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Process development for the production of beneficiated titania slag
Thesis (PhD)--University of Pretoria, 2009.
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University of Pretoria
2013
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| _version_ | 1867613475013918720 |
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| access_status_str | Open Access |
| author2 | Pistorius, Petrus Christiaan |
| author_browse | Pistorius, Petrus Christiaan |
| author_facet | Pistorius, Petrus Christiaan |
| collection | Thesis |
| dc_rights_str_mv | © 1999, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Thesis (PhD)--University of Pretoria, 2009. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/28654 |
| institution | University of Pretoria (South Africa) |
| last_indexed | 2026-06-10T12:36:43.949Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2013 |
| publishDateRange | 2013 |
| publishDateSort | 2013 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/28654 Process development for the production of beneficiated titania slag Pistorius, Petrus Christiaan upetd@up.ac.za Van Dyk, Jacobus Philippus Iron migration Pigment Beneficiation Upgraded slag Rutile Chloride process Titania slag Oxidation Titanium dioxide Ilmenite UCTD Thesis (PhD)--University of Pretoria, 2009. There is a range of feed materials available for the production of Ti02 pigment. These range from natural materials like ilmenite and rutile to synthetic materials like synthetic rutile. There is a large increase in the price of titaniferous feed materials as the Ti02content of the material increases. To take advantage of the difference in price between chloride grade slag and natural rutile a process was developed to increase the Ti02 content of chloride grade slag from ~85% to more than 95%. This beneficiated titania slag product (BTS) should be ideal as feed material to the chloride pigment process. Initially several processes were evaluated. Particular emphasis was placed on the slag pre-treatment procedure. This was necessary as impurities could only be leached with difficulty from as-cast slag. A suitable pre-treatment procedure would render the impurities easily leachable, while the titanium is retained in an insoluble form. The results indicated that a process consisting of oxidation and reduction roasting would satisfy these requirements. Detailed process development was then undertaken on this process. The first phase of the process development was conducted in a coal fired fluid bed roaster. This allowed a set of semi optimised process parameters to be established, but the highest Ti02 content that could be achieved was 94%. A second stage of process development was under taken under more controlled conditions, using a small fluid bed reactor connected to a gas mixing system. Based on the results in this phase of the process development a new set of optimum process parameters was established. They are oxidation at 850°C for 1.5 h in an atmosphere containing 8% O2; reduction at 850°C for 10 min in a 100% CO atmosphere and leaching in boiling 20% hydrochloric acid for 12 h. Under these conditions it was possible to produce BTS containing > 97% Ti02. During oxidation of titania slag several important morphological changes occur. These are the conversion of the original M305 phase in the slag to a mixture of rutile/anatase, hematite and ferric M305. In the process the iron in the slag migrates to the outside surfaces of the slag particles where it is easily accessible during leaching. The iron containing phases are converted to ilmenite during reduction and during leaching the ilmenite is removed. This yields the BTS product. As the oxidation roast appeared to be a very important of the BTS process it was decided to investigate the mechanism of titania slag oxidation. A mechanism based on the nucleation energy that is required to form the relevant phases during oxidation was proposed. This mechanism was tentatively confirmed through selected experiments. Materials Science and Metallurgical Engineering unrestricted 2013-09-07T14:02:08Z 2009-10-12 2013-09-07T14:02:08Z 1999-11-01 2009-10-12 2009-10-12 Thesis Van Dyk, JP 1999, Process development for the production of beneficiated titania slag, PhD thesis, University of Pretoria, Pretoria, viewed yymmdd < http://hdl.handle.net/2263/28654 > H336/ag http://hdl.handle.net/2263/28654 http://upetd.up.ac.za/thesis/available/etd-10122009-144157/ © 1999, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf University of Pretoria |
| spellingShingle | Iron migration Pigment Beneficiation Upgraded slag Rutile Chloride process Titania slag Oxidation Titanium dioxide Ilmenite UCTD Process development for the production of beneficiated titania slag |
| title | Process development for the production of beneficiated titania slag |
| title_full | Process development for the production of beneficiated titania slag |
| title_fullStr | Process development for the production of beneficiated titania slag |
| title_full_unstemmed | Process development for the production of beneficiated titania slag |
| title_short | Process development for the production of beneficiated titania slag |
| title_sort | process development for the production of beneficiated titania slag |
| topic | Iron migration Pigment Beneficiation Upgraded slag Rutile Chloride process Titania slag Oxidation Titanium dioxide Ilmenite UCTD |
| url | http://hdl.handle.net/2263/28654 http://upetd.up.ac.za/thesis/available/etd-10122009-144157/ |