METHOD FOR PROCESSING METALS FROM POROUS MATERIALS CONTAINING THEM

Claims

1. A method for processing a metal or several metals M, selected from metals belonging to columns 8-12 of the Periodic Table of the Elements, present at least partly in the form of metal sulfides in a porous material A, which contains at least one inorganic oxide and has a sulfur content greater than or equal to 2 wt.%, characterized in that it includes the following successive steps: (1) at least one step of heat treating material A in the presence of oxygen at a temperature in the range of 350°C to 900°C; (2) at least one step of washing the material A' obtained in step (1) with an aqueous solvent; (3) at least one step of extracting the metal or metals M by bringing the material A", obtained in step (2), into contact with a solution S containing at least one carboxylic acid; and (4) at least one step of depositing at least one portion of the metal or metals M on the porous material B, different from said material A, by bringing the solution S' obtained in step (3) into contact with said material B.

2. The method according to the previous paragraph, characterized in that the metal or metals M are selected from iron, cobalt, nickel, copper and zinc, and preferably from nickel, copper and zinc.

3. A method according to any one of the preceding claims, characterized in that the material A contains a single metal M belonging to columns 8-12 of the Periodic Table of Elements, wherein said metal M is preferably nickel, copper or zinc.

4. The method according to any of the preceding claims, characterized in that the material B contains one or more refractory inorganic oxides selected from aluminum oxides, silicon oxides, aluminosilicates, zeolites, zirconium oxides, titanium and boron oxides, as well as mixtures of such oxides, and preferably from aluminum oxides, silicon oxides, aluminosilicates, and more preferably from aluminum oxides.

5. The method according to any of the preceding claims, characterized in that the heat treatment step (1) is carried out at a temperature in the range from 400 to 600°C, preferably from 450 to 580°C, and more preferably from 480 to 570°C.

6. The method according to any one of the preceding claims, characterized in that the aqueous solvent used in the washing step (2) contains at least 50% by weight of water, preferably at least 75% by weight, even better at least 90% by weight of water, and even better the solvent consists of water.

7. The method according to any of the preceding claims, characterized in that the washing step (2) is carried out at a temperature in the range from 20°C to 150°C, preferably from 25 to 100°C, and more preferably from 30 to 70°C.

8. The method according to any of the preceding claims, characterized in that the carboxylic acid or carboxylic acids present in the solution S used in step (3) are selected from mono-, di- and tricarboxylic acids, preferably containing from 1 to 8 carbon atoms.

9. The method according to the previous paragraph, characterized in that the carboxylic acid or carboxylic acids are selected from acetic acid, citric acid, maleic acid, glycolic acid and mixtures of these acids, and preferably from acetic acid, citric acid and mixtures thereof.

10. The method according to any of the preceding claims, characterized in that the solution S has a total content of carboxylic acids in the range from 5 to 50 wt.%, preferably from 10 to 30 wt.%, of the total mass of the solution S.

11. The method according to any of the preceding claims, characterized in that step (3) is carried out at a temperature in the range from 20°C to 150°C, preferably from 50 to 130°C, and more preferably from 80 to 120°C.

12. The method according to any of the preceding paragraphs, characterized in that step (4) is carried out by impregnating material B with solution S', carried out as dry impregnation, as impregnation until the pore volume is saturated, or as soaking material B in a large excess of solution S'.

13. A method according to any of the preceding claims, characterized in that during step (4) the solution S' is kept in contact with said material B for a period of from 1 to 30 hours, preferably from 5 to 25 hours, and even better from 10 to 20 hours.

14. A method according to any one of the preceding claims, characterized in that step (4) is repeated by bringing the material B into contact either with the same solution S' or with another solution S0' obtained by treating, by means of steps (1) to (3), the starting material A0, which is different from A and which contains a metal or several metals M0', which may be identical to or different from the metal or metals M.

15. A method according to any of the preceding claims, characterized in that it comprises, after step (4), a step of drying the material B, carried out at a temperature in the range from 80°C to 300°C, preferably from 100°C to 150°C.