PURPOSE: To recover efficiently and inexpensively a high purity Zn component from a material contg. Zn by adding an aqueous soln. of ammonium thiocyanate to the material and taking out the Zn component as a rhodane compound.
CONSTITUTION: To a material contg. Zn as industrial waste is added an aqueous soln. of NH4SCN such as rhodane waste liquor, and they are mixed and filtered. The insoluble residue contg. an iron component is reutilized as an iron source for iron manufacture, and the filtrate is recovered as a soln. contg. an extracted Zn component[Zn(SCN)2 soln.]. In stages A, the soln. is concd. and subjected to primary cooling and crystallization. Zn(SCH)2 crystals separated by filtration are redissolved in a fresh aqueous soln. of NH4SCN, and the resulting soln. is subjected to secondary cooling and crystallization to obtain high purity Zn(SCN)2 crystals. The Zn component may be recovered in stages B or C.
MARUKAWA YUUJIYOU
TSUTSUMI MASAKATSU
HIDAKA CHIKARA
TANAKA KOGYO
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