Method for recovering and reusing quartz powder waste in out-of-tube deposition process

A method for preparing an optical fiber preform rod having a functional quartz cladding, comprising steps of:

• (S0) recovering quartz powder waste in an out-of-tube deposition process, comprising steps of
• (1) acid washing:
• reacting a quartz powder collected in a treatment of a tail gas from deposition of an optical fiber preform rod in a hydrochloric acid solution, precipitating the quartz powder out and draining the acid solution on a surface thereof, and washing the quartz powder with pure water;
• (2) separation:
• draining surface water from the quartz powder diluted with pure water obtained in Step (1), centrifuging, and separating the quartz powder;
• (3) drying:
• drying the quartz powder obtained in Step (2) in a dryer lined with high-purity quartz and drying to a moisture content of 2% or less;
• (4) calcinating:
• calcinating the quartz powder dried in Step (3) in a device lined with high-purity quartz;
• (5) crushing:
• taking out the calcinated quartz, placing in a device lined with high-purity quartz, crushing and grinding to an average particle size of 0.2-1 mm;
• and
• (6) pre-water removal:
• placing the ground quartz powder in a sealed container, and introducing a nitrogen-chlorine mixture containing 15%-25% chlorine;
• (S1) assembly of optical fiber preform rod and filing filling:
• assembling a cladding sleeve having a cladding tail handle and a core rod having a core tail handle after Step (1) acid washing, filling a gap between the cladding sleeve and the core rod with the quartz powder prepared in step (S0) after assembly, and then filling a tail high-purity quartz column with the quartz powder;
• (S2) mounting of tail cover plate:
• mounting a tail cover plate having a gas gauge, a gas inlet, a gas extraction port and three polytetrafluoroethylene sealing rings, to fix the core rod in place;
• and
• (S3) hanging the optical fiber preform rod to a melt shrinkage device, doping the quartz powder, and then melt shrinking and sintering to obtain a transparent glass rod, wherein the doping gas is silicon tetrachloride or silicon tetrafluoride.