It was a long while before the crowd around the Weasley twins dispersed, then Fred, Lee and George sat up counting their takings even longer, so it was well past midnight when Harry, Ron and Hermione finally had the common room to themselves.
There are no more uses of "disperse" in the book.
Show samples from other sources
By the start of the second round, everyone at our table is dispersing among the crowd.
Colleen Hoover -- Slammed
We engaged in the preliminaries: small talk about Betsy’s family, college, career (all stellar, A-list, awesome), and drinks dispersed for everyone (soda pops and Clamato, which Go and I had come to believe was an affectation of Tanner’s, a quirk he thought would give him character, like my wearing fake glasses in college).