Column leaching of low-grade saprolitic laterites and valorization of leaching residues

Komnitsas, Kostas; Petrakis, Evangelos; Bartzas, Georgios; Karmali, Vasiliki

doi:10.1016/j.scitotenv.2019.01.381

Cited by 45 publications

(14 citation statements)

References 59 publications

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“…It is seen that this rocking band disappears after firing at 400 °C (Fig.7d), thus indicating that phase transformations took place and may have resulted in the increase of the compressive strength. The strong single peak at 1016 cm -1 shown in Figure 7b (IP produced using 8M NaOH) reveals the formation of reaction products in the IPs after exposure to highly alkaline solution [41,57,58]. The structural reorganization as result of the alkaline activation is more noticeable in the broader bands shown in the same region (800-1200 cm -1 ) for the IPs immersed in HCl solution or fired at 400 °C (Figure 7c and d, respectively).…”

Section: Morphology-μicrostructure Of Inorganic Polymersmentioning

confidence: 93%

Assessment of Alkali Activation Potential of a Polish Ferronickel Slag

et al. 2019

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In this study, the alkali activation potential of a Polish ferronickel slag (PS), for the production of inorganic polymers (IPs), is investigated. The effect of the main synthesis parameters, i.e., strength of the activating solution, consisting of NaOH and Na2SiO3 solutions and affecting (SiO2 + Al2O3)/Na2O and other important molar ratios in the reactive paste, pre-curing period, curing temperature and time and ageing period was investigated. The structural integrity of the produced specimens was tested after their (i) immersion in distilled water and acidic solutions for a period of 7–30 days, and (ii) firing at temperatures between 200 °C and 1000 °C. Several analytical techniques including X-ray diffraction, X-ray fluorescence, Fourier transform infrared spectroscopy, Differential scanning analysis-Thermogravimetry and Scanning Electron Microscopy were used for the characterization of the produced IPs. Results show that under the optimum synthesis conditions the IPs obtain compressive strength that exceeds 65 MPa. An innovative aspect of this study is that after heating at 400 °C, the specimens acquire compressive strength of 115 MPa and this indicates that they can be also used as fire resistant materials. This study highlights the potential of alkali activation for the valorization of a ferronickel slag and the production of IPs that can be used as binders or in several construction applications, thus improving the sustainability of the metallurgical sector.

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Section: Morphology-μicrostructure Of Inorganic Polymersmentioning

confidence: 93%

Assessment of Alkali Activation Potential of a Polish Ferronickel Slag

et al. 2019

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“…In fact, waste can be a useful source of raw materials and energy, too. Metals, glass, and textiles have long been collected and put to new use; for example, the extraction of nickel and cobalt from raw materials, as well as from waste, is strategically important for industry and society Komnitsas et al (2019). Waste can be turned into energy too, enabling the value of products, materials, and resources to be maintained on the market for as long as possible, minimizing waste and resource use in the wake of the objectives of circular economy Malinauskaite et al (2017).…”

Section: Introductionmentioning

confidence: 99%

Waste Management Analysis in Developing Countries through Unsupervised Classification of Mixed Data

Caruso

Gattone

2019

Social Sciences

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The increase in global population and the improvement of living standards in developing countries has resulted in higher solid waste generation. Solid waste management increasingly represents a challenge, but it might also be an opportunity for the municipal authorities of these countries. To this end, the awareness of a variety of factors related to waste management and an efficacious in-depth analysis of them might prove to be particularly significant. For this purpose, and since data are both qualitative and quantitative, a cluster analysis specific for mixed data has been implemented on the dataset. The analysis allows us to distinguish two well-defined groups. The first one is poorer, less developed, and urbanized, with a consequent lower life expectancy of inhabitants. Consequently, it registers lower waste generation and lower C O 2 emissions. Surprisingly, it is more engaged in recycling and in awareness campaigns related to it. Since the cluster discrimination between the two groups is well defined, the second cluster registers the opposite tendency for all the analyzed variables. In conclusion, this kind of analysis offers a potential pathway for academics to work with policy-makers in moving toward the realization of waste management policies tailored to the local context.

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“…Another advantage of AL is the potential to valorize the leach residues. Komnitsas et al [15] found that column leaching residues can be alkali activated with the use of NaOH and Na 2 SiO 3 as activators. Inorganic polymers with high strength, almost 40 MPa, can be produced, when 10 wt % metakaolin is added to the residue.…”

Section: Introductionmentioning

confidence: 99%

Iron Control in Atmospheric Acid Laterite Leaching

et al. 2019

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Iron control in the atmospheric acid leaching (AL) of nickel laterite was evaluated in this study. The aim was to decrease acid consumption and iron dissolution by iron precipitation during nickel leaching. The combined acid leaching and iron precipitation process involves direct acid leaching of the limonite type of laterite followed by a simultaneous iron precipitation and nickel leaching step. Iron precipitation as jarosite is carried out by using nickel containing silicate laterite for neutralization. Acid is generated in the jarosite precipitation reaction, and it dissolves nickel and other metals like magnesium from the silicate laterite. Leaching tests were carried out using three laterite samples from the Agios Ioannis, Evia Island, and Kastoria mines in Greece. Relatively low acid consumption was achieved during the combined precipitation and acid leaching tests. The acid consumption was approximately 0.4 kg acid per kg laterite, whereas the acid consumption in direct acid leaching of the same laterite samples was approximately 0.6–0.8 kg acid per kg laterite. Iron dissolution was only 1.5–3% during the combined precipitation and acid leaching tests, whereas in direct acid leaching it was 15–30% with the Agios Ioannis and Evia Island samples and 80% with the Kastoria sample.

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Column leaching of low-grade saprolitic laterites and valorization of leaching residues

Cited by 45 publications

References 59 publications

Assessment of Alkali Activation Potential of a Polish Ferronickel Slag

Assessment of Alkali Activation Potential of a Polish Ferronickel Slag

Waste Management Analysis in Developing Countries through Unsupervised Classification of Mixed Data

Iron Control in Atmospheric Acid Laterite Leaching

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