NARUTO 465 SPOILER PICS AND SUMMARIES!

Conference room
We enter through the crack in the wall
Ao: "They're coming!"
Danzou: "..."
Footsteps...
Fuu: "Above!?"
Everyone looks up

Sasuke comes upside down through the ceiling and meets Danzou's eye.
Mifune jumps up and is about to kill Sasuke with his sword
Sasuke evades the sword
Mifune: "I'll take care of you"
Ao: "!'
Karin: "Sasuke! Danzou's escaping!"

Ao jumps over the desk and chases Danzou: "Mizukage-sama, Choujuurou, stay here! I'll chase Danzou! The conference still hasn't been concluded yet!"
Mizukage: "I understand... But don't chase him too far!"
Ao: "Okay! Well then, I'll leave the Akatsuki insurgents to you"

Tsuchikage: "I've got my back to worry about. Everyone else, do as you please"
Akatsuchi: "Are you okay with that?"

Sasuke comes down from the ceiling: "Karin, come!"
Karin: "IE~~~~~~~~!"
Sasuke: "!!"
Syrupy liquid? attacks Sasuke, but he evades it
The wall melts

Sasuke glares at the Mizukage
As the Mizukage restrains her mouth: "Akatsuki, who toyed with the Fourth Mizukage and overran Kirigakure... ...Now that I get a good look, you're still a good-looking man, aren't you. Uchiha clan..."
Choujuurou: (I came out... Mizukage-sama's kekkei genkai - The Youton technique...!!)

Sasuke: "You're in my way"
Mizukage: "Haa... You really are a good-looking man... far more than you deserve"

Sasuke VS the Five Kage - To a complete collision...!!
The end ☆Bye~☆

The Four-Tails and its jinchuuriki Roushi used an element called Youton, later revealed to be all-melting lava. According to the spoilers, the Mizukage also uses an element called Youton. The question is if this Youton is the same as the Four-Tails'.

The Four-Tails' Youton is written as 熔遁. On its own, the first kanji means 'to melt,' 'to dissolve,' 'to thaw'. It is an uncommon variant of the kanji 溶, which is the kanji used to write the Mizukage's youton (溶遁).
The difference between the kanji is the left radical; in 熔, the left radical is fire, in 溶, the radical is water. The two kanji mean and are pronounced the same.

The difference in kanji used might indicate that although similar, the Mizukage's Youton is water-related, while the Four-Tails' Youton is fire-related. There's a slight problem, though. It is extremely easy to make a mistake in writing these kanji. As I said before, 熔 is uncommon. Accidentaly writing 溶 instead of 熔 is easy and in fact, Kishimoto-sensei did exactly this in Roushi's third databook entry.
It should also be pointed out that the word 'lava,' the element of the Four-Tails' Youton, has consistently been written as 溶岩 (yougan), thus with the water-radical 溶 kanji and not the fire-radical 熔 kanji. Therefore, making such a clear distinction between the kanji is odd at the least.

About the possibility of the Mizukage's Youton being acid: I would think that Kishimoto-sensei would use the actual kanji for 'acid' if he wanted to create an Acid Release: 酸遁 (Santon).