Developing Sustainable Agromining Systems in Agricultural Ultramafic Soils for Nickel Recovery (original) (raw)
Related papers
2015
Serpentine (i.e. ultramafic) outcrops in Europe cover more than 10,000 km2 and have a low-fertility and low-productivity, making them unattractive for traditional agriculture. Many of these areas are slowly abandoned by local farmers, with rural exodus and landscape closure. However, ultramafic landscapes have the potential to provide multiple ecosystem services and can contribute to Europe’s goals towards insuring food security, production of renewable raw materials and renewable energy. Phytomining (Agromining) cultivates plants that are able to accumulate trace metals from metal-rich soils and transport them to the shoots (>1%), which can then be harvested as a bio-ore to recover highly valuable metals, e.g. nickel (Ni). Nickel agromining can offer an eco-efficient alternative to classical pyro- or hydrometallurgical processes, as well as providing biomass for local energy production. Phytomining agroecosystems can lead to better soil resource efficiency and can offer a fully ...
Production of nickel bio-ore from hyperaccumulator plant biomass: Applications in phytomining
Biotechnology and Bioengineering, 2004
An important step in phytomining operations is the recovery of metal from harvested plant material. In this work, a laboratory-scale horizontal tube furnace was used to generate Ni-enriched bio-ore from the dried biomass of Ni hyperaccumulator plants. Prior to furnace treatment, hairy roots of Alyssum bertolonii were exposed to Ni in liquid medium to give biomass Ni concentrations of 1.9% to 7.7% dry weight; whole plants of Berkheya coddii were grown in Ni-containing soil to produce above-ground Ni levels of up to 0.49% dry weight. The concentration of Ca in the Ni-treated B. coddii biomass was about 15 times greater than in A. bertolonii. After furnace treatment at 1200jC under air, Ni-bearing residues with crystalline morphology and containing up to 82% Ni were generated from A. bertolonii. The net weight loss in the furnace and the degree of concentration of Ni were significantly reduced when the furnace was purged with nitrogen, reflecting the importance of oxidative processes in Ni enrichment. Ni in the B. coddii biomass was concentrated by a factor of about 17 to yield a residue containing 8.6% Ni; this bio-ore Ni content is substantially higher than the 1% to 2% Ni typically found in mined ore. However, the B. coddii samples after furnace treatment also contained about 34% Ca, mainly in the form of hydroxyapatite Ca 5 (PO 4 ) 3 OH. Such high Ca levels may present significant challenges for further metallurgical processing. This work demonstrates the feasibility of furnace treatment for generating Ni-rich bio-ore from hyperaccumulator plants. The results also suggest that minimizing the uptake of Ca and/or reducing the Ca content of the biomass prior to furnace treatment would be a worthwhile strategy for improving the quality of Ni bio-ore produced in phytomining operations. B 2004
Implementing nickel phytomining in a serpentine quarry in NW Spain
Journal of Geochemical Exploration, 2018
In Galicia (NW Spain), ultramafic outcrops represent approximately 5% of the land surface and several mining and quarrying activities take place in these areas. Resulting mine-soils present physical, chemical and biological properties which limit plant growth and soil functioning. Nickel phytomining, an eco-friendly strategy for metal recovery, could potentially be applied to these areas. A one-year field experiment was carried out in a serpentine quarry to evaluate the performance of four Ni hyperaccumulating plant species, comparing the Mediterranean spp. Bornmuellera emarginata and Odontarrhena muralis with the native populations of Noccaea caerulescens and Odontarrhena serpyllifolia. Field plots were established and amended with inorganic NPK fertilisers or composted sewage sludge. Three replicate plots (4 m 2) were planted for each plant species and fertilisation regime. Amending with compost reduced pH from 7.8 to 6.6, and increased soil cation exchange capacity (CEC), nutrient concentrations and Ni availability. Moreover, compost-amended mine-soil presented higher microbial density and activity, parameters which were further stimulated by plant growth. Plant biomass production of all plant species was significantly higher in compost-amended soils than that after NPK fertilisation, being most pronounced for O. muralis and B. emarginata. Despite the reduction in shoot Ni concentrations observed in plants (except O. muralis) grown in compost-amended plots, the increased biomass production led to significantly higher Ni yields (in kg ha −1) in B. emarginata (2.9), N. caerulescens (1.9) and O. muralis (2.3). All plant species were able to establish and grow in the mine-soil (with the Mediterranean species showing a higher capacity for adaptation) and to generate moderate Ni yields. Nonetheless, the results highlight the need for further optimisation in order to enhance the Ni phytoextraction efficiency. Finally, the improvement in soil quality after compost amendment and plant growth support the idea that phytomining systems can be effective approaches for the rehabilitation of soils affected by quarrying operations after mine closure.
Agromining: farming for metals in the future?
Environmental Science & Technology, 2015
Phytomining technology employs hyperaccumulator plants to take up metal in harvestable plant biomass. Harvesting, drying and incineration of the biomass generates a high-grade bio-ore. We propose that "agromining" (a variant of phytomining) could provide local communities with an alternative type of agriculture on degraded lands; farming not for food crops, but for metals such as nickel (Ni). However, two decades after its inception and numerous successful experiments, commercial phytomining has not yet become a reality. To build the case for the minerals industry, a large-scale demonstration is needed to identify operational risks and provide "real-life" evidence for profitability.
Huge areas in the world are covered by soils containing high contents of metal. Phytomining aims at recovering these metals by growing hyperaccumulating plants and treating the metal-rich biomass by pyrometallurgical or hydrometallurgical processes. This contribution is an overview of the results we have obtained for several years in Ni phytomining. Hyperaccumulating plants, Alyssum murale, are grown in the Balkans (Albania) and high Ni yields are reached: 100 kg Ni per ha. Once harvested and dried, A. murale biomass is incinerated and the ashes are treated by a hydrometallurgical process that we have designed and patented to produce a high value added salt: sulfate and ammonium nickel double salt hexahydrate, used for electrolytic surface treatment. The process steps are described and the main results presented. Our results have demonstrated the feasibility of the synthesis of this nickel double salt after phytoextraction. This process is currently up-scaled to the pilot scale. A start-up project has been launched to develop this activity with two directions: the production of Ni salt and consulting activity for phytoextraction.
2021
Huge areas in the world are covered by soils containing high contents of metal. Phytomining aims at recovering these metals by growing hyperaccumulating plants and treating the metal-rich biomass by pyrometallurgical or hydrometallurgical processes. This contribution is an overview of the results we have obtained for several years in Ni phytomining. Hyperaccumulating plants, Alyssum murale , are grown in the Balkans (Albania) and high Ni yields are reached: 100 kg Ni per ha. Once harvested and dried, A. murale biomass is incinerated and the ashes are treated by a hydrometallurgical process that we have designed and patented to produce a high value added salt: sulfate and ammonium nickel double salt hexahydrate, used for electrolytic surface treatment. The process steps are described and the main results presented. Our results have demonstrated the feasibility of the synthesis of this nickel double salt after phytoextraction. This process is currently up-scaled to the pilot scale. A ...
Plant and Soil, 2019
Aim The identification and use of hyperaccumulator plants in mining projects has been recognized as an important component of mine planning at several sites around the world. The objective of this research was to provide information on relevant plant tissue chemistry and an indicative assessment of the potential for phytomining at Weda Bay Nickel (WBN), Halmahera. Methods The first stage was the identification of native nickel hyperaccumulator plants. In total, 280 plant tissue samples from 10 nickel accumulator species and 46 matching rhizosphere soil samples were collected. Chemical analyses of plant tissue samples were performed and physico-chemical parameters of the rhizosphere soils were also measured. Results A total of three species were considered as metal crops: Rinorea aff. bengalensis (up to 22,200 mg kg −1 dry weight at 2 m above ground level), Ficus trachypison (1060 mg kg −1) and Trichospermum morotaiense (5180 mg kg −1), but only R. aff. bengalensis has sufficiently high Ni concentrations in biomass to warrant field trials. Conclusions Utilising a successional planting strategy, F. trachypison and T. morotaiense could be used to facilitate site conditions, followed by the metal crop R. aff. bengalensis. Using this design, a nickel yield of 330 kg per hectare would be possible every 4 years. In addition to allowing the recovery of nickel, this approach could be an integrated mine site rehabilitation strategy to mitigate environmental impacts, improve soil quality and facilitate transition to other land-uses such as native forest.
International Journal of Phytoremediation, 2019
In Albania, ultramafic outcrops cover 11% of the surface and have the potential to support nickel phytomining. In a large-scale in-situ experiment on an ultramafic Vertisols in Pojsk€ e we are studying the influence of agronomical practices on Ni phytoextraction yield of Odontarrhena chalcidica (syn. Alyssum murale). Three cropping systems were compared in three plots in 2016-2017; POJ-1 Plot (0.3 ha) was established with plants that had germinated spontaneously without any treatments; POJ-2 plot (0.3 ha) was covered by plants that had germinated spontaneously and was treated with mineral fertilizer (N50P50K50 kg ha À1); and POJ-3 Plot (400 m 2) was divided in four sub plots, where O. chalcidica was planted at a density of 4 plants m À2 on which, we neither applied fertilizer, nor NPK fertilizer (N65P65K65), pig (FPM; N260:P105:K260 þ 15 kg ha À1 N, P, K) or chicken manure (FCHM; N260:P390:K260 þ15 kg ha À1 N, P, K. Irrigation and mechanical control of weeds was done on POJ-3. After 8 months, shoot Ni concentration, biomass, and Ni yields were higher in O. chalcidica treated with manure and the cost of biomass production was smaller. Nickel yield was more promising (145 kg ha À1) than in previous field trials. This study highlights that, using manure, the Ni yield increases Ni phytomining net values, thus agromining can become an economically justifiable agricultural cropping system.
Several industrial sites suffer from the contamination of soils from heavy metals, which are emitted among others by anthropogenic mining and metallurgical activities. Effective and economic physicochemical technologies for remediation of these sites remain complicated and costly. A new alternative remediation technique is the so-called phytoremediation. This is based on the ability of some plants to accumulate very high concentrations of metals from soils and thus providing the basis for a remediation of the contaminated sites. This technique as an emerging branch of natural biotechnology, has several advantages compared to the sophisticated physicochemical techniques of soil remediation. It is not only environmentally friendly but also its costs are quite low since it is solar driven. Furthermore plants can accumulate metals to such levels that the mineral recovery maybe feasible even in conventional Ni refinery or smelting operations. In this work, the potential of many plants to...
Ultramafic soils and nickel phytomining opportunities: A review
Revista Brasileira de Ciência do Solo
Ultramafic soils are originated from ultramafic rocks such as peridotite and serpentinite and are highly enriched in metals (e.g., Ni, Cr, and Co) and depleted in plant nutrients (e.g., P, K, and Ca). Such characteristics make these soils unfavorable for agriculture and have raised environmental concerns on metal release to the environment. From another perspective, ultramafic soils host a diverse flora with higher endemism than surrounding non-ultramafic areas, which has provided scientists with an opportunity to investigate the evolutionary genetics of plant adaptation. Some plant species adapted to these stressful edaphic conditions developing the ability to accumulate uncommonly high metal concentrations in the harvestable biomass. Such species, called metal hyperaccumulators, can extract metals from ultramafic soils, especially Ni, in a circular economy approach in which the metal-rich biomass is incinerated to generate valuable bio-ores. Phytomining promises to turn ultramafic soils and low-grade ore bodies into economically viable alternatives to metal extraction. Here, we review the current knowledge on ultramafic soils and the most promising hyperaccumulators used to exploit them in temperate and tropical climates. In the tropics, including Brazil, the search for new hyperaccumulator candidates for phytomining and the knowledge to crop these species is incipient and holds untapped opportunities. Despite the feasibility of the phytomining chain has been proven, large-scale demonstrations of profitability are needed to establish the technology.