PURPOSE: To make it possible to separate and recover Na2CO3, a phosphate and vanadic acid salt in high yields, by treating a dephosphorized and desulfurized slag, e.g. molten iron prepared with Na2CO3, etc., with water and CO2, and adding the a Ca compound and an organic substance to the resultant treated slag.
CONSTITUTION: A slag generated in dephosphorizing and desulfurizing a molten iron or steel with Na2CO3 is cooled, pulverized and then treated with water and CO2 to elute the Na2O in the slag as Na2CO3 in the water. A sulfide, phosphate and vanadate of the Na are eluted simultaneously. FeSO4 is added to the resultant extracted solution to precipitate and remove the S content therein as FeS, and CaO is added to the extracted solution to precipitate and recover the P content therein as Ca3(PO4)2. The residual solution is then concentrated to crystallize and recover the Na2CO3, and an organic substance, e.g. an amine, is added and mixed with the concentrate. The resultant mixture is then allowed to stand to extract V, and the organic substance layer is separated. Ammonia is then added to the organic layer to precipitate and recover V as NH4VO3 or V2O5.
MARUKAWA YUUJIYOU
TSUTSUMI MASAKATSU
HIDAKA CHIKARA
TANAKA KOGYO
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