Vametco Processing Plant Visit

January 2019


4 February 2019

Following our enthralling tour of the Vametco mine, we continued on to the Vametco processing plant. Before we dive into the detailed processing sequence covered within this article, it is recommended readers take a look at Ophidian's outline of Vametco Processing for some helpful background information. 

Vametco is a highly sophisticated chemical processing plant. It may surprise readers to know that Vametco employs a more sophisticated processing operation than Largo (who produce V2O5 only) and Rhovan ( producers of V2O5 and a smaller volume of FerroVanadium). Vametco produces the highly efficient, patented product Nitrovan (Vanadium Carbonitride) and FerroVanadium and, at different stages of the process also produces Ammonium Metavanadate and Modified Vanadium Oxide (MVO/V2O3). The latter of these intermediate compounds - MVO, may be of particular relevance to VRFB electrolyte production. We shall return to this point in future articles. 

Looking at the diagrammatic view of Vametco's process shown below, the majority of mines processing for other minerals would typically adopt a process up to stage 4. Vametco's process incorporates a number of further steps to produce a more nuanced and diverse product range. 

Due to time constraints we were not permitted to inspect the entirety of Vametco's processing facilities however the approximate location of each stage of production is shown below for reference. 

The grinding circuit (1) is easily identified by the stockpiles created during each stage of grinding. Wet magnetic separation (2) seems to occur in the building with the three yellow horizontal stripes at the left rear. Once complete, the non-magnetic material is transported to the large beneficiation tailings mound (3) whilst the black Magnetite material which contains the V2O5 is clearly the very dark stockpile at (4). 

The Magnetite containing V2O5 is then fed into the 4.8m diameter, 60m long rotary kiln (5) which is the most recognisable feature of this and all other primary Vanadium processing plants, shown in the image below. 

Magnetite, Sodium Sulphate and Sodium Carbonate are fed into the kiln on the left hand side - by the visible chimney - whilst powderised coal is blown in at the other end. The coal dust is immediately ignited and driven through the kiln by the pressure of a large fan (I suggest that this is located on the right hand, cold, side). Magnetite and Sodium salts are then engulfed by the burning coal dust and get heated to a balmy 1,150 celsius. The right hand end of the kiln is deliberately slightly lower than the left in order to ensure that the hot solids created from this reaction proceed to propagate slowly along the kiln as it rotates. 

The chimney shown in the image above exhausts only steam. Significant work has recently been undertaken to improve the emissions for regulatory reasons. Comparisons with historic imagery here demonstrate that the chimney appears to have been completely replaced. There are now also a number of new constructions visible at the chimney end of the kiln which suggest a new 'off-gas' scrubbing circuit.

Upon leaving the kiln, (via the grey/green building shown above), the hot solids are mixed with water and cooled. This takes place in the second lighter coloured rotating barrel which can be located in the image above, just next to the 'stop' sign. Following the high temperature salt-roast process in the kiln the Vanadium contained within the mixture is now in the form of Sodium Metavanadate which dissolves readily in the cooling water. At this point the process has created a solution which contains all the Vanadium, whilst all the remaining Magnetite (Fe3O4), Titanium Dioxide and other minerals are separated and left as solids. These solids are subsequently dried and then carted away to the leach tailings pile at (6) (one careful owner, buyer collects etc, ring Fortune not me).

The 'pregnant' solution containing Vanadium is then pumped to the precipitation plant at point (7) where mixed with Ammonium Sulphate it now precipitates out of solution as Ammonium Metavanadate. Buildings to the north and west (8) of this then undertake further processing steps - Logically, the building midway between points (7) and (4) must be the sulphate recovery plant as that would deposit the solid sodium sulphate close to the entry point of the rotary kiln -  precisely where it is needed.

Modified Vanadium Oxide (MVO) is then created by reduction of the solid Ammonium Metavanadate, potentially located at position (8). There the MVO is mixed with around 20% carbon, formed into briquettes and fed into the Nitrogen shaft furnace where Nitrogen gas is introduced into the briquettes in a controlled way to act as a substitute for the carbon. This approach yields two grades of Nitrovan® - 12 and 16. Both grades contain approximately 76-81% Vanadium. Nitrovan® 12 however contains 10-14% Nitrogen and up to 10% Carbon whilst briquettes of Nitrovan® 16, perhaps benefiting from being cooked hotter or longer, contain 14-19% Nitrogen and no more than 6% Carbon.

As part of Vametco's quality control processes, each batch of briquettes is rigorously tested in the on-site laboratory for Vanadium, Carbon, Oxygen and Nitrogen content, plus 8 other 'impurity' elements. Different batches of briquettes are, similarly to an export whisky, blended together to make batches that meet the precise specifications of Nitrovan® 12 and 16. The perfectly mixed briquettes are then packed into sealed, moisture resistant paper bags in building (9), measured in lbs for US and Kg and KgV for everyone else. The choice of packaging ensures ease of transport, measurement and a straightforward method of managing orders of different sizes. Similarly to bags of instant barbecue coals, the bags also burn easily meaning you can add the bagged, weighed Nitrovan directly into a steel furnace, creating a simple process with minimal waste. Once packaged, bags of Nitrovan are then loaded into wooden 1.5Tonne palleted boxes that can be forklifted into shipping containers. Each wooden box contains just over a tonne of Vanadium - currently worth about USD 80,000 at today's prices.

Visiting Vametco delivered many fascinating insights, not least a sense of the impressive scale of the operation. It is also very apparent that alongside improved geological controls within the mine area there is also a significant transformation underway for the processing plant. Evidently a major amount of production (I heard a figure of 30% of the lost expected production) was lost this year due to ongoing improvement and maintenance operations. Simply put, the plant needed some long overdue TLC. However it is worth noting that the result of this work will be a far more effective, efficient and crucially, reliable plant for the important and exciting years of growth ahead.   

For context, it should be noted that Vametco is a facility that is older than many of our BMN investment community. However, as detailed in  the previous article relating to this visit the legacy owners ran Vametco with a process built upon adding high grade Vanadium slag from their smelting operations to the run of mine ore. The resultant effect was that much of the plant, and perhaps most importantly the kiln, was not run with as much material passing through it as it now is. As a result it may have been possible for the previous operators to ignore regular maintenance operations that would in any other circumstance have been considered a necessity.

Finally, and in conclusion to this article, we are now able to answer a question that has long been discussed within our community;

'Why does Nitrovan® currently only receive a relatively small premium of 5-10% compared with FerroVanadium, despite being some 40% more effective?'

Surprisingly, it appears that previous plant owners Evraz, had deliberately chosen to price Nitrovan® and Ferrovanadium, (which they also produced at a number of other locations), at identical prices. It is suggested that this was perhaps to avoid undue extra demand for the better quality Nitrovan®.

As the world's appetite for safe construction and higher quality steel rebar increases and steelmakers discover they improve efficiency and reduce costs with Nitrovan® we should expect premiums to increase.  It can be hypothesised that an extended period of high Vanadium prices may naturally accelerate a deepening market reappreciation of Nitrovan®.

Go to part 3 (Eskom Battery Test Site) ...

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