Abstract: In order to recycle white carbon black from the waste generated from the preparation of optical fiber preforms，im- purities in the waste were removed by drying，grinding，calcination，acid treatment，washing，and other harmless treatments to regenerate the ultrafine silicon dioxide particles.The optimum calcination conditions were explored especially.Through the analysis of weight loss，the content of the impurity element（Fe），the product particle size distribution under the different cal- cination conditions，a conclusion was drawn that the best calcination temperature was 500 ℃ and the best calcination time was about 1 h.The quality parameters of the product reached or were close to the national standards.

Key words: optical fiber preform waste, calcination, white carbon black