Ammonium nitrate prill having a non-hygroscopic shell

An in-situ process for converting a prilled ammonium nitrate to a quantity of sealed prills, where the quantity of sealed prills are non-hygroscopic, comprising:

• drying the prilled ammonium nitrate under a vacuum and at an elevated temperature, over an extended time period, therein producing a quantity of dried prills;
• selecting a desired shell weight percent, where the desired shell weight percent is a weight percentage of the quantity of dried prills;
• preparing a first solution having a total first volume comprising a first reactant having a moiety with an affinity for ammonium nitrate and at least two epoxy groups, and a first dilution solvent having a partial first volume accounting for most of the total first volume, wherein the first dilution solvent is miscible with a nonpolar reaction diluent;
• preparing a second solution having a total second volume comprising a second reactant having at least two nucleophilic groups, wherein each of said at least two nucleophilic group reacts with at least one epoxy group, and a second dilution solvent having a partial second volume that accounts for most of the total second volume, and wherein the second dilution solvent is miscible with the nonpolar reaction diluent;
• adding to a reaction vessel a desired weight of the quantity of dried prills, a volume of the reaction diluent sufficient for covering the dried prills, and an inflow of a purge gas, which is a dry inert gas;
• clearing the reaction vessel of any residual air, which contains moisture, by several repetitions of purging the vessel and vacuuming out the purge gas;
• heating and gently moving the dried prills and the reaction diluent in the reaction vessel;
• adding dropwise the first solution to the reaction vessel, wherein the first solution contains a weight quantity of the first reactant that is about a first half of a needed equivalents to form shells on the dried prills added to the reaction vessel, and wherein when added the first reactant migrates through the nonpolar reaction diluent to the dried prills;
• adding dropwise the second solution to the reaction vessel, wherein the second solution contains a weight quantity of the second reactant that is about a second half of a needed equivalents to form shells on the dried prills added to the reaction vessel, wherein when added the second reactant reacts with the first reactant that has collected on the dried prills, therein beginning an in-situ formation of shells having a shape that is specific to an individual prill;
• heating and gently mixing the reaction vessel at about 80° C. for multiple hours, maintaining a positive inert gas pressure, therein reacting in-situ the first reagent with the second reagent forming a plurality of highly crosslinked polymeric shells for individually encapsulating and sealing all of the dried prills, wherein the formed plurality of highly crosslinked polymeric shells have a cumulative weight based on the desired shell weight percent;
• and
• using vacuum filtration for isolating the quantity of sealed dried prills, wherein the AN is not hygroscopic.