Kaixi Jiang, Sanping Liu, Haibei Wang, Honggang Wang, Ailing Feng
The purity of zinc leaching solution is very critical for the electrowinning and stripping of zinc
plate. In order to meet with the strict requirement of long-period electrowinning and automatic
stripping equipment. The investigations were carried out by Beijing General Research Institute of
Mining and Metallurgy (BGRIMM), Yunnan Chihong Company and Zijin Mining Company.
In general, Cu and Cd is removed with cementation by zinc powder until Cu and Cd content in solution
is less than 0.2 mg/L and 0.18 mg/L. In the second stage, Ni and Co are removed by zinc powder
and antimony salt. The experimental results have shown that Ni and Co content in solution are
both less than 0.1 mg/L after 3.0 h at 85 C.
Fluoride and chloride removal by copper slag. Copper slag came from Cu/Cd residue after sulfuric
acid leaching to dissolve Cd. It contains 72 % Cu and a little Zn, Cd and V. At 60 C chloride was
reduced from 614 mg/L to 51.4 mg/L. The efficiency is about 92 %.
In some zinc smelter tannin was used to precipitate germanium and some zinc oxide ore also used
SX-EW to produce zinc metal. Organic should be removed from the solution. The principle is that
the wetting angle and surface tension is much different between aqueous and organic. It causes oil
particles to agglomerate into big size and float on the surface of the solution to separate from aqueous.
The continuous pilot tests were done and the results indicated that organic content in solution
can be reduced less than 2 mg/L from 50 mg/L.