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Recovery of Critical and Rare Earth Elements from Spent Batteries
Published in Abhilash, Ata Akcil, Critical and Rare Earth Elements, 2019
Chunwei Liu, Hongbin Cao, Yi Zhang, Zhi Sun
Besides vacuum carbothermal reduction, sulfation roasting is also a promising method to recycle spent LIBs in mild operating conditions. Wang et al. [96–98] studied the elemental transformation during sulfation roasting of spent LiCoO2. The sulfation was done by mixing a certain amount of sulfate (K2S2O7 or NaHSO4) with LiCoO2 powder; then the mixture was roasted for 0.5 h at a temperature less than 600°C. It was demonstrated that Co and Li gradually transform to different forms of sulfates, accompanied with release of SO2, O2 gases. More recently, Wang et al. [98] studied the occurrence evolution of the Li and Co elements during sulfation roasting and water leaching. They found that by controlling the amount of NaHSO4·H2O, Li and Co could be selectively transformed to LiNa(SO4) and Co3O4, which are easily separated by simple water leaching. SO3 was demonstrated to play a key role in high-temperature transformation. Compared to the traditional pyrometallurgical process, sulfation roasting consumes lower energy, but the application of sulfur triggers aggressive corrosion of the furnace due to the release of SO2 and SO3. Hence, it is still a challenge to implement sulfation roasting technologies at industrial level.
Roasting Equipment for Coffee Processing
Published in Hii Ching Lik, Borém Flávio Meira, Drying and Roasting of Cocoa and Coffee, 2019
Vanúsia Maria Carneiro Nogueira, Thomas Koziorowski
Coffee is roasted by dry heating which, unlike what is usual for many other natural products, is terminated at relatively high temperatures of up to 250°C. The transmission of heat to the surface of the coffee beans takes place by means of convection, radiation and conduction. Heat conduction inside the beans progresses from the outside inward. The most important parameter in the roasting process is the specific quantity of thermal energy made available to the coffee beans. The coffee temperature profile, that is, the course of the coffee temperature throughout the roasting time, is dependent heavily on it. The temperature profile is therefore the decisive parameter for homogeneous roasting as well as for the physical changes and chemical reactions.
Carbothermic Processing of Copper–Cobalt Mineral Sulphide Concentrates and Slag Waste for the Extraction of Metallic Values
Published in Sheila Devasahayam, Kim Dowling, Manoj K. Mahapatra, Sustainability in the Mineral and Energy Sectors, 2016
Yotamu R. S. Hara, Animesh Jha
The purpose of roasting is to convert the mineral sulphides into acid-soluble compounds (e.g. metal sulphates) which is achieved by blowing oxygen into the feed of mineral sulphide concentrate. Individual and overall reactions occurring between the mineral sulphides and oxygen gas are shown in Equations 7.5 through 7.8. It is necessary to control both the reaction temperature and time of roasting by minimising the formation of sparingly soluble copper and cobalt ferrites for acid leaching by keeping the exothermic roast reaction temperature below 973 K (Rosenqvist, 1983). However, the unfavourable kinetic conditions below 973 K affect the lower than equilibrium concentrations of SO2 in the off-gas, which makes it difficult for use in the manufacture of sulphuric acid or elemental sulphur (Bodsworth, 1994; Davenport et al., 2002). It is well known in the non-ferrous industry that the failure to capture SO2 gas from off-gas leads to environmental threats not only due to the release of greenhouse gases, but also from the increased acidity of air, soil and water in the ambient eco-system of a non-ferrous metal operation. () () () ()
Multistage leaching of rare earth elements from primary source: a sustainable approach to avoid fluorine contamination by roasting with aluminum hydroxide
Published in Canadian Metallurgical Quarterly, 2023
Subsequently, a 100 g sample was mixed with 10 g of aluminium hydroxide homogenously in a porcelain boat, and then a mixed sample was roasted at 500°C for 1 h in a muffle furnace. It was allowed to cool for 2 h and then saved the roasted ore for further experimentation. Roasting can effectively promote mineral decomposition. The aim of roasting is to bring the metal to a more soluble state, to vaporise some impurities so as to make them harmless for subsequent leaching, and to make the metal compounds porous to facilitate dissolution. The results obtained from this study show that both REE (Ce, La) dissolution efficiencies increased nearly to 98% after roasting with aluminum hydroxide (Al(OH)3) and further leaching with hydrochloric acid curing and water leaching processes.
The Direct Leaching of Nickel Sulfide Flotation Concentrates – A Historic and State-of-the-Art Review Part III: Laboratory Investigations into Atmospheric Leach Processes
Published in Mineral Processing and Extractive Metallurgy Review, 2022
Nebeal Faris, Mark I. Pownceby, Warren J. Bruckard, Miao Chen
The sulfation roasting process has been researched in the past for the treatment of whole nickel sulfide ores and low-grade concentrates between the 1960s and 1990s (Yu, Utigard, and Barati 2014a). The sulfation roasting of base metal bearing iron sulfide concentrates was in commercial operation at the Falconbridge iron ore plant (Canada) and the Kokkola works (Finland) which were described in Part I of this review. Sulfation roasting is a process whereby sulfide concentrates are roasted under an oxidizing atmosphere with the objective of converting iron sulfides to oxides and non-ferrous metal sulfides to water-soluble sulfate salts. Different strategies have been proposed for achieving this such as (a) roasting under an atmosphere of SO2/SO3, (b) roasting to oxidize sulfides followed by sulfation of the calcine through addition of an alkali sulfate, (c) direct addition of an alkali sulfate to the concentrate during roasting and combinations thereof (Fletcher and Shelef 1963). Yu, Utigard, and Barati (2014a) initially investigated the sulfation roasting of a pentlandite concentrate from Sudbury (Canada) under an oxidizing atmosphere (air) in the absence of an alkali sulfate. Formation of Ni and Co sulfates occurred once the iron sulfides in the concentrate had been oxidized; however, temperatures above 650°C resulted in decomposition of the sulfates to their respective oxides. Extractabilities of Ni and Co from roasted calcines via water leaching were poor, the best results obtained being 20% and 40%, respectively, from the calcine after roasting at 650°C.
Review of Vanadium Production Part I: Primary Resources
Published in Mineral Processing and Extractive Metallurgy Review, 2022
Feng Gao, Afolabi Uthmon Olayiwola, Biao Liu, Shaona Wang, Hao Du, Jianzhong Li, Xindong Wang, Donghui Chen, Yi Zhang
In view of the foregoing, it is clear that technologies based on roasting have inherent disadvantages due to sluggish mass transfer during roasting as well as difficulty in process water recycling. Therefore, designing of new process based on hydrometallurgical methodology would be an attractive approach. In this regard, a new process featuring direct alkaline leaching has been proposed by the Institute of Process Engineering, Chinese Academy of Sciences, and practiced in Hebei Iron and Steel Group. The new process is demonstrated in Figure 12. Direct leaching of vanadium can be realized by using 40–60 wt. % alkaline solutions at 150–200°C under autogenous pressure (Zheng et al. 2012). Oxygen is continuously introduced into the reactor to oxidize the slag, and after oxidative alkaline leaching for 3–5 h, most vanadium (more than 90%) has been converted to Na3VO4 and dissolved in the alkaline solution(Wang et al. 2014a). The main impurity in the leaching process is Si, and its dissolution principle is as follows: