Select 7-Zip > Extract Files . 7-Zip will automatically combine all pieces and output the full BIN file.
Some users find ISO more accessible. You can do a two-step conversion: how to convert 7z to bin
If your final goal requires BIN, you can often convert from ISO to BIN easily. Select 7-Zip > Extract Files
What is the final purpose of this .bin file (e.g., game emulator, firmware update, or disc mounting)? or disc mounting)?