The Journal of Explosives Engineering - November/December 2022 - 28

Understanding Single
Salt, Dual Salt, and
Multiple Salt Bulk
Emulsions and Emulsion
Blends
By D. Scott Scovira, Dr. Bronwynne Victor, and Quentin Steyl
Abstract
Bulk emulsions and emulsion blends may be formulated with a single salt, dual salts, or multiple salts. Single
salt bulk emulsions and emulsion blends, based on ammonium nitrate, are familiar to many blasting professionals
as they are manufactured and employed on a global basis. Blasting professionals may be less acquainted
with dual and multiple salt emulsion and emulsion blends that may include calcium nitrate, sodium nitrate,
and urea in their formulations. These salts can impart various beneficial qualities to address end user needs and
blasting results.
The process of heterogenous seed driven crystallization that effects single salt bulk emulsions is described.
Dual and multiple salt emulsions are inherently chemically resistant to heterogenous seed driven crystallization,
and the chemistry and manufacturing process behind this resistance is described. Dual salt emulsions have
been demonstrated to resist oxidiser and fuel phase separation during transport, breakdown by repeated repumping,
and salting out during extended storage times.
In field practice, single salt AN bulk emulsions and bulk emulsion blends have been observed to generate
considerable post blast NOx fume while dual salt ANCN bulk emulsions and emulsion blends have been noted
to produce lesser degrees of NOx. Regarding mine water discharge quality, on a per kilogram basis, the generation
of NH3
0 (unionized or free ammonia) is shown to be less with a salt equivalent percentage ANCN dual salt
emulsion formulation as compared to a AN single salt emulsion formulation.
To realize reliable performance and optimal results of single salt, dual salt, and multiple salt emulsions and
emulsion blends, it is important to understand the relationship between hole diameter, product densities, and
maximum hole depth. This relationship must be understood by the user to insure there is enough void space in
the bulk product at the bottom of the hole to insure detonation sensitivity.
Company propriety computer detonation codes are used to calculate relative weight strength and relative
bulk strength energy values. The energy values generated by these various computer codes while useful in
comparing products within a manufacturer's product line, often create confusion for the end user when trying
to compare published energy values between manufacturers.
Underwater bubble testing can be useful for making relative physical measurements of shock and gas energies
realized by bulk explosive products. Recent underwater bubble tests of single salt, dual salt, and urea inhibited
emulsions and emulsion blends record interesting differences in total energy, and shock and gas energy
partitions between formulations.
28
The Journal of Explosives Engineering
November/December 2022
The Journal of Explosives Engineering - November/December 2022

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