Mr.Ahmed zayed, you can apply for China visa from Kazakhstan, you don't need to return to Egypt for the application, there is China embassy in Astana, there is no China consulate in Almaty.

For your supevisor, the required documents are his passport, one passport photo, one completed visa application form, the original invitation letter and one visa notification letter issued by on authorized Chinese government office, such as urumqi city foreign affairs office, you also need the visa notification letter (the host company in Urumqi)can get them for you.

if you and your supervisor doesn't have the original invitation letter, please get them first.