98% of cobalt successfully leached from cobalt hydroxide material in preliminary testing with solvent extraction processes used to further remove deleterious elements
Cobalt extraction tests have begun and will be followed by sulphate crystallization to produce cobalt sulphate; results expected by the end of the quarter
Potential to increase plant throughput through the exclusion of the autoclave circuit
Trent Mell, President & Chief Executive Officer, commented:
Today's results give us further confidence that the First Cobalt Refinery flowsheet can produce cobalt to supply the North American market. Having achieved this milestone, we are driving ahead with the next phase of testing including the production of cobalt sulphate, which we expect to have completed before the end of the quarter. The lower price of cobalt hydroxide on the market today points to increased margin potential through upgrading readily available supply of cobalt intermediates. We continue to explore sources of non-equity capital to finance the recommissioning of the Refinery, which could provide cash to finance future work at our flagship Iron Creek Cobalt Project in Idaho, USA.
In late 2018, SGS Canada was engaged to test cobalt hydroxide with the existing flowsheet of the First Cobalt Refinery to determine whether cobalt hydroxide could be suitable feedstock for the Refinery (see November 8, 2018 press release). The existing flowsheet includes an autoclave circuit and a number of solvent extraction (SX) processes for treating various elements, as well as product precipitation and filtration stages. The testing by SGS Canada simulates these circuits to determine the ability to process cobalt hydroxide into cobalt sulphate heptahydrate (cobalt sulphate), a critical component of lithium-ion batteries.
Initial testing successfully leached 98% of cobalt from the cobalt hydroxide and further improved leach liquor quality through the removal of deleterious elements using an impurity SX step. SGS Canada will now test an additional SX process for cobalt extraction, to be followed by polishing to remove remaining impurities and then sulphate crystallization to produce cobalt sulphate.
The cobalt hydroxide currently being tested has head grades in excess of 20% cobalt and would not require the Refinery's autoclave to be reactivated, providing encouragement for higher production potential than projected in an independent study prepared by Primero Group. On October 10, 2018, the Company announced the results of three studies undertaken to estimate capital requirements, operating costs, permit renewal timelines, potential feedstock options and offtake opportunities. The study by Primero Group to estimate capital requirements and operating costs assumed the Refinery's hydrometallurgical autoclave system would be used to process arsenic-rich ores with head grades of up to 15% cobalt. Under this base case scenario, a feed rate of 24 tonnes per day was assumed, yielding annual production of 1,063 tonnes of cobalt per annum. The autoclave was identified as a potential bottleneck for a higher production rate absent additional capital expenditures. Readers are cautioned that results are preliminary and that additional work, including detailed engineering, will be required to confirm potential nameplate capacity of the First Cobalt Refinery.
The first two stages of testing are intended to determine the efficacy of the leaching process and to closely track deleterious elements throughout the flowsheet to the production of cobalt sulphate, with the overall objective of producing cobalt sulphate for the North American market. The cobalt hydroxide sample tested graded 23.2% Co, 3.45% Mg, 3.27% Mn, 2.4% Fe, 1.6% Cu and 1% Si, while all other deleterious elements graded significantly less than 1% each.
The first leach test sought to leach cobalt from the sample at three different pH levels, 2.5, 2, and 1.5, targeting approximately 10 g/L Co in the resulting leach liquor. The material leached well under atmospheric conditions, implying that the autoclave circuit in the refinery would likely not be required under this scenario. Cobalt concentration in the leach liquor was consistent at all three pH levels tested, ranging from 11.3 to 11.7 g/L Co. At pH 1.5 with 94% of the total sample going into solution and 98% of the cobalt being leached.
To further remove deleterious elements and improve product quality, the initial SX contacts were conducted using D2EHPA as the organic reagent at different pH levels between 3 and 5. These tests separated cleanly with no formation of crud. The manganese level as measured by the ratio of cobalt to manganese had a starting Co:Mn ratio of 14 in solution after releaching. Tests at consecutively higher pH levels were conducted that increased the manganese loading as expected, resulting in 82% of the manganese being removed and yielding a Co:Mn ratio of 68 after a single contact. These impurity SX contacts also removed 99% of Zn and 29% of Ca from the sample.
The Co:Mn ratio that has been achieved is sufficient for this scoping level program to begin the next phase of testing, the extraction of cobalt through another SX process involving loading, scrubbing and stripping tests to upgrade the cobalt purity with the intention of producing cobalt sulphate through cobalt sulphate crystallization. Results of these steps are expected before the end of the quarter.
The First Cobalt Refinery
The First Cobalt Refinery is a hydrometallurgical cobalt refinery in the Canadian Cobalt Camp, approximately 500 kilometres from the US border. The First Cobalt Refinery has the potential to produce either a cobalt sulphate for the lithium-ion battery market or cobalt metal for the North American aerospace industry or other industrial applications. The Company is engaged in discussions with companies specializing in the marketing and sourcing of concentrates to secure sources of ethically produced cobalt as feedstock for the First Cobalt Refinery.
A final decision on whether to put the Refinery back into production has not been made at this time and any decision is contingent on the outcome of the foregoing studies as well as the Company's ability to source viable feedstock.
On October 10, 2018, the Company released the results of three independent studies undertaken to estimate capital requirements, operating costs, permit renewal timelines, potential feedstock options and offtake opportunities. At a 24 tonne per day feed rate and using the current flowsheet, the capital cost of the restart is estimated at US$25.7M (including a 30% contingency) and a permitting review concluded that a restart is possible within 18 months of selecting a feedstock.