Studies on flocculation characteristics of chromite’s ore process tailing: Effect of flocculants ionicity and molecular mass

Dwari, Ranjan; Angadi, Shivakumar I.; Tripathy, Sunil Kumar

doi:10.1016/j.colsurfa.2017.10.069

Cited by 41 publications

(17 citation statements)

References 41 publications

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“…The fines are commonly de-slimed using hydro-cyclone and cyclone underflow processed using gravity concentrators like spirals and tables. As a result, chromite concentrated ore is obtained, and roughly 50% to 70% of the chromite losses are in the fine fractions (tailings), where the fraction below 75 µm contains about 9-20% Cr 2 O 3 [2,6].…”

Section: Field Settingsmentioning

confidence: 99%

“…The XRF composition is consistent with XRD results, which shows the presence of goethite (α-FeO(OH)), hematite (Fe 2 O 3 ), gibbsite (Al(OH) 3 ), chlorite ((Fe,Mg,Al) 6 (Si,Al) 4 O 10 (OH) 8 ), and chromite (FeCr 2 O 4 ), as the main crystalized mineral phases in the fresh tailing sample. Dwari et al [6] found additional mineral phases in chromite tailings from Sukinda valley, including kaolinite (Al2Si2O5(OH)4), quartz (SiO2), and magnesioferrite (Mg(Fe)2O4). The concentrated ore sample is enriched in chromite with some traces of lizardite, hematite, and goethite.…”

Section: Tailings and Concentrated Ore Characterizationmentioning

confidence: 99%

“…The environmental risk is directly related to the mineralogical composition of chromite tailings and its susceptibility to release toxic elements into the environment. Typically, chromite ore process tailings contain a heterogeneous mixture of iron and chromium oxides, silicates, and aluminum silicate minerals [6]. In the tailings studies, mineral phases included chromite, which is the main Cr mineral on earth.…”

Section: Does Chromite Tailing Represent An Environmental Risk?mentioning

confidence: 99%

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(Bio)leaching Behavior of Chromite Tailings

et al. 2018

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Chromite beneficiation operations in Sukinda valley (India) produce large amounts of tailings, which are stored in open air. In this study, bioleaching experiments were carried out in batch reactors with Acidithiobacillus thiooxidans or Pseudomonas putida in order to determine the potential leachability of metals contained in these tailings due to biological activity. Acidic and alkaline pH resulted from the incubation of tailings with A. thiooxidans and P. putida, respectively. Tailings were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), and scanning electron microscopy (SEM), and chemical extraction of Cr(VI) with KH 2 PO 4 was performed. Mineralogical investigations showed that tailings are mainly composed of chromite, hematite, lizardite, chlorite, and goethite, which are all known as Cr-bearing phases. During the leaching with A. thiooxidans and P. putida, total Cr was initially extracted as Cr(VI) due to the presence of phosphates in the medium, and subsequently decreased because of Cr(VI) adsorption and reduction to Cr(III). Reduction was associated with bacterial activity, but also with the presence of ferrous iron. Despite the occurrence of siderophores in the tailings after incubation with P. putida, under acidic conditions, Fe extracted remained higher. Extracted Ni, Mn, and Al concentrations also increased over time. Given the significant amount of chromite tailings produced every year, this study shows that tailings storage and leachability represent a potential source of chromium. However, our findings suggest that the presence of bacterial communities, as well as physicochemical processes, favor Cr(VI) reduction.

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Section: Field Settingsmentioning

confidence: 99%

Section: Tailings and Concentrated Ore Characterizationmentioning

confidence: 99%

Section: Does Chromite Tailing Represent An Environmental Risk?mentioning

confidence: 99%

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(Bio)leaching Behavior of Chromite Tailings

et al. 2018

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“…Polyacrylamide (PAM) and derivative products are well-known flocculants widely applied in various fields, such as wastewater treatment [1,2], fine sedimentation [3,4], and agglomeration flotation [5] in mineral processing. There are three main types of PAM: anionic, cationic, and nonionic, and amongst them, the anionic PAM (APAM) usually exhibits a strong flocculating effect and has been used effectively for the flocculation-sedimentation process of tailings slurry [4,6]. The APAM polymer usually contains a large number of polar groups such as acyl and carboxyl groups, resulting in a high adaptability and strong adsorption capacity at alkaline pH.…”

Section: Introductionmentioning

confidence: 99%

“…In order to improve the flotation performance for using PAM as flocculants and reduce the adverse effect of residual PAM in the recycle wastewater, dispersants [12,13] could be applied in the slurry after flocculation, such as sodium hexametaphosphate (NaPO 3 ) 6 , and water glass, among others. Dispersants can produce a high degree of dispersion for fine suspension; however, it does not help affect the PAM molecular structure and its adsorption on particles.…”

Section: Introductionmentioning

confidence: 99%

A Study on the Flocculation and Sedimentation of Iron Tailings Slurry Based on the Regulating Behavior of Fe3+

Tao

Chen

et al. 2018

Minerals

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Based on the regulating behavior of Fe 3+ , flocculation and sedimentation tests of iron tailings slurry flocculated using 2 mg/L anionic polyacrylamide (APAM) were studied, including the tests of Fe 3+ dosage, regulating time, and pH. Flocculation-sedimentation tests showed that: a recommended addition of 56 mg/L Fe 3+ produced a surprisingly bad flocculation effect; sedimentation ability decreased with the increase of regulating time, however, the regulating ability during the first 1 min was low; Fe 3+ displayed a high regulating effect at pH 6-7, and then decreased with the increase of slurry pH. Size analysis demonstrated that the regulating ability of Fe 3+ was related to the change of floc size, which increased with the decrease of size. Zeta potential analysis and calculation showed that small concentrations of Fe 3+ and certain hydroxyl complex ions (such as Fe(OH) 2+ and Fe(OH) 2 + ) adsorbed onto the APAM molecular chains, resulting in a decreased charge density of the APAM molecules, and this electrostatic adsorption was able to make the polymer curl more easily. Fourier Transform Infrared Spectroscopic (FTIR) indicated the APAM on the hematite was slightly degraded into a monomer-like short-chain polymer while adding certain concentration of Fe 3+ . Scanning Electron Microscope (SEM) imaging showed that the network structure of APAM molecules treated by Fe 3+ collapsed, and the APAM adsorption amount on hematite was significantly reduced. Therefore, the effect of Fe 3+ on the APAM could be recommended as a new method for desorption and degradation of the APAM contained in the tailings slurry or flocs.

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Coagulation/flocculation process for marble processing plant effluent: Modelling and optimization through response surface methodology

Çırak

Atay

2019

Asia-Pacific J Chem Eng

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In this study, the coagulation‐flocculation of a wastewater discharged from a marble processing plant was statistically analyzed and optimized. To make a systematic investigation on the coagulation‐flocculation of the highly turbid wastewater (>1000 NTU), the response surface methodology was used to estimate a capable quadratic model with R‐squared value of 98.84%. According to this model, the most critical parameter was the suspension pH with a p‐value < 0.0001. Furthermore, the PEO‐flocculant was proven as a substantial agglomerating reagent specifically at pH 12. On the other hand, no significant turbidity removal was observed upon the addition of the Fe‐coagulant. When the experimental parameters of the coagulation‐flocculation were optimized, it was found out that the minimum supernatant turbidity value of 3.81 NTU can be achieved by using the minimum amount of the Fe‐coagulant:50 mg/l, and the maximum amount of the PEO‐flocculant of 1.5 ppm at pH 11.5‐12.0. In conclusion, it was proved that the significance of the calcium dissolved from the marble particles was greater than the Fe‐coagulant in this process. The hydrolyzed calcium (CaOH+) species established a chemical bridge between the particle and the polymer and, as a result, enhanced the performance of the flocculation at the alkaline pH values.

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Studies on flocculation characteristics of chromite’s ore process tailing: Effect of flocculants ionicity and molecular mass

Cited by 41 publications

References 41 publications

(Bio)leaching Behavior of Chromite Tailings

(Bio)leaching Behavior of Chromite Tailings

A Study on the Flocculation and Sedimentation of Iron Tailings Slurry Based on the Regulating Behavior of Fe3+

Coagulation/flocculation process for marble processing plant effluent: Modelling and optimization through response surface methodology

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