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18 pages, 23303 KiB

Open AccessArticle

Effective Utilization of Limonitic Nickel Laterite via Pressurized Densification Process and Its Relevant Mechanism

by Yuxiao Xue, Deqing Zhu, Jian Pan, Zhengqi Guo, Congcong Yang, Hongyu Tian, Xi Duan, Qingzhou Huang, Liaoting Pan and Xuezhong Huang

Minerals 2020, 10(9), 750; https://doi.org/10.3390/min10090750 - 25 Aug 2020

Cited by 17 | Viewed by 2178

Abstract

Limonitic laterite contains low iron and nickel grades and much high smelting minerals and loss on ignition (LOI), identified as refractory iron ore for sintering. Thus, sinter pot tests of limonitic laterite via pressurized densification sintering and its intensification mechanism were conducted, and [...] Read more.

Limonitic laterite contains low iron and nickel grades and much high smelting minerals and loss on ignition (LOI), identified as refractory iron ore for sintering. Thus, sinter pot tests of limonitic laterite via pressurized densification sintering and its intensification mechanism were conducted, and the industrial application prospect was explored. The results indicate that the sintering performance of the limonitic laterite of the new process is significantly improved with the tumble index and productivity increased by 19.2% and 18.6%, respectively, and solid fuel rate lowered by 10.3%. The external pressure field promotes the synchronization of heat front velocity and combustion front velocity for better sintering heat and mass transfer conditions, which also greatly improves the mineral compositions and microstructure of the product sinter. The microstructure is converted from large thin-wall pores into small thin-wall or large thick-wall pores with the sinter porosity decreased by 42.4%. Much close interlocking texture between hercynite and silico-ferrite of calcium and alumina (SFCA) is formed with hercynite grains aggregation and growth, and SFCA amount substantially increased. The better sintering performance will bring about a remarkable economic benefit of 282.78 million RMB/a if the industrial application is implemented. The pressurized densification sintering process is considered as one of the effective technologies for improving limonitic laterite sintering. Full article

(This article belongs to the Special Issue The Processing of Alternative and Urban Ores)

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12 pages, 5432 KiB

Open AccessArticle

The Effect of Alkali Roasting Pretreatment on Nickel Extraction from Limonite Ore by Using Dissolved SO₂-Air

by Winny Wulandari, Meiyer Marthen Kinda, Rahmaditha Murida and Tjokorde Walmiki Samadhi

Minerals 2020, 10(8), 701; https://doi.org/10.3390/min10080701 - 7 Aug 2020

Cited by 2 | Viewed by 3843

Abstract

Extraction of limonite ore using dissolved SO₂–air is an alternative hydrometallurgical method for nickel recovery. This process is carried out at atmospheric pressure and is shown to have good selectivity of nickel over iron, but with a low recovery yield. The [...] Read more.

Extraction of limonite ore using dissolved SO₂–air is an alternative hydrometallurgical method for nickel recovery. This process is carried out at atmospheric pressure and is shown to have good selectivity of nickel over iron, but with a low recovery yield. The literature refers to the application of alkali roasting as pretreatment in laterite ore leaching to increase nickel recovery. Thus, this study aims to apply the combination method of alkali roasting and leaching to extract nickel from limonite ore (1.33% Ni, 46.61% Fe) from the Southeast Sulawesi region. Three alkali compounds were included in the study (NaOH, Na₂CO₃ and Na₂SO₄). The batch-leaching process was carried out at pH 1 and 3 and temperatures of 55 and 80

°

C for 180 min. The leach liquors were sampled at 15, 60, 90 and 120 min, and concentrations of the extracted metals were measured by Atomic Absorption Spectrometry (AAS). A mineralogy characterization of the raw ore and its residue after leaching was undertaken by using X-Ray Diffraction (XRD), while the thermal decomposition behavior of the ore was characterized by Thermogravimetry Analyzer (TGA)/Differential Scanning Calorimetry (DSC). The addition of Na₂CO₃, Na₂SO₄ and NaOH in the ore pretreatment increases nickel recovery from 14.80% without alkali roasting to 23.99%, 28.15% and 39.22%, respectively. The optimum extraction condition for nickel recovery is at pH 1 and a temperature of 80

°

C. However, the highest Ni/Fe selectivity of 24,947 is obtained at pH 3 and a temperature of 80

°

C, preceded by roasting in the absence of alkali. Compared to other hydrometallurgical processes, the process studied in this work exhibits lower recovery, but provides an alternative to extract nickel from low-grade limonite ore. Full article

(This article belongs to the Special Issue The Processing of Alternative and Urban Ores)

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19 pages, 4001 KiB

Open AccessArticle

Effects of Sample Shapes and Thickness on Distribution of Temperature inside the Mineral Ilmenite Due to Microwave Heating

by Mas Irfan P. Hidayat, Dian M. Felicia, Ferdiansyah I. Rafandi and Affiani Machmudah

Minerals 2020, 10(4), 382; https://doi.org/10.3390/min10040382 - 23 Apr 2020

Cited by 10 | Viewed by 2944

Abstract

The study of interaction between microwave radiation and minerals is gaining increasing interest in the field of minerals and material processing. Further studies are, however, still required to deepen the understanding of such microwave heating mechanisms in order to develop innovative techniques for [...] Read more.

The study of interaction between microwave radiation and minerals is gaining increasing interest in the field of minerals and material processing. Further studies are, however, still required to deepen the understanding of such microwave heating mechanisms in order to develop innovative techniques for mineral treatment using microwave heating. In this paper, effects of sample shapes and thickness on the distribution of temperature inside the mineral ilmenite (FeTiO₃) due to microwave heating were numerically studied using the finite element (FE) method. The analysis was carried out in such a way that the flux of microwave energy was converted into an equivalent amount of heat generation in the mineral through the Poynting theorem of conservation of energy for the electromagnetic field. In this study, as a first attempt, the cylinder and slab of ilmenite were modeled to be irradiated from top and bottom surfaces with the variation of cylinder and slab thicknesses. Temperature-dependent material properties of ilmenite were taken into account in the FE simulation. Corresponding boundary conditions were then applied accordingly to the cylinder and slab of ilmenite with comparable characteristic length. Numerical results showed that, in terms of temperature differences between locations having maximum and minimum temperatures, slab geometries tended to produce higher values in comparison to those of cylinder geometries with the thickness variation, while the profiles of temperature inside the ilmenite samples were similar for both geometries. For the same duration of microwave heating, the slab geometry, hence, induced greater non-uniformity of temperature inside the ilmenite. It was also observed that, for the ilmenite samples with thickness value greater than 1.5 cm, the hotspot locations were not in the center of the sample, but on the surface of sample. Moreover, from several thickness values considered in this study, the ilmenite sample with thickness value of 3 cm gave a good trade-off between the maximum temperature value attained and temperature differences inside the sample, for both geometries. Thus, the shape and thickness of ilmenite samples affect the effectiveness of microwave heating of ilmenite, in terms of maximum temperature attained, temperature differences, and uniformity of temperature. Full article

(This article belongs to the Special Issue The Processing of Alternative and Urban Ores)

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14 pages, 5971 KiB

Open AccessFeature PaperArticle

Thermodynamic and Experimental Study on Efficient Extraction of Valuable Metals from Polymetallic Nodules

by Kun Su, Xiaodong Ma, John Parianos and Baojun Zhao

Minerals 2020, 10(4), 360; https://doi.org/10.3390/min10040360 - 17 Apr 2020

Cited by 12 | Viewed by 4392

Abstract

Polymetallic nodules are promising resources for the extraction of valuable metals such as copper, nickel, and cobalt, as well as manganese alloys. To achieve efficient extraction of useful metals from the emerging resource, high-temperature carbothermic reduction of nodules was investigated by optimizing the [...] Read more.

Polymetallic nodules are promising resources for the extraction of valuable metals such as copper, nickel, and cobalt, as well as manganese alloys. To achieve efficient extraction of useful metals from the emerging resource, high-temperature carbothermic reduction of nodules was investigated by optimizing the reductant addition, slag and alloy systems. Thermochemical software FactSage was used to predict the liquidus temperature of the slag system, which is not sensitive to FeO, CaO and Al₂O₃, but decreases significantly with decreasing MnO/SiO₂ mass ratio. The experiments were designed to reduce the oxides of Cu, Co and Ni completely, and reduce FeO_x partially depending on the amount of graphite addition while leaving the residual slag for further processing into ferromanganese and/or silicomanganese alloys. Co, Cu and Ni concentrations in the alloy decreased with increasing graphite addition. The optimal reduction condition was reached by adding 4 wt% graphite at the MnO/SiO₂ mass ratio of 1.6 in slag. The most effective metal-slag separation was achieved at 1350 °C, which enables the smelting reduction to be carried out in various furnaces. Full article

(This article belongs to the Special Issue The Processing of Alternative and Urban Ores)

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10 pages, 2773 KiB

Open AccessFeature PaperArticle

Effect of Graphite on Copper Bioleaching from Waste Printed Circuit Boards

by Linlin Tong, Qianfei Zhao, Ali Reza Kamali, Wolfgang Sand and Hongying Yang

Minerals 2020, 10(1), 79; https://doi.org/10.3390/min10010079 - 19 Jan 2020

Cited by 13 | Viewed by 3242

Abstract

The efficient extraction of copper as a valuable metal from waste printed circuit boards (WPCBs) is currently attracting growing interest. Here, we systematically investigated the impact of bacteria on the efficiency of copper leaching from WPCBs, and evaluated the effect of graphite on [...] Read more.

The efficient extraction of copper as a valuable metal from waste printed circuit boards (WPCBs) is currently attracting growing interest. Here, we systematically investigated the impact of bacteria on the efficiency of copper leaching from WPCBs, and evaluated the effect of graphite on bioleaching performance. The HQ0211 bacteria culture containing Acidithiobacillus ferrooxidans, Ferroplasma acidiphilum, and Leptospirillum ferriphilum enhanced Cu-leaching performance in either ferric sulfate and sulfuric acid leaching, so a final leaching of up to 76.2% was recorded after 5 days. With the addition of graphite, the percentage of copper leaching could be increased to 80.5%. Single-factor experiments confirmed the compatibility of graphite with the HQ0211 culture, and identified the optimal pulp density of WPCBs, the initial pH, and the graphite content to be 2% (w/v), 1.6, and 2.5 g/L, respectively. Full article

(This article belongs to the Special Issue The Processing of Alternative and Urban Ores)

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21 pages, 6282 KiB

Open AccessArticle

Sulfides Formation in Carbothermic Reduction of Saprolitic Nickel Laterite Ore Using Low-Rank Coals and Additives: A Thermodynamic Simulation Analysis

by Sri Harjanto and M. Akbar Rhamdhani

Minerals 2019, 9(10), 631; https://doi.org/10.3390/min9100631 - 15 Oct 2019

Cited by 10 | Viewed by 3162

Abstract

In this paper, a systematic thermodynamic analysis of carbothermic reduction of saprolitic nickel laterite ore was carried out. Different carbon sources—such as pure C, sub-bituminous, and lignite—were used for the carbothermic reduction at 1000 °C (1273 K). The effect of the different additives—such [...] Read more.

In this paper, a systematic thermodynamic analysis of carbothermic reduction of saprolitic nickel laterite ore was carried out. Different carbon sources—such as pure C, sub-bituminous, and lignite—were used for the carbothermic reduction at 1000 °C (1273 K). The effect of the different additives—such as S, FeS, Na₂S, Na₂SO₄, and CaSO₄—was also systematically evaluated. The thermodynamic calculations suggested that the use of low rank coals (sub-bituminous and lignite) do not significantly affect the nickel grade and nickel recovery, but affect the total metals recovery. The presence of S in these C-sources promoted the formation of sulfides. At 1000 °C (1273 K), only a small amount of C-sources (C, sub-bituminous, lignite) are needed to significantly metallize the nickel in the laterite, i.e., between 4–6 wt %. The additives S, FeS, Na₂S, Na₂SO₄, and CaSO₄ were predicted to promote the formation of liquid sulfides, and at the same time reduce the formation of the (Fe,Ni) alloy, thus reducing the nickel and total metals recovery. Therefore, consideration is needed to balance the two aspects. The calculations predicted that S, Na₂SO₄, and CaSO₄ additions provided an increase in the nickel grade; while FeS and Na₂S reduced the nickel grade. Full article

(This article belongs to the Special Issue The Processing of Alternative and Urban Ores)

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19 pages, 2229 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Recovery of Metals from Waste Lithium Ion Battery Leachates Using Biogenic Hydrogen Sulfide

by Giles Calvert, Anna H. Kaksonen, Ka Yu Cheng, Jonovan Van Yken, Barbara Chang and Naomi J. Boxall

Minerals 2019, 9(9), 563; https://doi.org/10.3390/min9090563 - 17 Sep 2019

Cited by 25 | Viewed by 6097

Abstract

Lithium ion battery (LIB) waste is increasing globally and contains an abundance of valuable metals that can be recovered for re-use. This study aimed to evaluate the recovery of metals from LIB waste leachate using hydrogen sulfide generated by a consortium of sulfate-reducing [...] Read more.

Lithium ion battery (LIB) waste is increasing globally and contains an abundance of valuable metals that can be recovered for re-use. This study aimed to evaluate the recovery of metals from LIB waste leachate using hydrogen sulfide generated by a consortium of sulfate-reducing bacteria (SRB) in a lactate-fed fluidised bed reactor (FBR). The microbial community analysis showed Desulfovibrio as the most abundant genus in a dynamic and diverse bioreactor consortium. During periods of biogenic hydrogen sulfide production, the average dissolved sulfide concentration was 507 mg L⁻¹ and the average volumetric sulfate reduction rate was 278 mg L⁻¹ d⁻¹. Over 99% precipitation efficiency was achieved for Al, Ni, Co, and Cu using biogenic sulfide and NaOH, accounting for 96% of the metal value contained in the LIB waste leachate. The purity indices of the precipitates were highest for Co, being above 0.7 for the precipitate at pH 10. However, the process was not selective for individual metals due to simultaneous precipitation and the complexity of the metal content of the LIB waste. Overall, the process facilitated the production of high value mixed metal precipitates, which could be purified further or used as feedstock for other processes, such as the production of steel. Full article

(This article belongs to the Special Issue The Processing of Alternative and Urban Ores)

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Review

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19 pages, 2666 KiB

Open AccessReview

Platinum Group Elements in Geosphere and Anthroposphere: Interplay among the Global Reserves, Urban Ores, Markets and Circular Economy

by Juris Burlakovs, Zane Vincevica-Gaile, Maris Krievans, Yahya Jani, Mika Horttanainen, Kaur-Mikk Pehme, Elina Dace, Roy Hendroko Setyobudi, Jovita Pilecka, Gintaras Denafas, Inga Grinfelde, Amit Bhatnagar, Vasiliy Rud, Vita Rudovica, Ronald L. Mersky, Olga Anne, Mait Kriipsalu, Ruta Ozola-Davidane, Toomas Tamm and Maris Klavins

Minerals 2020, 10(6), 558; https://doi.org/10.3390/min10060558 - 21 Jun 2020

Cited by 19 | Viewed by 6105

Abstract

Industrial and strategic significance of platinum group elements (PGEs)—Os, Ir, Ru, Rh, Pd, Pt—makes them irreplaceable; furthermore, some PGEs are used by investors as “safe heaven” assets traded in the commodity markets. This review analyzes PGEs from various aspects: their place in the [...] Read more.

Industrial and strategic significance of platinum group elements (PGEs)—Os, Ir, Ru, Rh, Pd, Pt—makes them irreplaceable; furthermore, some PGEs are used by investors as “safe heaven” assets traded in the commodity markets. This review analyzes PGEs from various aspects: their place in the geosphere, destiny in the anthroposphere, and opportunity in the economy considering interactions among the exploration, recycling of urban ores, trade markets, speculative rhetoric, and changes required for successful technological progress towards the implementation of sustainability. The global market of PGEs is driven by several concerns: costs for extraction/recycling; logistics; the demand of industries; policies of waste management. Diversity of application and specific chemical properties, as well as improper waste management, make the recycling of PGEs complicated. The processing approach depends on composition and the amount of available waste material, and so therefore urban ores are a significant source of PGEs, especially when the supply of elements is limited by geopolitical or market tensions. Recycling potential of urban ores is particularly important in a long-term view disregarding short-term economic fluctuations, and it should influence investment flows in the advancement of innovation. Full article

(This article belongs to the Special Issue The Processing of Alternative and Urban Ores)

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