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Ma B.,Beijing General Research Institute of Mining And Metallurgy | Ma B.,National Engineering Technology Research Center for Comprehensive Utilization of Metal Mineral Resources | Wang C.,Beijing General Research Institute of Mining And Metallurgy | Wang C.,National Engineering Technology Research Center for Comprehensive Utilization of Metal Mineral Resources | And 6 more authors.
Minerals Engineering | Year: 2013

The selective extraction of nickel and cobalt over iron from an Indonesian limonitic laterite was investigated using nitric acid pressure leaching (NAPL). The mineralogical analysis showed that the major minerals were goethite and magnetite, and the content of the divalent iron was as high as 7.06%. Nickel and cobalt were mainly distributed in these two minerals; however, the distribution was non-uniform. A series experiments were conducted to examine the basic parameters and propose the optimal conditions for the extraction. When the ore was treated via HPAL under the optimal condition, the extracted nickel and cobalt were less than 75%, and the iron concentration in the leach liquor was over 12.5 g/L. By contrast, over 85% of nickel and cobalt were extracted and about 1.8 g/L iron was achieved using NAPL. The loss of nickel and cobalt can be mainly attributed to the undissolved magnetite and manganese minerals. The leaching process of NAPL is a dissolution-oxidation-precipitation mechanism, and in this process nitric acid acts as both a lixiviant and an oxidant. The formation of hematite results in a low iron concentration in the leach liquor without oxygen injected. Meanwhile, the oxidation and the precipitation of dissolved divalent iron results in a calculated savings in acid consumption of about 120 kg nitric acid per ton of ore can be obtained, which is equal to over 93 kg of sulfuric acid per ton of ore. Moreover, lower residual acid (20 g/L nitric acid) is a significant advantage of NAPL. The iron residues had a high iron content (>56 wt%) with no sulfur, making it suitable as raw materials for ironmaking. © 2013 Elsevier Ltd. All rights reserved. Source


Ma B.,Beijing General Research Institute of Mining And Metallurgy | Ma B.,National Engineering Technology Research Center for Comprehensive Utilization of Metal Mineral Resources | Wang C.,Beijing General Research Institute of Mining And Metallurgy | Wang C.,National Engineering Technology Research Center for Comprehensive Utilization of Metal Mineral Resources | And 6 more authors.
International Journal of Mineral Processing | Year: 2013

Nickel, cobalt, iron, and chromium are potentially valuable metals contained in laterite ores. Mineralogical analysis results revealed that the laterite from the Philippines contained predominantly fine iron oxide/oxyhydroxide, as well as a small amount of slightly coarse chromite and gangue mineral aggregates. Additionally, the coarse cores of minerals were closely surrounded and adhered by a matrix of fine minerals. The chemical components were closely related to the particle sizes of constituent minerals. Based on these findings, a classification method was devised and three samples with different components were obtained under the proposed optimal scheme. About 50% of Mg and Si were removed from the fine fraction (S1) and more than 85% of Fe and Ni distributed in it. The other two samples are Co-riched and the content in the intermediate fraction (S2) and the coarse fraction (S3) was 0.22% and 0.28%, respectively. Cr in S2 was as high as 6.75%. A technical route was designed for processing these three samples and the preliminary tests indicate that the recoveries of Fe, Ni, Co and Cr can reach about 94%, 85%, 70% and 30%, respectively; Fe content in the prepared iron concentrate is over 61% and Cr content in the obtained Cr-riched residue is above 12%. Consequently, comprehensive utilization of Philippine laterite ore can be realized following the proposed route. © 2013 Elsevier B.V. Source

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