Sülfürlü Cevher Flotasyonunda Oksitlenmenin Olumsuz Etkilerinin Azaltılması
Özet
Although sulfide minerals generally are easy to recover by flotation, surface oxidation can cause significant impact on flotation performance. Some measures can be taken to prevent the ores from oxidizing at the mine sites prior to flotation, but the oxidation is inevitable during the mining operations.
In the literature, many studies have been done to reduce the negative effect of oxidation. It has been observed that these studies have different effects on the ores and affect the flotation performance to different degrees.
Gediktepe ore deposit is composed of two main zones as oxide and sulphide. In this thesis, composite ore of sulphide zone was studied. The composite ore contains four different ore formations (massive pyrite, massive pyrite-magnetite, disseminated sulfur, enriched). In this study, the effect of oxidation on flotation performance of Gediktepe Cu-Zn composite ore was determined. The representative sample, which was approximately 100 kg for use in the experiments, was kept open in the core boxes for a long time. The degree of oxidation of the ore was determined by EDTA test. Cu-Zn selective flotation test was applied to the sample under the condition determined as the base condition of Gediktepe ore. According to this condition, surface oxidation decreased the mineral selectivity in Cu flotation. In the base condition of flotation test, Cu rougher recovery was 82,85% while Zn recovery was 90,25% in the Cu flotation section. High grade Cu concentrate could not be obtained in cleaning circuits due to high recovery Zn minerals in Cu circuit,. In the Zn circuit, there was not enough floating material and Zn could not be obtained as a concentrate.
Different methods have been studied to mitigate the selectivity problem of the ore due to oxidation. Tests were carried out at different dosages of Na2S and MBS used as depressants in the grinding circuit and optimum dosages were determined. The surface cleaning effect of the mineral surfaces of the ultrasonic bath was determined by EDTA test. Before flotation, high speed conditioning and sulfidization tests were performed. The best results in terms of flotation performance were obtained by using high speed conditioning and sulfidization together.
Under the best determined flotation condition, in Cu circuit, Cu rougher concentrate was obtained with 73.71% recovery and Zn recovery in the Cu circuit was reduced to 47,41%. At the end of 3 stage cleaning, the grade of Cu concentrate increased to 26,14%. In the Zn circuit, the Zn rougher concentrate was obtained with 41,47% recovery and Zn concentrate was obtained with 31,39% Zn grade.
