Ayhan Ali Sirkeci

RECOVERY OF Co, Ni, AND Cu FROM THE TAILINGS OF DIVRIGI IRON ORE CONCENTRATOR

In the Sivas-Divriği Iron Ore Concentrator, 600,000 t of tailings are discarded annually. There are already 1 million t of tailings deposited in ponds from the previous production activities. The presence of Co, Ni, and Cu in the tailings makes the beneficiation of those tailings attractive. In the experimental work, sulphide concentrates were produced from these two types of tailings by flotation. Under optimum flotation conditions, a bulk sulphide concentrate assaying 0.376% Co, 0.721% Ni, and 0.403% Cu was obtained with 83.1% Co, 57.7% Ni, and 59.0% Cu recoveries from the old tailings. On the other hand, another concentrate containing 0.384% Co, 0.687% Ni, and 0.393% Cu was produced under the same flotation conditions with 94.7% Co, 84.6% Ni, and 76.8% Cu recoveries from the new process tailings.

Beneficiation of the gold bearing ore by gravity and flotation

Gold concentration usually consists of gravity separation, flotation, cyanidation, or the combination of these processes. The choice among these processes depends on the mineralogical characterization and gold content of the ore. Recently, the recovery of gold using gravity methods has gained attention because of low cost and environmentally friendly operations. In this study, gold pre-concentrates were produced by the stepwise gravity separation and flotation techniques. The Knelson concentrator and conventional flotation were employed for the recovery of gold. Gold bearing ore samples were taken from Gümüşhane Region, northern east part of Turkey. As a result of stepwise Knelson concentration experiments, a gold concentrate assaying around 620 g/t is produced with 41.4wt% recovery. On the other hand, a gold concentrate about 82 g/t is obtained with 89.9wt% recovery from a gold ore assaying 6 g/t Au by direct flotation.

Improved Fine Coal Dewatering by Ultrasonic Pretreatment and Dewatering Aids

The effects of ultrasonic pretreatment and surface active reagents to improve the efficiency of fine coal dewatering in high frequency vibrating screen have been carried out. The results showed that hydrophobic surface active reagents increased the contact angle and decreased surface tension of the solution reducing the moisture content of fine coal particles. Polyethylene glycol 400 monooleate (PEG-400) was found to be the most effective reagent. Furthermore, when ultrasonic pretreatment was introduced to the fine coal slurry, the residual total moisture content of the fine coal was further decreased.

STUDY OF THE SETTLING OF TINCAL MINERAL PARTICLES IN DIFFERENT FLUID MEDIA

The aim of this study is to investigate the behavior and velocity ratio of tincal particles in different fluid media containing clay minerals, so that the diversion of tincal particles into slime product or not can be estimated. Tests were carried out using a settling unit and parameters such as clay content of the pulp and dissolved tincal concentration were investigated. Test results were evaluated by measuring the particle-size distribution in the settled product at the end of predefined durations. Average particle size of the settling product at the end of 8 min was observed to be 35 µm at 5% solids ratio by weight in the pulp; however, it was 55 µm at 20% solids ratio by weight. On the other hand, the presence of clay in the fluid medium was observed to directly affect the settling rate of the particles. In the suspension containing 100 g/l of clay and 5% of tincal, particle size of the settling fraction was 55 µm at the end of 8 min, which well compared to 35 µm in the clay-free suspension. The classification medium that contained considerable amounts of clay acted as a heavy and viscous medium and it was determined that fine tincal particles were lost into the tailings during the classification processes in Kırka Tincal Concentrator.

SOLVENT EXTRACTION OF URANIUM FROM WET PROCESS PHOSPHORIC ACIDS

In this investigation solvent extraction of uranium from wet process phosphoric acids was realized using industrially available organic extracts 2-Ethylhexyl phosphoric acid (D2EHPA) and Tri-n-octyl phospine oxide (TOPO). The results of initial tests showed that, the effect of different parameters such as uranium oxidation stage, temperature and the molar ratio of D2EHPA/TOPO on the uranium recovery was in good agreement with those of previous investigations. The effect of acid concentration and acid/organic phase ratios suggested that the mechanism of D2EHPA/TOPO synergism was rather complex and it presented different trends.