Iron Removal of Yaliköy Sand Dunes

"In general, the processing of glass sand may involve comminution, washing, wet classification and attrition scrubbing. Additional processes may include magnetic separation, flotation and leaching in various combinations.Yaliköy sand dune deposit is located near to Istanbul on the European side by the Black Sea coast. The reserve of deposit is around 70 million tons. Iron content of Yaliköy sand dunes is 0.48 % Fe2O3 and not suitable for glass manufacture. The iron content of glass sand should be less than 0.15 % Fe2O3 for window glass manufacture and 0.05 % Fe2O3 for glassware. In this study, it was aimed to produce glass sand with less than 0.15 % Fe2O3 for window glass and with less than 0.05% Fe2O3 for glassware manufacture from Yaliköy sand dunes. A representative sample with a weight of 200 kg was taken from Yaliköy sand dunes deposit through opening small pits.• Mineralogical studies have shown that iron is present in three forms:• Hematite, limonite, clay and iron silicate minerals such as epidote and garnet occur in free form.• Quartz grains are coated by hematite and limonite.• Iron is also present in the cracks of quartz grains.Free iron minerals such as hematite and limonite and silicate minerals were subjected to magnetic separation and flotation for removal. Iron coatings were tried to be removed by scrubbing and leaching. Iron removal in the cracks of quartz grains was attempted by grinding and leaching.Under optimal conditions, sand concentrate with 0.38 % Fe2O3 was obtained by means of high intensity disc type magnetic separation. Grinding and scrubbing were applied to see the effect of size reduction and attrition at room temperature and 90 ºC, by using non-magnetic fraction. Sand concentrate with 0.13% Fe2O3 was obtained at 90 ºC in this test.Sand sample which was previously ground to minus 0.5 mm and scrubbed, was floated by using sulphonates as collector. After flotation tests, sand Concentrate was obtained with 0.11 % Fe2O3.The optimum iron removal was achieved by H2SO4 leaching at 90 ºC depending on acid concentration and leach duration in static, percolation and agitation leaching. Agitation leaching was done by the use of mixer at 600 rpm, 50% solids and leach duration was 15 minutes."