Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
The burn rate of calcium sulfate dihydrate-aluminium thermites
Dissertation (MEng)--University of Pretoria, 2018.
Saved in:
| Other Authors: | |
|---|---|
| Format: | Thesis |
| Language: | English |
| Published: |
University of Pretoria
2018
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867613652512669697 |
|---|---|
| access_status_str | Open Access |
| author2 | Focke, Walter Wilhelm |
| author_browse | Focke, Walter Wilhelm |
| author_facet | Focke, Walter Wilhelm |
| collection | Thesis |
| dc_rights_str_mv | © 2018 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 | Dissertation (MEng)--University of Pretoria, 2018. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/66196 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:39:33.363Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2018 |
| publishDateRange | 2018 |
| publishDateSort | 2018 |
| 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:2263/66196 The burn rate of calcium sulfate dihydrate-aluminium thermites Focke, Walter Wilhelm u12190952@tuks.co.za Govender, Desania Raquel UCTD Cast thermite Burn rate Calcium sulfate dihydrate Aluminium Engineering, built environment and information technology theses SDG-09 Engineering, built environment and information technology theses SDG-12 Dissertation (MEng)--University of Pretoria, 2018. The energetics of cast calcium sulfate dihydrate-aluminium thermites was explored and its use as a potential metal-cutting tool was investigated. Thermite is a pyrotechnic composition that undergoes a highly exothermic reaction that burns relatively slowly. It is often used in cutting, welding and incendiary devices. Consolidation of thermite by casting was chosen to enable control of the burning front. The base case thermite comprised 60 wt-% calcium sulfate dihydrate oxidiser and 40 wt-% aluminium fuel. Addition of additives were considered for their effect on the cast thermite’s setting time, density, surface temperature, reaction products and burn rate. EKVI and FactSage thermodynamic simulations were used to determine optimum compositions for the various systems. The thermite powder compositions were sieved before mixing with water and casting in a mould. The casts were allowed to set for 3 days to form calcium sulfate dihydrate-aluminium compositions. The copper sulfate pentahydrate additive was found to significantly decrease the setting time of the casts. The heat of hydration of the base case was 59 ± 8 J g−1 . The compressive strength reached 2.9 ± 0.2 MPa, the open air burn rate was 12.0 ± 1.6 mm s −1 and a maximum surface temperature of 1370 ± 64 °C was recorded using a pyrometer. Bomb calorimetry indicated an energy output of 7.96 ± 1.07 MJ kg−1 , slightly lower than predicted by the EKVI simulation. The density of the castings was varied by either adding hollow sodium borosilicate glass spheres or by adding excess water. The glass spheres resulted in a burn rate that decreased nonlinearly with decreasing cast density. The excess water made no changes to the burning, except for increasing the burn rate of the copper sulfate pentahydrate-based thermite. Calcium sulfate in the casts was also dehydrated by thermal treatments at 155 °C and 200 °C. This resulted in significant increases in the burn rate due to the porosity created by the evaporation of the hydration waters. Castings that were thermally treated in an oven at 155 °C were successful in puncturing part of an aluminium block in confined burn tests. A hole with a diameter of ~13.6 mm and depth of ~7 mm was produced. It is recommended that the composition with copper sulfate pentahydrate be used as a binder in further tests. mi2026 Chemical Engineering MEng Unrestricted SDG-09: Industry, innovation and infrastructure SDG-12: Responsible consumption and production 2018-08-17T09:42:37Z 2018-08-17T09:42:37Z 4/19/18 2018 Dissertation Govender, DR 2018, The burning rate of cast calcium sulfate dihydrate-aluminium thermites, MEng Dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/66196> A2018 http://hdl.handle.net/2263/66196 en © 2018 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 University of Pretoria |
| spellingShingle | UCTD Cast thermite Burn rate Calcium sulfate dihydrate Aluminium Engineering, built environment and information technology theses SDG-09 Engineering, built environment and information technology theses SDG-12 The burn rate of calcium sulfate dihydrate-aluminium thermites |
| title | The burn rate of calcium sulfate dihydrate-aluminium thermites |
| title_full | The burn rate of calcium sulfate dihydrate-aluminium thermites |
| title_fullStr | The burn rate of calcium sulfate dihydrate-aluminium thermites |
| title_full_unstemmed | The burn rate of calcium sulfate dihydrate-aluminium thermites |
| title_short | The burn rate of calcium sulfate dihydrate-aluminium thermites |
| title_sort | burn rate of calcium sulfate dihydrate aluminium thermites |
| topic | UCTD Cast thermite Burn rate Calcium sulfate dihydrate Aluminium Engineering, built environment and information technology theses SDG-09 Engineering, built environment and information technology theses SDG-12 |
| url | http://hdl.handle.net/2263/66196 |