Development of copper recovery process from flotation tailings by a combined method of high‒pressure leaching‒solvent extraction

Sulfide copper mineral, typically Chalcopyrite (CuFeS₂), is one of the most common minerals for producing metallic copper via the pyrometallurgical process. Generally, flotation tailings are produced as a byproduct of flotation and still consist of un‒recovered copper. In addition, it is expected that more tailings will be produced in the coming years due to the increased exploration of low‒grade copper ores. Therefore, this research aims to develop a copper recovery process from flotation tailings using high‒pressure leaching (HPL) followed by solvent extraction. Over 94.4% copper was dissolved from the sample (CuFeS₂ as main copper mineral) by HPL in a H₂O media in the presence of pyrite, whereas the iron was co‒dissolved with copper according to an equation given as C_Cu = 38.40 × C_Fe. To avoid co‒dissolved iron giving a negative effect on the subsequent process of electrowinning, solvent extraction was conducted on the pregnant leach solution for improving copper concentration. The result showed that 91.3% copper was recovered in a stripped solution and 98.6% iron was removed under the optimal extraction conditions. As a result, 86.2% of copper was recovered from the concentrate of flotation tailings by a proposed HPL‒solvent extraction process.