Spain and Portugal together with France, Belgium, Luxemburg and Federal Republic of Germany are known to have occurrences of EU-bearing monazite. The main objective is the economic recovery of the European monazite sands (and its primary stages of concentration) by means of high technical efficiency and sustainable procedures, in order to achieve maximum added value from their rare earths content. Matamulas (Ciudad Real) monazite sands in Spain may be the first profitable monazite rare earth deposit in Europe. Matamulas ore deposit but also other European ores could be incorporated as a technical application example.
- Compilation of monazite sand deposits worldwide will be reviewed and feasibility study and technological use of rare earth (RE) from medium to long term. Monazite sands deposits will be compared with other rare earths sources.
- Physical survey, economic and strategic assessment of monazite sands resources in the European Union addressed to added value, either for their rare earth concentration or their potential development. To consider Matamulas deposit as a major source of rare earths in the European context of raw material supply.
- Determination of the environmental impacts inherent to monazite sands processing and setting up corrective measures according to the European regulatory context. Application of these rules to the Matamulas deposit and others that could arise during the research stages. Determination of corrective-predictive-preventive environmental actions:
• Detection of environmental impacts associated with mining, mineral processing and metallurgy of monazite sands;
• Description of remediation actions;
• Treatment of radioactive minerals.
- Selection of the best available technologies (BAT) addressed to the recovery of rare earths from the Hercynian Arc. Determination of the most appropriate hydrometallurgical design.
- Geological research and mineralogical survey of monazite ores, focused in final processes performance (solubilization and extraction of rare earths contained in the ore). Determination of the parameters and preliminar conditions of both the minerallurgical and metallurgical concentration process.
- Improvement or adequacy of the BAT application aimed to one or more ore deposits in Europe by means of laboratory, batch and pilot tests in order to get preliminary parameters related with final products (carbonate, hidroxide or oxalate type).
- Preliminary separation tests to extract oxide/carbonate products from the monazite ores in order to define the process flowsheet (definition of operating parameters) and the industrial engineering design.
- Pilot Plant Construction and Process Flowsheet:
Usual metallurgical treatment of an alluvial material comprises two main plants, a concentration plant at the mine site producing heavy mineral concentrate of REO (rare-earth oxides) -bearing minerals together with ilmenite (Fe2TiO3) and zircon concentrates, and a refinery (located adjacent to the concentration plant) which treats the REO mineral concentrate to produce a mixed RE carbonate plus (usually y) a small amount of uranium concentrate.
Both plants are quite conventional with the mine site plants incorporating standard mineral sands mineral dressing techniques while the refinery utilizes conventional sulphate roasting, water leach purification steps and product recovery using precipitation with carbonate. Also it is planned testing more innovative systems and improvements in the circuit.
The mine site concentration plant entails treating the mined material through a wet separation plant followed by a dry separation plant to produce a REO. The initial stages comprise a simple material preparation plant to remove relatively barren coarse material as well as troublesome fines or ‘slimes’. Gravity recovery processes such as spirals are then utilised to upgrade the wet concentrates. The Dry Plant utilizes magnetic and electrostatic characteristics of the minerals to produce a ‘clean’ REO-bearing mineral concentrate at about 40% REO grade.
Various precipitation steps then follow that allow removal of unwanted iron, thorium and phosphorous, recovery of uranium concentrates and recovery of the RE elements as a mixed RE carbonate.
It is planned to process a large bulk sample (~1,000kg) from each ore tested (including Matamulas deposit) through the trommelling and slimes rejection as well as the spirals and dry plant tests using induced rolls and magnetic separation.
- Recovery of new rare earth deposits as green fields (advantages, disadvantages)
- Value enhancement of brown fields resources: The Matamulas deposit contains 20 000 t of potential rare earth oxides, with the possibility of expansion, in terms of economic recovery and sustainable mining.
- Technical improvements applicable for other conventional deposits, mainly applied to the final stages of the processing (hidrometallurgy), rare earth extraction and precipitation as carbonates and if possible oxides separation.
- Important reduction on rare earths dependency in the supply to the European Union. Production forecasted is estimated on 1 000 to 2 000 t per year (oxide form), reaching almost 3% of the European Union needs.
- Increasing rare earths treatment capacity within European Union taking in account that technological development is no important or almost nonexistent. Also is considered an important technological development impact.
- Employment available opportunities by skills requirements due to the new processing plants (direct and indirect employment)
- The processing of the monazitic sands is itself an innovation related with the rare earths production, broading the recovery of this type ores.
- The metallurgy of rare earths monazite sands requires an improvement in solubilization process suitable to their characteristics, and the definition of the recovery method specific for each ore type.
- Economical oxides separation from precipitation concentrates would also result in a real innovation, both in technological terms and environmental focus.
This project is totally innovative and appropriate because it uses minerals resources of rare earth that haven't be used until now. In Europe will have several opportunities in the next futures years. Also, one of the main project's objectives is involved about the use of the well know Matamulas deposit located in the province of Ciudad Real (Spain).
The Universidad Politécnica de Madrid (UPM) through its School of Mines will be responsible for coordinating the project where both engineering firms and other university entity as the Instituto Superior de Engenharia do Porto are included. The UPM will coordinate actions related both the objectives formulation within the inventory of European monazite sands and its valuation methodology. UPM also will be responsible for the first definition of actions and pilot tests on RE concentrates from mineral deposits chosen for their special potential importance, such as the Matamulas ore in Ciudad Real, Spain. The UPM will be responsible for ensuring the project quality and meeting deadlines.