The invention belongs to the technical field of
environmental protection, and relates to the recycling of
chromium-rich
sludge, in particular to a method for producing
chromium sesquioxide through
chromium-rich
sludge. The method comprises the following effective steps: a, firstly, washing and
drying chromium-containing
sludge; b, then, evenly
grinding the dried chromium-containing sludge, transferring the chromium-containing sludge into a calcining
kiln to directly heat the chromium-containing sludge, increasing the temperature of the chromium-containing sludge to 530 to 570 DEG C within 1.5to 2 hours, and then maintaining the temperature for 1 to 1.5 hours; c, transferring the chromium-containing sludge into a cooling
kiln after heating is accomplished, reducing the temperature of the chromium-containing sludge to 60 to 90 DEG C, adding
hydrochloric acid and water at the end of cooling, and uniformly stirring; d, transferring the uniformly stirred chromium-containing sludge into a
filter press to perform filter pressing on the chromium-containing sludge, and washing filter residue to be neutral; e, adding water and
hydrofluoric acid to the washed filter residue, stirring for 0.5hour, then transferring the filter residue into a
filter press to perform filter pressing on the filter residue, and washing the filter residue to be neutral; f, then transferring the filter residueinto a high-temperature calcining
kiln, performing burning and heating on the filter residue through
coal gas, increasing the temperature of the filter residue to 1320 to 1400 within 2 hours, maintaining the temperature for 50 to 80 minutes, and then transferring the filter residue into the cooling kiln to reduce the temperature of the filter residue to below 40 DEG C, so as to obtain a finished product namely the
chromium sesquioxide.