The invention discloses a method for extracting and recovering
chromium from cold rolling
chromium sludge. The method comprises the following steps: 1), soaking cold rolling
chromium sludge in concentrated
hydrochloric acid 20-37% in weight percentage, stirring for mixing, so as to enable Cr elements in cold rolling chromium
sludge to exist in the form of chromium (iii), then leaving to stand and filtering out insoluble
solid matters to obtain a solution I; 2), adding Zn
powder to the solution I, fully separating out non-active
metal deposition, filtering out deposition to obtain a solution II; 3), regulating the pH value of the solution II to be 7-8, introducing CO2, heating to enable
Zinc (ii) and Ca (ii) to precipitate in the form of ZnCO3.3Zn(OH)2 and CaCO3, and enable Cr elements in the solution II to exist in the form of CrCl3, leaving to stand to filter out precipitate to obtain the solution III for standby application; 4), regulating the pH value of the solution III to be 8-9, heating to enable CrCl3 in the solution III to be hydrolyzed to form CrOCl precipitate, the formed CrOCl precipitate is the
chromium product. According to the method for extracting and recovering chromium from cold rolling chromium sludge, the
recovery rate of chromium from the cold rolling chromium sludge can reach 95% or above, the
recovery rate of chromium is greatly improved, innocent treatment on cold rolling chromium sludge is fully realized, the
energy consumption is reduced, and the chromium
recovery additional value is increased.