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1

Removal of hazardous air pollutants based on commercial coal preparation plant data

Ozbayoglu G.

Physicochemical Problems of Mineral Processing

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2013

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Vol. 49, iss. 2

621--629

EN

This paper investigates the concentration, distribution, and rejection of hazardous air pollutants, specifically identified by the US Clean Air Act Amendments of 1990, based on commercial coal preparation plant data obtained on-site. The samples were collected from the products of the different cleaning circuits of the operating plant. The concentrations of twelve potentially hazardous trace elements, including As, Cd, Co, Cr, Hg, Mn, Ni, Pb, Se, Th and U in those samples were determined. Compared with the average concentration of the trace elements in Turkish coals, the run-of-mine coal fed to the existing plant appears to contain higher concentrations of Cd, Hg, Mn, Th and V. However, the concentrations of As, Cd, Cr, Mn, Se, Th, U and V of the run-of-mine coal are above the world averages. Cd, Cr, Hg, Mn, Pb and Th concentrations of run-of-mine coal were easily removed at commercial coal preparation plant refuse in the range of 51.8% to 77.4 %, while only a small reduction was achieved for U and V as they were concentrated in clean coals. The present study reveals that conventional coal preparation technologies could significantly reduce hazardous air pollutants concentrations in coal.

2

Partitioning of major and trace elements of a Turkish lignite with size and density

Ozbayoglu G.

Physicochemical Problems of Mineral Processing

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2011

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Vol. 47

51-60

EN

This research was devoted to determine the concentration and distribution of major and trace elements in a Turkish lignite and to investigate the partitioning behaviour of them in various size and density fractions to estimate the possibility of removal of trace elements by conventional coal cleaning. Three size fractions which were used in industrial coal cleaning processes were chosen. Each size fraction was separated into various density fractions by float and sink tests, which were evaluated for major and trace elements. These tests showed that by applying the same size and density fractions of industrial coal cleaning processes, more than 70% of Mo, Nb, Nd, W, Hg and Zr could be removed, which were approximately equal to the result achieved for ash removal.

3

The effect of different starting materials on the synthesis of lithium triborate

Depci T., Ozbayoglu G., Yilmaz A.

Physicochemical Problems of Mineral Processing

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2007

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Vol. 41

101-105

EN

Lithium triborate (LiB3O5) was synthesized using different starting materials. The effect of these materials on the phase purity of LiB3O5 was investigated in each case. Identification and characterizations of the products were carried out by powder X-ray diffraction (XRD) and infrared (IR) analyses. The present study showed that the starting materials play an important role in the synthesis of lithium triborate with respect to phase impurity.

PL

Syntezowano trójboran litu (LiB3Os) stosując różne materiały wyjściowe. Badano wpływ tych materiałów na końcową czystość LiB3O5. Identyfikowano i charakteryzowano produkty syntezy za pomocą dyfrakcji rentgenowskiej (XRD) oraz analizy spektroskopowej w podczerwieni (IR). Badania wykazały, że wyjściowe materiały grają ważna rolę w czystości syntezowanego trójboranu litu.

4

Investigation of structural chemistry of thermal processes applied for improvement of grindability of ulexite.

Sener S., Ozbayoglu G.

Physicochemical Problems of Mineral Processing

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2000

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Vol. 34

25-33

EN

In this investigation, mechanism of the thermal processes and effect of the mineralogical and structural modifications on the grindability of ulexite were investigated. The mechanism of the thermal reactions were examined by thermo-anal. methods including TGA and DTA. The mineralogical and structural modifications were investigated by XRD and SEM techniques, respectively. The results indicated that ulexite thermally decomposes within 60-500°C. The structure was first transformed into NaCaB5O6(OH)6.3H2O and then NaCaB5O decomposes 6(OH)6.H2O and finally became as completely X-ray amorphous phase accompanied with the thermal processes in the sequence of two-stage dehydration and two-stage dehydroxylation reactions resulting in two endothermic DTA peaks at 151°C and 180°C. Further treatment caused two-stage recrystallization. processes resulting in an exothermic DTA peak at 636°C and an endothermic peak at 855°C. The changes in the grindability of ulexite were determined. in terms of work index by the Hardgrove Grindability Test. The results showed that work index of ulexite was found as 7.11kWh/shton and decreased to 3.5 kWh/shton level within 200-280°C for 60 min. Further heating lead to 8.49 kWh/shton at 640°C for 60 minutes.

PL

W pracy badano mechanizmy procesów termicznych i wpływ przemian mineralogicznych i strukturalnych na rozdrobialność ulexytu. Badania mechnanizmów reakcji prowadzono metodą analizy termicznej w tym TGA i DTA, a zmiany mineralogiczne i struktutralne.za pomocą technik XRD i SEM. Wyniki wskazują, że ulexyt ulega termicznemu rozkładowi w zakresie 60-500 st.C. Najpierw powstaje NaCaB5O6(OH)6*3H2O a potem NaCaB3O6(OH)6*H2O) ostatecznie stając się amorficzny. Towarzyszą temu procesy termiczne, kolejno, dwustopniowe odwodnienie i dwustopniowa dehydroksylacja powodując dwa endotermiczne piki na krzywej DTA przy 151 st. C i 180 st.C. Dalsze ogrzewanie powoduje dwustopniową rekrystalizację powodując egzotermiczny pik przy 636 st. C. oraz endotermiczny pik przy 855 st. C. Zmiany rozdrabialności ulexytu określono za pomocą test rozdrabialności Hardgrove'a. Stwierdzono, ze indeks rozdrabialnosci ulexytu wynosi 7,11 KWh/krotka tonę i maleje do 3,5 KWH/krótką tonę dla probek wygrzewanych w zakresie 200-280 st. C. Przez 60 minut. Dalsze ogrzewanie w temp. 640 st.C przez 60 minut podnosi wartość indeksu do wartości 8,49 KWh/krótką tonę.