Raikage would win. Don't overestimate the iron sands effect on lightning. it is true that Iron conducts electricity, but iron is a very weak conducter at 10MS/m, better only than bronze and stainless steel. also, the "armour" u speak of is made up, not any sort of confirmed technique--even if he does use the iron as a shield there's nothing to suggest it is or would be as perfect as it's described in your post. Plus, we don't know which nature's are used for kazekage's kekkei genkai, but i believe it must be earth-based like Kakuzu's Iron Skin tech which Raikiri cut through like butter. if that's true, lightning--especially at the 3rd raikage's level--would blast right through it. and the whole blood-bending thing is also nothing more than conjecture and should not be used in any argument, as well as the idea of kazekage sending iron into the body to choke someone to death or whatever. Even if these things seem possible, they are neither used nor discussed. and even if kazekage did use the "perfect" iron shield u describe, raikage would simply not attack. kazekage does not have an infinite amount of iron sand so he could either attack or defend with it. basically, the second he makes a hole in the shield in order to attack, raikage would be right there to punch through the hole and hit kazekage directly--he's easily fast enough to dodge the attacks used in an attempt to stop him (this is how deidara beat gaara--he took advantage of the fact that gaara attacked with his defensive sand). and this is even if kazekage had such a perfect iron shield. and as powerful as raikages body was, i don't think any of the kazekage's iron weapons could penetrate his skin. so even with poison on the iron blades, it wouldn't matter. also, water is a much better conductor of electricity. raikage would be in much more danger charging into a wall of water with his lightning armor blazing at full capacity than he would be blasting apart some iron. while iron does conduct electricity, raikage would not be injecting electricity into the iron. instead, he is using the electricity in his body to supercharge his speed and power so his punches would just blast the iron apart, electricity would not have a chance to come back to him. raikage runs an inhuman amount of electricity throughout his body, so as weak a conductor as iron is it wouldn't effect raikage even if it somehow got sent back into him. in order to hurt raikage, the electricity produced by his lightning would have to be amplified beyond its already inhuman levels and sent back to him. Iron would not do this, it would not amplify it at all. And I have no idea what you mean by saying magnetism can’t be pushed aside… sakura blasted tons of attacks away from her, it doesn’t matter if it was a puppet it’s the same power—it’s the same iron used in the same way manipulated by the same chakra. The magnetism is used mostly to bind the iron powder together into a more dense state, creating very hard and very strong weapons. And while magnetism is a strong force, it’s not like kazekage could use it to hurl his weapons at the speed of light. Raikage is more than fast enough to dodge them and more than strong enough to bash them aside. His super speed, raw power, and skin that neither Gyuuki nor 10,000 enemies could damage, raikage takes this.
Also, you said science does come into play. Having said that, you do know that to demagnetize metal you heat it up beyond its Curie temperature right? Well, for Iron, the curie temp is 770 Celsius. U have any idea how hot lightning is? It’s upwards of 30,000 Celsius. Raikage could actually use the heat of his lightning to demagnetize the iron. Then what does the Kazekage have? Even if not, he’d win for reasons stated above.
