发明名称 |
PROCESS FOR RECOVERING CHROMIC ANHYDRIDE FROM EXHAUSTED AQUEOUS CHROMIUM PLATING BATH SOLUTIONS WITH EXPLOITATION OF THE RECOVERED CHROMIUM |
摘要 |
The chromic anhydride contained in soluble form (chromic acid) in exhausted, polluted chromium plating baths is recovered by alkalizing the exhausted chromium plating liquid to a pH comprised between 3 and 7 at a temperature of 70 DEG C with a commercial sodium hydroxide solution, keeping the mass in reaction at this temperature for an hour and filtration separating the precipitate obtained. The filtered solution having a specific gravity of 1.25 kg/l, contains CrO3 (22 % in weight) which is then reduced with sulphur dioxide to obtain a solution containing basic chromium sulphate and sodium sulphate, suitable for use as a tanning bath; in this manner pollution is avoided and the waste chromium is exploited. The solution containing CrO3 can also be introduced into a hexavalent chromium salt production cycle. |
申请公布号 |
WO8909188(A1) |
申请公布日期 |
1989.10.05 |
申请号 |
WO1988IT00038 |
申请日期 |
1988.05.24 |
申请人 |
LUIGI STOPPANI S.P.A. |
发明人 |
BRUZZONE, GIUSEPPE;GHELLI, GIOVANNI;PERRONE, DIEGO |
分类号 |
C01G37/033;C01G37/08;C01G37/14;C14C3/06;(IPC1-7):C01G37/08 |
主分类号 |
C01G37/033 |
代理机构 |
|
代理人 |
|
主权项 |
|
地址 |
|