Defluorination of bastnaesite by steam roasting process

Author(s):  
Shuchen Sun ◽  
Ying Yang ◽  
Ganfeng Tu ◽  
Faxin Xiao
Keyword(s):  
2008 ◽  
Vol 73 (3) ◽  
pp. S165-S171 ◽  
Author(s):  
I. López-Galilea ◽  
I. Andriot ◽  
M. P. de Peña ◽  
C. Cid ◽  
E. Guichard

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 730
Author(s):  
Wen Yu ◽  
Xiaojin Wen ◽  
Wei Liu ◽  
Jiangan Chen

In this study, the carbothermic reduction and nitridation mechanism of vanadium-bearing titanomagnetite concentrate are investigated in terms of phase transformation, microstructure transformation, and thermodynamic analyses. The differences in the reaction behavior of titanomagnetite and ilmenite in vanadium-bearing titanomagnetite concentrate, as well as the distribution characteristic of V in the roasted products, are emphatically studied. It is observed that the reaction sequences of titanomagnetite and ilmenite transformations into nitride are as follows: Fe3−xTixO4→Fe2TiO4→FeTiO3→M3O5→(Ti, V)(N, C); FeTiO3→M3O5→Ti(N, C). The reduction of M3O5 to TiN is the rate-limiting step of the entire reaction, and metal iron is an important medium for transferring C for the reduction of M3O5. Titanomagnetite is faster to convert into nitride than ilmenite is, and the reasons for this are discussed in detail. During the entire roasting process, V mainly coexists with Ti and seems to facilitate the conversion of titanium oxides into (Ti, V)(N, C).


Author(s):  
Hailin Long ◽  
Kaihua Chen ◽  
Caixia Xu ◽  
Haoyu Li ◽  
Huimin Xie ◽  
...  

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 558
Author(s):  
Hui Li ◽  
Wei Xiao ◽  
Jianping Jin ◽  
Yuexin Han

The oxidation roasting of carbon-bearing micro-fine gold can eliminate or weaken the robbing effect of carbonaceous materials and clay, and destroy the encapsulation of micro-fine gold. The micropores produced by gas escaping during the roasting process are conducive to the diffusion of leaching agents, thus enhancing the cyanide leaching of gold. In this paper, the influence of the aeration rate during roasting on the leaching rate of fine-grained carbonaceous gold ore and its mechanism were studied using thermodynamic calculations, crystal structure analysis, surface chemical groups and bonds analysis, microporous structure analysis, and surface morphology detection. Under suitable roasting conditions, the carbonaceous and pyrite in the ore are oxidized, while carbonate minerals such as dolomite and calcite as well as clay minerals are decomposed, and the gold-robbing materials lose their activity. The experimental results have theoretical and practical significance for the popularization and application of oxidation roasting technology of fine carbon-bearing gold ore.


2011 ◽  
Vol 24 (2) ◽  
pp. 244-275 ◽  
Author(s):  
Bradley W. Bolling ◽  
C.-Y. Oliver Chen ◽  
Diane L. McKay ◽  
Jeffrey B. Blumberg

Tree nuts contain an array of phytochemicals including carotenoids, phenolic acids, phytosterols and polyphenolic compounds such as flavonoids, proanthocyanidins (PAC) and stilbenes, all of which are included in nutrient databases, as well as phytates, sphingolipids, alkylphenols and lignans, which are not. The phytochemical content of tree nuts can vary considerably by nut type, genotype, pre- and post-harvest conditions, as well as storage conditions. Genotype affects phenolic acids, flavonoids, stilbenes and phytosterols, but data are lacking for many other phytochemical classes. During the roasting process, tree nut isoflavones, flavanols and flavonols were found to be more resistant to heat than the anthocyanins, PAC and trans-resveratrol. The choice of solvents used for extracting polyphenols and phytosterols significantly affects their quantification, and studies validating these methods for tree nut phytochemicals are lacking. The phytochemicals found in tree nuts have been associated with antioxidant, anti-inflammatory, anti-proliferative, antiviral, chemopreventive and hypocholesterolaemic actions, all of which are known to affect the initiation and progression of several pathogenic processes. While tree nut phytochemicals are bioaccessible and bioavailable in humans, the number of intervention trials conducted to date is limited. The objectives of the present review are to summarise tree nut: (1) phytochemicals; (2) phytochemical content included in nutrient databases and current publications; (3) phytochemicals affected by pre- and post-harvest conditions and analytical methodology; and (4) bioactivity and health benefits in humans.


2005 ◽  
Vol 82 (2) ◽  
pp. 383-388 ◽  
Author(s):  
D. Minić ◽  
Nada Štrbac ◽  
I. Mihajlović ◽  
Ž. Živković

JOM ◽  
2011 ◽  
Vol 63 (5) ◽  
pp. 55-59 ◽  
Author(s):  
Mira B. Cocić ◽  
Mihovil M. Logar ◽  
Saša Lj. Cocić ◽  
Snežana S. Dević ◽  
Dragan M. Manasijević

2021 ◽  
Vol 172 ◽  
pp. 106996
Author(s):  
Jingxia Fu ◽  
Yajing Zhao ◽  
Jinguang Chen ◽  
Kai Liu ◽  
Yingdong Li ◽  
...  
Keyword(s):  

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