How can you separate sodium nitrate from a solution of sodium nitrate and water?

There is some sodium nitrate dissolved in water. You have to obtain the sodium nitrate. Now, I know that normally you can use evaporation to get the solute. However, sodium nitrate may explode if heated.

We have learned about the following separation techniques:
Filtration
Evaporation
Crystallisation
Simple Distillation
Fractional Distillation
Separating Funnel
Chromatography

I thought about crystallization but don't you need a saturated solution (and therefore have to heat it to make it) for crystallization to take place. On the other hand, would chromatography separate these?

So how can you separate the sodium nitrate from the solution?

sodium nitrate with NOT explode when heated in solution ...

Quoting http://www.softschools.com/formulas/chemistry/sodium_nitrate_uses_properties_structure_formula/275/

"Chemical properties: Sodium nitrate is the salt of a strong acid and hence, dissociates completely in water into sodium and nitrate ions. It is a stable solid at room temperature, however upon prolonged heating, it can explode and release toxic fumes. It is a strong oxidizer and reacts violently with strong reducing agents and flammable materials."