Pyro-metallurgy Update: Vanadium Test Results -
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19 June 2014 |
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Bushveld Minerals Ltd
("Bushveld" or the "Company")
Bushveld Vanadium Project
Pyro-metallurgy Update: Salt Roast Test Results - Vanadium Extraction Tests
Bushveld Minerals Limited (AIM: BMN), a diversified mineral development company with projects in Africa, is pleased to provide an update on pyro-metallurgical testwork at its Vanadium Project in Limpopo Province, South Africa.
As recently reported, Bushveld has been conducting a pyro-metallurgical testwork programme for the beneficiation of the Main Magnetite Layer (MML) as part of the Scoping Study for the Bushveld Vanadium Project. The test work evaluated two alternative processing routes: a) the salt roast process to produce vanadium pentoxide flakes and/or ferrovanadium and b) the smelting route to produce pig iron or steel and high-grade vanadium slag.
The Company announced encouraging results from a modelling exercise conducted on the MML using the smelting route on 11 June 2014. Bushveld has since completed physical laboratory-scale testing of vanadium extraction from the ore via the salt-roast route.
Highlights:
The vanadium extraction tests were conducted on concentrates from the MML Deposit by Mintek (South Africa) for the production of a vanadium pentoxide product and yielded the following results:
· Up to 86% recoveries for vanadium extraction at 1200° C using a NaCO3 (sodium carbonate salt) roast;
· Up to 79% recoveries for vanadium extraction using a NaSO4 (sodium sulphate salt) roast;
· NaCO3 roast tests were conducted on a matrix of temperatures and duration to determine optimal roast times;
· Recoveries match values predicted during independent modelling by Hatch Goba; and
· Predicted overall vanadium recovery of 74% in the plant, including downstream precipitation of the vanadate solution.
Fortune Mojapelo, CEO of Bushveld Minerals, said: "Having reported the results of the modelling exercise undertaken on the smelting processing route last week, we are pleased that results from the salt roast route, including lab-scale vanadium extraction, prove we have two viable processing options to consider.
Both of these processes are proven and in operation using ore similar to that within the MML, which is obviously encouraging. We look forward to building on these results in our Scoping Study which is underway and expected out in the coming months."
BENEFICIATION OF THE MML
For the beneficiation of MML ore Bushveld is considering two processing routes, namely:
· Smelting of pre-reduced MML ore, followed by the recovery of high-grade vanadium slag and a pig iron product. Results of a modelling exercise on this flow sheet demonstrated scope to produce a pig iron product and a high grade (>24% V2O5) vanadium slag (announced 11 June 2014).
· Salt-roasting followed by leaching to produce vanadium pentoxide and, if further beneficiated, ferrovanadium. The salt-roasting process is the standard flowsheet used for the production of vanadium pentoxide, as used by Glencore at its Rhovan Vanadium Mine near Rustenburg, North-West Province, South Africa.
Bushveld below summarises the results of the test work conducted on the salt roast process route.
Although not necessary for a Scoping-Study, the Company has conducted physical laboratory-scale salt-roasting and leaching tests on concentrates produced from the MML ore. In so doing, the Company intends to confirm theoretical predictions of vanadium extraction, and to enable a rapid progression from a Scoping Study to a Pre-Feasibility Study. A sample of concentrate was produced at SGS Laboratories in Johannesburg using Low-Intensity Magnetic Separation (LIMS) at a -45 µm grind size. Subsequently, the Pyro-metallurgy Division of Mintek in Johannesburg, South Africa, carried out roasting and leaching tests. In addition, these results confirmed the outcomes of independent modelling of vanadium extraction carried out by Hatch Goba, the metallurgical consultants to the project.
Vanadium roasting and leaching tests were conducted using both NaCO3 and Na2SO4. For roasting, magnetite concentrates were mixed with a saturated sodium salt solution in a ratio of 100:6.91, dried, and then roasted in a muffle furnace. Following roasting, products were leached by boiling in water (1.66:1 liquid:solid ratio) and then filtered, and mass losses recorded. Both residues and products underwent chemical assaying to determine extraction efficiency.
Tests using NaCO3 occurred at a range of temperatures between 900° C and 1200° C, for time periods ranging between 45 minutes and 180 minutes.
A summary of the test results is shown below:
|
Temperature (° C) |
Time (minutes) |
Vanadium extraction (based on residue) |
Vanadium extraction (based on solution) |
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900 |
45 |
67.31 |
53.9 |
|
900 |
120 |
67.33 |
57.3 |
|
900 |
180 |
66.31 |
56.0 |
|
1000 |
45 |
70.12 |
59.6 |
|
1000 |
120 |
73.70 |
61.2 |
|
1000 |
180 |
71.82 |
60.8 |
|
1100 |
45 |
85.59 |
78.3 |
|
1100 |
120 |
86.52 |
70.6 |
|
1100 |
120 |
83.88 |
|
|
1100 |
180 |
76.37 |
55.7 |
|
1200 |
45 |
77.70 |
60.8 |
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1200 1200 |
120 |
86.11 |
67.8 |
|
1200 |
180 |
85.28 |
70.1 |
Following these tests, 120 minutes was identified as the optimal time for tests to be run, and roasting tests were carried out using NaSO4 at a range of temperatures for 120 minutes. These test results are shown below:
|
Temperature (° C) |
Time (minutes) |
Vanadium extraction (based on residue) |
Vanadium extraction (based on solution) |
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900 |
120 |
57.36 |
44.3 |
|
1000 |
120 |
61.10 |
49.7 |
|
1100 |
120 |
73.00 |
61.3 |
|
1200 |
120 |
79.42 |
67.0 |
An independent model of vanadium extraction from the MML concentrate was based on similar vanadium extraction operations currently in operation. This model predicts an 83% recovery for vanadium conversion through roasting, and applies a 93% recovery during leaching, with 3% downstream losses during purification of the leached vanadium, for an overall vanadium recovery of 74%.
Bushveld will provide further pyro-metallurgical and Scoping Study updates for its MML deposit in due course.
For more information please contact:
Enquiries: info@bushveldminerals.com
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Bushveld Minerals Fortune Mojapelo |
+27 (0) 11 268 6555 |
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Strand Hanson Andrew Emmott |
+44 (0) 20 7409 3494 |
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Fox Davies Jonathan Evans |
+44 (0) 20 3463 5000 |
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RFC Ambrian Jonathan Williams |
+44 (0) 20 3440 6800 |
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Tavistock Communications Jos Simson/ Nuala Gallagher |
+44 (0) 20 7920 3150 |
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Tielle Communications Stéphanie Leclercq |
+27 (0) 83 307 7587 |
- ENDS -
Notes to the editor
Bushveld Minerals Limited is a mineral development company with a portfolio of vanadium-and titanium bearing iron ore and tin assets in Southern Africa. The Company owns the Bushveld Iron Ore Project and Mokopane Tin Project, both located on the northern limb of the Bushveld Complex, South Africa. In addition, Bushveld has a controlling 52.22% interest in Lemur Resources (ASX: LMR), that owns the Imaloto coal project in Madagascar.
Bushveld was admitted to the AIM Market of the London Stock Exchange in March 2012.
This information is provided by RNS
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