How long does it usually take for a patent to be published?

Just because you have an application number doesn't mean you have a patent number. If an application has been rejected, but it has not passed the strict examination or other authorization of the patent office, it is not a patent and cannot become a patent number.

Application number: When the patent applicant filed a patent application in China National Intellectual Property Administration, China National Intellectual Property Administration gave the patent application acceptance notice and patent application number.

Patent number: After the patent applicant obtains the patent right, the patent number on the patent certificate issued by China National Intellectual Property Administration is ZL (patent initials)+application number.