Gülhan Özbayoğlu

Beneficiation of bastnaesite by a multi-gravity separator

The preconcentration of bastnaesite of Beylikahir ore was achieved by attrition scrubbing of the original ore crushed to -1.65 mm. After scrubbing the sample at 50% solid pulp density for 1 h, the pulp was diluted and deslimed by cycloning. The slime (cyclone overflow) that was collected as a preconcentrate, assayed 28% REO (rare earth oxides) with 72.6% recovery. The preconcentrate was fed to a Mozley multi-gravity separator (MGS) for further upgrading. As a result, a bastnaesite concentrate with 35.5% REO grade and 48% recovery (on original ore basis) was produced. Chemical analysis of the concentrate was as follows: Ce, 13.75%; La, 11.81%; Nd, 2.30%; Pr, 1%; Sm, 0.15%; Y, 0.064%. H 2 SO 4 curing and water leaching of the preconcentrate indicated that >75% of REE (rare earth elements) could be taken into solution.

Effect of Microwave Radiation on Coal Flotation

Abstract Most low-rank coals are high in moisture and acid functional groups, therefore showing poor floatability. Drying, which removes the water molecules trapped in the pores and adsorbed at the surface of coal, decreases the hydrophilic character and improves the floatability. Microwave heating, whose simplest application is drying, was applied at 0.9 kW power level for 60 sec exposure time in the experiments to decrease the moisture content of coal in order to enhance the hydrophobicity. The flotation tests of microwave-treated coal by using heptanol and octanol lead to a higher flotation yield and ash removal than original coal.

Comparison of non-ionic and ionic collectors in the flotation of coal fines

Some ionic collectors were used as an alternative to conventional non-ionic collectors to obtain clean concentrates from fine coal samples containing 46.1% ash. Mixtures of kerosene and pine oil were used as conventional reagents while commercial fatty acids were used as ionic collectors. Flotation results showed that conventional collectors could not reduce the ash content of concentrate below 21.0% whereas, ionic collectors were found significantly better at reducing the ash content down to 16%, but their yields were lower.

Selective flotation of scheelite using amines

Abstract The present work deals with the flotation behaviour of a mixture of scheelite and calcite. A number of amines, as collector and depressants, were tested. It was observed that the pH of the pulp was important. Flotation combined with washing and/or cleaning operations, was carried out on this mixture. Concentrates containing 63.59–65.51 % WO3 with 96.54–91.41 % recoveries were obtained by using Amine D Acetate as collector from a feed containing 5.93 % WO3. The reason for the high selectivity of flotation combined with washing and/or cleaning was investigated with infrared spectrophotometry and adsorption-desorption tests.

Super-clean coal production from Turkish bituminous coal

Abstract The possibility of producing super-clean coal from Zonguldak bituminous coal by heavy medium separation and flotation techniques was investigated. The coal sample used was a −50 mm + 18 mm size jig concentrate from the Central Washery of Zonguldak. It was composed of 12.11% ash and 0.41% total sulfur. The vitrain band of the same coal contained 3.28% ash and 0.22% total sulfur. By applying a two-step heavy medium separation, it was possible to reduce the ash content from 12.11% to 4.00%. Additional cleaning to less than 3.0% ash was carried out by flotation. To determine the optimum flotation conditions required for the production of super-clean coal, the effects of different types of frothers, pH and collector dosage were studied. The optimum result was obtained using 170 g/t kerosene and 160 g/t MIBC. The investigation showed that it was possible to produce a coal containing 2.16% ash and 0.42% total sulfur from Zonguldak bituminous coals.

The effects of amine and electrolytes on the zeta-potential of scheelite from Uludag, Turkey

Abstract In order to investigate the zeta-potential of Turkish Scheelite Ore the electrophoresis technique was used. The effects of pH, amine and some electrolytes on the zeta potential of scheelite were investigated. Scheelite ore from Uludag, Turkey has negative zeta potential and only divalent and trivalent ions and amines can change the surface charge of scheelite from negative to positive values.

Environmentally Sound Coal-Derived Binder for Coal Briquetting

Conventional coal binders such as coal tar pitch and petroleum refinery residue provide agglomerates of satisfactory quality. However, their use has been banned for a quarter century due to their hazardous effect on human health and their contribution to air pollution. On the other hand, environmentally sound binders such as molasses, dextrin, etc. provide poor water-resistant agglomerates. In this research, coal-derived humic acid was used as coal binder. It was extracted from Afsin-Elbistan lignite by nitric acid oxidation and ammoniation processes. During briquetting, the effect of heat treatment, amount of binder added, particle size, pressure, and moisture content of the briquetting charge on the quality of the briquette have been investigated. The briquette produced at 165°C for 1 h heat treatment by adding 5% humic acid and 10.50% moisture showed that the radial compressive strength was 80 kg/briquette and abrasion resistance was 87.03%, with no water disintegration.

Desulphurization of Coal to Protect the Environment

The major coal desulphurization technologies prior to combustion are physical coal cleaning, chemical and biological methods. Each has some technical and economical limitations. Physical coal cleaning can only remove limited amount of inorganic sulphur due to insufficient liberation. Fine grinding can liberate fine pyrites, where novel coal cleaning techniques are required for separation. Advanced froth flotation, oil agglomeration, selective flocculation and heavy media cycloning are the novel cleaning techniques, most of which have been, or nearly being, commercially deployed. Chemical cleaning techniques, due to their high processing costs, and bicrobiological desulphurization, with its technical and economical uncertainties, are not already commercially applied. Preliminary cost estimations have shown that pre-combustion desulphurization techniques might be competitive with the current post-combustion technologies.

Briquetting of Tuncbilek lignite fines by using ammonium nitrohumate as a binder

Abstract Results of experiments on the briquetting of Tuncbilek lignite fines using ammonium nitrohumate (anh), a low calorific value, young lignite-derived humic acid salt solution, are reported. The particulate material was blended with ammonium nitrohumate serving as the binder. In the briquetting tests, the effects of moisture content, pressure, binder content, nitrogen content and heat treatment were investigated. Durable briquettes, in terms of mechanical strength and water resistance, were produced with a 7% binder content at 10.5% moisture, following pressing at 1280 kg/cm2 and drying at 165°C for 1 h. The briquettes produced with ammonium nitrohumate had better combustion properties than run-of-mine samples; the contribution of the binder to smoke and sulphur emissions was very low, and fine dust particles were negligible.

Utilization of Fine Coal Tailings by Flotation Using Ionic Reagents

Fatty acid type ionic collectors were used as an alternative to conventional oily collectors, kerosene, and pine oil mixture in the flotation of coal tailing with 46.1% ash. The conventional collectors could not reduce the ash content of the concentrate below 22%. On the other hand, ionic collectors were found to be significantly better at reducing the ash content down to 13%. It was concluded that despite their lower flotation yield and higher consumptions, certain ionic collectors could be used successfully in coal flotation where cleaner concentrates are required from coal fines with high ash content.