I do not think it goes into his pocket. But last I read of it, it goes into a fund controlled by the President -- a slush fund, in olden terms.
Just as he does not personally own the US Steel golden shares which were the price for allowing the sale to the Japanese. But the President personally controls those shares, and he personally has veto over everything US Steel does.
One of the alleged differences between socialism and fascism is that a socialist government owns the means of production while a fascist government "merely" controls them. It's a distinction without a meaningful difference.
The big picture point is, he claimed banning the export of those chips to China was a matter of national security. Now it turns out that paying an unconstitutional 25% export tax into a fund controlled by the President makes the national security aspect vanish. There are names for this kind of corruption.