My anger will not go on for more than three minutes.
This is the noun version of 怒る. So instead of being "to be angry," it's just the idea and concept of anger and wrath.
Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You haven't learned this reading yet, so here's a mnemonic to help you:
I have a lot of anger because I carry (いかり) all of my own things (books, luggage, drinks) and no one will ever carry them for me. Plus, the more things I carry, the more anger I carry inside. Ahh!