Selective reduction of an Australian garnieritic laterite ore

AbstractNickeliferous limonitic laterite ores are becoming increasingly attractive as a source of metallic nickel as the costs associated with recovering nickel from the sulphide ores increase. Unlike the sulphide ores, however, the laterite ores are not amenable to concentration by conventional mineral processing techniques such as froth flotation. One potential concentrating method would be the pyrometallurgical solid state reduction of the nickeliferous limonitic ores at relatively low temperatures, followed by beneficiation via magnetic separation. A number of reductants can be utilized in the reduction step, and in this research, a thermodynamic model has been developed to investigate the reduction of a nickeliferous limonitic laterite by hydrogen. The nickel recovery to the ferronickel phase was predicted to be greater than 95 % at temperatures of 673–873 K. Reductant additions above the stoichiometric requirement resulted in high recoveries over a wider temperature range, but the nickel grade of the ferronickel decreased.

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Research on Selective Reduction of Laterite Nickel Ore by CO2/H2 Mixed Gas

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1025-1026.814 ◽

2014 ◽

Vol 1025-1026 ◽

pp. 814-819

Author(s):

Song Chen ◽

Shu Qiang Guo ◽

Yu Ling Xu ◽

Lan Jiang ◽

Wei Zhong Ding

Keyword(s):

Activity Theory ◽

Thermodynamic Analysis ◽

Calculation Result ◽

Gas Flow ◽

Selective Reduction ◽

Mixed Gas ◽

Metallization Rate ◽

Lateritic Nickel ◽

Laterite Ore

In this paper, thermodynamic analysis on reduction of lateritic nickel ore by CO2/H2 mixed gas was performed based on activity theory. Effects of CO2/H2 ratio and temperature on selective reduction of laterite ore were investigated. The calculation result shows that the metallization of Fe and Ni could be promoted by each other because of the variation of the Fe and Ni activity, which accounts for the inescapability of Fe metallization. When laterite nickel ore was reduced by mixed gas with a CO2/H2 ratio of 9/1 and a gas flow of 100mL/min at 800°C for 1h, a product with a Ni metallization rate over 95% and a Ni/Fe ratio as much as 2.6 was prepared.

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Effects of temperature, CO content, and reduction time on the selective reduction of a limonitic laterite ore

Minerals Engineering ◽

10.1016/j.mineng.2021.107277 ◽

2021 ◽

Vol 174 ◽

pp. 107277

Author(s):

Ningjie Sun ◽

Zhe Wang ◽

Zhancheng Guo ◽

Guangqing Zhang ◽

Tao Qi

Keyword(s):

Selective Reduction ◽

Reduction Time ◽

Effects Of Temperature ◽

Laterite Ore

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The effect of sulfur, temperature, holding time and reductant on the selective reduction of limonite ore

10.21203/rs.3.rs-65184/v1 ◽

2020 ◽

Author(s):

Fathan Bahfie ◽

Achmad Shofi ◽

Fajar Nurjaman ◽

Ulin Herlina ◽

Nanda Ayu Septiana ◽

...

Keyword(s):

Grain Size ◽

Metal Oxide ◽

Magnetic Separation ◽

Selective Reduction ◽

Holding Time ◽

Average Grain Size ◽

Laterite Ore

Abstract Laterite ore is used as the manufacture of ferronickel. One method that can increase the levels of nickel in limonite ore is selective reduction. Selective reduction is a process to reduce the metal oxide to the metal with additives. The selective reduction of limonite ore by using the reductant 5%, 10%, and 15% and the sulfur 10 % as additive. The process of selective reduction is performed at the temperature of 950, 1050, and 1150°C with a holding time of 60, 90, and 120 minutes and followed by magnetic separation to separate between the concentrate and tailings. AAS characterization indicates the optimum value at the temperature of 1150°C with 5% reductant and the reduction of the holding time for 60 minutes which give the effect on the grade and recovery of nickel those are 3.72wt% and 95.67%, respectively. The decreasing of grain size of ferronickel in the sample form an average grain size of 38.07μm and the forming of FeS phase which is caused the addition of sulfur.

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Metal-Free Photoredox-Catalyzed C–H/C–H Coupling of Arenes Enabled by Interrupted Pummerer Activation

10.26434/chemrxiv.9158564 ◽

2019 ◽

Author(s):

Miles Aukland ◽

Mindaugas Šiaučiulis ◽

Adam West ◽

Gregory Perry ◽

David Procter

Keyword(s):

Natural Product ◽

Selective Reduction ◽

Cross Coupling ◽

One Pot ◽

Complex Molecules ◽

Pummerer Reaction ◽

Metal Free ◽

Bond Forming ◽

Coupling Partner ◽

Bioactive Natural Product

<p>Aryl–aryl cross-coupling constitutes one of the most widely used procedures for the synthesis of high-value materials, ranging from pharmaceuticals to organic electronics and conducting polymers. The assembly of (hetero)biaryl scaffolds generally requires multiple steps; coupling partners must be functionalized before the key bond-forming event is considered. Thus, the development of selective C–H arylation processes in arenes, that side-step the need for prefunctionalized partners, is crucial for streamlining the construction of these key architectures. Here we report an expedient, one-pot assembly of (hetero)biaryl motifs using photocatalysis and two non-prefunctionalized arene partners. The approach is underpinned by the activation of a C–H bond in an arene coupling partner using the interrupted Pummerer reaction. A unique pairing of the organic photoredox catalyst and the intermediate dibenzothiophenium salts enables highly selective reduction in the presence of sensitive functionalities. The utility of the metal-free, one-pot strategy is exemplified by the synthesis of a bioactive natural product and the modification of complex molecules of societal importance.</p>

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