Some human remains and parts of the wreckage of the China Eastern Airlines passenger plane that crashed into a mountain in Guangxi on Monday have been recovered at the crash site, an official told a press briefing on Wednesday.

The wreckage and human remains have been handed over to the investigation team, said Zheng Xi, head of the fire brigade of the Guangxi Zhuang autonomous region, adding that rescuers from the brigade had covered a search area of 46,000 square meters by 7 pm Wednesday.

The exterior of the black box from the crashed plane recovered on Wednesday was severely damaged, and it was initially believed as the cockpit voice recorder, said Zhu Tao, head of the aviation safety office of the Civil Aviation Administration of China (CAAC).
A flight recorder is an electronic recording device placed in an aircraft for the purpose of facilitating the investigation of aviation accidents and incidents. Flight recorders are also known by the misnomer black box—they are, in fact, painted bright orange in color to aid in their recovery after accidents.

The black box is made up of two separate pieces of equipment: the flight data recorder (FDR) and a cockpit voice recorder (CVR). FDRs record things like airspeed, altitude, vertical acceleration and fuel flow. The CVRs track the crew’s interactions with each other and air traffic control, but also background noise that can give vital clues to investigators.
They are compulsory on any commercial flight or corporate jet, and are usually kept in the tail of an aircraft, where they are more likely to survive a crash.

This box is made of Titanium metal and is enclosed in a Titanium box which gives it the strength to withstand any shock if it falls in the sea or falls from the height.
It can work for 30 days without any electricity. It can withstand a temperature of 1100°C. When this box is lost anywhere, it keeps on emitting the waves along with a beep sound for about 30 days.

sources: weibo, xin hua, onlinecn