Patent EA-001278-B1 (EA)
Title: Process and device for recovering raw materials from waste and residues
Inventor: KASZAS-SAVOS MELANIA
IPC: B01D53/75
Filed: 1998-04-28
Abstract: 1. Process for recovering raw materials from wastes and residues, in particular for recovering heavy metals, in which a liquid or paste-like feed mixture and/or a feed mixture comprising comminuted or milled constituents is first produced, where the recovery of the raw materials from the feed mixture is carried out by means of a chemical-thermal treatment and the waste gases are conveyed from the furnace through a multistage filter unit, where the first filter in each case is configured as a hot filter and the waste gases are subsequently cooled and flow through at least one second filter, are preheated and are then burnt at a high temperature, characterized in shat  - the liquid, paste-like and/or solid feed mixture is first mixed, as a function of its composition, with additives,  - the feed mixture is blown together with an oxidizing or reducing agent into the furnace,  - the feed mixture is subsequently subjected to the chemical/thermal treatment in the furnace by the furnace atmosphere flowing at a predetermined flow velocity through the blown-in feed mixture at a predetermined temperature,  - so as to form, as a function of the air composition and temperature, low-density flakes containing heavy metals which are conveyed by the air flow velocity established in the furnace through the filter unit. 2. Process according to claim 1, characterized in that the thermal treatment is carried out in a reducing/oxidizing atmosphere. 3. Process according to claim 1 or 2, characterized in that milled plastics or granulated plastic are/is added as reducing agent. 4. Process according to claim 1, 2 or 3, characterized in that the thermal treatment is carried out at a temperature in the range from 350 degree C to above 700 degree C depending on the respective feed mixture. 5. Process according to claim 1, characterised in that the temperature of the filter unit is in the range from 200 degree C to 800 degree C. 6. Process according to any of claims 1 to 5, characterized in that the flue gas formed, which can contain CO2, SO2, Cl2, etc. , is, after filtration, treated further in a flue gas purification plant to recover hydrochloric acid and sulphuric acid. 7. Process according to any of claims 1 to 6, characterized in that the formation of chromium(III) oxide in chlorine-free systems occurs via decomposition of the chromium-containing materials and reduction/oxidation of the chromium. 8. Process according to any of claims 1 to 6, characterized in that the formation of chromium(III) oxide in chlorine-containing systems occurs via decomposition of the chromium- and chlorine-containing materials, formation of chromyl chloride (CrO2Cl2), decomposition of chromyl chloride and formation of chromium(III) oxide. 9. Process according to any of claims 1 to 8, characterized in that the recovery of chromium as chromium(III) oxide from wastes having a complicated composition is carried out by extraction with chlorine, with chromyl chloride being formed as intermediate. 10. Apparatus for carrying out the process according to any of claims 1 to 9 using a thermal reactor for the chemical-thermal treatment of the raw materials, where a multistage filter unit is connected immediately downstream of the reactor and an afterburning chamber is connected downstream of the filter unit in the flow direction of the waste gases or is arranged downstream of dust separation, characterized in that the thermal reactor is a rotary tube furnace or fluidized-bed furnace whose furnace temperature is, depending on the mineralization temperature of the end products to be produced, in the range from 350 degree C and 1250 degree C, in that the temperature of the first filter of the multistage filter unit is about 800 degree C and in that the second filter is operated at a temperature of about 200 degree C. 11. Apparatus according to claim 10, characterised in that a cooling device is installed downstream of the first filer. 12. Apparatus according to claim 10 or 11, characterized in that the second filter is configured as a textile filter. 13. Apparatus according to any of claims 10 to 12, characterized in that a heating device for preheating the waste gases is arranged between the filter unit and the afterburning chamber.