Recovery of metals from Cuban nickel tailings by leaching with organic acids followed by precipitation and magnetic separation.
The percolation leaching of the Cuban nickel tailings containing 0.34% Ni, 0.08% Co and 44.2% Fe was investigated by using tartaric and oxalic acids at different concentrations. About 70% Ni, 80% Co and 30% Fe were extracted after 5 days of leaching with the mixture of 0.15 mol/L tartaric acid and 0.05 mol/L oxalic acid at ambient temperature and normal pressure. Nickel and cobalt extraction of 80% as well as iron extraction of 50% were achieved from the pregnant solution by means of precipitation at 80 degrees C for 2h. The precipitation at ambient temperature led to a similar result after 16 days. Cobalt, nickel and iron oxalates were found in the precipitate by using the X-ray diffraction method. The regeneration of acids during the precipitation step made possible the reuse of the raffinate at the leaching step. Heating of the precipitate at 200 degrees C increased the metal concentration to 1.22% Ni and 0.33% Co, which can be fed in the existing nickel plant in Moa, Cuba. The magnetic processing of the leaching residues led to a non-magnetic product containing less than 20% Fe and a magnetic product containing more than 50% Fe.
Hernández
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High Institute of Mining and Metallurgy Dr. Antonio Núnez Jiménez, Moa, Cuba.
Banza
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AN
Gock
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D002264:Carboxylic Acids / Q000737:chemistry*; D011232:Chemical Precipitation; D003462:Cuba; D006863:Hydrogen-Ion Concentration; D008280:Magnetics; D008670:Metals / Q000737:chemistry* / Q000302:isolation & purification*; D009532:Nickel / Q000737:chemistry*; D019815:Oxalic Acid / Q000737:chemistry; D010084:Oxidation-Reduction; D012492:Salts / Q000737:chemistry; D012996:Solutions; D013644:Tartrates / Q000737:chemistry; D013696:Temperature; D013997:Time Factors
D002264:Carboxylic Acids; D008670:Metals; D012492:Salts; D012996:Solutions; D013644:Tartrates; D009532:Nickel; D019815:Oxalic Acid; C029768:tartaric acid