Recovering Cobalt Products From Waste Bearing Cobalt

In this article the productions, such as cobalt oxide, cobaltous oxide and ultrafine cobalt powder, were recovered from the scraps of cobalt and lithium film and residues of treating hard alloys.According to the constituent characteristics of the scraps of cobalt and lithium film, the flow sheet includes these steps, such as removing aluminum by alkali solution, leaching cobalt by hydrochloric acid, removing aluminous, cupric and ferric, depositing cobalt with ammonium oxalate and calcining the cobalt oxalate. After laboratory experiments studying, the optimum conditions of every process were determined. In the processing of removing the aluminum by alkali solution, when theoptimum conditions were ratio of liquid and solid 4:1, temperature 80℃,reacting time 1 hour, nNaOH/3nAl(in residues) 1-1. more than 85% Al enter into the solution. In order to reducing the consumption of hydrochloric acid using in leaching and of alkali using in neutralizing, two steps of leaching were used. At the first step the optimum conditions were hydrochloricacid 2.4~2.5mol/L , temperature 80℃, reacting time 2 hours. Throughincreasing the terminal hydrochloric acid concentration of the second decomposition step, the cobalt content in the residues is lower than 1.0% and leaching ratio is more than 99.5%. In the process of removing Fe, Alby spray-pour method, temperature was more than 80℃ and terminal pHvalue was controlled ranging from 5.5 to 6.0. The content of Fe, Al in the purified solution was lower than 0.008g/L and 0.014g/L respectively. The cobalt content in the purified residues was lower than 1.0% averagely and the direct and sum recovery is 91.5% and 95.4% respectively. The quality of cobalt oxide accords with the requirement of grade Y of national standards.The flow sheet includes roasting, leaching, depositing Fe and Cu by spray-pour method, directly depositing cobalt by ammonium oxalate and calcining. The product of grade T1 was recycled from the residues of treating hard alloys. According to the characteristic of residues that cobalt exists in Co9S8 form, sodium nitrate is used as oxidant. The optimumconditions of roasting are W(NaNO3)/W(residues) 0.8 times, temperature 750℃, time 2.5 hours. The spray-pour method is used during the processof purification, which avoids forming the iron hydroxide colloid. The terminal pH value was controlled ranging from 5.5 to 6.0, some impurities, such as Fe3+ and Cu2+, can be removed thoroughly. The average cobalt content in the purified residues is about 1.0% and the direct and sum recovery is 90.15% and 92.78% respectively. The recovery of tantalum is 85% and the tantalum content in residues is more than 15%.Ultrafine, monodispersed, spherical cobalt powder has been fabricated by reducing cobalt hydroxide with glycol. The basic material of cobalt hydroxide was produced by depositing cobalt chloride solution which is recycled from the scraps of cobalt and lithium film. It was investigated that the increasing of NaOH concentration speeds the reaction rate greatly. The concentration of cobalt hydroxide and surfactant bring about effects on the morphology and particle size.