Processing of Hafik-Madentepe copper slags using conventional and leaching methods

Abstract

In this research, it was aimed to beneficiate Hafik Madentepe slags with 2.62% Cu, which was formed during smelting operations 150-200 years ago and has a reserves of a few million tons. In the scope of the study, gravity-separation (shaking table, Humphreys Spiral, MGS), magnetic separation, flotation and leaching (sulphuric acid, acidic ferric sulphate and ammonia) were investigated. The mineralogical composition of slag was determined by microscopic techniques and XRD analysis. Copper in slag consists mainly of native copper (or copper matte) with small amounts of chalcopyrite (CuFeS2) and tenorite (CuO). Other minerals are fayalite (Fe2SiO4), augite (Ca(Mg,Fe)Si2O6), magnetite (Fe3O4) and hematite (Fe2O3). Gravity-separation and magnetic concentration studies could not produce concentrates with desired grade and recovery. A concentrate of 10.78% Cu with 62.17% recovery were obtained by flotation at pH=9, using Aerofloat-238, pine oil and Na2SiO3 reagents. Among the three leaching methods investigated, all methods were able for copper extraction with high recoveries. However ammonia leaching was more advantageous if reagent consumptions are taken into consideration.