FIELD: chemistry.
SUBSTANCE: invention relates to methods of treating natural or artificial sludge, particularly sludge contaminated with heavy metal or organic substances, e.g. contaminated soil or sludge which forms when cleaning channels. To realise the method, fractions of particles with the largest size in a sludge suspension are separated. Phosphoric acid is added to the sludge and the sludge is foamed in controlled conditions which provide intense stirring sufficient for obtaining foam with density less than 90% of the density of the sludge. The foam is dried. The said foaming and passivation are carried out together. In preferred versions of the method, density of the foam is less than 85% of the density of the sludge or even ranges from 55 to 65%. The foam is dried using a technique similar to composting. After drying for 12 days, content of dry substance in the dried sludge exceeds 65%. The dried sludge is then annealed at temperature ranging from 550° to 750°C. The annealing product is mixed with water and then set and hardened.
EFFECT: method ensures cheap treatment of sludge, fast processing of sludge into products with mechanical strength and which can be easily processed later.
10 cl, 1 dwg, 6 tbl, 6 ex
