Ceramics-Silikáty 54, (1) 60 - 64 (2010)

Granite and granodiorite deposits are widely scattered throughout in Eastern Black Sea region of Turkey. These granitic bodies also contain considerable amounts of quartz, Na-feldspar, K-feldspar, mica and other color-imparting ferruginous impurities. Average chemical composition of these rocks are SiO₂ = 65.00 ±5.60; K₂O = 3.05 ±1.35; Na₂O = 3.50 ±1.47 %. Modally, these rocks contain 21.5 ±5.2 quartz; 19.3 ±4.8 K-feldspar and 48.3 ±10.2 % plagioclase. Although the chemical composition of these run-of-mine granite masses cannot meet the specifications required for the glass and ceramic industry, application of some mineral processing methods may recover quartz, Na-feldspar and K-feldspar as separate products. This study deals with the selective separation of sodium feldspar from potassium feldspar from weathered granite using cationic flotation technique (HF + amine) in the presence of NaCl. The most striking result in this experimental study is the depressive effect of NaCl on Na-feldspar. NaCl addition controls amine adsorption on sodium feldspar through adsorption of Na⁺ ions onto mineral surfaces. The use of NaCl in flotation was found to increase the K-feldspar grade in the concentrate. This study clearly demonstrates that an effective separation of sodium feldspar from potassium feldspar from a weathered granite can be achieved by cationic flotation in HF medium using NaCl as a depressant.