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US-20260124651-A1 - METHOD FOR THE INCINERATION OF WASTE CONTAINING FLUORINE AND NOBLE METALS

US20260124651A1US 20260124651 A1US20260124651 A1US 20260124651A1US-20260124651-A1

Abstract

A method for the incineration of waste containing fluorine and noble metals in a chamber furnace, the fluorine content of the waste lying in the range of >5 to 70 wt. %, and the noble metal content of the waste lying in the range of 0.1 to 30 wt. %, and the furnace chamber of the chamber furnace being lined with a chromium corundum material comprising ≥80 wt. % alpha-Al 2 O 3 , 1 to 20 wt. % Cr 2 O 3 and 0 to 5 wt. % SiO 2 .

Inventors

  • Christian NOWOTTNY
  • Thomas OEHMEN
  • Dieter Schäfer

Assignees

  • HERAEUS PRECIOUS METALS GMBH & CO. KG

Dates

Publication Date
20260507
Application Date
20230928
Priority Date
20221012

Claims (9)

  1. 1 . A method for the incineration of waste containing fluorine and noble metals in a chamber furnace, wherein the fluorine content of the waste lies in the range of >5 to 70 wt. %, and the noble metal content of the waste lies in the range of 0.1 to 30 wt. %, and wherein the furnace chamber of the chamber furnace is lined with a chromium corundum material comprising ≥80 wt. % alpha-Al 2 O 3 , 1 to 20 wt. % Cr 2 O 3 and 0 to 5 wt. % SiO 2 .
  2. 2 . The method according to claim 1 , comprising the successive steps of: (1) introducing waste containing fluorine and noble metals to be incinerated, which waste has a fluorine content in the range of >5 to 70 wt. % and a noble metal content in the range of 0.1 to 30 wt. %, into the furnace chamber of a chamber furnace, (2) incinerating the waste, and (3) removing the ash formed after the completion of step (2), wherein the furnace chamber of the chamber furnace is lined with a chromium corundum material comprising ≥80 wt. % alpha-Al 2 O 3 , 1 to 20 wt. % Cr 2 O 3 and 0 to 5 wt. % SiO 2 .
  3. 3 . The method according to claim 1 , wherein the waste containing fluorine and noble metals is chemical waste, fuel cell waste and/or electrolysis cell waste.
  4. 4 . The method according to claim 1 , wherein the fluorine content of the waste containing fluorine and noble metals lies in the range of 15 to 60 wt. %.
  5. 5 . The method according to claim 1 , wherein the noble metal content of the waste containing fluorine and noble metals lies in the range of 0.5 to 8 wt. %.
  6. 6 . The method according to claim 1 , wherein the chromium corundum material comprises or consists of 80 to 95 wt. % alpha-Al 2 O 3 , 1 to 20 wt. % Cr 2 O 3 and 0 to 5 wt. % SiO 2 .
  7. 7 . The method according to claim 1 , wherein the chromium corundum material comprises or consists of 85 to 95 wt. % alpha-Al 2 O 3 , 2 to 15 wt. % Cr 2 O 3 and 0 to 2 wt. % SiO 2 .
  8. 8 . The method according to claim 1 , wherein the chromium corundum lining is designed in the form of a ramming mass, as pre-compacted fibers and/or as a chromium corundum brick.
  9. 9 . The method according to claim 1 , wherein the furnace temperature during incineration is in the range of 650 to 950° C. as a continuous temperature.

Description

The invention relates to a method for the incineration of waste containing fluorine and noble metals. The noble metal-enriched ash residue obtained after the method has been carried out can be processed to recover the noble metal contained therein. The term “noble metal” is used herein. Noble metals within the meaning of the present invention are silver, ruthenium, rhodium, palladium, iridium and platinum, each one alone or in any combination of two, a plurality of or all of these metals. EP 2 700 726 A 1 discloses a method for the incineration of waste containing fluorine and noble metals with the aim of enriching noble metals. When such waste is incinerated, hydrogen fluoride or hydrofluoric acid is produced, among other things. As a thermal treatment plant in which the incineration takes place, EP 2 700 726 A 1 discloses a chamber furnace with a refractory insulation lining in the form of a ramming mass in the interior of the furnace chamber, wherein the refractory insulation lining has a high proportion of aluminum oxide of 85 wt. % (weight %) or more, in particular of 88 wt. % or more. In addition to aluminum oxide, the refractory insulation lining can also comprise calcium oxide and silicon dioxide in varying proportions. Despite the proportion of up to 15 wt. %, in particular up to 12 wt. % of calcium oxide and/or silicon dioxide in the ramming mass, according to EP 2 700 726 A 1 it is not corroded by hydrofluoric acid. EP 2 700 726 A 1 states that the disclosed method is preferably suitable for processing materials which have a fluorine content of up to 5 wt. %. Preferably, the waste materials used in the method that are to be subjected to heat treatment are fluoroorganic materials, PTFE films, fuel cells, catalysts and/or pastes. In principle, the method is suitable for all materials having a fluorine content of up to 5 wt. %, which decompose at a temperature of approximately 800° C., in particular of approximately 600° C., i.e., below, but at the latest when said temperature of approximately 800° C., in particular of approximately 600° C., is reached. The object of the present invention was that of finding a method, used for the enrichment of noble metals, for the incineration of waste containing fluorine and noble metals with a particularly high fluorine content. It had been found that the method known from EP 2 700 726 A 1 reaches its limits as soon as the fluorine content in the material containing fluorine and noble metals to be incinerated exceeds 5 wt. %, in particular if this is regularly the case, for example, for each or substantially each batch. The object could be achieved by virtue of a method for the incineration of waste containing fluorine and noble metals in a chamber furnace, the fluorine content of the waste lying in the range of >5 to 70 wt. %, and the noble metal content of the waste lying in the range of 0.1 to 30 wt. %, and the furnace chamber (the furnace space, the furnace interior) of the chamber furnace being lined with a chromium corundum material comprising ≥80 wt. % alpha-Al2O3, 1 to 20 wt. % Cr2O3 and 0 to 5 wt. % SiO2. The method according to the invention comprises the successive steps of: (1) introducing waste containing fluorine and noble metals to be incinerated, which waste has a fluorine content in the range of >5 to 70 wt. % and a noble metal content in the range of 0.1 to 30 wt. %, into the furnace chamber of a chamber furnace, (2) incinerating the waste, and (3) removing the ash formed after the completion of step (2), the furnace chamber of the chamber furnace being lined with a chromium corundum material comprising ≥80 wt. % alpha-Al2O3, 1 to 20 wt. % Cr2O3 and 0 to 5 wt. % SiO2. If the fluorine content and/or the noble metal content of waste containing fluorine and noble metals to be incinerated by means of the method according to the invention is not directly known, it/these can be determined using conventional analytical methods known to a person skilled in the art. A person skilled in the art will choose the analytical method(s) depending on the type of waste. If necessary, the waste can first be homogenized—at least macroscopically. The fluorine content of a waste sample can be determined, for example, by combustion digestion (pyrohydrolysis) followed by ion chromatography (combustion IC). To determine the noble metal content, a waste sample can be examined directly or after incineration in a laboratory furnace using X-ray fluorescence analysis; alternatively, the noble metal content of the ash can be transferred into an aqueous solution using wet chemicals, for example using aqua regia, and determined using ICP-OES analysis, for example. The method according to the invention is a discontinuous method; it can be executed in batches, wherein identical, similar or different batches of waste containing fluorine and noble metals to be incinerated can be incinerated one after the other in accordance with the methodology according to the invention, i.e., in