| 摘要 |
PURPOSE:To regenerate an FeCl2 aq. soln. to an FeCl3 aq. soln. by adding an iron piece to an FeCl3 waste liquid contg. Cr and Ni which is obtained by treating stainless steel and precipitating and removing Cr and thereafter by adding iron powder to the filtered liquid to precipitate and remove Ni and blowing Cl2 into the residual liquid contg. FeCl2. CONSTITUTION:Since Cr and Ni are contained in a liquid wherein stainless steel is subjected to etching treatment by an FeCl3 aq. soln., an iron piece of the excess amount than the amount necessary to change the residual FeCl3 to FeCl2 is added and allowed to react with each other at 1-3 pH at 50-90 deg.C temp. to precipitate Cr as Cr(OH)3 and thereafter it is filtered, removed and recovered. Iron powder having >=150 mesh is added to the FeCl2 aq. soln. of the residual liquid in >=1 time mol for contained Ni and allowed to react at 80 deg.C for 2-8hr to precipitate the contained Ni and it is filtered and recovered. The FeCl2 aq. soln. wherein Cr and Ni are removed therefrom is blown with gaseous Cl2 and regenerated as the FeCl3 aq. soln. and reutilized as a treating liquid of stainless steel. |
