Identification of the significant factors determining extractability of Ni and Cu after sulfation roasting of a PGM-bearing chromitite ore

Mpinga, Cleophace Ngoie; Eksteen, Jacques; Aldrich, Chris; Dyer, Laurence

doi:10.1016/j.mineng.2017.04.019

Cited by 13 publications

(6 citation statements)

References 40 publications

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“…Thus, Ozer et al (2017) stated that it was not possible to obtain a selective sulfation without any additive between copper and iron in the roasting of tailings that had been stored for a long time and oxidized under atmospheric conditions, at any temperature due to their heterogeneous structure and mineralogicalchemical compositions [24]. [21] In order to improve the sulfation conditions and obtain higher selectivity, a number of promoters such as Fe 2 [23,[25][26][27][28][29]. Especially the effects of alkali sulfates have been studied as additives in the selective sulfation processes of materials containing nonferrous metals such as copper, cobalt, and nickel.…”

Section: J Min Metall Sect B-metall 55 (3) B (2019) 315 -324mentioning

confidence: 99%

“…It is well known that the amount of SO 3 is a critical factor in the formation of sulfates during roasting. In addition, this type of sulfate compound can act as a reservoir of SO 3 and increase the SO 3 partial pressure in the roaster [28]. Some researchers suggested that Na 2 SO 4 can also enhance the degree of sulfation of non-ferrous metals by means of the catalytic effect of Na 2 SO 4 during the sulfation of complex sulfide ore as per the following cyclic reaction [10,30,31].…”

Section: J Min Metall Sect B-metall 55 (3) B (2019) 315 -324mentioning

confidence: 99%

“…It is well known from the literature that the roasting time is another factor that influences the selectivity in the sulfation roasting. The longer roasting time is, up to a certain point, the more non-ferrous sulfides to sulfate will convert, and this will lead to an increase of the metal extractions in the leaching step [28]. Therefore, the samples were subjected to roasting tests performed at 700ºC with the addition of 25% Na 2 SO 4 for various periods of time.…”

Section: Leaching Following Roastingmentioning

confidence: 99%

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Cobalt and copper recovery from the ancient flotation tailings by selective sulfation roast - leaching process

Özer

2019

J min metall B Metall

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The ancient flotation tailings from Lefke, Cyprus, have a potential for non-ferrous metals such as cobalt and copper from more than 9.5 million tons of reserves containing 0.38% Cu, 0.032% Co, and 22.6% Fe. Recovery of cobalt and copper from these tailings can provide great benefits from economic and environmental perspectives. While the ancient tailings were kept long time in storage in dumps, the characteristics of the material has become different from the common Co and Cu bearing ores. In order to extract these valuable metals, a process involving combination of roasting and leaching was applied in this study. Since this process responded to recovery to some extent, an innovative technique of using Na 2 SO 4 as a promoter during roasting was proposed. Utilizing of Na 2 SO 4 did not provide only higher metal extractions, but also resulted in high selectivity. In the scope of the study, following the determination of the mineralogy and chemical composition of the tailings, certain processes such as direct leaching and sulfation roasting with/without additives before leaching were applied. Since low metal extractions were obtained from direct leaching, a selective sulfation process was applied on the tailings before leaching in order to produce a pregnant solution containing higher amounts of Co and Cu metals by reducing the iron concentration. When sulfation roasting was performed without any additive, the desired selectivity could not be provided, since the sample was considerably oxidized under the atmospheric conditions in the past. Therefore, the usage of Na 2 SO 4 as an additive with the amount of 25% at a roasting temperature of 700ºC was tested. Consequently, Na 2 SO 4 improved the sulfation and resulted in higher cobalt (90.1%) and copper (71.2%) recovery during leaching. Beside this, an improvement with a selective sulfation was obtained by combined effect of Na 2 SO 4 addition and temperature, and the iron extraction decreased from 26.1% to 3.9%.

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Section: J Min Metall Sect B-metall 55 (3) B (2019) 315 -324mentioning

confidence: 99%

Section: J Min Metall Sect B-metall 55 (3) B (2019) 315 -324mentioning

confidence: 99%

Section: Leaching Following Roastingmentioning

confidence: 99%

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Cobalt and copper recovery from the ancient flotation tailings by selective sulfation roast - leaching process

Özer

2019

J min metall B Metall

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“…Response surface methodology (RSM) was used for the process optimization with a minimum number of experiments as well as analyzing the interaction between the factors [26][27][28]. Based on the previous work we have made, four major factors: CaF 2 dosage (wt %), H 2 SO 4 concentration (vol %), leaching time (min) and microwave power (W) were chosen as the independent variables because of the apparent affection on the V leaching.…”

Section: Experimental Designmentioning

confidence: 99%

Evaluation of Microwave Intensified Vanadium Bearing-High Carbonaceous Shale Acid Extraction Process

et al. 2018

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Abstract:The microwave assisted leaching of the vanadium bearing-high carbonaceous shale process was investigated using surface response methodology (RSM) based on Box-Behnken design (BBD). The effect of important factors such as CaF 2 usage, H 2 SO 4 concentration, leaching time and microwave power, as well as the interactive coefficients, the signification of the model and factors were analyzed. With the condition of 9.8 wt % CaF 2 , 23.0 vol % H 2 SO 4 , 170.6 min and 350 W, the actual values of vanadium (V) leaching efficiency in microwave heating (MH) and conventional heating (CH) were 85.43% and 79.64%, which agreed well with the predicted values. Meanwhile, the influence order of the factors in MH and CH was CaF 2 dosage > H 2 SO 4 concentration > leaching time. Microwave was an efficacious impetus for V extraction, but the microwave power itself was not a significant factor when the temperature of leaching system was high enough. The further characterization of mineral components before and after leaching confirmed that the prior dissolving of muscovite and pyrite in MH was intensified, while both minerals were in fine grains and filled with black carbon. The selective heating of carbon and pyrite sequenced the large temperature gradient between solids and liquids, which accelerated the dissolving reaction of muscovite with CaF 2 present in MH condition.

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“…Unlike one-factor-at-time (OFAT) experiments, statistical optimisation approaches can take into account the interactions of many variables in the generation of process responses (Goupy 1996). Design of experiments' (DOE) methods and response surface methodology (RSM) have been used in various fields, such as chemistry and chemical engineering (Tumay Ozer and Gucer 2011;Zolgharnein et al 2014) and minerals processing (Mohapatra et al 2009;Mpinga et al 2010;Yi et al 2010;Torralvo and Fernandez-Pereira 2011;Tripathy and Murthy 2012;Makokha et al 2012;Yaghobi Moghaddam et al 2012;McGrath et al 2013;Boylu 2013;Kokkılıc et al 2015;Wannachod et al 2015;Mbuya et al 2017) to optimise the process responses. In this work, the Plackett-Burman screening (Plackett and Burman 1946) and the Box-Behnken surface response plans (Box and Behnken 1960) will be sequentially considered for optimisation of limestone calcination.…”

Section: Introductionmentioning

confidence: 99%

Application of the response surface methodology to determine optimal conditions of castine calcination in a full-scale rotary kiln

Mbuya¹,

Kime

Kawama³

et al. 2019

Mineral Processing and Extractive Metallurgy

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The optimisation of the calcination process in industrial lime kilns is of particular importance because it affects the final quality of the lime, coal consumption, and pollutant emissions. This work investigated the effects of different operating variables of a full-scale rotary kiln on the minimisation of unburned castine and reactivity of produced lime. The L 8 (2 7 ) Plackett-Burman's experimental plan was used for screening the significant variables on the calcination yield and the quality of the lime. Sequentially, Box-Behnken design approach, L 15 (3 3 ), under Response Surface Methodology (RSM) was used to determine the best combination of the variables optimising the calcination of castine. Quadratic models were developed to characterise the influence of selected significant variables, temperature of the smoke chamber (x 1 = 400, 500, and 550°C), kiln rotational speed (x 2 = 120, 90, and 70 s/revolution) and coal flow rate (x 4 = 0.5, 0.7, and 1.0 t/h), on the responses obtained. Under optimised conditions, the lime produced yielded 0.93% of unburned castine and a reactivity of 93.96°C, corresponding to the configuration: x 1 = 120, x 2 = 0.5, and x 3 = 550°C. Analysis of variance was conducted to assess the strength of evidence of the developed models. Good correlation coefficients were obtained for unburned castine (R 2 = 0.92, p < 0.031) and reactivity (R 2 = 0.96, p < 0.006), indicating that the models developed could be used to estimate castine calcination response.

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Identification of the significant factors determining extractability of Ni and Cu after sulfation roasting of a PGM-bearing chromitite ore

Cited by 13 publications

References 40 publications

Cobalt and copper recovery from the ancient flotation tailings by selective sulfation roast - leaching process

Cobalt and copper recovery from the ancient flotation tailings by selective sulfation roast - leaching process

Evaluation of Microwave Intensified Vanadium Bearing-High Carbonaceous Shale Acid Extraction Process

Application of the response surface methodology to determine optimal conditions of castine calcination in a full-scale rotary kiln

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