GOSPODARKA SUROWCAMI MINERALNYMI-MINERAL RESOURCES MANAGEMENT, cilt.33, ss.5-23, 2017 (SCI İndekslerine Giren Dergi)
In this paper, synthetic carnallite (MgCl2 center dot KCl center dot 6H(2)O) and amorphous silica (SiO2) preparation possibilities were investigated by utilizing chromite beneficiation plant tailings which contain 3.44% chromite (Cr2O3) and 30.55% magnesium oxide (MgO) by weight. Firstly, laboratory scale high intensity wet magnetic separator was applied for removing the magnetic materials such as chromite, iron (II) and manganese (II) minerals in the tailings. About 85.75% of chromite, 91.22% of MnO and 64.71% of Fe2O3 were removed by single stage magnetic separation. After the magnetic separation, hydrometallurgical recovery was initiated by leaching of the tailings with hydrochloric acid (HCl). Amorphous silica particles and the other solids were separated from the leach solution by filtration. Impurities were precipitated from the leach solution by elevating the solution pH via magnesium hydroxide (Mg(OH)(2)) adding. The purified magnesium chloride (MgCl2) solution was mixed with potassium hydroxide (KOH) at stoichiometric ratio. According to the XRD and chemical analysis, the synthetic carnallite was synthesized by controlled heating of this solution at 90-100 degrees C. Also, the amorphous silica with 96.5% SiO2 content and 84.38% recovery yield was obtained by additional magnetic separation treatment.