Ahmadi, Eltefat (2018) Synthesis Of Titanium Tetrachloride Through Arbothermal Reduction And Chlorination Of Ilmenite Oncentrate. PhD thesis, Universiti Sains Malaysia.
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Abstract
Titanium oksikarbonitrida (TiOxCyNz) yang di sintesis daripada ilmenit dan pengklorinan pada suhu rendah untuk menghasilkan titanium tetraklorida (TiCl4) telah di kaji pada projek ini. Kesan karbotermal penurunan dan penitridaan pada suhu, masa, suasana dan penambahan plastik polietilena (PET) kedalam arang batu terhadap pembentukan besi (Fe) dan TiOxCyNz daripada ilmenit telah di kaji dalam proses CTRN pada suhu 1100-1250 °C selama 60 ke 180 minit dengan empat nisbah berbeza iaitu PET kepada arang bermula daripada 25% kepada 100%. Mikroskop elektron pengimbasan pancaran (FESEM) dilengkapi dengan analisis spektrum X-ray dispersif tenaga (EDX) menunjukkan bahawa produk yang disintesis oleh 75% PET mempunyai mikrostruktur yang unik di mana zarah Fe sfera secara jelas dipisahkan dari fasa TiO0.02C0.13N0.85. Kadar karbotermal pengurangan dan nitridasi tertinggi untuk sampel yand disintesiskan oleh 75% PET adalah pada 99.15% dan 85.47%. Penyingkiran besi juga dilakukan dengan proses larut lesap pengudaraan jenis Becher pada 70 °C dengan adanya amonium klorida (NH4Cl) dan 0.1 wt% AQ-2 (anthraquinone-2-sulfonat asid natrium garam monohidrat) sebagai pemangkin berkesan. Kecekapan penyingkiran Fe adalah 98.5%, dan kandungan akhir Fe bebas pada TiO0.02C0.13N0.85 mengandungi 0.48 wt% Fe sebagaimana ditentukan oleh analisis ICP-OES. Mekanisme pengklorinan titanium nitrida (TiN) dan ilmenit nitrida telah dikaji secara meluas pada 250 °C - 400 °C. Tahap pengklorinan meningkat dengan kadar sederhana dengan meningkatkan suhu dan pengurangan saiz zarah TiN pada kadar aliran campuran gas N2-Cl2. Pengklorinan TiN yang tertinggi pada 250 °C dan 400 °C adalah 85.6% dan 97.7% dalam 60 minit. Hasil eksperimen ini juga menunjukkan bahawa model teras menyusut dengan mekanisme kawalan campuran mengawal kadar pengklorinan. Permukaan pada reaksi kimia terhadap gas klorin pada permukaan zarah TiN adalah kadar mengawal pada peringkat awal dan, pada peringkat kemudian, penyerapan dalaman (liang) melalui lapisan produk perantaraan adalah langkah mengawal kadar. Tenaga pengaktifan yang jelas (Ea) 10.97 kJ/mole diperolehi untuk pengklorinan TiN. Tahap pengklorinan TiO0.02C0.13N0.85 adalah 93.5% pada 400 °C dalam 60 minit. TiCl4 dengan ketulenan 99% yang telah dihasilkan dari ilmenit Malaysia dan sisa pengklorinan yang mengandungi unsur nadir bumi (REEs) dengan jumlah yang tinggi serta logam. Projek ini menunjukkan bahawa tiga tahap proses yang boleh menjadi kaedah yang boleh dilaksanakan dan kebolehupayaan untuk pengeluaran titanium tetrachlorida yang agak tulen daripada ilmenit. _______________________________________________________________________________________________________ The synthesis of titanium oxycarbonitride (TiOxCyNz) from ilmenite and its chlorination at low temperatures for production of titanium tetrachloride (TiCl4) was investigated in this research. The effects of reduction/nitridation temperature, time, atmosphere and addition of waste polyethylene terephthalate (PET) plastic into coal on the formation of TiOxCyNz and iron (Fe) from ilmenite were investigated in carbothermal reduction and nitridation (CTRN) process at 1100-1250 °C for 60-180 minutes with four different PET-to-coal ratios (C/Ored) ranging from 25 to 100 wt%. Field-emission scanning electron microscopy (FESEM) equipped with energy dispersive X-ray spectrometer (EDX) analyses showed that the product synthesized by 75 wt% PET had a unique microstructure in which spherical Fe particles were distinctly separated from TiO0.02C0.13N0.85 phase. The highest extents of reduction and nitridation of the sample synthesized by 75 wt% PET were 99.15% and 85.47%, respectively. Iron was also removed by an aeration leaching process at 70 °C in the presence of ammonium chloride (NH4Cl) and 0.1 wt% AQ-2 (Anthraquinone-2- sulfonic acid sodium salt monohydrate) as the effective catalysts. The efficiency of Fe removal was 98.5%, and final TiO0.02C0.13N0.85 contained 0.48 wt% Fe as determined by inductively coupled plasma-optical emission spectroscopy (ICP-OES) analysis. The chlorination mechanism of titanium nitride (TiN) and TiOxCyNz were extensively investigated at 250 °C - 400 °C. The extent of chlorination moderately increased with increasing the temperature and decreasing particle size of TiN at constant flow rate of N2-Cl2 gas mixture. The highest extents of chlorination of TiN at 250 °C and 400 °C were about 85.6% and 97.7% in 60 minutes, respectively. The results also indicated that a shrinking core model with mixed-control mechanism governed the chlorination rate. The surface chemical reaction of chlorine gas on the surface of TiN particles was rate controlling in the initial stage and, during later stage, internal (pore) diffusion through the intermediate product layer was rate controlling step. The apparent activation energy (Ea) of about 10.97 kJ/mole was obtained for the chlorination of TiN. The extent of chlorination of TiO0.02C0.13N0.85 was 93.5% at 400 °C in 60 minutes. The TiCl4 with the purity of about 99% was eventually produced from ilmenite and the residue of the chlorination contained high amounts of rear earth elements (REEs) as well as refractory metals. This research demonstrated that a three-step process could be a feasible and sustainable method for production of relatively pure TiCl4 from ilmenite.
| Item Type: | Thesis (PhD) |
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| Uncontrolled Keywords: | Full text is available at http://irplus.eng.usm.my:8080/ir_plus/institutionalPublicationPublicView.action?institutionalItemId=4607 |
| Subjects: | T Technology T Technology > TN Mining Engineering. Metallurgy > TN263-271 Mineral deposits. Metallic ore deposits. Prospecting |
| Divisions: | Kampus Kejuruteraan (Engineering Campus) > Pusat Pengajian Kejuruteraan Bahan & Sumber Mineral (School of Material & Mineral Resource Engineering) > Thesis |
| Depositing User: | Mr Mohd Jasnizam Mohd Salleh |
| Date Deposited: | 06 May 2019 02:53 |
| Last Modified: | 06 May 2019 02:53 |
| URI: | http://eprints.usm.my/id/eprint/44268 |
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