A PREMIUM Sulphate of Potash (SoP) fertiliser comprising 51-52 per cent potassium oxide with less than 0.5pc chloride and insoluble material is the aim of one of two companies working to produce SoP locally from next year.
Kalium Lakes Limited (KLL) last week announced duplicated production trials in Germany and Canada, using harvest salts from its Beyondie SoP project based on a string of salt lakes on Kumarina pastoral lease 160 kilometres south east of Newman, confirmed the potential high quality.
“Optimisation” work for batch trials using more than a tonne of salts from pilot evaporation ponds at Beyondie, in the Little Sandy Desert 70 kilometres east of the Great Northern Highway, also confirmed individual batch recovery rates between 90 and 98pc, it said.
The trials conducted by K-UTEC, the privatised former Germany potash industry research and development organisation, and Saskatchawan Research Council confirmed a potential overall SoP recovery rate of better than 80pc, allowing for possible pond leakage and harvest losses, KLL said.
Ongoing trials using a further eight tonnes of salts from Beyondie are continuing with KLL having said it aims to produce a suite of three commercial SoP products for domestic and export markets from next year - a premium fertiliser, granular fertiliser and horticulture grade soluble fertiliser.
It said trial results so far exceeded production quality and quantity assumptions used in a pre-feasibility study completed last year.
As previously reported, Perth-based KLL has negotiated two Native Title agreements and spent three years working with State and Federal environment authorities towards approvals expected in the third quarter this year for the project.
It recently applied for mining tenure for stage one which it expects to receive in the current quarter.
It intends to then progress to a construction phase with mining start-up in the second half of this year.
A modular processing plant for the project has been designed by K-UTEC.
High potassium content brine pumped from beneath salt lakes will be gravity flowed through a sequence of lined evaporation ponds where calcium, sodium, potassium and magnesium mixed salts will be sequentially precipitated in separate ponds.
Crystallised salts will be mechanically harvested and stockpiled for treatment in a natural gas-fired purification plant to convert potassium salts into schoenite and separated from halite through a conversion and recycling process.
The schoenite slurry will be heat treated, dried and compacted into a commercial SoP fertiliser ready for bulk sale or export via Geraldton port about 800 kilometres away.
Managing director Brett Hazelden said duplicating test work in Germany and Canada allowed KLL to “independently verify and optimise the repeatability” of the proposed flow sheet.
“Utilising salts from our large scale pilot evaporation ponds has allowed us to produce representative mixed potassium salt samples which have then been used to optimise the process,” Mr Hazelden said.
“The results to date have been considerably better than our pre-feasibility assumptions and we have continued to improve the final SoP product quality.
“We are now moving to the final phase of testing and optimisation with a further eight tonnes of material harvested and sent to the two international facilities.
“This material will provide bulk samples for equipment vendor testing to enable process guarantees to be put in place, as well as producing marketing samples for potential off-take customers,” he said.
KLL has a memorandum of understanding (MoU) with Yunnan Jing Yi Feng Supply Chain Management Co Ltd (JYF), a major Chinese chemicals and fertiliser distributor, to sell 50,000-80,000 tonnes of its SoP products a year to customers in Yunnan, Guizhou and Sichuan provinces in south-west China.
It also has a similar non-binding take-off agreement with Hamburg, Germany-based global bulk and containerised commodity and specialty fertiliser marketing and distribution giant, Wittraco Düngmittel GmbH, for 20 per cent of the Beyondie project’s annual SoP output during its first five years.
KLL has said its life-of-mine calculations are based on annual SoP production of 150,000 tonnes but it has not yet announced whether it will choose a lower cost less risky staged start-up option of 75,000t a year.
As well as SoP production proposed to begin next year, trials conducted with EcoMag Ltd to recover high purity hydrated magnesium carbonate (HMC) from residual brines in KLL’s evaporation ponds at Beyondie have also proved successful.
Mr Hazelden said larger scale trials processing brine from the Beyondie evaporation ponds at EcoMag’s Karratha facility had confirmed initial laboratory results from last year.
The pilot plant produced 99.5pc pure HMC, with overall magnesium recovery exceeding 95pc from a brine feedstock with magnesium content of 8 to 9pc provided by KLL.
HMC is used in a range of applications, including chemically-toughened glass and fire retardants, and may in future be used in new-generation magnesium batteries.
Its recovery will add a further level of profitability to the Beyondie project, Mr Hazelden said.
KLL also has a joint exploration venture with BCI Minerals Ltd based on Lake Carnegie, about 220 kilometres north-east of Wiluna, where preliminary bore holes and test pump sampling has indicated the brine is potentially suitable for SoP production.
Australian Potash Ltd (Australian Securities Exchange code APC) last month in an investor presentation said it was also aiming to produce SoP fertiliser from remote salt lake brine next year.
But based on proposed timelines in its presentation, APC looks likely to be the second Perth-based company to produce SoP locally.
It plans to complete long-term pump testing and initial evaporation pond trials by producing a SoP sample from harvest salts in the first half of this year at its Lake Wells project 160 kilometres north-east of Laverton.
It also plans to provide SoP samples to two major Chinese fertiliser companies, Hubei Agricultural Means of Production Group and Sino-Agri Holdings Company, and later this year hopes to convert MoUs with them into firm supply contracts.
APC will also engage in what it describes as a “marketing roadshow” to the United States of America, UK, Europe and Asia to promote its potential products.
A feasibility study on the project is expected to be completed and environmental approvals received in the second half of this year.
APC has not defined particular commercial SoP products it intends producing from Lake Wells brine but has estimated initial production of SoP at 150,000 tonnes a year ramping up to 300,000.
It intends trucking its product to a railhead near Leonora then railing it to either Kwinana or Esperance ports for export.
A third Perth-based company, Agrimin (AMN), is targeting SoP fertiliser production for 2021 at its Lake MacKay project on the WA/Northern Territory border 500 kilometres east of Alice Springs.
Last month in an investor update it said it planned to complete a pre-feasibility study in the second quarter this year.
It is proposing annual production of 370,000 tonnes of SoP.
With a brine resource only 0.4 of a metre below the salt crust at Lake MacKay, WA’s biggest salt lake, AMN is proposing to collect brine in trenches rather than pump it from bores through the crust as proposed at Beyondie and Lake Wells.
Australia currently imports all of its SoP fertiliser, about 40,000t per annum, which sells bulk for up to $950 a tonne, but its usage is predicted to grow to 70,000t/pa or more if it can be produced more cheaply locally.
SoP sells for about US$500/t on a global market estimated to be worth US$60 billion a year and growing about 5pc a year since 2012.
