Effects of temperature, CO content, and reduction time on the selective reduction of a limonitic 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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Migration and Aggregation Behavior of Nickel and Iron in Low Grade Laterite Ore with New Additives

Metals ◽

10.3390/met11122033 ◽

2021 ◽

Vol 11 (12) ◽

pp. 2033

Author(s):

Yuanbo Wang ◽

Chaoqun Nie ◽

Bo Li ◽

Yonggang Wei

Keyword(s):

Calcium Fluoride ◽

Low Grade ◽

High Grade ◽

Recovery Efficiency ◽

Optimum Conditions ◽

X Ray Diffraction ◽

Aggregation Effect ◽

Activating Agent ◽

Effects Of Temperature ◽

Laterite Ore

This study focused on the preparation of high-grade ferronickel concentrate, the behavior of efficient migration and the polymerization of ferronickel particles during reduction roasting, by adding calcium fluoride and a ferronickel concentrate to low-grade laterite ore from Yunnan. The effects of temperature, holding time, reductant content, ferronickel concentrate content and magnetic field intensity on the preparation of the ferronickel concentrate were studied and the optimum conditions were determined as follows: 30% ferronickel concentrate (metal Ni-4.68%, metal Fe-45.0%), 8% coal, 7% calcium fluoride, reduction temperature of 1250 °C, reduction time of 60 min and the intensity of magnetic separation is 150 mT. The proportion of nickel and iron in ferronickel concentrate was 88.7% (metal Ni-8.62%, metal Fe-80.1%), and the recovery efficiency of nickel and iron are 98.8% and 82.4%, respectively. X-ray diffraction and scanning electron microscopy indicated that ferronickel-concentrate, as an activating agent, improved the aggregation effect of ferronickel particles. The efficient migration and polymerization of ferronickel particles in the ore significantly increased the size of the ferronickel particles with additives, therefore a high-grade ferronickel concentrate was prepared, and the reduction and recovery efficiency of laterite nickel ore was improved.

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