Process for preparing a high-purity nickel sulphate solution

Patent metadata

Field	Value
Publication number	US-12570542-B2
Application number	US-202218720697-A
Country	US
Kind code	B2
Filing date	Dec 20, 2022
Priority date	Dec 20, 2021
Publication date	Mar 10, 2026
Grant date	Mar 10, 2026

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

The invention claimed is:

1 . 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, and if present, zinc, manganese, cadmium, and/or copper; 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 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 the residual magnesium content from said aqueous raffinate solution using a second organic phase comprising a second alkylphosphorus extractant (H), different from said first alkylphosphorous extractant (I), and a second diluent, thereby obtaining an aqueous nickel sulphate solution having reduced magnesium content relative to the aqueous raffinate 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,
wherein said first alkylphosphorus extractant (I) and said second alkylphosphorous extractant (II) comprise nickel, and
whereby said first organic phase and said second organic phase provided in steps ii. and iii. comprise said first and said second alkylphosphorus extractant, respectively, in an amount of 5 to 50 vol. %, relative to the total volume of said organic phases, and said diluents in an amount of 50 to 95 vol. %, relative to the total volume of said organic phases.

2 . The process according to claim 1 , whereby said mineral acid is hydrochloric acid.

3 . The process according to claim 1 , whereby said aqueous feed solution further comprises zinc, copper, cadmium, and/or manganese.

4 . The process according to claim 1 , whereby nickel is scrubbed from said cobalt-rich organic phase and/or from said magnesium-enriched organic phase.

5 . The process according to claim 1 , whereby said aqueous feed solution is obtained by removing iron and/or aluminium from an aqueous feed solution comprising nickel, cobalt, calcium, magnesium, sulphate, and if present zinc, copper, cadmium and/or manganese, and further comprising iron and/or aluminium, respectively.

6 . The process according to claim 5 , whereby said iron and/or aluminium is removed by precipitation using a precipitating agent, said precipitating agent comprising a calcium base.

7 . The process according to claim 5 , whereby said iron and/or aluminium is removed by precipitation using a precipitating agent, said precipitating agent comprising a magnesium base.

8 . The process according to claim 5 , whereby said iron and/or aluminium is removed by precipitation using a precipitating agent, said precipitating agent comprising a nickel base.

9 . The process according to claim 5 , 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.

10 . The process according to claim 1 , whereby said second alkylphosphorus extractant (II) has a higher selectivity for magnesium than said first alkylphosphorus extractant (I).

11 . The process according to claim 1 , whereby said first and said second alkylphosphorus extractants are converted to their nickel salts, containing nickel with a concentration of at least 20% of the available extractant capacity.

12 . The process according to claim 11 , whereby said first and said second alkylphosphorus extractants are converted to their nickel salts and neutralized with sodium hydroxide, and whereby said first and said second organic phases comprise less than 2 g/L sodium.

13 . The process according to claim 1 , whereby extracting cobalt, calcium, and, at least in part, magnesium, and if present, zinc, copper, cadmium, and manganese, in step ii. is performed at a temperature between 25 and 55° C.

14 . The process according to claim 1 , whereby extracting the residual magnesium content from said aqueous raffinate solution in step iii. is performed at a temperature between 40 and 70° C.

15 . The process according to claim 1 , whereby said stripping step iv. is performed at a temperature between 40° C. and 50° C.

16 . The process according to claim 1 , 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.

17 . The process according to claim 1 , 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.

18 . The process according to claim 1 , whereby said high-purity aqueous nickel sulphate solution obtained after removal of residual magnesium in step iii. is subjected to crystallization or granulation.

19 . The process according to claim 1 , whereby said first organic phase, after stripping with said mineral acid, is washed with sulphuric acid.

20 . The process according to claim 1 , 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