Calcium sulfate as a possible oxidant in “green” siliconbased pyrotechnic time delay compositions

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dc.contributor.author Tichapondwa, Shepherd Masimba
dc.contributor.author Focke, Walter Wilhelm
dc.contributor.author Del Fabbro, Olinto
dc.contributor.author Kelly, Cheryl
dc.date.accessioned 2015-10-01T09:55:16Z
dc.date.issued 2015-08
dc.description.abstract Chemical time delay detonators are used to control blasting operations in mines and quarries. Slow burning Si-BaSO4 pyrotechnic delay compositions are employed for long time delays. However, soluble barium compounds may pose environmental and health risks. Hence inexpensive anhydrous calcium sulfate was investigated as an alternative “green” oxidant. EKVI simulations indicated that stoichiometry corresponds to a composition that contains less than 30 wt. % Si. However combustion was only supported in the range of 30-70 wt. % Si. In this range the bomb calorimeter data and burn tests indicate that the reaction rate and energy output decrease with increasing silicon content. The measured burn rates in rigid aluminium elements ranged from 6.9 to 12.5 mm s1. The reaction product was a complex mixture that contained crystalline phases in addition to an amorphous calcium containing silicate phase. A reaction mechanism consistent with these observations is proposed. en_ZA
dc.description.embargo 2016-08-31
dc.description.librarian hb2015 en_ZA
dc.description.sponsorship Supported in part by AEL Mining Service and by the National Research Foundation of South Africa (Grant 83874). en_ZA
dc.description.uri http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1521-4087 en_ZA
dc.identifier.citation Tichapondwa, SM, Focke, WW, Del Fabbro, O & Kelly, C 2015, 'Calcium sulfate as a possible oxidant in “green” siliconbased pyrotechnic time delay compositions', Propellants, Explosives, Pyrotechnics, vol. 40, no. 4, pp. 518-525. en_ZA
dc.identifier.issn 0721-3115 (print)
dc.identifier.issn 1521-4087 (online)
dc.identifier.other 10.1002/prep.201400202
dc.identifier.uri http://hdl.handle.net/2263/50139
dc.language.iso en en_ZA
dc.publisher Wiley en_ZA
dc.rights © 2015 Wiley -VCH Verlag GmbH & Co. KGaA Weinheim. This is the pre-peer reviewed version of the following article: (name of article) in Propellants, Explosives, Pyrotechnics, vol. 40, no. 4, pp. 518-525, 2015. doi : 10.1002/prep.201400202. The definite version is available at : http://onlinelibrary.wiley.comjournal/10.1002/(ISSN)1521-4087. en_ZA
dc.subject Silicon en_ZA
dc.subject Calcium sulfate en_ZA
dc.subject Time delay en_ZA
dc.subject Pyrotechnics en_ZA
dc.title Calcium sulfate as a possible oxidant in “green” siliconbased pyrotechnic time delay compositions en_ZA
dc.type Postprint Article en_ZA


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