PT Journal
AU Trpcevska, J
   Holkova, B
   Piroskova, J
   Ferencova, M
TI Microscopical Evaluation of Hard Zinc Refining by Aluminium
SO Manufacturing Technology Journal
PY 2012
BP 264
EP 267
VL 12
IS 2
DI 10.21062/ujep/x.2012/a/1213-2489/MT/12/2/264
DE Hot-dip galvanizing; hard zinc; refining
AB Hot-dip galvanizing is one of the most widely used method for protecting of structural steels against corrosion. In general galvanizing process dross called as "hard zinc" is formed on the bottom of the zinc bath. It is formed by the reactions between molten zinc and iron particles in the galvanizing kettle. Hard zinc represents valuable secondary raw material because of the high content of metallic zinc (94-97%). Bottom dross, being an alloy of zinc and intermetallic phase crystals containing 3-6% wt. Fe, has no direct use in the galvanizing process. For this reason there are attempts to elaborate the technology of obtaining a refined zinc containing less then 0,05% wt. Fe. Hard zinc refining with aluminium is one of the method for iron removing. Refining process is based on the formation of intermetallic particles of AlxFey type. Refining of hard zinc through removal of iron has been investigated in this study. The effect of various aluminium additions as a refining agent has been studied. Light microscopy and AAS (Atomic absorption spectroscopy) have been used in the evaluation of the refining process.
ER