METHOD FOR PROCESSING ASH, PARTICULARLY FLY ASH

• US 20150211094A1
• Filed: 11/30/2012
• Published: 07/30/2015
• Est. Priority Date: 12/02/2011
• Status: Active Grant

• Current Assignee: Jyvaskylan Energia Oy
• Original Assignee: Jyvaskylan Energia Oy
• Inventors: Vaisanen, Ari, Valkonen, Jussi, Peramaki, Siiri, Soikkeli, Ville, Ryymin, Risto
• Granted Patent: US 9,783,870 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: C01F 17/17 involving a liquid-liquid extraction
• CPC Class Codes: C01F 17/206 oxide or hydroxide being the only anion
• CPC Class Codes: C01G 5/00 Compounds of silver
• CPC Class Codes: C01G 55/00 Compounds of ruthenium, rhodium, palladium, osmium, iridium, or platinum
• CPC Class Codes: C01G 7/00 Compounds of gold
• CPC Class Codes: C22B 11/044 from pyrometallurgical residues, e.g. from ashes, dross, flue dust, mud, skim, slag, sludge
• CPC Class Codes: C22B 3/065 Nitric acids or salts thereof
• CPC Class Codes: C22B 3/08 Sulfuric acid , other sulfurated acids or salts thereof
• CPC Class Codes: C22B 3/165 with organic acids
• CPC Class Codes: C22B 3/44 by chemical processes treatment or purification of solutions by liquid-liquid extraction C22B3/26, by ion-exchange extraction C22B3/42
• CPC Class Codes: C22B 59/00 Obtaining rare earth metals
• CPC Class Codes: C22B 7/02 Working-up flue dust
• CPC Class Codes: Y02P 10/20 Recycling
• CPC Class Codes: Y02W 30/91 Use of waste materials as fillers for mortars or concrete

Abstract

Disclosed is a method for processing ash, particularly fly ash, in which method several elements are separated from the ash. In the method both noble metals and rare earth elements are separated.

Claims

1-15. -15. (canceled)

16. Method for processing ash, particularly fly ash, in which method several elements are separated from the ash, characterized in that in the method both noble metals and rare earth elements are separated so that the elements are separated in two extraction processes, in the first extraction process of which noble metals are separated and in the second extraction process of which rare earth elements are separated.

17. Method according to claim 16, characterized in that the solutions obtained in the extraction processes are precipitated in two steps, in the first step of which noble metals are precipitated and in the second step of which rare earth elements are precipitated.

18. Method according to claim 17, characterized in that the extraction processes and steps are integrated with each other.

19. Method according to claim 16, characterized in that in the first extraction process noble metals are dissolved using a water solution with an oxalate content.

20. Method according to claim 16, characterized in that in the second extraction process rare earth elements are dissolved out of the undissolved ash in the first extraction process, by means of a solution which is a mixture of sulphuric and nitric acid.

21. Method according to claim 16, characterized in that the oxalate-extraction solution obtained from the first extraction process is processed in at least two stages, in such a way that a first precipitation solution containing sulphide and ammonium chloride is first of all added to the oxalate-extraction solution, in order to separate iridium and copper, the pH of the remaining solution being raised in order to precipitate the rest of the noble metals in the second precipitation stage.

22. Method according to claim 21, characterized in that in the first stage of the precipitation process the pH of the oxalate-extraction solution is arranged to be 1.5±

0.3 and in the second stage the pH of the solution is arranged to be 8.5±

0.3.

23. Method according to claim 16, characterized in that an oxalic-acid solution is added to the extraction solution obtained from the second extraction process, in order to separate rare earth elements as a third precipitation stage.

24. Method according to claim 23, characterized in that in the third precipitation stage the pH of the extraction solution is arranged to be 1.5±

0.3.

25. Method according to claim 23, characterized in that an oxalic-acid solution is added to the third precipitation stage.

26. Method according to claim 16, characterized in that ash undissolved in the extraction processes is washed with water in wash stages before the following treatment.

27. Method according to claim 26, characterized in that the wash solution formed in the washing is returned to the extraction processes after the wash stages.

28. Method according to claim 16, characterized in that the extraction processes and/or the first, second and third precipitation stages are boosted by adjusting the temperature, adjusting the pressure, agitating the solution, treating the solution mechanically, and/or directing ultrasound to the solution.

29. Method according to claim 22, characterized in that in the second stage of the precipitation process the pH is adjusted by means of ammonia and area the nitrogen remaining after the second stage is collected as fertilizer.

30. Method according to claim 23, characterized in that the oxalic acid used in the rare-earth-elements precipitation stage is recycled to the first extraction process.