laboratory tests resulted in the concentration increasing to 433ppm after 14 days under constant temperature conditions, 24 hours per day.
Anson’s managing director Bruce Richardson said: “The company has moved quickly
to replicate the first stage laboratory benchtop test work with in-field evaporation ponds.
“This continues the strategy of fast-tracking the Paradox Lithium Project into production.
“The correlation of results is very pleasing.
“It provides confidence that the pilot plant to be designed through benchtop test work will be successful in extracting lithium and other minerals of high concentration once completed. “Concentrated brine from this process will be used to produce sample lithium carbonate for testing by potential offtake partners and investors.”
Work to design process flow chart
This forms part of Anson’s test work to design a process flow chart for the recovery of lithium and other minerals from the supersaturated brines and to assist in fast-tracking the project into production.
On-site tests were carried out on a bulk sample extracted from the Cane Creek 32-1 well.
The pond evaporation tests were carried out on-site where the daily temperature ranged from 13 to 39 degrees Celsius, with 12 hours of sunlight and rainfall occurring on some days.
The metals concentration in the solution during evaporation. Sodium and potassium concentrations decreased,
precipitating out as chloride salts.
These conditions result in the water temperature of the ponds varying compared to the laboratory’s constant temperature and explains why evaporation is slower than in the laboratory.
The lithium values during the evaporation test work were assayed both in the saturated brine and the crystal salts by standard lithium assay methods.
The precipitated crystals also entrap the crystallising mother liquor and some lithium in it.
As in regular mineral processing, the lithium in the crystals can be extracted by further processing.
Data from the ongoing tests will assist in developing a process flowchart to optimise production of lithium and other minerals.
In addition to the option of utilising evaporation ponds, the company is conducting tests using other extraction techniques.
A comparison of the increase in concentrations for the laboratory and pond tests over time.
The on-site test work has continued but the ponds are drying up.
This may cause the lithium concentration to plateau as it did in the bench-top test work.
READ: Anson Resources test work shows grades of lithium and boron rising higher
Unlike the lab work the concentrated brine can’t be combined and the evaporation cycle continued with the current configuration of the ponds.
However, the concentrated brine will be extracted and sent to the metallurgical laboratories carrying out the lithium carbonate production test work.
Test work will be conducted at these laboratories to determine the benefit of a higher lithium feed grade of around 398ppm compared to that at time of extraction.