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Optimum separation route for semi bituminous coal using semi-pilot scale pneumatic stratification jig

Boylu F., Cetinel T., Guven O., Karakas F., Cinku K., Karaagaclioglu I. E., Celik M. S.

Physicochemical Problems of Mineral Processing

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2015

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Vol. 51, iss. 2

559--573

EN

Nowadays, dry beneficiation technologies with an air dense medium fluidized bed come into prominence in the field of coal preparation. In this study, the optimum conditions for different operational parameters such as discharge stargate rate, pulsation frequency, and superficial air velocity were investigated on separation of semi bituminous coal from Soma (Imbat) region using a semi pilot scale Allair jig unit. The experimental studies were carried out with two coal size fractions of -15+4 and -4+1 mm by applying rougher and scavenging stages. After the optimization of each parameter, the results for the rougher stages indicated that clean coal products could be obtained with 11.80% and 16.74% ash contents for -15+4 mm and -4+1 mm size ranges, respectively. In addition, discardable tailings with 65.44% and 60.95 % ash contents could be obtained as the result for the scavenging stages. Finally, the combination of these results for -15+1 mm size exhibited that 59.80% of the feed material with 37.70% ash content can be upgraded to clean coal products with low ash content as 19.80% while the remaining part was discarded as tailings with 68.60% ash content. These values suggested that optimizing the operational parameters of unit brings better results which are applicable in industrial application of dry processes compared to wet processes.

2

Investigation of adsorption behavior of phosphonium salts onto Na-montmorillonite

Cinku K., Baysal B.

Physicochemical Problems of Mineral Processing

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2014

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Vol. 50, iss. 2

417--432

EN

Montmorillonite is an important clay mineral due to its cation exchange capacity and technological properties such as swelling and gelling. It has been widely used in many scientific applications like organoclay. Adsorption studies, involving montmorillonite in the presence of variety of organic compounds, like ammonium and phosphonium salts, are very important because of their application in organoclay and polymer nanocomposites. These materials have a high thermal resistivity. Different types of phosphonium salts, including hexadecyl triphenyl phosphonium bromide (HTPB), hexadecyl tributyl phosphonium bromide (HTBPB), and tetraphenyl phosphonium bromide (TPB), were used to investigate their adsorption on Na-montmorillonite. They have different structures and TPB contains only one aromatic part without any organic chain, HTBPB possess an organic chain with three branches while HTPB has an organic chain and an aromatic part. The adsorption of the surfactants was supplemented with other properties such as zeta potential, surface tension, and ability to flocculation. The results indicated that the adsorption behavior of these surfactants depended on their structure.

3

Effect of calcinated magnesite on rheology of bentonite suspensions. Magnesia-bentonite interaction

Cinku K., Karakas F., Boylu F.

Physicochemical Problems of Mineral Processing

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2014

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Vol. 50, iss. 2

453--466

EN

In this study, the effect of calcination temperature and time on the structure of calcinated magnesite was investigated. In addition, the effect of calcinated magnesite on rheology when added into bentonite suspension was also examined. Electrokinetic, rheological and stabilization studies including coagulation and gelation tests were performed to explain the mechanism of viscosity increase in bentonite suspension upon addition of the calcinated products. FTIR, SEM, BET analyses and rheological data were used to determine the transition degree of MgCO3 to MgO, and evaluate the structure of MgO and bentonite suspensions. The results from this study showed that specific surface area (SSA) and mean pore radius (MPR) values for the calcinated products were directly affected by the calcination temperature and time. According to the ignition loss and transition ratio from MgCO3 to MgO of the calcinated samples, it was found that the calcination was completed above 800 oC. In order to obtain a bentonite suspension with higher viscosity, interaction of the sufficient amount of MgO particles with bentonite particles were necessary. Based on these results, the formation of gelation and heterocoagulation between MgO and bentonite particles were found to be responsible for these effects.