The move is designed to head off other recalls, and is specifically retroactive (which the article says is to help out Sheriff Joe Arpaio). From what I can tell, Arizona would be only the second state to have a specified recall primary, with Wisconsin being the other.
Note that this law would have another effect -- cutting into the amount of time allowed to get a recall on the ballot. In Arizona, recalls must be held on Election Day. Now, petitioners would need to get in the signatures early enough to qualify for primary day. Arizona has also passed a law limiting elections to once every two years, so that limit can really matter.