Recovery of Metallic Values From WC-Based Alloy Scraps

Authors: Gökhan ORHAN, Ercan AÇMA

Abstract: In this study, the recovery conditions of copper and cobalt metals from solutions containing 25-100 g Co/1 and 45-60 g Cu/1 obtaited during treatment of hard alloy scraps, by hydroxide precipation and reduction were determined. In initial experiments, it was found that copper hydroxide can be precipated with an efficiency of 99.9% with no kobalt precipitation by adding NaOH at 60 ^0C and pH = 4.5 for 0.5 hours. In the second step of precipitation, the solution from which copper and other empurities are removed, was used. In this run, it was shown that Co(OH)2 can be also precipitated with an efficiency of 99.9% using NaOH at 60 ^0C in order to keep pH at 11.0. After precipitation experiments, black copper with 97.4% purity was obtained by carbotermal reduction of Cu(OH)2, with additions of 10 wt % coal and 10 wt% flux (Na2CO3), at 1150 ^0C for 1 hour. The efficiency of this reduction was 98%. Co3O4 is produced by decomposition of Co(OH)2 precipitatate at 300 ^0C for 30 minutes. Then Cobalt powder with an average surface area of 1.145 m2/g and with 99.92% purity was obtained by reducing Co3O4 with H2 gas at 800 ^0C for 2 hours.

Keywords: Hard alloy scrap, polimetallic solution, hydroxide precipitation, copper, cobalt.