Title of Invention	"A PROCESS FOR THE RECOVERY OF PURE NICKEL SULPHATE FROM THE SPENT NICKEL STRIPPER SOLUTION'
Abstract	The present invention provides a process for the recovery of pure nickel sulphate from the spent nickel stripper solution using sulphuric acid for precipitating the organic materials and roasting the impure nickel sulfate crystals at optimum temperature and duration and finally employing active charcoal treatment to get pure nickel sulfate solution from which nickel sulfate salts are crystallized. The novelty of the present invention is that impure nickel sulphate salt crystallized from nickel stripper solution is decomposed to break the nickel proprietary organic complex at 300-600°C in the roasting operation of the impure salt to liberate nickel in the form of pure nickel oxide.

Title of Invention

"A PROCESS FOR THE RECOVERY OF PURE NICKEL SULPHATE FROM THE SPENT NICKEL STRIPPER SOLUTION'

Abstract

The present invention provides a process for the recovery of pure nickel sulphate from the spent nickel stripper solution using sulphuric acid for precipitating the organic materials and roasting the impure nickel sulfate crystals at optimum temperature and duration and finally employing active charcoal treatment to get pure nickel sulfate solution from which nickel sulfate salts are crystallized. The novelty of the present invention is that impure nickel sulphate salt crystallized from nickel stripper solution is decomposed to break the nickel proprietary organic complex at 300-600°C in the roasting operation of the impure salt to liberate nickel in the form of pure nickel oxide.

Full Text	present invention relates to a process for the recovery of pure nickel sulphate from the spent nickel stripper solutionA large volume of spent nickel stripper solution is generated in the electroplating process of automobile wheels. The stripper solution is a proprietary one containing organic compounds like amine and nitro compounds. It is used to strip nickel selectively from the rejects of electroplated steel components so that the steel base can be reused. Hitherto, nickel is recovered from waste pickling / stripping / etching solution by electrolysis using ion exchange membrane at a current density of 5-70 A/cm2 and a voltage of 2 - 6 V. The drawback is that nickel is recovered only as nickel-iron alloy but not as pure nickel metal. The stability of membrane separator is affected in the highly acidic environment of the solution on long term usage. ( European patent App.Ep 435,382 (C1C23G1/36) 1991) In other methods, nickel is recovered from waste solution by solvent extraction (Flett.D.S.,Solven extraction.S.Afr.Pat.,7800/61(1978) and ion exchange (Fekete,L., Polish Pat. 80271 (1973) methods. But in the case of stripper solution where nickel is already complexed with properitory organics , these methods are not effective in extracting nickel selectively. In most of the cases , the spent nickel stripper solution containing nickel and organic compounds is discharged into streams creating pollution problems. The solution is also evaporated for collecting impure nickel sulphate crystals (60% purity) which is not suitable for any plating operation. The main object of the present invention is to provide a process for the recovery of pure nickel sulphate from the spent nickel stripper solution. Another object of the present invention is to use sulphuric acid for precipitating organic materials from the solution. Yet another object is to employ thermal treatment to decompose the nickel organic complexes from the impure nickel sulfate salts crystallized from the sulphuric acid treated spent stripper solution at optimum temperature and duration. Still another object is to employ active charcoal treatment for the nickel sulphate solution obtained from the roasted impure nickel sulphate salt. Still another object is to improve the purity level of nickel sulphate salt recovered. Accordingly, the present invention provides a process for the recovery of pure nickel sulfate from the spent nickel stripper solution which comprises the following steps; (a) treating the nickel stripper solution with sulphuric acid having concentration in the range of 0.5-1.0 M, (b) isolating the nickel sulphate salt crystallized from step (a) and characterized in that roasting it in a furnace at a temperature in the range of 300-600°C for a period in the range of 5-30 minutes to get nickel oxide, (c) treating the nickel oxide obtained in step (b) with dilute sulphuric acid and active charcoal, (d) isolating the nickel sulphate in crystallized form from the solution. In the embodiment of the present invention the temperature employed for thermal treatment is in the range of 300°C to 600°C. In another embodiment of the present invention, the duration for roasting is in the range of 5 to 30 minutes. In yet another embodiment of the present invention the active charcoal used is in i the range of 2 to 10 g for 1 litre of nickel sulphate solution obtained after dissolving the roasted nickel salt. The present invention provides a process for the recovery of pure nickel sulfate from the spent nickel stripper solution using sulphuric acid for precipitating the organic materials and roasting the impure nickel sulfate crystals at optimum temperature and duration and finally employing active charcoal treatment to get pure nickel sulfate solution from which nickel sulfate salts are crystallized The novelty of the present invention is that impure nickel sulphate salt crystallised from nickel stripper solution is decomposed to break the nickel proprietary organic complex at 300° - 600° C in the roasting operation of the impure salt to liberate nickel in the form of pure nickel oxide. 1 litre of spent stripper solution is treated with 0.5 - 1.0 M sulphuric acid with stirring till the completion of brown precipitate formation. The solution is filtered and the filtrate is evaporated and crystallised. The impure nickel sulphate crystalls are collected . The purity of crude nickel sulphate crystal is 50-60%. It is contaminated with amine compounds which form a strong chelation with nickel ions. 50gms of impure nickel sulphate crystal obtained from the spent stripper solution is roasted in an electrical muffle furnace at 350 - 450°C for a period of 10-30 minutes. The roasted blackish calcine is treated with dil. sulphuric acid and hydrogen peroxide with stirring at 50-60°C. Finally the solution is treated with 2 - 10 g active charcoal. The solution is filtered and the filtrate is evaporated for crystallisation. The pure nickel sulfate crystals are collected and analysed for its purity. The following examples are given by way of illustration of the present invention and therefore should not be construed to limit the scope of present invention. Example: 1 i) The nickel stripper solution is treated with sulphuric acid of concentration 0.1 M. ii) The impure nickel sulphate salt crystallised from step (i) is roasted in a muffle furnace at 300° C. iii) The duration of the roasting is 5 minutes. iv) The pure nickel oxide liberated in step (ii) is treated in sulphuric acid medium and with active charcoal of 2 gram per litre of the solution. v) The resulting nickel sulphate solution is crystallised by evaporation and the purity of the nickel sulphate salt collected is 99.5% vi) The over all recovery of nickel sulphate from nickel stripper solution is 80.0% Example: 2 i) The nickel stripper solution is treated with sulphuric acid of concentration 0.5 M. ii) The impure nickel sulphate salt crystallised from step (i) is roasted in a muffle furnace at 400° C. iii) The duration of the roasting is 10 minutes. iv) The pure nickel oxide liberated in step (ii) is treated in sulphuric acid medium and with active charcoal of 4 gram per litre of the solution. v) The resulting nickel sulphate solution is crystallised by evaporation and the purity of the nickel sulphate salt collected is 99.7% vi) The over all recovery of nickel sulphate from nickel stripper solution is 80.0% Example: 3 i) The nickel stripper solution is treated with sulphuric acid of concentration 0.3 M. ii) The impure nickel sulphate salt crystallised from step (i) is roasted in a muffle furnace at 400° C. iii) The duration of the roasting is 20 minutes. iv) The pure nickel oxide liberated in step (ii) is treated in sulphuric acid medium and with active charcoal of 8 gram per litre of the solution. v) The resulting nickel sulphate solution is crystallised by evaporation and the purity of the nickel sulphate salt collected is 99.6% vi) The over all recovery of nickel sulphate from nickel stripper solution is 72.0% Example: 4 i) The nickel stripper solution is treated with sulphuric acid of concentration 1.0 M. ii) The impure nickel sulphate salt crystallised from step (i) is roasted in a muffle furnace at 600° C. iii) The duration of the roasting is 30 minutes. iv) The pure nickel oxide liberated in step (ii) is treated in sulphuric acid medium and with active charcoal of 10 gram per litre of the solution. v) The resulting nickel sulphate solution is crystallised by evaporation and the purity of the nickel sulphate salt collected is 99.5% vi) The over all recovery of nickel sulphate from nickel stripper solution is 78.0% The main advantages of the present invention are: 1. The pure nickel sulfate is recovered from the stripper solution for captive use. 2. Nickel and organic material are removed from the stripper solution minimizing pollution problems. We Claim: 1. A process for the recovery of pure nickel sulfate from the spent nickel stripper solution which comprises the following steps; a) treating the nickel stripper solution with sulphuric acid having concentration in the range of 0.5-1.0 M, (b) isolating the nickel sulphate salt crystallized from step (a) and characterized in that roasting it in a furnace at a temperature in the range of 300-600°C for a period in the range of 5-30 minutes to get nickel oxide, (c) treating the nickel oxide obtained in step (b) with dilute sulphuric acid and active charcoal, (d) isolating the nickel sulphate in crystallized form from the solution. 2. A process claimed in claim 1, wherein the purity of nickel sulphate crystal obtained is in the range of 99.5-99.7%. 3. A process claimed in claims 1-2, wherein the recovery of nickel sulphate from the spent nickel stripper solution is in the range of 72- 80%. 4. A process for the recovery of pure nickel sulfate from the spent nickel stripper solution substantially as herein described with reference to the examples.

Full Text

present invention relates to a process for the recovery of pure nickel sulphate
from the spent nickel stripper solutionA large volume of spent nickel stripper solution is generated in the electroplating
process of automobile wheels. The stripper solution is a proprietary one containing
organic compounds like amine and nitro compounds. It is used to strip nickel selectively
from the rejects of electroplated steel components so that the steel base can be reused.
Hitherto, nickel is recovered from waste pickling / stripping / etching solution by
electrolysis using ion exchange membrane at a current density of 5-70 A/cm2 and a
voltage of 2 - 6 V. The drawback is that nickel is recovered only as nickel-iron alloy but
not as pure nickel metal. The stability of membrane separator is affected in the highly
acidic environment of the solution on long term usage. ( European patent App.Ep
435,382 (C1C23G1/36) 1991)
In other methods, nickel is recovered from waste solution by solvent extraction
(Flett.D.S.,Solven extraction.S.Afr.Pat.,7800/61(1978) and ion exchange (Fekete,L.,
Polish Pat. 80271 (1973) methods. But in the case of stripper solution where nickel is
already complexed with properitory organics , these methods are not effective in
extracting nickel selectively.
In most of the cases , the spent nickel stripper solution containing nickel and
organic compounds is discharged into streams creating pollution problems. The solution
is also evaporated for collecting impure nickel sulphate crystals (60% purity) which is not
suitable for any plating operation.
The main object of the present invention is to provide a process for the recovery
of pure nickel sulphate from the spent nickel stripper solution.
Another object of the present invention is to use sulphuric acid for
precipitating organic materials from the solution.
Yet another object is to employ thermal treatment to decompose the nickel
organic complexes from the impure nickel sulfate salts crystallized from
the sulphuric acid treated spent stripper solution at optimum temperature
and duration.
Still another object is to employ active charcoal treatment for the nickel
sulphate solution obtained from the roasted impure nickel sulphate salt.
Still another object is to improve the purity level of nickel sulphate salt
recovered.
Accordingly, the present invention provides a process for the recovery of
pure nickel sulfate from the spent nickel stripper solution which comprises
the following steps;
(a) treating the nickel stripper solution with sulphuric acid having
concentration in the range of 0.5-1.0 M,
(b) isolating the nickel sulphate salt crystallized from step (a) and
characterized in that roasting it in a furnace at a temperature in the
range of 300-600°C for a period in the range of 5-30 minutes to get
nickel oxide,
(c) treating the nickel oxide obtained in step (b) with dilute sulphuric
acid and active charcoal,
(d) isolating the nickel sulphate in crystallized form from the solution.
In the embodiment of the present invention the temperature employed for thermal treatment is in the range of 300°C to 600°C.
In another embodiment of the present invention, the duration for roasting is in the
range of 5 to 30 minutes.
In yet another embodiment of the present invention the active charcoal used is in
i
the range of 2 to 10 g for 1 litre of nickel sulphate solution obtained after dissolving the
roasted nickel salt.
The present invention provides a process for the recovery of pure nickel sulfate from the
spent nickel stripper solution using sulphuric acid for precipitating the organic materials
and roasting the impure nickel sulfate crystals at optimum temperature and duration and
finally employing active charcoal treatment to get pure nickel sulfate solution from which
nickel sulfate salts are crystallized
The novelty of the present invention is that impure nickel sulphate salt crystallised
from nickel stripper solution is decomposed to break the nickel proprietary organic
complex at 300° - 600° C in the roasting operation of the impure salt to liberate nickel in
the form of pure nickel oxide.
1 litre of spent stripper solution is treated with 0.5 - 1.0 M sulphuric acid with
stirring till the completion of brown precipitate formation. The solution is filtered and the
filtrate is evaporated and crystallised. The impure nickel sulphate crystalls are collected .
The purity of crude nickel sulphate crystal is 50-60%. It is contaminated with amine
compounds which form a strong chelation with nickel ions.
50gms of impure nickel sulphate crystal obtained from the spent stripper solution
is roasted in an electrical muffle furnace at 350 - 450°C for a period of 10-30 minutes.
The roasted blackish calcine is treated with dil. sulphuric acid and hydrogen peroxide
with stirring at 50-60°C. Finally the solution is treated with 2 - 10 g active charcoal. The
solution is filtered and the filtrate is evaporated for crystallisation. The pure nickel sulfate
crystals are collected and analysed for its purity.
The following examples are given by way of illustration of the present invention
and therefore should not be construed to limit the scope of present invention.
Example: 1
i) The nickel stripper solution is treated with sulphuric acid of concentration 0.1 M.
ii) The impure nickel sulphate salt crystallised from step (i) is roasted in a muffle
furnace at 300° C.
iii) The duration of the roasting is 5 minutes.
iv) The pure nickel oxide liberated in step (ii) is treated in sulphuric acid medium and
with active charcoal of 2 gram per litre of the solution.
v) The resulting nickel sulphate solution is crystallised by evaporation and the purity
of the nickel sulphate salt collected is 99.5%
vi) The over all recovery of nickel sulphate from nickel stripper solution is 80.0%
Example: 2
i) The nickel stripper solution is treated with sulphuric acid of concentration 0.5 M.
ii) The impure nickel sulphate salt crystallised from step (i) is roasted in a muffle
furnace at 400° C.
iii) The duration of the roasting is 10 minutes.
iv) The pure nickel oxide liberated in step (ii) is treated in sulphuric acid medium and
with active charcoal of 4 gram per litre of the solution.
v) The resulting nickel sulphate solution is crystallised by evaporation and the purity
of the nickel sulphate salt collected is 99.7%
vi) The over all recovery of nickel sulphate from nickel stripper solution is 80.0%
Example: 3
i) The nickel stripper solution is treated with sulphuric acid of concentration 0.3 M.
ii) The impure nickel sulphate salt crystallised from step (i) is roasted in a muffle
furnace at 400° C.
iii) The duration of the roasting is 20 minutes.
iv) The pure nickel oxide liberated in step (ii) is treated in sulphuric acid medium and
with active charcoal of 8 gram per litre of the solution.
v) The resulting nickel sulphate solution is crystallised by evaporation and the purity
of the nickel sulphate salt collected is 99.6%
vi) The over all recovery of nickel sulphate from nickel stripper solution is 72.0%
Example: 4
i) The nickel stripper solution is treated with sulphuric acid of concentration 1.0 M.
ii) The impure nickel sulphate salt crystallised from step (i) is roasted in a muffle
furnace at 600° C.
iii) The duration of the roasting is 30 minutes.
iv) The pure nickel oxide liberated in step (ii) is treated in sulphuric acid medium and
with active charcoal of 10 gram per litre of the solution.
v) The resulting nickel sulphate solution is crystallised by evaporation and the purity
of the nickel sulphate salt collected is 99.5%
vi) The over all recovery of nickel sulphate from nickel stripper solution is 78.0%
The main advantages of the present invention are:
1. The pure nickel sulfate is recovered from the stripper solution for captive use.
2. Nickel and organic material are removed from the stripper solution minimizing
pollution problems.

We Claim:
1. A process for the recovery of pure nickel sulfate from the spent nickel
stripper solution which comprises the following steps;
a) treating the nickel stripper solution with sulphuric acid having concentration in the range of 0.5-1.0 M,
(b) isolating the nickel sulphate salt crystallized from step (a) and
characterized in that roasting it in a furnace at a temperature in the
range of 300-600°C for a period in the range of 5-30 minutes to get
nickel oxide,
(c) treating the nickel oxide obtained in step (b) with dilute sulphuric
acid and active charcoal,
(d) isolating the nickel sulphate in crystallized form from the solution.

2. A process claimed in claim 1, wherein the purity of nickel sulphate
crystal obtained is in the range of 99.5-99.7%.
3. A process claimed in claims 1-2, wherein the recovery of nickel
sulphate from the spent nickel stripper solution is in the range of 72-
80%.
4. A process for the recovery of pure nickel sulfate from the spent nickel
stripper solution substantially as herein described with reference to the
examples.

Documents:

214-DEL-2003-Abstract-(21-11-2008).pdf

214-del-2003-abstract.pdf

214-DEL-2003-Claims-(21-11-2008).pdf

214-del-2003-claims.pdf

214-DEL-2003-Correspondence-Others-(21-11-2008).pdf

214-del-2003-correspondence-others.pdf

214-del-2003-correspondence-po.pdf

214-DEL-2003-Description (Complete)-(21-11-2008).pdf

214-del-2003-description (complete).pdf

214-del-2003-form-1.pdf

214-del-2003-form-18.pdf

214-del-2003-form-2.pdf

214-DEL-2003-Form-3-(21-11-2008).pdf

214-del-2003-form-3.pdf

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Patent Number

227517

Indian Patent Application Number

214/DEL/2003

PG Journal Number

05/2009

Publication Date

30-Jan-2009

Grant Date

12-Jan-2009

Date of Filing

05-Mar-2003

Name of Patentee

COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH

Applicant Address

RAFI MARG, NEW DELHI-110 001,INDIA

Inventors:

#	Inventor's Name	Inventor's Address
1	PERIAIAH RAMACHANDRAN	CENTRAL ELECTROCHEMICAL RESEARCH INSTITUTE,KARAIKUDI,INDIA
2	VENKATARAMAN NANDAKUMAR	CENTRAL ELECTROCHEMICAL RESEARCH INSTITUTE,KARAIKUDI,INDIA
3	KUNNISSERI VENKATACHALAM VENKATESWARAN	CENTRAL ELECTROCHEMICAL RESEARCH INSTITUTE,KARAIKUDI,INDIA

PCT International Classification Number

C01G 53/10

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA