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Integrated innovative metallurgical system to benefit efficiently polymetallic, complex and low grade ores and concentrates

Periodic Reporting for period 2 - INTMET (Integrated innovative metallurgical system to benefit efficiently polymetallic, complex and low grade ores and concentrates)

Reporting period: 2017-08-01 to 2019-01-31

INTMET represents a unique technological breakthrough to overcome the limitations related to difficult low grade and complex ores to achieve efficient recovery of valuable metals (Cu, Zn, Pb, Ag) and CRM (Co, In, Sb). Main objective is applying on-site mine-to-metal hydroprocessing of concentrates enhancing substantially raw materials efficiency thanks to increase Cu+Zn+Pb recovery over 60% vs existing selective flotation. Three innovative hydrometallurgical processes (i.e. atmospheric, pressure and bioleaching), and novel more effective metals extraction techniques (e.g. Cu/Zn-SX-EW, chloride media, MSA, etc.) will be developed and tested at relevant environment aiming to maximise metal recovery yield and minimising energy consumption and environmental footprint. Additionally, secondary materials, including tailings and metallurgical wastes, will be also tested for metals recovery and sulphur valorisation. Technical, environmental and economic feasibility of the different approaches will be evaluated to ensure viability and competitiveness of the proposed business solution.

INTMET economically viability will rely on (1) products diversification (Cu, Zn, Pb), (2) high-profitable solution (producing commodities not concentrates), (3) lower operation and environmental costs (on-site hydroprocessing will avoid transport to smelters). All these will allow the mine-life extension through the development of a new business-model concept based on high efficient recovery of complex ores.

INTMET is fully aligned with EIP-RM validated in the PolymetOre Commitment. The market up-take are guaranteed by exploitation from industrially-driven consortia, including 4 Mines and tech providers.
Raw Materials Sampling and Characterization: Four materials obtained from mineral deposits from CLC, KGHM, BOR and Somincor were sampled and characterised. These included polymetallic ores and concentrates, complex or low-grade copper ores and concentrates and pyrite concentrates.

Enhanced Performance Flotation Process: This activity developed the necessary technology for bulk concentrate production and provides samples for lab-scale and pilot testing. Main areas of activity were comminution and flotation improvements and production of samples from the developed processes. Newly developed flotation reagents and microwave techniques have been applied.

Development of Integrative Atmospheric Leaching Process: Atmospheric leaching applied on bulk concentrates or middlings is one promising key technology for efficient metals recovery from low-grade, complex and polymetallic ores proposed by INTMET. Obtained results at lab and pilot scale have shown the high recoveries as expected (e.g. 94% Cu and 95% Zn recovery). It can be stated that a new technological approach has been developed to treat efficiently reserves of polymetallic primary sulphides by means of hydroprocessing.

Development of Integrative Pressure Leaching Process: High temperature pressure oxidation is a well proven process for Ni, Au and Zn production. A semi-commercial alternative process for Cu is currently under development - pressure oxidation in an autoclave at temperatures from 135°C to 210°C destroying sulphides rapidly at leach times lower than 60 minutes – releasing base metals into solution for further recovery. INTMET proposes this technology as an efficient way to recover base metals from bulk concentrates and middlings. Lab as well as pilot results obtained showed high Cu and Zn yields (Cu 95%, Zn 99%).

Development of integrative bioleaching process: Bioleaching is a process described as being “the dissolution of metals from their mineral source by certain naturally occurring microorganisms”. The bioleaching performance on four polymetallic samples was assessed by means of testing and detailed steady state mass balances. The results indicated maximum extractions achieved of 85% Cu, 75% Zn, 90% Pb, 90% Au and 80% Ag.

Valorisation of tailings, wastes and effluents: The project intended to limit the amount of wastes and effluents by valorising these streams using best tailored technologies. Flotation tailings, wastes materials and effluents are processed to recover iron, non-ferrous metals, CRMs and sulfuric acid. Obtained results showed the high potentiality to integrate the studied technologies improving the economy and the environmental footprint.

Technologies assessment and project evaluation: INTMET hydrometallurgical technologies are specifically designed to provide a suitable solution to every application. The developed technologies can deal efficiently with feed materials such as bulk concentrates and low-grade concentrates containing low tenor of base metals and precious metals, which cannot be processed in existing refineries. For instance, tested polymetallic concentrates samples from several mines in Europe ranged: 2-5% Cu, 5-15% Zn, 3-10% Pb, 50-500 ppm Ag.

Developed INTMET hydrometallurgical technologies can be an advantageous alternative to conventional processing technologies, allowing:
a) to increase 30-50% overall metals recovery in comparison to actual operations,
b) to process low-grade and complex ores containing impurities such as Hg, Sb, As, etc.
c) to produce in-situ refined metals (commodities),
d) to recover additionally some critical materials (e.g. In, Co, etc.),
e) to rise mineral reserves, reducing the cut-off, in definitive, to achieve a more robust and sustainable mining business.

All partners have participated in the communication and dissemination activities, including the presentation of results in scientific congress, and the organisation of a final clustering event to stablish synergies with other R&D project related with novel technologies in mining: INTMET Clustering Conference “Fostering Innovation in the Iberian Pyrite Belt”. More information and communication materials are included in www.intmet.eu.
Currently there is no economical and viable process for on-site metal extraction from Low Grade, Complex or Poly-metallic deposits, and even more, there is no industrial process or technology able to deal with polymetallic (Cu+Zn+Pb) concentrates, compelling the sale of concentrates of increasingly lower quality and incurring increasing penalties in prices. Recovery of the valuable metals from these Polymetallic and Complex or Low Grade ores could then be maximised by producing bulk concentrates or middling flotation products to feed novel hydrometallurgical processes, like the integral metallurgical system to be developed within INTMET project.

The INTMET approach represents a radical solution and a unique technological breakthrough to overcome definitively the limitations related to difficult, low grade and complex ores to achieve high efficient recovery of valuable metals such as Cu, Zn, Pb, Ag, and also critical metals like Co, In, Sb. The project will allow applying on-site mineral to metal (M2M) and integrated treatment of the produced concentrates, combining innovative hydrometallurgical processes (atmospheric, pressure and bioleaching), and novel more effective metals extraction techniques (e.g. Cu/Zn-SX-EW, chloride media, etc). Additionally, secondary materials like mining (tailings) and metallurgical wastes will be added to the process for valorisation and metal recovery.