Treatment of fly ash
A method for the treatment of fly ash obtained from an incineration process of a waste incineration plant, in particular for municipal solid waste, whereby fly ash is separated from the incineration process. Furthermore, a method for the operation of a waste incineration plant, in particular for municipal solid waste or the like. The process for the treatment of fly ash is further characterized in that metals and/or metal containing compounds, in particular heavy metals and/or heavy metal containing compounds, are separated from the fly ash, which is separated from the combustion process and preferably non-fractioned, in a separation step and subsequently the fly ash reduced by the metals and/or metal containing compounds is, preferably dosed, mixed with or added to the waste to be incinerated so that the mineral parts of the fly ash, reduced by its metals and/or metal containing compounds, are returned to the combustion process.
1. Method for the treatment of fly ash from a combustion process in a waste incineration plant of municipal solid waste, comprising the steps of:
fly ash is separated from a combustion process of municipal solid waste,
metals and/or metal containing compounds are separated from the fly ash, which is non-fractioned,
wherein the non-fractioned fly ash, in the metals and/or metal containing compounds separation step, is treated by a wet chemical leaching process, so that the fly ash is reduced by metals and/or metal containing compounds and/or earth alkaline metals, and
subsequently the fly ash, reduced by the metals and/or metal containing compounds is dosed, mixed with or added to the waste to be incinerated in the waste incineration process so that the mineral parts of the fly ash, reduced by its metals and/or metals containing compounds, are returned to the combustion process.
2. Method according to claim 1 , wherein the fly ash, reduced by its metals and/or metal containing compounds is pelleted, in predetermined quantities, in a pelleting device.
3. Method according to claim 2 , wherein the compacted fly ash, reduced by its metals and/or metal containing compounds, and formed into pellets, is stored in an intermediate reservoir as fly ash residue.
4. Method according to claim 1 , wherein the wet chemical leaching process is leaching extraction.
5. Method according to claim 4 , wherein in the metals and/or metals containing compounds separation step, the concentration of the heavy metals or heavy metal containing compounds in the fly ash is reduced by at least 50%, through the leaching process.
6. Method according to claim 4 , wherein the heavy metals or heavy metal containing compounds contained in the fly ash are extracted after the leaching step by means of a leaching solvent in an extraction step and/or, are precipitated in a solvent extraction process.
7. Method according to claim 4 , wherein the mineral fractions containing residue of the leaching process is returned to the incineration process.
8. Method according to claim 4 , wherein the fly ash is treated by means of ammonia alkaline leaching and/or by means of hydrochloric leaching.
9. Method according to claim 1 , wherein the amount of residues resulting from the incineration process that has to be disposed is reduced by 1.5 weight % and more of the amount of waste to be incinerated according to the mineral fractions of the fly ash.
10. Method according to claim 1 , wherein filter fly ash and/or boiler fly ash from flue gases of the waste incineration processes are subjected as non-fractioned fly ash to the separation step.
11. Method for the operation of a waste incineration plant for municipal solid waste or the like, whereby the method steps are performed according to claim 1 .
12. The method of claim 1 , wherein the metals and/or metal containing compounds are heavy metals and/or heavy metal containing compounds.
13. The method of claim 2 , wherein the fly ash is dewatered.
14. The method of claim 3 , wherein the intermediately stored, fly ash residue from the intermediate reservoir is mixed with or added to the waste to be incinerated.