Celestite-gypsum separation by flotation

The celestite ore from Sivas, Turkey which was subjected to this experimental study contained mainly celestite and gypsum as gangue minerals. Flotation behaviour of pure minerals, celestite and gypsum was investigated using oleate and sulphonate as collectors in a Hallimond tube. The zeta potential values of both minerals were measured with respect to pH in an attempt to explain the flotation mechanism of the collectors. Hallimond tube tests conducted with oleate as a collector suggested that gypsum floated best around pH 6, yet celestite floated best around pH 8.5. On the other hand, in the case of sulphonate, there was not a distinct pH value where gypsum and celestite were best floated. Flotation studies were also carried out in the Denver cell to obtain marketable celestite concentrates from an ore sample from same mine. Parameters such as pH, collector type and dosage were examined using microflotation tests. Contrary to microflotation test results, oleate was found non selective for celestitegpysum separation, while sulphonate type collector provided better selectivity. At pH 5, a celestite concentrate with 93.85% SrSO₄content was produced at 78.4% recovery using 2000 g/ton sulphonate.