METHOD FOR DECONTAMINATION OF MERCURY CONTAINING WASTES Russian patent published in 2019 - IPC C22B43/00 C22B7/00 B09B3/00 

FIELD: waste processing and disposal.

SUBSTANCE: invention relates to decontamination of wastes. Method of decontaminating mercury containing wastes involves combined grinding of wastes with powder of elemental sulfur, water and a homogenizing medium for binding metal mercury to a water-insoluble compound HgS in a rotating reactor in the form of a drum-type mill. Ratio of weight of mercury to elementary sulfur weight is equal to 1:4, bentonite is used as homogenizing medium in amount exceeding waste weight by 2–2.5 times, and water in amount exceeding weight of bentonite is 10–12 times. Preliminary homogenization is carried out for 20–30 minutes. Then mercury-containing wastes are loaded and grinding is carried out until binding of 90 % of weight of metal mercury to water-insoluble compound HgS. For complete bonding of metallic and oxidized mercury to water-insoluble compound HgS at the final stage of the process, a mixture of iron (III) chloride with iron (II) sulphide is added to suspension, wherein the weight of iron (III) chloride and the weight of iron (II) sulphide, respectively, are 10 and 20 times greater than the remaining mercury. Then the formed stable mobile suspension is drained from the mill and directly transferred for drying with further burial as class IV hazard wastes.

EFFECT: simplified technology and higher environmental safety of neutralization and further disposal of mercury-containing wastes.

1 cl, 1 tbl