EXTRAVAN: developing innovative technologies to extract vanadium resources in Europe
The EXTRAVAN project is developing innovative technologies for cost-efficient vanadium extraction that will limit associated impacts on the environment.
The project worked on resources of two types:
- BOF-slag, which has a vanadium content of around 1.5 - 3%,
- V-slag, which has vanadium concentrations of more than 10% and is produced from vanadium-rich concentrated iron ore co-processed with steel slag.
Innovation for Europe's economy and European industry
EXTRAVAN's scientific teams studied and developed innovations for the processing stages in which vanadium is recovered from steel slag, to improve technical and economic feasibility. The results are promising and open up prospects for advances not only in technical innovation but also in economic and environmental aspects.
Innovative extraction processes
The technical innovations developed for both types of resources investigated by the EXTRAVAN project, BOF-slag and V-slag, open up prospects for vanadium recovery from numerous resources in Europe.
Carbo-oxy-chloruration, a breakthrough process for vanadium extraction from BOF-slag, was developed by the BRGM. This is a selective process for producing water-soluble vanadium chlorides from the chlorine released by thermal decomposition of PVC. The process can therefore be used to recover both vanadium and the chlorine released by PVC waste incineration. The project obtained vanadium extraction rates above 95% in the laboratory.
The project partners developed a High Temperature Roasting (HTR) process to extract vanadium from V-slag. This reduces processing time by a factor of ten, and recovers 97% of the vanadium. The project teams also optimised lixiviation and selective precipitation conditions.
Although not all vanadium extraction techniques have reached the same level of maturity, they are complementary and offer recovery solutions from a range of resource types in Europe. Particular attention was also given to the waste materials and effluent produced throughout the processing chain, to put forward management solutions that can minimise environmental impacts.
Towards new economic prospects and better waste recycling in Europe
The results of the EXTRAVAN project open up prospects for better use of vanadium-rich steel slag, only half of which is currently re-used as a road-bed material, while the other half goes to landfill, as does PVC waste.
New technologies for vanadium recovery would reduce Europe's dependence on imports, and would also enable industries to take up positions on the market for processed waste from iron and steel smelting.
The EXTRAVAN project was financed by three European funding agencies under the European ERA-MIN programme for sustainable production of raw materials in Europe: Vinnova (Sweden), ADEME (France) and Tekes (Finland).
The project was run by the BRGM, GTK, the Finnish mining company Mustavaaran Kaivos Oy and KTH, and coordinated by the Swedish research institute Swerea MEFOS.
Vanadium production and use around the world
Vanadium is a hard metal mainly used in the manufacture of special high-resistance steel. It is a strategic metal for Europe's industries, which use about 13% of worldwide production (11kt en 2013).
Vanadium is found in certain iron ores. The main centres of production are outside the EU, in South Africa, Russia and Australia.
Vanadium resources in Europe
Although Europe has some vanadium resources, these are mainly deposits of titanium-bearing iron ore containing about 1% of vanadium, or steel slag containing up to 3%. Mining these resources is not economically viable and Europe is therefore highly dependent on vanadium imports, with attendant risks of supply disruptions.
Two stages in vanadium extraction
Vanadium is usually recovered after iron is extracted from the ore. Processing occurs in two stages:
- Roasting with sodium carbonate to form water-soluble vanadium compounds that can then be extracted,
- A series of hydrometallurgical processes (including lixiviation and selective precipitation) are then applied to recover the vanadium selectively.