Fertiliser project looks at salt sideline

31 Mar, 2018 04:00 AM

A WELL-advanced Sulphate of Potash (SoP) fertiliser project in the Little Sandy Desert will be assessed for sodium chloride (NaCl) salt production as a by-product.

Kalium Lakes Limited (KLL), which hopes to begin producing three SoP fertiliser products early next year at its Beyondie project based on a chain of salt lakes 160 kilometres south east of Newman, has signed a letter of intent with WA Salt Koolyanobbing.

The agreement to evaluate possible NaCl production as a by-product of SoP production, is similar to an agreement KLL has with another company to investigate the recovery of high-purity hydrated magnesium carbonate (HMC) from residual brines in evaporation ponds at Beyondie.

As previously reported in Farm Weekly, EcoMag Ltd has successfully produced 99.5 per cent pure HMC at its Karratha facility with overall magnesium recovery exceeding 95pc from a brine feedstock, with magnesium content of 8 to 9pc supplied by KLL from Beyondie.

WA Salt Koolyanobbing is part of the WA Salt Group and mines NaCl at Lake Deborah, north of Southern Cross, producing a range of food grade salts, specialised industrial and swimming pool salts and filter materials at its North Coogee salt refinery.

Commercial recovery of both NaCl and HMC at Beyondie will further improve the potential revenue stream from the project, KLL said last week in notifying the Australian Securities Exchange (ASX) of its agreement with WA Salt, but is not critical to the project.

KLL is due to complete a final feasibility study for its Beyondie SoP project in the third quarter this year.

It then plans to ramp up the pumping of brine from beneath the salt lakes and trial harvesting of mixed salts, including NaCl and HMC, precipitated sequentially at its large-scale gravity-flow evaporation ponds, to full-scale production of either 75,000 or 150,000 tonnes of SoP a year, depending on whether a staged commercial start-up is decided on.

Last week KLL told the ASX salt harvest testing so far on its plastic-lined evaporation ponds built adjacent to the lakes had indicated deposition of a 100-150 millimetre protective salt layer on the bottom of the ponds was necessary to protect pond liners during harvest operations.

While this layer took three-six months to develop before salts that could be harvested started accumulating on top, KLL said it represented “a significant time saving of at least 12 months” to first SoP production compared to evaporation ponds built on salt or clay-based lake surfaces.

Bench-marking with Dampier Salt had indicated a 400 millimetres salt layer was needed to make on-lake evaporation ponds trafficable by harvest equipment and that would take about 18 months to accumulate, KLL said.

KLL is one of five Perth-based companies in a race to produce SoP fertiliser from brine beneath salt lakes in remote WA locations but its closest competitors have built or intend to build their trial evaporation ponds on-lake because it is a cheaper construction option.

But on-lake ponds require brine to be pumped between ponds because gravity flow is not achievable on the flat lake surface.

Australia imports all of the 40,000t of SoP fertiliser currently used on high-value horticulture crops because of its price premium over alternative fertilisers, but it is estimated usage could increase to about 70,000t and extend to some broadacre crops in salt affected areas if it can be produced more cheaply locally.

On projected production targets, the first of the five companies to produce SoP will potentially corner all of the Australian market, worth about $38 million a year currently, plus a potential significant export share of a global market worth US$60 billion ($78b) a year and growing by about 5pc a year since 2012.

KLL told the ASX that in the past seven months, 164m litres of brine have been pumped in trials at Beyondie, with 83m litres pumped into the evaporation ponds.

More than 10,000t of salts have been produced so far, including 3160t of mixed potassium salts that can be processed into about 520t of SoP, KLL said.

Its tests have shown harvested potassium salts contain about 7.5pc potassium oxide, so seven tonnes of salts will produce one tonne of SoP when treated in a purification plant to remove residual sodium, magnesium and chloride salts.

Its evaporation pond trials have also produced more than 3000t of NaCl – salt growth in each of the 11 ponds varied in thickness from 95mm to 305mm during the seven-month trial period.

KLL said mixed salts will need to be harvested from the evaporation ponds, whether commercial off-take uses are found for them or not, to prevent the ponds gradually filling with salts and to avoid expensive earthworks later on to raise the height of pond walls.

Harvest trials are continuing using a grader, harvester similar in principle to a grain header, and a tracked chaser bin.

KLL managing director Brett Hazelden said the large-scale ponds, equivalent to about five Melbourne Cricket Grounds in area, have enabled the company to test all aspects of its proposal to accumulate and evaporate potassium-rich brine.

“It has enabled Kalium Lakes to assess pump and pipe requirements from bores and trenches, determine pond design parameters to achieve a fully gravity fed system, observe brine evaporation behaviour and measure salt crystallisation and growth, test harvesting techniques and identify maintenance requirements,” Mr Hazelden said.

“These are the largest-scale pilot pond trials in Australia, which provide government agencies, investors and prospective debt financiers with a high level of certainty on scale up parameters that are being included in the bankable feasibility study,” he said.

Testing of bulk samples of NaCl is also continuing after initial samples showed sufficiently high NaCl concentrations

WA Salt Group chief executive officer Lelio Gaudieri said he viewed the letter of intent as a first step in “an assessment that could deliver benefits for both our businesses”.

“A reliable source of high quality NaCl could potentially represent an attractive commercial opportunity,” Mr Gaudieri said.

KLL has said it intends to produce a premium fertiliser, granular fertiliser and horticulture grade soluble fertiliser comprising 51-52pc potassium oxide and less than 0.5pc chloride and insoluble material.



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