Leaching of a Cu-Co ore from Congo using sulphuric acidhydrogen peroxide leachants

Abstract

A Cu-Co ore from Katinga Province, the Republic of Congo containing 1.5% Co and 1.6% Cu was tested to determine the leachability of Cu and Co using sulphuric acid and hydrogen peroxide mixtures at different conditions. Without hydrogen peroxide, the maximum extraction of copper and cobalt were found to be ~80% and ~15%, respectively when the acid concentration was varied between 0.36 - 1.1M. When hydrogen peroxide was added (0.008-0.042M), Cu recovery was enhanced to ~90%. Recoveries of ~90% of Co could be achieved at 20ºC, using leachants consisting of 0.36M sulphuric acid and 0.025M hydrogen peroxide after 3 hours. The reaction time to reach 90% Co extraction was reduced to less than 2 hours at 30ºC. Stabcal modelling of the Eh-pH diagrams shows the importance of hydrogen peroxide as a reductant. The decrease of solution potential (300-350 mV) by adding hydrogen peroxide was confirmed by Eh measurements during the tests. The leaching follows the shrinking core model kinetics, where the rate constant is linearly dependent on hydrogen peroxide concentration in the range 0-0.025M and proportional to (1/r2) where r is the average radius of the mineral particles. The activation energy for the leaching process is 72.3 kJ/mol

Valuable Metals—Recovery Processes, Current Trends, and Recycling Strategies

“…In the Sherrit-Gordon process,sulfidic cobalt ores are leached with aqueous ammonia solution. [40] In another case,itwas shown with the example of an Indian laterite that the presence of SO 2 has ab eneficial effect on leaching with sulfuric acid. [26] Av apor metallurgical procedure is available as an alternative to pyrometallurgical or hydrometallurgicalt reat- Figure 5.…”

“…[26] More recent approaches are based on the use of hydrogen peroxide.Asanexample,90% of the Co of aCu-Co ore from the Congo (Co content 1.5 wt %) can be successfully extracted at 30 8 8Cw ithin 2hby adding H 2 O 2 to the leaching process with sulfuric acid, whereas in the absence of H 2 O 2 only 15 %was obtained. [40] In another case,itwas shown with the example of an Indian laterite that the presence of SO 2 has ab eneficial effect on leaching with sulfuric acid. In this way, the cobalt leaching rate climbed from 85 %t o9 7%,w hile impurities largely remained in the solid residue.…”

Wertmetalle – Gewinnungsverfahren, aktuelle Trends und Recyclingstrategien

“…So ließ sich Co aus einem Cu‐Co‐Erz aus dem Kongo (Cobaltgehalt 1.5 Gew.‐%) durch Zugabe von H 2 O 2 zum schwefelsauren Laugungsprozess bereits bei 30 °C innerhalb von 2 h zu 90 % extrahieren. Ohne H 2 O 2 ‐Zusatz wurden lediglich 15 % mobilisiert . In einem anderen Fall wurde an einem indischen Laterit gezeigt, dass sich die Gegenwart von SO 2 bei schwefelsaurem Aufschluss vorteilhaft auswirkt.…”

Copper and cobalt recovery from pyrite ashes of a sulphuric acid plant

“…The use of hydrogen peroxide (H 2 O 2 ) is known to increase the rate of copper and cobalt dissolution (Mantuano et al, 2006;Seo et al, 2013). In hydrogen peroxide-added sulphuric acid leaching tests, addition of hydrogen peroxide was detected to decrease the Eh (redox potential) of the solution by 300-350 mV.…”