Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: the potential to serve as a strategic economic driver for the country if a local processing and
production industry could be successfully established. According to the US Geological
Survey, conducted in January 2009, South Africa has approximately 14% of the world’s
reserves in ilmenite and rutile, the two most important titanium-containing minerals, but
no metal producing abilities. The only role players, Exxaro and Richards Bay Minerals, have
smelting operations and produce an enriched titania slag, but all the slag is exported.
The processing steps between titanium-containing minerals and the metal represent a
significant portion of the total production costs and this study is chiefly concerned with
recommending a more cost-effective alternative for these steps. The existing industrial
process is archaic, cost and energy intensive, batch operated with unfavourable economics.
A large number of internationally research initiatives are actively trying to address the
problem of high production costs by searching for and developing alternative, more costeffective,
processes.
It was the purpose of this study to provide the decision making authorities with a ranking
and evaluation of these alternatives to produce titanium metal. A 2-Phase Filtering System,
based on both qualitative and quantitative techniques, was designed to assess, evaluate
and formulate a final ranking. This evaluation was followed by a detailed sensitivity analysis
of both local and global parameters.
A total of 26 process alternatives were selected to be evaluated in this techno-economic
evaluation. The complete ranking is given in Table 8.8, and the four leading process
alternatives, based on this evaluation and the findings of the sensitivity analysis, are as
follows:
1. CardQIT: The Canadian affiliate of Rio Tinto, QIT, developed a high-temperature
titanium extraction process based on an electrolysis reaction, where molten titania
slag is the cathode.
2. ArmITP: The Armstrong process is a continuous process that produces titanium in a
very similar fashion as with the Hunter process, by the reduction of TiCl4 with sodium. TiCl4 vapour is injected into a stream of molten sodium to form titanium
powder as the reaction product.
3. Kroll: This process was developed in the 1950s and the reduction step remains
very much similar to the original process used by the USBM (United States Bureau
of Mines). Two criteria played a big part in the unexpected high ranking of the Kroll
process, and that were academic coverage, with almost 60 years of research, and
the commercial readiness of an industrial process.
4. FFC: Solid pre-forms are pressed and sintered from pigment grade TiO2, to be
directly electrochemically reduced to metallic titanium in a molten electrolyte of
CaCl2.
For future work, it is recommended that an additional filtering stage, a detailed profitability
analysis, be added to the decision model. The top 4 alternatives, as mentioned above,
should be used to estimate the cost-reduction potential as well as the capital investment
and production costs based on process, industrial and economic engineering fundamentals. / AFRIKAANSE OPSOMMING: Titaan is deur die Suid Afrikaanse regering geidentifiseer as 'n mineraalhulpbron met die
potensiaal om te dien as 'n strategiese ekonomiese drywer, indien 'n plaaslike verwerkingen
verwaardingsbedryf suksesvol op die been gebring kan word. Volgens die US Geological
Survey, wat in Januarie 2009 gedoen is, het Suid Afrika ongeveer 14% van die wêreld se
reserwes in ilmeniet en rutiel, die twee belangrikste titaanhoudende minerale. Suid Afrika
het egter geen metaal-vervaardigingsaanlegte nie. Die enigste twee rolspelers, Exxaro en
Richards Bay Minerals, het smelteraanlegte en vervaardig 'n verrykte
titaandioksiedkonsentraat, wat alles uitgevoer word.
Die waardetoevoegingsaktiwiteite tussen die titaanhoudende minerale en die metaal
verteenwoordig ‘n groot gedeelte van die produksiekoste van titaanmetaal en hierdie
studie is hoofsaaklik daarmee gemoeid om ‘n meer koste-effektiewe aanbeveling te maak,
m.b.t. dié stappe. Die bestaande bedryfsproses is argaïes, koste- en energieintensief, en is
ontwerp as ‘n lot proses met ongunstige ekonomiese eienskappe. 'n Groot aantal
internasionale navorsingsinstansies is aktief besig om oplossings te soek vir die probleem
van hoë verwerking- en vervaardigingkostes, deur alternatiewe opsies te ondersoek en te
ontwikkel.
Die doel van hierdie studie was om vir die besluitnemingsgesag 'n rangorde en vergelyking
van die alternatiewe opsies om titaniummetaal te vervaardig, te gee. 'n Tweeledige Filter
Stelsel, gebaseer op beide kwalitatiewe- en kwantitatiewe tegnieke, is ontwerp om die
rangorde te vorm, te bereken en te formuleer. 'n Sensitiwiteitsanalise is gedoen om die
besluitnemingsparameters se invloed op die finale rangorde en uitslag te toets.
'n Totaal van 26 prosesse is geidentifiseer en gekies om aan hierdie tegno-ekonomiese
evaluasie, te onderwerp. Die volledige rangorde word in Table 8.8 getoon, en die vier
leidende prosesalternatiewe, gebaseer op die uitkomste van dié evaluering en die
bevindinge van die sensitiwiteitsanaliese, is as volg:
1. CardQIT: Die Kanadese filiaal van Rio Tinto, QIT, het ‘n hoë-temperatuur titaan
ontginningsproses ontwikkel, gebaseer op ‘n elektrolitiese reaksie, waarin gesmelte
titaandioksiedkonsentraat die katode vorm. 2. ArmITP: Die Armstrong proses is ‘n kontinue opsie wat titaan produseer op ‘n baie
soortgelyke wyse as die Hunter proses, deur die reduksie van TiCl4 met natrium, Na.
TiCl4 damp word in ‘n gesmelte stroom natrium ingespuit om titaanmetaalpoeier te
vorm as die reaksie produk.
3. Kroll: Die proses is ontwikkel in die 1950s en die reduksie stap wat vandag gebruik
word is steeds soortgelyk soos die oorspronklike proses, aan gebruik deur die
USBM. Veral twee besluitnemingskriteria het ‘n belangrike rol gespeel om tot die
onverwagte hoë plasing van die Kroll proses te lei. Eerstens, akademiese dekking
en die feit dat omtrent 60 jaar se navorsing in hierdie opsie ingepomp is en
tweedens, die kommersiële gereedheid van hierdie prosesalternatief as ‘n
volskaalse bedryfsproses.
4. FFC: Gegoe vorms van pigmentgehalte TiO2, word gepers en gesinter om die
katodes te vorm wat dan direk elektrochemies gereduseer word tot titaanmetaal in
‘n gesmelte bad van CaCl2, as die elektroliet.
Vir toekomstige werk word aanbeveel dat ‘n addisionele filtervlak, ‘n
winsgewendheidsanalise, by die besluitnemingsmodel gevoeg word. Die vier
prosesalternatiewe, soos hierbo genoem, kan gebruik word en vir elk moet die kostebesparingspotensiaal,
die kapitaal insetkoste en die produksiekostes bereken word. Hierdie
berekeninge kan gebaseer word op proses-, bedryfs- en ekonomiese ingenieurswese
beginsels.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/4142 |
| Date | 03 1900 |
| Creators | Van Tonder, Willem |
| Contributors | Dimitrov, D. M., Von Leipzig, K. H., University of Stellenbosch. Faculty of Engineering. Dept. of Industrial Engineering. |
| Publisher | Stellenbosch : University of Stellenbosch |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 159 p. ; ill. |
| Rights | University of Stellenbosch |
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