Method for preparing a sorbent
A method is described for preparing a sorbent comprising the steps of: (i) mixing together a particulate copper sulphide material and a particulate calcined rehydratable alumina, (ii) shaping the mixture, and (iii) drying the shaped mixture to form a dried sorbent.
1. A method for preparing a sorbent comprising the steps of:
(i) mixing a particulate copper sulphide material and a particulate calcined rehydratable aluminato to form a mixture,
(ii) shaping the mixture, and
(iii) drying the shaped mixture to form the sorbent.
2. A method according to claim 1 wherein the calcined rehydratable alumina comprises a calcined amorphous alumina or a transition alumina that is one or more of rho-alumina, chi-alumina, or pseudo gamma-alumina.
3. A method according to claim 1 , wherein the particulate copper sulphide material (a) is manufactured by roasting copper or a copper compound with elemental sulphur,or (b) by precipitating copper sulphide from solution, sulphiding copper compounds using hydrogen sulphide, a mechanochemical process that is mixing powdered copper metal with elemental sulphur under conditions that cause the elemental copper and elemental sulphur to react to form one or more copper sulphides.
4. A method according to claim 1 , wherein the particulate copper sulphide material comprises one or more copper sulphides that is copper (II) sulphide, CuS, and/or substoichiometric copper sulphide of formula Cu 2−x S where x is in a range of from 0 to 1.
5. A method according to claim 1 , wherein the particulate copper sulphide material has an overall S:Cu atomic ratio of ≥0.8.
6. A method according to claim 1 , wherein the particulate copper sulphide material is in the form of a powder with an average particle size, [D50], in the range of 5 μto 100 μm.
7. A method according to claim 1 , wherein a copper content of the sorbent produced by the method is in a range of from 5% to 75% by weight expressed as CuS.
8. A method according to claim 1 , wherein the particulate calcined rehydratable alumina is a powder with a D 50 particle size in a range of 1 to 100 μm.
9. A method according to claim 1 , wherein a BET surface area of the calcined rehydratable alumina as determined by nitrogen adsorption is in a range of from 200 m 2 /g to 400.
10. A method according to claim 1 , wherein the sorbent produced by the method consists essentially of the particulate copper sulphide material and the particulate calcined rehydratable alumina.
11. A method according to claim 1 , wherein the shaping step comprises granulating the mixture in a granulator to produce granules of the sorbent.
12. A method according to claim 11 wherein the granulating is performed under a non-oxidising atmosphere.
13. A method according to claim 11 , wherein the granules are aged for a time of from 0.5 hours to 8 hours before drying.
14. A method according to claim 1 , wherein the sorbent is dried at a temperature up to 120° C. under a non-oxidising atmosphere.
15. A sorbent obtained by the method of claim 1 .
16. A process for removing one or more heavy metals from a heavy metal-containing fluid stream by contacting the fluid stream with the sorbent according to claim 15 .
17. A method according to claim 5 , wherein the overall S:Cu atomic ratio is ≥0.9.
18. A method according to claim 7 , wherein the copper content of the sorbent is in the range of 10 to 75% by weight expressed as CuS.
19. A method according to claim 8 , wherein the particle size of the particulate calcined rehydratable alumina is in the range of from 1 μm to 20.
20. A method according to claim 9 , wherein the BET surface area of the calcined rehydratable alumina as determined by nitrogen adsorption is in the range of from 250 m 2 /g to 300 m 2 /g.