Pyro-metallurgy Update: Vanadium Test Results -

RNS Number : 0071K

Bushveld Minerals Limited

19 June 2014

 



19 June 2014

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)
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
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)
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: [e-mail]

Bushveld Minerals Fortune Mojapelo	[phone]
Strand Hanson Andrew Emmott	[phone]
Fox Davies Jonathan Evans	[phone]
RFC Ambrian Jonathan Williams	[phone]
Tavistock Communications Jos Simson/ Nuala Gallagher	[phone]
Tielle Communications Stéphanie Leclercq	[phone]

- 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.

 

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