METHOD FOR RECOVERY OF HEXAVALENT CHROMIUM FROM PROCESS WASTE Russian patent published in 2023 - IPC C02F1/62 C02F1/70 C02F101/22 

FIELD: waste disposal.

SUBSTANCE: invention relates to neutralization of process waste containing compounds of toxic hexavalent chromium, namely for neutralization of catalyst sludge formed after dehydrogenation of isobutane. The invention relates to the field of disposal of process waste comprising compounds of toxic hexavalent chromium. The method for the recovery of hexavalent chromium from process waste includes the reduction of chromium (+6) to chromium (+3) and obtaining a precipitate of chromium hydroxide (+3). The raw material used is a suspension of catalyst sludge, which is a mixture of liquid and solid phases with a chromium content (+6) of 1 g/l. The suspension is loaded into the reactor and heated at 70-85°C. Then, sodium metabisulfite is introduced into the heated pulp at a ratio of reducing agent mass/pulp mass of 0.005/1 and mixed at a speed of 150-300 rpm for 20-35 minutes to obtain a solid phase containing chromium (+3), which is delivered for storage, and the liquid phase comprising sodium sulphite, which is delivered for regeneration.

EFFECT: neutralization of man-made wastes.

1 cl, 1 tbl, 6 ex