Production of hexagonal boron nitride by carbothermic reduction of colemanite-boric oxide mixtures

Kahramansoy, Eylem
Carbothermic production of hexagonal BN by using boric acid and ground colemanite mined from Bigadiç Region in Turkey was investigated by subjecting pellets prepared from B2O3, activated carbon and colemanite mixtures to nitrogen gas at 1500°C. Similar to CaCO3 addition, colemanite addition to the B2O3-C mixtures resulted in higher amounts of h-BN in the final products. As a result of the experiments conducted with colemanite and CaCO3 additions providing the same quantity of CaO to the initial mixtures, similar amounts of hexagonal BN in the reaction products were observed. As a result of the experiments conducted with different compositions of colemanite- B2O3- C mixtures, 5 wt % colemanite addition was determined to be the optimum composition giving the highest amount of hexagonal BN in the reaction products. Increasing duration of the experiments increased the amount and particle size of h-BN formed in the products. Optimum amount of colemanite addition resulted in higher amounts and coarser particles of h-BN in the products than the optimum amounts of CaCO3 addition.


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Aprotic solvents are organic solvents which do not easily react with a substance dissolved in it and they do not exchange protons despite of their high ion and polar group dissolving power. Therefore, this characteristic property makes aprotic solvents very suitable intermediates in many industries producing pharmaceuticals, textile auxiliaries, plasticizers, stabilizers, adhesives and ink. Dehydration of these mixtures and recirculation of valuable materials are substantial issues in industrial application...
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Nontronitic and limonitic type laterites from "Gordes" nickel deposit located in Western Turkey were subjected to sulfuric acid leaching at atmospheric pressure. Experiments were conducted in order to determine the optimum conditions for agitation leaching by studying various parameters, including time, acid concentration, leaching temperature and particle size. Agitation leach experiments showed that nickel and cobalt could be extracted from both ores. Nickel and cobalt extractions were 96.0% and 63.4% for...
Photocatalytic Activity of Mesoporous Graphitic Carbon Nitride (mpg-C3N4) Towards Organic Chromophores Under UV and VIS Light Illumination
Altunöz Erdoğan, Deniz; SEVİM, Melike; Kisa, Ezgi; Emiroglu, Dilara Borte; Karatok, Mustafa; Vovk, Evgeny I.; Bjerring, Morten; Akbey, Umit; Metin, Onder; Ozensoy, Emrah (2016-09-01)
A template-assisted synthetic method including the thermal polycondensation of guanidine hydrochloride (GndCl) was utilized to synthesize highly-organized mesoporous graphitic carbon nitride (mpg-C3N4) photocatalysts. Comprehensive structural analysis of the mpg-C3N4 materials were performed by XPS, XRD, FT-IR, BET and solid-state NMR spectroscopy. Photocatalytic performance of the mpg-C3N4 materials was studied for the photodegradation of several dyes under visible and UV light illumination as a function o...
Synthesis of boron nitride nanotubes from ammonia and a powder mixture of boron and iron oxide
Ozmen, Didem; Sezgi, Naime Aslı; BALCI, FATMA SUNA (2013-03-01)
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Chemical preparation of the binary compounds of CaO-Al2O3 system by combustion synthesis
Uysal, O; Tas, AC (1997-05-07)
The binary compounds (C(3)A: Ca3Al2O6, C(12)A(7): Ca12Al14O33, CA: CaAl2O4, CA(2): CaAl4O7 and CA(6): CaAl12O19) of CaO-Al2O3 system have been synthesized as high compound-purity ceramic powders by using the Combustion Synthesis (CS) method. Materials characterization of the above-mentioned phases were performed by powder XRD, FTIR, SEM and EDXS. It has hereby been shown that by using this synthesis procedure it would be possible to manufacture high-purity ceramic powders of CA, CA(2), and C(12)A(7) at 850 ...
Citation Formats
E. Kahramansoy, “Production of hexagonal boron nitride by carbothermic reduction of colemanite-boric oxide mixtures,” M.S. - Master of Science, Middle East Technical University, 2011.