Process for preparing a high-purity nickel sulphate solution

Patent metadata

Field	Value
Publication number	US-2024417274-A1
Application number	US-202218720697-A
Country	US
Kind code	A1
Filing date	Dec 20, 2022
Priority date	Dec 20, 2021
Publication date	Dec 19, 2024
Grant date	—

Abstract

The present invention provides a process for preparing a high-purity nickel sulphate solution, comprising the steps of: i. providing an aqueous feed solution comprising nickel. cobalt, calcium and magnesium: ii. extracting cobalt, calcium, and partly magnesium from said aqueous feed solution using a first solvent comprising a first alkylphosphorus-based acidic extractant, thereby obtaining an aqueous raffinate comprising nickel and magnesium: iii. extracting magnesium from said aqueous raffinate solution comprising nickel and magnesium using a second solvent comprising a second alkylphosphorus-based acidic extractant, thereby obtaining a high-purity aqueous nickel sulphate solution comprising nickel and magnesium: iv. stripping the first loaded solvent comprising cobalt, calcium and magnesium with an aqueous solution comprising a mineral acid.

First claim

1 - 24 . (canceled)

25 . A process for preparing a high-purity nickel sulphate solution, comprising the steps of:
i. providing an aqueous feed solution comprising nickel, cobalt, calcium and magnesium; ii. in a first solvent extraction circuit, extracting cobalt, calcium and, at least in part, magnesium, and if present zinc, copper, cadmium and manganese, from said aqueous feed solution using a first organic phase comprising a first alkylphosphorus-based extractant (I) and a first diluent, thereby obtaining an aqueous raffinate solution comprising nickel and a residual magnesium content and a cobalt-rich and calcium containing organic phase; iii. in a second solvent extraction circuit, extracting magnesium from said aqueous raffinate solution using a second organic phase comprising a second alkylphosphorus-based extractant (II) and a second diluent, thereby obtaining a magnesium-depleted, high-purity aqueous nickel sulphate solution and a magnesium-enriched organic phase; and iv. stripping said cobalt-rich organic phase obtained in step ii. with an aqueous solution comprising a mineral acid,
whereby said first solvent extraction circuit and said second solvent extraction circuit operate at a different temperature and/or with a different extractant.

26 . The process according to claim 25 , whereby said mineral acid is hydrochloric acid.

27 . The process according to claim 25 , whereby said aqueous feed solution further comprises zinc, copper, cadmium and/or manganese.

28 . The process according to claim 25 , whereby nickel is scrubbed from said cobalt-rich organic phase and/or from said magnesium-enriched organic phase.

29 . The process according to claim 25 , whereby said aqueous feed solution is obtained by removing iron and/or aluminium from an aqueous feed solution comprising nickel, cobalt, calcium, magnesium, and if present zinc, copper, cadmium and/or manganese, and further comprising iron and/or aluminium, respectively.

30 . The process according to claim 29 , whereby said iron and/or aluminium is removed by precipitation using a precipitating agent, said precipitating agent comprising a calcium base.

31 . The process according to claim 29 , whereby said iron and/or aluminium is removed by precipitation using a precipitating agent, said precipitating agent comprising a magnesium base.

32 . The process according to claim 29 , whereby said iron and/or aluminium is removed by precipitation using a precipitating agent, said precipitating agent comprising a nickel base.

33 . The process according to claim 29 , whereby said iron and/or aluminium is removed by precipitation in two or more precipitation steps, whereby a different precipitating agent or a combination of precipitating agents may be used in each precipitation step.

34 . The process according to claim 25 , whereby said first and second alkylphosphorus-based extractants comprise an alkylphosphorus-based acid and/or nickel salts thereof.

35 . The process according to claim 25 , whereby said second alkylphosphorus-based extractant (II) has a higher selectivity for magnesium than said first alkylphosphorus-based extractant (I).

36 . The process according to claim 25 , whereby said first alkylphosphorus-based extractant (I) comprises an alkylphosphonic acid and/or nickel salts thereof, and whereby said second alkylphosphorus-based extractant (II) comprises an alkylphosphinic acid and/or nickel salts thereof.

37 . The process according to claim 25 , whereby said first and said second alkylphosphorus-based extractants are converted to their nickel salts, containing nickel with a concentration of at least 20% of the available extractant capacity.

38 . The process according to claim 37 , whereby said first and said second alkylphosphorus-based extractants are converted to a nickel salt, and whereby said first and said second organic phases comprise less than 2 g/L sodium.

39 . The process according to claim 25 , whereby said first and said second organic phases provided in steps ii. and iii. comprise said first and said second alkylphosphorus-based extractant, respectively, in an amount of 5 to 50 vol. %, relative to the total volume of said solvents, and said diluents in an amount of 50 to 95 vol. %, relative to the total volume of said solvents.

40 . The process according to claim 25 , whereby said extraction in step ii. is performed at a temperature between 25 and 55° C.

41 . The process according to claim 25 , whereby said extraction in step iii. is performed at a temperature between 4° and 70° C.

42 . The process according to claim 25 , whereby said stripping step iv. is performed at a temperature between 40° C. and 50° C.

43 . The process according to claim 25 , whereby said magnesium-depleted, high-purity aqueous nickel sulphate solution comprises nickel in a concentration of 40 to 180 g/L, and magnesium in a concentration of at most 5 mg/L.

44 . The process according to claim 25 , whereby said aqueous feed solution provided in step i. comprises nickel in an amount of at least 60 at. %, relative to the total metal content of said aqueous feed solution, and whereby said aqueous feed solution provided in step i. comprises cobalt, calcium, magnesium and optionally zinc, copper, cadmium and manganese in an amount of at most 40 at. %, relative to the total metal content of said aqueous feed solution.

45 . The process according to claim 25 , whereby said high-purity aqueous nickel sulphate solution obtained after removal of residual magnesium in step iii. is subjected to crystallization or granulation.

46 . The process according to claim 25 , whereby said first organic phase, after stripping with said mineral acid, is washed with sulphuric acid.

47 . The process according to claim 25 , whereby said first and/or second organic phases, after washing or stripping with sulphuric acid, are loaded with nickel using an alkali hydroxide and a nickel salt-containing solution, and subsequently recycled in step ii. and/or step iii., this way closing the loop of the process.

Assignees

• Umicore Nv

Inventors

• Rondas Francis
• Luyten Jan
• Roosen Joris
• De Moor Wannes
• Schurmans Maarten

Classifications

• C01G53/01

  Preparation or separation involving a liquid-liquid extraction, an adsorption or an ion-exchange · CPC title

• C01P2006/80

  Compositional purity · CPC title

• B01D11/0446

  Juxtaposition of mixers-settlers · CPC title

• B01D9/0054 Primary

  Use of anti-solvent · CPC title

• B01D11/0492

  Applications, solvents used · CPC title