When it rains, it puddles. Spilled salt cycles between wet and dry with humidity. Is this akin to a phase change?

I have some spilled un-iodized table salt (NaCl). It is very humid where I live, and when it gets very humid for a few days, the salt absorbs so much water that it becomes a puddle of (probably) saturated salt water. When the humidity drops for a few days, the water evaporates and I have *dry salt crystals* again. This is repeatable.


My questions about this process are:


1. What is this process called exactly? As far as I understand "deliquescence" is a *property* and not a process. Does the exchange of water between my pile of salt and the air have a specific terminology? Something that would go along with terms like evaporation, sublimation, condensation, etc.? Perhaps some mash-up of *adsorption* and *dissolution*?
2. Is this process akin to a phase change in some way? For example, if I had a sealed box of air with a dish of salt and a beaker of water, and I could ramp the temperature slowly enough, would I see a plateau at a certain humidity as the salt hit a threshold and started absorbing water until saturated?




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Some may be familliar with the [Morton Salt](https://en.wikipedia.org/wiki/Morton_Salt) logo and slogan "When it rains, it pours" meaning that other moisture-absorbing materials in the package will keep the sodium chloride as *table salt* from absorbing too much water and becoming stuck and un-pourable:


[Source](https://en.wikipedia.org/wiki/File:Morton_Salt_Umbrella_Girl.svg)


[![enter image description here](https://i.stack.imgur.com/tSw5T.png)](https://i.stack.imgur.com/tSw5T.png)





> 
> What is this process called exactly? As far as I understand
> "deliquescence" is a property and not a process. Does the exchange of
> water between my pile of salt and the air have a specific terminology?
> Something that would go along with terms like evaporation,
> sublimation, condensation, etc.? Perhaps some mash-up of adsorption
> and dissolution?
> 
> 
> 


The property of salts to become wet as I mentioned in another post [Scientific Reason for Salt Solution Gaining Volume](https://chemistry.stackexchange.com/questions/112911/scientific-reason-for-salt-solution-gaining-volume/112914#112914) is deliquescence. The corresponding verb is to deliquesce. It is a pretty old word. From OED (not open access):



> 
> To melt or become liquid by absorbing moisture from the air, as certain salts.
> 
> 
> 1756 C. Lucas Ess. Waters i. 14 They attract the humidity of the
> air, and deliquesce, or run liquid.
> 
> 
> 1781 Philos. Trans. 1780 (Royal Soc.) 70 349 This
> pot-ash..deliquesces a little in moist air.
> 
> 
> 1876 D. Page Adv. Text-bk. Geol. (ed. 6) xvi. 299 Pure chloride of
> sodium is not liable to deliquesce.\*
> 
> 
> 


Regarding phase changes, there were many phases changes involved in that process. The water as gas became liquid. The solid NaCl phase become one phase with a liquid. Once it evaporated, you got the solid again.


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