The invention discloses a method for recycling
fluorine and aluminum resources in waste
cathode carbon blocks, and belongs to the field of comprehensive utilization of
aluminum electrolysis solid waste resources. The method mainly comprises the following steps:
grinding and crushing the waste
cathode carbon block, sieving, leaching villiaumite,
cryolite and the like in the waste
cathode carbon block by adopting an aluminum
salt solution, and carrying out
solid-liquid separation to obtain primary filtrate and primary filter residue;
fluoride, aluminum
oxide and the like in the primary filter residues are leached out through a strong acid solution, and secondary filtrate and secondary filter residues are obtained through
solid-liquid separation; mixing the primary filtrate and the secondary filtrate under the conditions of certain temperature and proper pH value to generate hydrated aluminum hydroxyfluoride precipitate,
roasting the generated hydrated aluminum hydroxyfluoride to obtain aluminum
trifluoride, returning the filtrate to a leaching process for repeated recycling, and recovering
sodium salt in the filtrate through a fractional
crystallization method. The method is simple in technological process, mild in condition and high in
recovery efficiency, and a new technology is provided for green
recovery of fluorides in the waste cathode carbon blocks in the electrolytic
aluminum industry and high-value utilization of aluminum and
fluorine resources.