Report on Sustainability through Resource Conservation and Recycling '14

Sustainability through Resource Conservation and Recycling '14 (SRCR '14) was held at the St. Michael's Hotel, Falmouth, Cornwall, from June 11-12, 2014, and was sponsored by Outotec, Ecoseed, Industrial Minerals and AT International.

Thursday 12th June

SRCR is one of MEI's smaller conferences, and this morning Jon welcomed the 38 delegates, nine of whom were here earlier in the week for Biohydromet '14. Despite the relatively small number, 17 countries are represented at the conference, Australia, Belgium, Brazil, Canada, Chile, China, Finland, France, Japan, Morocco, South Africa, South Korea, Spain, The Netherlands, Turkey, UK, USA.

Jon with Markus Reuter

Metals are an essential and critical component of today’s society; their ubiquitous presence in virtually all energy and material production processes, products, infrastructure, confirms this. Metals play a key role in enabling sustainability through societies various high-tech applications. However, the resources of our planet are limited, as is the strain to which we can subject it in terms of emissions, pollution, and disposal of waste. For these reasons, finding ways to lower the environmental footprint of our collective existence and therefore lowering greenhouse gas emissions and help mitigate climate change is a vital priority. This was the theme of the keynote lecture from Markus Reuter, of Outotec, Finland, and MEI's consultant, who summarised the UNEP report on Metal Recycling: Opportunities, Limits, Infrastructure.

Glen Corder, of the University of Queensland, Australia, then discussed the translation of global knowledge on industrial ecology to enhance uptake of metals recycling in an Australian context. Australia’s rich stocks of mineral resources have been the source of national wealth and competitive advantage in the past. However, the security of this wealth is not guaranteed into the future, and what were once considered waste materials are now becoming accessible and valuable as ‘above-ground’ mineral resources. Globally there is growing capacity and innovation in recycling, closed-loop supply chains and Australia’s role as a global leader in primary production must anticipate and adapt to the implications of a rise in the importance of recycling.

Alan Jean-Marie of Altran Research, France, then took us up to the coffee break with a presentation on the coupling life cycle assessment and process simulation to evaluate the environmental impacts of plastic waste management applied to PET bottles recovery.

Antoinette van Schaik of MARAS, The Netherlands, took the floor after coffee with 10 design for recycling rules. Based on the information gathered in this study combined with the expertise of the authors as also published in the recent UNEP report on Metal Recycling, comprehensive simulation based Design for Recycling (DfR) rules and guidelines have been developed. These rank from simple guidelines and material (in) compatibility tables to detailed recycling system based DfR rules. The rules address the technological and economical possibilities and limits in the entire recycling system from design to metallurgy in relation to material interactions, recovery, losses and emissions and resource efficiency.

The concept of sustainability, which is now well entrenched in the minerals industry, can be an effective driver for higher levels of innovation, as discussed in a second paper by Glen Corder. With the minerals industry venturing into riskier locations, new mining projects need to deliver both strong sustainability benefits while meeting the necessary technical and financial requirements. Improved approaches to recycling, resources conservation, energy and water efficiency, greenhouse gas reduction, biodiversity, local enterprise development, and community development programs all meet the aims of good sustainability practice and require innovative techniques to move away from the ‘business as usual’ paradigm.

Glen Corder with Hiroki Hatayama of Japan

The global demand for minerals is defined by social and financial needs, and to ensure effective environmental protection, a number of tools and techniques have been developed. One of the most widespread tools is the Environmental Impact Assessment (EIA). This technique has many advantages, but it has also a number of disadvantages. Jorge Castilla-Gómez, of Madrid School of Mines, Spain discussed the development of a methodology to establish an environmental analysis focusing on the evolution of impacts on the environment with time.

Jorge Castilla-Gómez with Isabelle Demers of UQAT, Canada

The long-term generation of acid rock drainage (ARD) from sulfide-bearing mine waste is a major environmental liability for the mining sector. Previous studies have demonstrated that these ARD risks can be effectively avoided, and resource recovery simultaneously improved, through the pre-disposal removal of sulfide minerals, by means of flotation, as discussed by Jennifer Broadhurst, of the University of Cape Town, South Africa. She showed how life cycle assessment tools have been used to quantify and rigorously assess the environmental consequences of the flotation process for the desulfurisation of copper sulphide tailings, using a xanthate collector. The desulfurisation flotation process results in a significant decrease in human and eco-toxicity impacts, but an increase in GHG emissions and global warming potential, in comparison to conventional tailings disposal. Information from this study is used to identify improvement opportunities and guide further developmental studies.

Jennifer Broadhurst with Rabei Argane of Morocco

Following the lunch break Elisabeth Maris of Institut de Chambéry, France, presented a case study of a proposed methodology for characterisation of plastics contained in WEEE, then Liang Li of the Pangang Group Research Institute, China presented a thermodynamic analysis of the extraction of titanium from Ti-bearing BF slag.

Elisabeth Maris, with Amanda, and Chris Brough (UK)

Hiroki Hatayama of the National Institute of Advanced Industrial Science and Technology, Japan discussed methods of improving mineral extraction by reducing losses in mining and recycling.

Hiroki Hatayama (right) with Ryo Kasuya of Japan

Abandoned tailings ponds have been exploited without control for many years in the Moulouya region of Morocco, as a source of aggregate for rendering mortars. The aims of research presented by Rabei Argane of Université Cadi Ayyad, Morocco, was to assess the durability of the resulting tailings-based renders and to study their behavior when exposed to standard detrimental agents. The results confirmed that the use of mine tailings as aggregates engender a negative impact on the durability of renders.

The weather was perfect in the late afternoon for the 9 km coastal path walk into old Falmouth, and beers at the 17th century Chain Locker pub (see also posting of 13th June)

Overlooking Falmouth from the coast path

Friday 13th June

Christopher Brough of SRK Consulting Ltd, UK) discussed the former Bicapa-Tarnaveni chemical works in Romania, whhich processed chromite ore to create a sodium dichromate product. Inappropriate environmental stewardship of hexavalent chromium resulted in a significant contamination legacy. A recent environmental assessment of the site recommended that the waste storage facility (WSF) should be capped and a groundwater pump and treat solution should be installed, to treat the already contaminated groundwater. However, a second reprocessing option has been assessed, and if successful will significantly reduce the liability associated with the site and turn the WSF into a resource. Initial resource assessments of the WSF have established a potential resource for chromium, magnesium and calcium.

Management of acid mine drainage from diffuse sources is a major challenge facing the mining industry in South Africa. Semi-passive or low maintenance treatment options are most appropriate. Rob van Hille, of the University of Cape Town, discussed the optimisation of a semi-passive process, based on biological sulphate reduction with subsequent partial sulphide oxidation in a floating sulphur biofilm.

Two papers by Isabelle Demers, of UQAT, Canada showed how in operating mines acid mine drainage (AMD) is often treated using lime. This process generates a significant amount of sludge that contains metal hydroxide precipitates, gypsum, and unreacted lime. The sludge may have interesting geotechnical and geochemical properties and might be used as a partial cover (oxygen barrier) to prevent AMD generation from waste rocks and tailings. The results showed that mixtures of sludge and waste rocks, sludge and tailings and sludge and soil may be integrated in an AMD prevention and control strategy at Doyon mine site in Canada. Furthermore, the sludge stored at the Doyon mine site harbours significant vegetation after only a short period of time.

Zeynal Erguler of Dumlupinar University, Turkey also discussed the rehabilitation of acid mine drainage, at an abandoned lignite mine site, utilising egg-shell as an absorbent. He also discussed the effect of particle size on acid mine drainage.

Barbara with Zeynal Erguler and Ozlem Bicak of Turkey

The ASTER^TM  process is used to bioremediate cyanide- (CN-) and thioocyanate- (SCN-) containing waste water. This process reduces the CN- and SCN- concentrations efficiently to below 1 mg/l, facilitating reuse of process water or safe discharge. Two papers presented by Rob Huddy of the University of Cape Town discussed characterisation of the complex microbial community associated with the ASTER^TM  thiocyanate biodegradation sysstem and the evaluation of the ASTER^TM  process in the presence of susspended solids.

Rob Huddy and Rob van Hille with Jorge Castilla-Gómez

The morning session finished with a paper from Kyoung Kuen Yoo of the Korea Maritime and Ocean University, who discussed the effect of hydrogen peroxide addition on the citric acid leaching of Pb from contaminated soil.

Relaxing between sessions in the hotel gardens

The final session commenced with a presentation by Chenna Borra of Katholieke Universiteit Leuven, Belgium on the leaching of rare earths from red mud, and later in the afternoon Quentin Dehaine of Université de Lorraine, France discussed the recovery of the rare-earths Ce, La and Nd and rare-metals Nb, Sn, and W from wastes of a kaolin production plant in Cornwall.

Nitrate is released into the environment during mining operations, due to the use of N-based explosives and leaching agents such as cyanide. Stefano Papirio of Tampere University, Finland presented work on the assessment of nickel on denitrification of mining waters in fluidized-bed reactors.

Electric cables are essential constituents of consumer goods such as automobiles and electrical and electronic equipments. Scrap cables are traditionally sorted by physical separation methods. These techniques have limitations and lead to a loss of copper in the reject fractions that cannot currently be recycled and which are landfilled. Fanny Lambert of the University of Liege, Belgium presented a study to assess the feasibility of recovering copper from these reject fractions by using hydrometallurgy.

Fanny Lambert (right) with Elisabeth Maris

Mauricio Torem of the Catholic University of Rio de Janeiro, Brazil also presented biotechnology work, on the enhancement of biosorption of lead and cadmium ions from aqueous solution by the microorganisms Rhodococcus opacus and Rhodococcus ruber.

Mauricio Torem with Romke Kuyvenhoven (Chile) and Beatriz Firpo (Brazil)

We have two representatives from the Pangang Group Research Institute in China, and Lian Li presented their work on process optimization in vacuum distillation for titanium sponge preparation and magnesium recycling.

Liang Li and co-author Kaihua Li, with Li Jing of
Liaoning University of Science and Technology, China

The conference closed with a presentation by Sadan Kelebek of Queen's University, Canada who discussed the mineralogical characteristics of nickel and copper values in waste refractory bricks and their potential for upgrading by flotation and magnetic separation.

Sadam Kelebek (right) with Chenna Rao Borra (Belgium)

In closing the conference, Outotec's Markus Reuter stressed that minerals are at the centre of sustainability. The aim of the SRCR series of conferences has been to transfer the rich source of mineral processing knowledge accumulated over the years to a wider community dealing with waste processing and untilisation, recycling etc. Acknowledging this we have decided to change the title of future conferences to Sustainable Minerals, and Jon closed the conference with an invitation to scientists of all related disciplines to convene in Falmouth in June 2016 for Sustainable Minerals '16.

The Proceedings from SRCR '14 are available from MEI and selected papers will be published in a special issue of Minerals Engineering after peer-review.